Fire Pistons

[Ogri the trog]

Hi Everybody,
I'm a sucker for trying to make my own kit, the most recent of which is a fire piston.
Has anyone else made a working example?
I've got an 8mm polished bore, piece of tubing and had (did you notice that) until recently an 8mm dowell from a wooden arrow. The seal was so good that the wood stuck inside the tube and now I need to drill it out or make another :( I gave up on trying to make a wooden cylinder as I couldn't think of a way of polishing the internal bore, being so small.
If you've made a working model, can you point me in the direction of sucess.

Once I get it cracked, I'll post up here what I used.

TIA

Ogri the trog

[Ogri the trog]

C'mon, someone must know something about these.
As an update, a slight modification earlier today managed a glowing ember :D A work collegue asked what I was doing and got really interested when I told him. I ended with three good embers but since then have not been able to replicate any more :confused:

It must be the state of the tinder but I haven't fathomed out what the secret is yet.

Ogri the trog

[Goose]

There has been a link about buying them i seem to remember, I think they used some form of gasket, but keep us informed I would like to have a go at that too.
Got to be better than the @***@* bow drill :D

[Ogri the trog]

Thanks Goose
I have seen them for sale, but for an item that used to be very commonplace, I think they're very expensive. I have no doubt that bought ones will be of superb quality, but as I said at the beginning - I like to make my own!

I found that I couldn't drill a hole of the necessary surface finish, even in plastic. So I improvised, Drilled a larger diameter hole and used a few inches of commercial airline inside the blind hole.
I turned a piece of aluminium (favoured for now over wood as it is stronger) to fit inside with a waisted section for an O-ring seal and an open cup at the business end.
The compression was OK but not stunning so I fitted a cut down pneumatic blank inside the bore to give it a flat bottom. This was the state that gave me the embers, but, as mentioned - nothing since. I'm using char cloth by the way - if anyone knows where, or has a supply of tinder fungus, please let me know.

The reason that I want to make one, is that being an aged biker - my knees are shot to pieces - and kneeling to use a bow drill is abject agony. Hence, anything to save my knees for another use is more than welcome.

Have a go Goose, there's plenty of info on the web. The ones made out of PVC hose and wooden dowel look to be simplicity itself (famous last words).

ATB

Ogri the trog

[Bardster]

All the ones I have seen commercially seem to have some kind of string wrapped around the barrel to provide the gasket.

[Stuart]

I would suggest making the shaft of a slightly narrower diameter to stop it binding and work on a seal (possibly leather?) to prevent the escape of the air around the shaft.

the tinder is critical is fire pistons charcloth works well though and there is lots of information achived here on how to make it

[Lithril]

I know the ones that you buy commercially have thread gasket, think its slightly greased. If you do manage to free it, sand a fraction off and then try binding some cotton or simlar to the bottom.

[innocent bystander]

Yeah, it's string wrapped around, and beesway/tallow for the lube. I have tried vaseline as the lube and it worked, but i think it may be too greasy. Unfortunately the string has slipped now, so the seal isn't there anymore. More work to do on it me thinks...

[leon-1]

I have only seen them and never tried one, but a fair few are made from buffalo horn which can be very highly polished.

I would suggest that when making one bore out a hole of the same diameter as the dowelling that you intend to use, but use wet and dry inside the hole that you have bored out to make it nice and smooth/polished.

This will mean that you will probably end up with about a 0.5mm difference between the dowelling and the walls of the chamber. Then you can either slightly recess a grove into the dowelling and bind the string onto it or cut a peice of leather soak it and stretch it over the dowelling (when it dries it will shrink fit). once that has ben done wax the string or leather washer and this is what will make your seal.

Hopefully this should provide a tight enough seal, as I say, I have not got one or used one, Stuart could probably tell you if the theory would work :)

[Ogri the trog]

Once again,
I was having a play in the warm afternoon sun and managed to get 3 or 4 good embers. Each using the same charcloth as before and each lasted about half a minute before burning out. I had two that ignited but fell out of the cup inside the cylinder, filling it with smoke but by the time they had been recovered with a metal spike, had gone out.
Does anyone know whether I should be packing the tinder cup tight or leaving some air-space - (up to now, tight helps to keep the cloth/ember in the cup whereas loose allows straggling threads to get caught in the seal, I think, causing leaks).
I'm using an aluminium shaft with an O-ring on it for the time being, with the intention of modifying to a wound gasket and wooden shaft and cylinder as and when I become proficient and aware of how each change affects the performance of the original.

I'm going to retract my earlier statement about them being expensive, for the amount of time and effort I've put in up to now trying to get mine to work, the likes of Jeff Wagner must have been sweating blood to get repeatable performance out of natural materials - I take my hat of to you.

ATB

Ogri the trog

[clcuckow]

Have you seen this thead over on BB?

http://www.britishblades.com/forums/showthread.php?t=1019&page=1&pp=15

[Jeff Wagner]

Not as easy as it looks is it... :)

[Ogri the trog]

Not as easy as it looks is it... :)

Oh no Jeff's turned up - I must admit that I wan't looking forward to this moment :o

Jeff,
as I said before, when you started out, you must have been sweating blood to get these things to work everytime. I'm sure you'll smile at my attempts to do the same. I'm trying on borrowed equipment, with tooling that is meant for other things.
When I do finally get a result, whether it be a working model or a big pile of bits, I'll contact you for one of your fine examples.

Thanks for visiting

Ogri the trog

[Jeff Wagner]

Making fire pistons is a bit like flint knapping - its not so hard ....once you know how its done. There is a clearly a learning curve and I had a number of failures myself while figuring out what works and what doesn't. My first severaI working models were fashioned without benefit of power tools with the exception of an electric drill. Just for the challenge aspect, I am currently working to fabricate one using only primitive, non-metalic tools. Will let you know how it comes out.

[Ogri the trog]

Jeff,
You put us all to shame!

Good luck in your venture - not as though you need it.

Ogri the trog

[Schwert]

The workmanship of Jeff's looks just incredible. I am expecting one of his very soon as I am fairly certain I could not possibly make one that worked. When mine turns up I will let you know how it works.

[Jeff Wagner]

Ooops. Caught slacking again off again....better get back to the work shop. :o Thanks for your comments. Will do my best to make it of heirloom quality.

[Jeff Wagner]

the tinder is critical is fire pistons

I meant to comment on tinder previously. With a fire piston having good compression I find that a variety of natural, unproccessed tinders can be used effectively. This is one of the features of the fire piston that I find most attractive. In a woodland environment what tinder is more easily obtained than rotten punk wood for example? Once a person makes the mental adjustment from the modern world expectation of fire by instant flame to fire by coal, the advantages become apparent. I may have trouble finding suitable tinders and dry fibers to be ignited by my fire steel, but I can always find dry punk even in a rain storm.

[Ogri the trog]

For a moment I thought I'd cracked it again,
Had a few embers again last night and this afternoon - only to be thwarted again by repeatability issues.

I'll keep trying

Ogri the trog

[Jeff Wagner]

What materials are you working with?

[Ogri the trog]

Hi Jeff, thanks for taking an interest,

Materials - I found that I couldn't drill a hole of the necessary surface finish, even in plastic. So I improvised, drilled a larger diameter hole and used a few inches of commercial airline inside the blind hole, rigid body and a polished bore.
I turned a piece of aluminium as the piston, with a waisted section for an O-ring seal and an open cup at the business end.
The compression was OK but not stunning so I fitted a cut down pneumatic blank inside the bore to give it a flat bottom. This was the state that gave some the embers, but, as mentioned - not repeatably. The most recent modification, is a thin plastic spacer (about 1/16th inch) to give a bit of clear "head room" for the tinder, I'm using char cloth by the way.

When I get it repeatable, I intend to start replacing items one-by-one, hopefully maintaining the performance, until I get an all natural example.

What are your thoughts?

Cheers

Ogri the trog

[jim_w]

Yeah, I'd appreciate a few tips here too. I've got a reasonably air-tight prototype, but I can't for the life of me get it to work. I'm using a bit of plumber's copper pipe with an end cap and a wooden piston with two rubber O-rings, greasing it with lard and using odds and ends as tinder. I suppose I should be using charcloth as tinder, but I'm too idle to make any. ;-P

[Jeff Wagner]

Problem solving is half the fun. Firstly, I will need to know if the pistons are not performing due to loss of compression or some other factor. If the pistons can be made to fully bottom-out without too much effort, they are leaking. It will be necessary to determine where the leakage is occuring. Commercial tubing may have a smooth bore surface, however there is no guarantee that the bore is round. I would evaluate for ovality.

[jim_w]

Well, even if my tube is perfectly round, I can assure you my piston isn't! I had hoped that the squishyness (technical term ;)) of the O-ring would make up for that - perhaps not. Let me make a short list of the things that I'm aware of having to be perfect:

- the fit of the piston (roundness and size)
- the air-tightness of the tube (test with water)
- the quality of the tinder (one site said ordinary dry paper would do; others say stuff like charcloth)

I'm sure there are more that I'm missing... :D

[Jeff Wagner]

There are four places where leakage can occur. If your cylinder and piston are made of non-porous materials, you have reduced that to two places. Its either leaking over the o ring ( blow-by between the cylinder wall and o ring ) or under the o ring ( between the O ring and piston groove ). An O ring that is too squishy ( technical fire piston term...:) may deform to allow blow-by as the pressure increases.

[Ogri the trog]

Yeah, I'd appreciate a few tips here too. I suppose I should be using charcloth as tinder, but I'm too idle to make any. ;-P

Jim,
Before Jeff laughs out loud at you, go make some charcloth and show a bit of commitment to heeding his advice. I might also be overstepping the mark to suggest that anything over 10mm in diameter is a bit ambitious for a hand operated fire piston.

Jeff,
I'm using an O-ring that is available through my work and the hardness (Shore number) could be allowing blow-by and hence be the reason why I can't get repeatability. I might try widening the groove for a second seal or maybe try making a square section rubber seal that is a tighter fit. If there is any machining to do, it'll have to wait till I get back to work in the middle of next week. For now, I'll persevere with it as is.

Continued thanks for your interest.

Ogri the trog

[jim_w]

Jim,
Before Jeff laughs out loud at you, go make some charcloth and show a bit of commitment to heeding his advice. I might also be overstepping the mark to suggest that anything over 10mm in diameter is a bit ambitious for a hand operated fire piston.

Ogri the trog

Yeah, next time I get a chance I will, but living in a city makes it rather difficult to light an open fire whenever I want, and sharing a house means I'm too afraid to do it in the oven! ;)

Have you seen "fire dust" from "light my fire"? It's scrapings from some kind of pine tree, and burns really well. Would some of this do as tinder? How about the head of a match (just to test, obviously! :)) ?

10mm eh? That's... (goes to google) about 0.4 inches. Aaaah. I'll try a smaller tube if I can find one. I'd naively thought that a bigger tube would be easier!

Jeff:

Well, my O-rings are glued in place, so I doubt it's leaking under them - that only leaves over. I'll fill the thing up with water and see what happens. To be honest, I think I'm probably going to end up buying one! I'm really impressed by anyone who can make one of these out of natural materials, but I find it slightly odd that it's not possible to buy cheap plastic versions. Not enough demand? Or maybe the sort of person who wants a firepiston also wants it wooden. :P

Thanks both of you for all your help, and good luck Ogri! :-)

[Ogri the trog]

Jim,
Have you seen the "Alternative Charcloth Tutorial"? Making char-cloth in a piece of copper pipe, it still gives off plenty of smoke and smell, but I recon you could do it in a flower pot using a blow torch! There's even a guy selling charcloth on Ebay!
The Maya dust I've tried is not much good unless you can get it really hot with a spark, I've tried without success in my fire piston, though Jeff has recommended wood punk.
"I'd naively thought that a bigger tube would be easier!" I think that a smaller diameter is more efficient - just think of the volume of air that you are trying to compress. Its a Force X Area thing, and your arms are only so strong, reduce the area and your input force becomes more effective.
I'm not sure about glueing the O-rings into place either - allowing them to deform under pressure to fill any voids might be better rather than making them rigid and inflexible with glue.

Sorry about the rant earlier on, when you said you were too idle, I took it as "Failing to prepare - preparing to fail" and a slight on Jeff's well intentioned advice, rather than thinking about the constraints of your circumstances.

ATB

Ogri the trog

[Jeff Wagner]

Size - 10mm will work, but 9mm will work better.

Charcloth - Personally, I never use it, but it is an option if that is all that is available to you. A shoe polish tin will make all the charcloth you will need and in a stiff breeze the neighbors will not know where that stink is coming from... :D

Pine pitch / fat wood - Great stuff when igninted by flame but of no use in a fire piston

Mass produced, cheap, plastic fire pistons...... :eek: Good Heavens !!

Your water testing is on the right path. This is a useful diagnstic method.

When all is working well your piston should be stopped by a cushion of compressed air and rebound at a point about 10mm short of full insertion. If you can achive this, you can ignite rotten wood, mullein pith and amadou.

[Ogri the trog]

Thanks again Jeff,
I'll collect some tinder while out today, rotten wood should be no problem. Can't say that I've seen any Mullein, but that wont stop my trying with similar UK varieties. Amadou is my holy grail for the moment, try as I might I can't find any locally - butI'll get around that in due time.

Cheers

Ogri the trog

[Jeff Wagner]

Good luck on your efforts. Since you have birch its curious that you dont have tinder fungus ( inonotus ) however there must must be other native alternatives. I've heard that king alfed cakes and crampballs light up in the piston but I have not had an opporunity to try for myself.

[Ogri the trog]

Thanks for your good wishes Jeff,
Once the children are back in school tomorrow I can spend a bit more time practicing, if theres any news, I'll post it here ;)

Ogri the trog

[jim_w]

<sounds of brain-wheels turning slowly>

Thanks jeff and og - you've both been most helpful :D

p.s. og: I didn't even notice the rant; I assumed you were joking too! A lot of social stuff just goes right over my head - I'm a little autistic I think :P

[Jeff Wagner]

Here's a photo of a horn piston for your ogling enjoyment. The piston top has a hollow cavity for the storage of lubricant.

[Ogri the trog]

Hmmmm,
.....a minor redesign is on the cards I think. I checked mine with water and it holds with my weight on it :eek: but I have a feeling that I'm getting blow by under the O-ring in air. My thoughts are to remake (or rework) the piston with a larger diameter waisted section for the O-ring.
I found some rotten wood which I have dried as tinder but its not staying in the cup too well. Mullein and amadou are remaining elusive but I have to say that this learnning curve is getting exciting.
Is there any specific way of preparing the fungus other than drying it out?

Ogri the trog

[Jeff Wagner]

I would retry the water test at various depths. What holds at the top may leak further down due to variations in cylinder bore diameter.

The natural tinders I use, Inonotus, milkweed, mullein, punk, etc. require no special treatment other than drying.

[Ogri the trog]

I tried the test with smaller amounts of water but with the piston "bounce" on the air above the water it became difficult to determine whether it was leaking or not.
To my mind the only other thing that would be stopping the formation of an ember is that the tinder is contacting the flat bottom of the bore and robbing the precious heat from where it is needed, a bit like stubbing out a cigarette.
...thats assuming of course that there are no dark secrets that I am, as yet unaware of



....Of course there are secrets, without them I wouldn't be hanging on to Jeffs every word.

I'm striking the piston into the bore with a forcefull hand slap with the bore rested on a solid surface, then pulling the piston out as soon as I can. There may be other methods, such as holding the piston and then jerking it down with bodyweight. The demonstration videos of folk "clapping" them between their hands is a way off pipe dream for the time being.

I'm off to peruse Jeffs site again.

Ogri the trog

[Jeff Wagner]

Well, it certainly sounds like you have good compression. Hold it up to the monitor so I can have a look.... ;)

Seriously, can you send a photo? Perhaps I can see what the problem is.

When you insert the dry piston, does it exhibit the same bouce-back as with water? Tinder contact with the bottom should make no difference.

[Jeff Wagner]

[The demonstration videos of folk "clapping" them between their hands is a way off pipe dream for the time being.

That so called "clapping" ignition method was developed out of shear necessity. I probably hold the world's record for most tinder ignitions by fire piston. As a result I acquired a very sore palm. I came up with this "crunch" method to reduce the damage to my poor hand. It works so well however that its become my standard technique for lighting the pistons. In an unsupported palm strike, the cylinder is able to move away, thereby absorbing some of the force. The crunch method drives both piston and cylinder together simultaneously for increased effectivness.

[Ogri the trog]

Well, it certainly sounds like you have good compression. Hold it up to the monitor so I can have a look.... ;)

Seriously, can you send a photo? Perhaps I can see what the problem is.

When you insert the dry piston, does it exhibit the same bouce-back as with water? Tinder contact with the bottom should make no difference.

Ermm,
Don't quite know how to put this..... of the cameras we have here, the only one I can download from is currently 100 miles away :o .
I'll try a verbal image.
8mm diameter piston with a full stroke of about 100mm. End cup is approx 6mm diameter and 3mm deep, the O-ring groove is 5mm back from the tip and is 2.5mm wide. O-ring is about 1.8mm in section so there is a small amount of free longitudinal movement of the seal.
Bore is flat bottomed with a 2mm buffer at the bottom for head space but has suffered some damage (from early attempts) near the mouth of the cylinder, so it rebounds to about the 60mm point, allowing 20mm for damage it is starting to look as though ther is a small problemette.
I can hold the piston at the bottom of its travell without too much effort......
..... and now I'l thinking........
I'm using a liner of industrial air hose (for smoothness and concentricity of bore) inside a plastic body (for rigidity). When assembling the body, I used epoxy glue - of which a lot was forced back along the inner tube...
...what I'm thinking is that I might be loosing compression between the two layers which might have been masked by the water being so much more dense. I think I might have to replace the inner hose and pay more attention to sealing the bottom end of the cylinder.

What with my earlier post about a rehash of the piston, this is sounding like a "back to ye drawing board" moment, though it will be later in the week before I can get near any materials and machinery.
Rest assured that when I get a reliable working model I'll post a picture of it somehow, even if I have to continue using charcloth!

Jeff thanks for being the "ear in the ether" it has helped a lot to bounce my ideas and thoughts off you.

Ogri the trog

PS I've managed 2 embers this evening, but when trying for a third - nothing!

[Ogri the trog]

Aargh hang the expense,
Jeff I've just placed an order for a scout kit. I could have gone for a finished item but then I could have bought a lighter from the corner shop, I feel as though I need to work for the goal to better understand the processes going on.

This won't stop me continueing with my home made one though.

Ogri the trog

[Jeff Wagner]

Thank you Sir. I shall apologize now for the extended delivery time. I am making them as fast as possible, however we continue to have a significant backlog. Ah...but a lighter will not provide you with the same level of satisfaction nor a warm fire in the wind... :)

[match]

On the subject of fire piston advice from the experts, I've got a perspex fire piston I got cheaply some time ago - I've done all the tests with water etc, and the seal seems fine, but I can't really get it to spark.

I've used tinder fungus and charcloth in it - I can very occasionally get tinder fungus to ignite, but most of the time it fails. I've tried all sorts of approaches to hitting/pushing the piston, but with no real consistent effect. I almost always get a smell of smoke in the tube once I withdraw the piston, but no glow.

Can anyone offer me a (more) foolproof method to this?
Do I need to do anything to my tinder? i.e fray it/compress it/use more/less etc?

Feel free to say 'keep practicing!' :)

[Jeff Wagner]

Assuming one begins with a capable fire piston ( it is possible to have excellent compression but no heat generation ) and suitable tinder, there are two primary reasons for ignition failure. 1- inadequate speed and force on the down stroke and 2 - excessive delay on extraction. It is necessary to drive the piston into the compression zone toward the end of the piston travel. Then it is necessary to get the resulting coal out into the air where it can breath. Attempting to describe this process in words sounds more diffilcult than it actually is. If you've had an opportunity to view the video clips, you can see that it is nearly effortless. I am not familiar with the piston mentioned. Where was this obtained?

[Jeff Wagner]

Ah...The "perspex" term caused a bit of confusion. Now I see this is an English word for PMMA or acrylic. There are only two makers of clear plastic fire pistons to my knowledge. Does your's have two rubber o rings, black plastic piston and a rather small tinder cavity?

[match]

Ah...The "perspex" term caused a bit of confusion. Now I see this is an English word for PMMA or acrylic. There are only two makers of clear plastic fire pistons to my knowledge. Does your's have two rubber o rings, black plastic piston and a rather small tinder cavity?

Yep - that sounds right, although I'm not sure what you define as small - the cavity is (I'm guessing from memory here) about 5-6mm in diameter and probably about the same in depth.

I take it from the way you mentioned that one specifically that either you know this type to be usually successful (or knowing my luck) usually unsuccessful? :rolleyes:

[Jeff Wagner]

I believe this type of piston likes to be lubicated with a light oil.

There is an extreme lighting method that sometimes works when others fail. I hesitate to recommend it however as there is an element of risk.of injury and it can be hard on the components. Place the end of the cylinder against an unyielding suface at about waist level such as a table top. With the piston inserted in the usual manner, ram the piston home using a stiff arm such that the upper body weight is applied to the stroke. Use care to avoid a slip as the end of the cylinder can pop out from underneath if the force is not applied straight down.

[Ogri the trog]

Ok we're on to mark two,
I replaced the bore liner with a new piece of similar tubing. The first was showing signs of damage from where the piston had kicked over sideways a few times when I was learning the art of the slap. I abraded the outer surface and epoxied into the body to eliminate the possibility of leakage between the two layers.
Next was the piston itself - but the first cut on the lathe was a bit too ambitious, it bent over to one side and was smashed into two bits. Another remake with a shallower O-ring groove, which means a much tighter fit of piston in the bore.
This tighter fit has made it very lubricant hungry - one stroke and thats it, so I'll look out for something a bit thicker. This might even lead my to using a different sealing medium, heading towards the all natural item that would be an ultimate goal.
Initial trials with the new and improved version were/are promising, several coals last night, but some of them took several attempts and some never made it at all.
Overall it has done what I had intended, taken a step towards improving the performance of the item and increased my understanding of what goes on. I'll continue to work on it and report any earth-shattering finds here.

Thanks eternal to Jeff for his input, especially to this thread I really appreciate your help - what a great guy!

Ogri the trog

[Ogri the trog]

On a roll now,
Just had my first, single strike ember.
No messing about, tear off some tinder, put it into the cup, locate piston in the cylinder, whack, there you go.

Pleased as punch.

Ogri the trog

[Jeff Wagner]

Attaboy... :d

[Galemys]

Jeff (or any other person who can help me out of my misery),

:confused: just out of interest, why is it that the tinder is placed in the cylinder rather than on top of the piston?
To me -blissfully unaware of any detailed fire piston knowledge- it would seem logical to somehow attach the tinder to the top of the piston which would make it easier to retrieve after the formation of a coal.

But as I said before, I am not quite an expert in this field (I once managed to render a bicycle pump completely useless in my attempt to make a fire piston :rolleyes: ) so can one of you guys enlighten me?

[Ogri the trog]

[QUOTE=Galemys]Jeff (or any other person who can help me out of my misery),

:confused: just out of interest, why is it that the tinder is placed in the cylinder rather than on top of the piston?
To me -blissfully unaware of any detailed fire piston knowledge- it would seem logical to somehow attach the tinder to the top of the piston which would make it easier to retrieve after the formation of a coal. QUOTE]

Galemys,
I think you might have some lines crossed there buddy. The tinder is placed in a cup shaped hollow in the end of the piston, which is then inserted into the cylinder. It is this cup that allows the removal of the coal after the stroke, and some amount of handling thereafter. Some trials have been done using transverse drillings on the piston head which,I believe, were successful.

Are you going to join in and have a go at making one?

Mine is providing good service at the moment, thanks to Jeff's advice.

ATB

Ogri the trog

PS a bicycle pump would be way too big a diameter to make a fire piston, unless you were the Incredible Hulk. Better off sticking to a bore size, I guess, between 6 to 9 millimeters.

[Galemys]

Ogri,

thanks for your quick reply and for clearing up this foggy brain!

I am tempted to try and make one myself now but I dare say it will be at a slightly less professional level as you guys. I am currently scavenging the laboratory (I work in a blood bank laboratory, testing for allergies) for eh... MacGyver-style fire piston essentials (glass & perspex test tubes & rubber stoppers). I do think those test tubes need some kind of very heavy reinforcement though. But if they might work they will be easily replaceable.

Don't know how long it will take for version 1.0 to emerge, I have cut my thumb yesterday while doing some vaguely bushcrafty kind of thing which involved a Buck knife and a stick. Also I am feeling a bit tired due to antibiotic treatment for Lyme borreliosis (lovely beasties, ticks... :cool: )

I'm off to the gym now, training my arm muscles for the new bicycle pump... :D

Tom

[Jeff Wagner]

I was reading over the recent entries and a thought occurred - It happens some times...

Please do not confuse the traditional fire piston with those large glass laboratory replicas of the Hymen fire syringe. In the latter, the combustible is placed in the bottom of the cylinder as mentioned above. Other than utlizing the same principle of adiabatic compression, the two have little in common - especially in terms of performance. For example, a fire piston actually works ;) and can be used to ignite the cooking fire. The other makes an interesting flash of light at ignition for the amusement and entertainment of physics students....

[Ogri the trog]

The other makes an interesting flash of light at ignition for the amusement and entertainment of physics students....

Ha ha ha just spat my coffee over the keyboard.

Nice one Jeff. ;)

Ogri the trog

I suppose I'm going to have to learn how to post pictures now.

[shadow57]

Hello..

I spent a few months trying to make a fire piston from different materials. The only one that I got to work, was made out of brass.

Attached, is a simple drawing that should give you an idea.

The ideal lubricant was butter and parrafin 50/50.

Obviously you need a lathe and the fit needs to be free. The "O Ring" was sliced from a piece of rubber tubing that is used on fishing floats. Once you put the ring on , the compression can be felt. Its important that you get the correct combustion chamber size, or it will not work.

If your really good, you could add extra screw fitting on the end to keep spare rings or tinder.

Its amazing the look on peoples faces when I use this for lighting gas at work.

It takes about an hour to make one fire piston .

If anybody is really desperate ...I will gladly swop one for something...no cash please..

Hope this helps John

[Jeff Wagner]

Hmmmm...brass...very interesting.

My first few wooden ones were made without a lathe. It might be of interest to know it is quite possible to make a perfectly round shaft , accurate to within 0.002 inches, by hand and without power tools. I hope to make instructions available very soon.

[rich59]

Having access to plastic medical syringes I have several times tried to adapt one to light a piece of tinder. I would seal the outlet with a bit of bluetak. I usually end up snapping the plunger. I did once get a bit of paper to turn a little brown.

I have also played around a lot with bicycle pumps. I think the diameter is too big.

I occaisionally work on my own design of fire syringe (without gasket) where I just have a metal tube (currently a piece of towel rail) open at both ends. The bottom I close with a plastic bung that fits fairly snuggly. I once spent a couple of days playing with a "carrot and stick" experiment. In this experiment I pushed the tip of a carrot (that self trimmed by the tube cutting a solid cylinder of the carrot) into the top of the tube. I place it upright on a solid surface. I then pushed the carrot piece down the tube with a stick. As I let go the pressure at the bottom of the push phase the bottom bung jumps out releasing the contents . On this occasion out also came a cloud of steam - presumably from the carrot getting super heated - followed by the bit of carrot. Most repeats of this however merely got a bit of sludged carrot.

I think I am on the right lines and if I can figure out how to get a snuggly fitting top bung that slides down the cylinder without twisting then it might work.

I did try the more conventional idea of a gasket made of cordage (set into a slightly thinned down plunger to stop it slipping) but could not figure out how to deal with the bit that had double thickness of the cordage where it crosses over itself to lock it in position (as in a traditional sort of whipping). Any tips greatfully received.

[Ogri the trog]

Having access to plastic medical syringes I have several times tried to adapt one to light a piece of tinder. I would seal the outlet with a bit of bluetak. I usually end up snapping the plunger. I did once get a bit of paper to turn a little brown.

I have also played around a lot with bicycle pumps. I think the diameter is too big.

I occaisionally work on my own design of fire syringe (without gasket) where I just have a metal tube (currently a piece of towel rail) open at both ends. The bottom I close with a plastic bung that fits fairly snuggly......
I think I am on the right lines and if I can figure out how to get a snuggly fitting top bung that slides down the cylinder without twisting then it might work.

I did try the more conventional idea of a gasket made of cordage (set into a slightly thinned down plunger to stop it slipping) but could not figure out how to deal with the bit that had double thickness of the cordage where it crosses over itself to lock it in position (as in a traditional sort of whipping). Any tips greatfully received.

Hi Rich59,
Its good to know that there are others playing with similar ideas.
FWIW, I reckon that medical syringes would be a little too flimsy for a fire piston cylinder, possibly allowing a leakage at the critical point of maximum compression. Same with the "Blutack" bung, likely to give way too early in the cycle. Try using charcloth as a tinder, or some of the ones mentioned elsewhere in this thread - it really does make a difference. Paper is not easy to light by fire piston in my experience.
Bicycle pumps would be a bit ambitious I think, unless you have the strength of many men.
The towel rail cylinder might be on the right track but also strikes me as a bit too large a diameter. I have seen a video clip on the web of a working piston of about 1/2 inch diameter, but you're technique would have to be pretty good. I've stuck to the 7mm to 10mm range for my experiments, 8mm being the most successful so far.

As to your cordage overlap problem, I had thought of carving a small longitudinal groove so that the under layers of seal material restore the original contour - I haven't tried it myself yet, but it might work.

Good luck with it, and I really would like for you to prove me wrong where sizes are concerned.

ATB

Ogri the trog

[browndrake]

It has been some time since anybody has posted to this thread. I was wondering how people are progressing with there fire pistons.

I am new here. I found this site searching for info on fire pistons. I saw them last night while looking at some nice chipped knives online. I was fascinated by them and HAD to make one.... Went out to my garage and made a couple last night....didn't work of course. I hadn't read enough to know anything really that I needed to do, and I used wood that was too porous and let the air escape...

Today I am going to attempt it again, with better suited wood. From what I have read, I have my work cut out for me. I sure wish I had a lathe right about now...or knew Jeff's secret to making wood round without power tools..

No matter, I will have fun trying. If I am successful I will let you know.....Rather ...when I am successful...Not sure when that will be though.

[Ogri the trog]

Welcome Browndrake,
May I be the first to wish you the best of luck in making your own firepiston. I went through several tries before hitting on a design that worked, though I haven't tried it for a while now, I have one of Jeff's that works every time, he is uncannily good you know.

All the best

Ogri the trog

[browndrake]

Well, I didn't get a lick of work done all day. I played with fire pistons in various stages of development. Ruined my first, drilling it out. ....But, it was pretty...even if only good for kindling (oh yes, and the education it gave) I think that is the most difficult thing for me, getting a nice, clean bore.

Whoever thinks that Jeff, or anybody else, is charging too much hasn't built one himself.. If I charged my regular shop time, for one (at the rate I built mine today) I could buy several of Jeff's, and his would all work.

I did get one ember. One out of many, many, many trys.

I am not sure what the problem is. It may be my tinder. It may be my compression isn't quite good enough. I don't know.

I will go back to the drawing board and start over. Much easier to make a fire with bow drill than with my fire piston.

All of you experienced piston people, if you have any other hints, secrets, experiences, etc that you are willing to share (to make the learning curve a bit nicer, or to avoid common pitfalls) I am always willing to listen carefully and follow directions..

Thanks for all that everybody has posted thus far. Without it, I doubt I would have ever gotten a spark. (and probably not the blisters on my hand either...from slamming that poor piston so many times.)

Here are some pics of my first fire piston (not counting the two I made Friday out of porous wood)
I suppose This fire piston has reached the peak of its career and will retire today...

http://www.cfwoodwork.com/test/firepiston/fp1.jpg
http://www.cfwoodwork.com/test/firepiston/fp2.jpg
http://www.cfwoodwork.com/test/firepiston/fp3.jpg

[oops56]

there is one way that i know its called lapping it just like you hone a brake cylinder well that's how i would do it where i use to work we also lap in gears with turkey bone real fine maybe that's how its done lapping it to make smooth you need a hard dowel little smaller the the hole wet the dowel put some fine grit of some kind turn it in out as you go by hand little at a time i think that's how would do it or a reamer mite do it mite be to rough for wood or a steel rod red hot in and out to get the fuzz smooth or just very hot

[Ogri the trog]

http://www.cfwoodwork.com/test/firepiston/fp3.jpg

Well it looks to me as though you have the skills to get it going, now comes the difficult bit - getting it reliable ;)

Well done by the way.

ATB

Ogri the trog

[Jeff Wagner]

Ha...the secret to making a round piston shaft without power tools is not so difficult, but it is time consuming. After having bored the hole in the cylinder, cut a square piece of wood of the correct length and width to become your shaft. Using a file, remove the four corners to create an octagonal shaft. Sanding or filing away the corners of the octagon leaves a shaft that is pretty much round. Continue to remove wood until you can start the shaft into the hole in the cylinder. Now it becomes a process of fit and try. By removing the shiny contact areas each time, you will eventually have a perfectly fitted shaft that is straight and round to within about 0.003 inches.

[browndrake]

Just a quick update:

I made another fire piston. This one works better than the first. I think that my greatest obsticle now is getting/making some good tinder.

Just to try it out, I used some make shift charcloth.I got around a dozen embers. Three or four times it lit the first time I hit it, but a few times I had to do it 2 or 3 times to get a spark. A couple times I got nothing until I switched out my tinder

My piston could probably use some work (the only ones I have seen thus far are those I have made and those you all have online.) Also, I think that I need to use a larger string for the gasket. It seems that perhaps it should be a mite tighter.

I am quite certain that my tinder is lacking. Does anybody know where one can purchase tinder fungus? I dont believe that we have any in these parts. I guess I could go out to the woods and find something that works well though, or make up some good charcloth.

Being that I am the only person that I have ever seen use a fire piston (except for a couple of short video clips online) I'm not sure how my technique is. It could perhaps use some coaching also.

All in all, I have had a wonderful experience thus far. My kids have all been waiting for me to get the piston working well so that they can try it out. Tomorrow will be a fire making day. We will be using fire pistons and bow drills.

Thanks again for the help. Any further tips, hints always welcomed. I really want to get this thing perfected. Perhaps I'll have to save my pennies and buy one from the master fire piston crafter to see what I have done right and wrong.

[Jeff Wagner]

Muddy Duck - You can see my lighting techinique here. Also take a peek at the hand drill clip. For those frustrated by the bow drill, I think this is easier to accomplish.

http://www.wildersol.homestead.com/HowTheyWork.html

[browndrake]

lol, thanks for the link. I will have to give the hand drill a try. I have been using bow drills my whole life and am quite proficient, yet I have never attempted a hand drill.

As far as technique, I seem to be doing the same as you. As for my gasget, yours appears to move as easily as mine (though difficult to assess by video). Today, I will find or make some good tinder and see if that makes the difference. I am not at all unhappy with last nights results, but would like to learn more and get better.

BTW, allthough muddy ducks are wonderful and make a good nick and fun time, my name comes from the little creature that entices large trout up to my line.

[Jeff Wagner]

Ah...sorry for the confusion. I tie a mean Adams myself. :)

[jason01]

Ahhhh a useful project to make on my new lathe :D Can someone tell me the diameter fof the cylinder bore and the piston rod and the rough overall size, I have no idea what sort of size these things are.

[browndrake]

I read somewhere around here that 3" deep and 3/8" diameter would work. That is what I made mine, perhaps a mite deeper, and it seems to be working pretty well. MIne is 4 3/4" overall length.


Good luck with it. I have been having a blast. Half the people at school want one now....and the other half thought it was a pot pipe.

Having a lathe would be tops for doing this. You should have fun.


take care.

[jason01]

I read somewhere around here that 3" deep and 3/8" diameter would work. That is what I made mine, perhaps a mite deeper, and it seems to be working pretty well. MIne is 4 3/4" overall length.


Good luck with it. I have been having a blast. Half the people at school want one now....and the other half thought it was a pot pipe.

Having a lathe would be tops for doing this. You should have fun.


take care.

Thanks Browndrake, actually I just mixed you up with Firemaker, doh, I posted a pic of my fire piston efforts at the end of his piston post in a seperate thread :rolleyes:

[browndrake]

your pics look pretty good. I hope that you can get the lathe working to finish them.

Thanks for the compliments on mine. No, I dont have a lathe, BUT, I was turing them. Ihave built furniture and cabinets all of my life, so I have a shop full of tools. I could just never justify a lathe. There are, however, ways to work around most problems. I jimmy rigged to turn mine, but cant turn and drill at same time.

good luck...and carefull: I have found out that this is very addictive.

[jason01]

your pics look pretty good. I hope that you can get the lathe working to finish them.

Thanks for the compliments on mine. No, I dont have a lathe, BUT, I was turing them. Ihave built furniture and cabinets all of my life, so I have a shop full of tools. I could just never justify a lathe. There are, however, ways to work around most problems. I jimmy rigged to turn mine, but cant turn and drill at same time.

good luck...and carefull: I have found out that this is very addictive.

Cheers Browndrake! My situation re lathes was similar to yours then I got this one at a price I couldnt resist :rolleyes: I fancied a pole lathe but dont really have the space to set one up and while theyre good for turning spindles theyre not so good for boring and changing chucks etc and its nice to have a bit of power too. I guess a pole lathe with a big heavy flywheel would be a good bit of kit though.