Fire Piston Gasket

[Brian Curnel]

Usually the cotton gasket on a fire piston will not last too long especially in humid climates. They fray easily and wick moisture which causes more drag on the plunger. I used mine for the entire 4 month outing. On day 2 I was haing problems with high humidity and lack of compression, on day 6 the gasket broke. I had more to use but opted to use it for a candle wick. Instead I used some nylon upholstry thread from my survival kit that I use for fishing line or repair. Using nylon did two things that cotton would not.
1. Would not wick moisture
2. Was stronger than cotton.

So I got nearly 17 days with the nylon set up.

If you use a fire piston use a nylon thread for a gasket.

 

[bazil]

what about a rubber 0 ring?

or sinew as is traditionally used?

 

[Simon E]

I use the inner strands of Parachute cord for the initinal wrap, I then use dental floss to 'fine tune' the performance. The dental floss is excellent, its easy to apply, you dont need to trap the ends as it seems to want to stick together. If you get the waxed version it will not wick and its super easy to take it off and re-apply it without having to go throught the whole winding process with cord.

 

[Brian Curnel]

@ bazil: Traditionally yes sinew would be best but here in the US ut's not always a viable resource. Upholstry string was what I had available so I used it and it worked great so I pass along that to the BCUK community. It's up to each member how they use the information.

 

[oops56]

Not me if mine don't work on 3 trys get the other one and the other out of three one should work and if that don't work i know my flint and steel will

 

[bazil]

@ bazil: Traditionally yes sinew would be best but here in the US ut's not always a viable resource. Upholstry string was what I had available so I used it and it worked great so I pass along that to the BCUK community. It's up to each member how they use the information.

of course......sorry was just saying.....sinew is what you would have to use in the wilderness....or the cotton of the dead man in the pack

 

[Brian Curnel]

of course......sorry was just saying.....sinew is what you would have to use in the wilderness....or the cotton of the dead man in the pack

No worries mate. I agree that there are several options but usually when you have nothing else, you will have thread from a rucksack or some other equipment. That was all I was saying. Thanks!!!

 

[rich59]

I seem to have mislaid the instructions and spare cordage that came with mine. This discussion sounds useful. Can you tell me how to secure the ends if I ever need to know?

 

[Brian Curnel]

I seem to have mislaid the instructions and spare cordage that came with mine. This discussion sounds useful. Can you tell me how to secure the ends if I ever need to know?

I first started by hanging the string vertical along the shaft.

Next holding the top with the opposite thumb, start a wrap clockwise around the piston shaft. You will have to make an effort to keep the first layer of line from several overlaps, if you don't the wrap will have gaps and create air pockets.

Wrap down until you have covered about an 1/8th on an inch to 1/16th of an inch and flush with the shaft.

To secure the end make a wrap loosely then over & under the thread pull tight.
(do this step at least three times.)

 

[Ed]

I found that the grease used for lubricant stops the cotton wicking moisture and have never had this problem. Waxed cotten thread will also work well, but make sure it is well lubed otherwise you may find that it tends to stick.


Ed

 

[Jeff Wagner]

I seem to have mislaid the instructions and spare cordage that came with mine. This discussion sounds useful. Can you tell me how to secure the ends if I ever need to know?

Rich - If you would please provide me with your email address I will send a fresh set of instructions.

 

[Jeff Wagner]

Usually the cotton gasket on a fire piston will not last too long especially in humid climates. They fray easily and wick moisture which causes more drag on the plunger. I used mine for the entire 4 month outing. On day 2 I was haing problems with high humidity and lack of compression, on day 6 the gasket broke. I had more to use but opted to use it for a candle wick. Instead I used some nylon upholstry thread from my survival kit that I use for fishing line or repair. Using nylon did two things that cotton would not.
1. Would not wick moisture
2. Was stronger than cotton.

So I got nearly 17 days with the nylon set up.

If you use a fire piston use a nylon thread for a gasket.

Something's not right here. A cotton string gasket should last for months not days. Sounds like your bore fit may be a bit too tight.

Sinew wont work, by the way. It dries hard and stiff and makes a terrible seal.

 

[riddleofsteel]

Beware of coarse or hard materials for your gasket. It can cause wear in the piston bore and ruin the piston. Lube is essential. My piston is made from coco bolo and I ordered a matching tinder safe for it. Eventually I ended up putting Vasoline in the tinder safe. It is great lube and is a decent fire starter if smeared on a cotton ball or other porus material. If your string gasket is wearing out look to your lube first.