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Picture of How to Make a Fire Piston
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This is an easy way to make a fire piston. A fire piston is a method of creating a fire by compressing air, causing heat, and igniting some tinder! More info on the fire piston.

DISCLAIMER:

I AM NOT RESPONSIBLE FOR ANY ACCIDENTS CAUSED OR RELATED TO THIS INSTRUCTABLE.
 
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Step 1: Materials

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Supplies needed for the fire piston:

1 Bolt 4'' x 1/2''

1 Hex cap 3/8''

1 O-Ring 1/2'' x 5/16'' x 3/32''

1 Steel pipe nipple 3/8'' x 3''

Some J-B Weld

Vaseline


Tools needed:

Grinder

Circular shaped files

Drill and drill bits (range of sizes from small to LARGE)

Oil

Awl and small hammer (optional, but helpful)

Large clamp

Q-tips

Dowel

Water and soap

Step 2: Checking your steel pipe nipple

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In this step we are going to be looking at your steel pipe nipple. We are looking to see if your pipe has a bumpy ridge inside of it. If it does, go to step 3, if it doesn't, go to step 4.

Step 3: Getting rid of the ridge

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To get rid of the ridge in the steel pipe nipple, take your file, and file it down! Now, this does take a while, so put on some tunes! :P After you are done, it should be smooth.

Step 4: Assembling the chamber

To assemble the chamber, grab your J-B Weld, hex cap, and steel pipe nipple. Mix up just enough J-B Weld to fill the hex cap up about half way. Also, put some in the steel pipe nipple. Screw the steel pipe nipple onto the hex cap. Take your dowel and pack/tap the J-B Weld down in the chamber. After you have packed/tapped the J-B Weld down, set the chamber upright in a safe place for the night so it can dry.

Step 5: Grind the piston

Now we are going to work on the piston. You are going to take the bolt and grind all of the threads down with the grinder. You want it ground to about 7/16 '' in diameter. Once you have all the threads flattened, (doesn't need to be completely smooth), make a notch in the bolt about 1/4"-1/2" of the way from the tip, just deep enough for the O-Ring to sit in snugly, but small enough to fit in the chamber. What I did was I started the notch with the grinder, but then finished it with the file. I would strongly suggest using the file unless you are skilled with a grinder.

While I was making the notch, every once and a while, I would slide the O-ring onto the bolt into the notch and test it in the chamber to see if it would fit yet.

After finishing the notch, I suggest filing down the rest of the bolt to get rid of any burs or pokey things.

Take the O-ring off after you are done.

Step 6: Finishing the chamber

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Once the J-B Weld in the chamber is dry, take your file and file the edge down where the opening of the chamber is.

Step 7: Drill a Hole in the Piston

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Now we are going to drill a hole in the piston to hold the fuel (char cloth, paper, string, etc.). Start by placing the bolt into the clamp. Next, take your awl, put it in the center of the bolt, and hammer it lightly with your small hammer a couple times to get a small dent in it. This will help when drilling to keep the drill bit from sliding all over the place. Now, take your drill, and put your smallest drill bit in it, and drill a hole about 1/4" deep. Once this is done, move on to a bigger size drill bit, and drill into the smaller hole. CAREFUL, the advancement in bit size might grab at the bolt. To avoid this, push slowly down on the drill. Continue drilling holes increasingly bigger. When you get to around 3/32 size bit, or start seeing smoke, put a couple drops of oil in the hole, or enough to fill the hole. Continue to add oil in between drill bit changes, or when it starts smoking.

Step 8: Finishing the piston

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To finish the piston, squirt some soap onto the bolt, and rinse it under hot water. Next, take the Q-Tip, and wipe out the inside of the hole you just drilled in the last step. After that, take the O-Ring and stretch it onto the the bolt(piston).

Step 9: Grease the O-Ring

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Take some petroleum jelly(Vaseline), or some other type of lubricant, and spread some on the O-Ring with your finger. Once greased, put it in the chamber, and push it in and out a couple times to spread the lubricant throughout the chamber. You should feel resistance, but the piston should be able to glide smoothly through the chamber. You may need to add additional lubricant to the O-ring because the grease will spread through the chamber.

Step 10: FINISHED! :D

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Now you are done! :D

How to use your new fire piston!

Put some fuel in the hole at the end of the bolt/piston, such as char-cloth, paper, dry grass, etc. Put the bolt in the chamber, and set the chamber on something solid. Push quickly but hard on the piston. When you push on the piston, you want to compress the air in the chamber as much as possible. Remember to remove the bolt quickly after slamming the piston into the chamber, otherwise the tinder will smother and die. There you go! You have just made a spark with the fire piston! If you didn't get it the first time, blow in the chamber to get fresh air in it like you blow in a bottle to make a sound, and try again. Once you get your spark, you want to help it along with some more tinder, or maybe a cotton ball. All you want to do is to get that spark to transfer its heat to something else to make a fire.

I hope you had a fun time with my instructable! :D
KevinC48 months ago

the pic of you holding the screw to the grinder had me imagine the threads slicing into your hand shouldn't you have some sort of gloves on or is this scenario not possible I kind of want to know now.

salomon1996 (author)  KevinC46 months ago

I guess I didn't have a problem, as far as I remember... Gloves would be a good extra safety measure though! :D

For safety sake please do not wear gloves while using a bench grinder. Hold the item with some sort of clamp/vice grips etc. if it is too small to safely hold by hand. Look up de-gloving sometime to see what I mean. PSA over lol.

This is a slick little tool btw, once you get the hang of it it works great.

salomon1996 (author)  dwalden52 months ago

Thanks for correcting me! Always good to learn how to properly use equipment. :)

Morpheus1 year ago

This is awesome! I made one and it worked first time! The only changes I made were using a much longer bolt with a short thread. I cut the threaded end off, and didn't have to worry about filling the threads. I followed all the rest of the instructions as listed (I did use a silicone o-ring). A great 'ible, even two years on...

salomon1996 (author)  Morpheus6 months ago

Thanks for sharing, and nice improvement on it too!

nkz756 months ago

I understand the working principle for this.

Are you able to compress the air hard enough so you can reach really high temperatures? Looks a bit optimist to say the least.

Thanks for the instructable!

salomon1996 (author)  nkz756 months ago

It may look optimistic, but it is possible! May take a few tries, but you can get it!

Thanks! :)

fetech2 years ago
Have you thought of using an appropriate sized eye bolt instead of a carriage bolt?
awesome
salomon1996 (author)  fetech2 years ago
I guess I would prefer the Carriage Bolt. You could sure try an eye bolt, but wouldn't the eye be in the way? Interesting to try though.
My thought was that one could get a better retraction pull by using the eye of the bolt. Just mental attempt at a better mouse trap.
salomon1996 (author)  fetech2 years ago
True, maybe one could just somehow make it more comfortable to push downward.
mikaleda3 years ago
you could use a lower grade bolt and it would be easier to drill it doesn't need to be a super hard bolt
salomon1996 (author)  mikaleda2 years ago
True.
godoggie3 years ago
One thing to keep in mind is that the petroleum jelly will eat away at the O-ring with time. Since this is simple to take apart, it would not be hard to replace, so it's ok. Good 'ible!
salomon1996 (author)  godoggie3 years ago
Thanks much! :D
did not work. AT ALL.
Why did you need to use J-B weld for this? Why can't you just screw on the cap, or maybe use a bit of gorilla glue/pipe dope to get it completely airtight?
salomon1996 (author)  masterbuilder3 years ago
Gorilla glue or pipe dope would most likely also work, J-B Weld was just what I used.
Thanks for posting; it worked out great. I filled the thread on the bolt with epoxy it made it easier to cut nice round grooves with my dremel and make it drag less on the down stroke. Also added an extra O-ring and polished the bore of the cylinder.
I found that by holding the top of the carriage bolt to the ground with two fingers and holding on to the cylinder part I can get a 90% success rate with most tinder materials. holding it in this fashion it is just alot easier to get a fast down stroke, hold for a second, and quickly remove the cylinder to expose the ember. This also keeps the ember from falling out if it's small and allows you to slowly blow it into an intense ember without having to move the piston around. So if you're working with crummy tinder you'll have a greater chance of blowing on it before it goes out.
salomon1996 (author)  1337gallagher3 years ago
Your welcome! Glad it worked and good ideas with the epoxy and extra O-ring and the technic for holding it! Could you post some photos of the O-rings? I'm curious about that one! :D
B2BSurvivor3 years ago
AWESOME! I have been looking for a simple plan to make an inexpensive fire piston. Yours is great, and well laid out. Excellent "instructable" !
salomon1996 (author)  B2BSurvivor3 years ago
Thank you much! :D
streetrod53 years ago
Good Instructable! - I'll try this, but I'm going to clamp the bolt into my vice, or clamp it flat to my steel table before drilling the end hole. It would also work to tack weld the bolt to the steel table (and grind it smooth later), but I think just using a C-clamp lying on the floor, I would put myself in the ER. Do you think plumbers' silicone grease would work on the O-ring?
salomon1996 (author)  streetrod53 years ago
LoL! :P

I tried some copier fuser roller silicone oil and it works GREAT! :D It's really thick and slick. I'm not sure if there is a lot of difference between plumbers' silicone grease and this stuff, but they are both silicone, so it should work, I would think. :)
malsonc3 years ago
Great Instructable! I have a couple of questions however. You are using a 3/8" bolt, but you say to grind the threads down to 7/16" - am I missing something? It seems like you would need a 1/2" bolt to have enough material to reduce it to 7/16".

The other question concerns the composition of your O-ring. If it is a common rubber O-ring, then petroleum jelly will cause it to breakdown prematurely. If it is a silicon rubber O-ring then you are OK. If it IS a common rubber O-ring I would suggest a silicon grease instead of the Vaseline.

I'm definitely going to try this when I can get back into my shop. I know I have all the parts there - it will just be a matter of finding them since the move.

Thanks again!
salomon1996 (author)  malsonc3 years ago
Thanks for pointing that out! I will try to figure that out... :P

That is some good information!

Your welcome! :D
jamilks3 years ago
Salomon, aloha~

Thanks for the fine Instructable! I'll have to try this one out....it helps that I have access to a lathe but you make it very do-able with common tools!
Question: is the purpose of the epoxy just to seal the cap to the pipe or is it to provide a solid base for the stroke?
salomon1996 (author)  jamilks3 years ago
Your welcome! :D

It is mostly for keeping it air tight.
good, I would think just buying a threaded end cap would be easier. I was trying to think of how a threaded end cap would NOT work here. I guess there's really no reason to use the epoxy unless the hardware store is otherwise out of stock.

I would venture a guess that the more expensive "seamless" type of steel pipe (contrast "welded") would be less likely to have the ridge down the inside that needs to be removed. That looked like a lot of work from over here.
salomon1996 (author)  kill-a-watt3 years ago
Ya, if you can find a seamless one, go for it! :P It would save you time and work! :D
Phil B3 years ago
Thank you. I appreciate it that you used very common items easy to find. I would like to try this sometime. I could see making one for the preschool at our church. Using it to start a fire would make an interesting demonstration for the kids. I would like to try this.
salomon1996 (author)  Phil B3 years ago
Your Welcome! :D I hope that if you do make it and use it for a demonstration that it will go well! :D God Bless!