Recently, I had to nick out a fuel cap gasket for a Primus Nr. 54, and I was beleagered as to find a material easy to find a suitable material, with a springy resiliance, but fuel resistant, that was easy to work with and yet hold up to fuel. Well, I went through the list of gasket material and found this at AutoZone - FEL-PRO 10" x 26" x 1/16" cork/rubber gaslet material sheet, part # 3018. You couldn't ask for a better material! The cork gives it a springy nature to seal the cap, with the rubber binder keeping it from crumbling, it's shown to be oil, gasoline and coolant resistant. It's also soft enough to be cut to size and shape with a Exacto type hobby knife, and the center hole can be done with a hand-held paper punch! And better yet is the price, all of $6.99, and it's a standard item on the shelves at all their stores, too! NAPA Auto also carries it, their part # is FPG 3018. Murph
I've found it ok for alcohol & water but long term to fail for paraffin. I've tried various, new & vintage stock. It may be the case that different spec is available in the USA
@Spiritburner , Ross, I'm waiting to see how it holds up to kerosene as well. I made one gasket from a bicycle inner tube, softened up and swelled in about a week, so I'm hopeful that this will work much better! Murph
Long term fail...like how long? If it lasts a season it is well worth it. Remember on old stoves the material used was not up to today's standards.
Months. I'm of a different view. As a fettler I've come across plenty of materials that work short term but some of my oldies don't get used frequently& I found it frustrating to find washers mushed or blown out the next time i went to use them. With material I use I've washers 5 years old that are as good as new.
http://www.efunda.com/designstandards/oring/oring_chemical.cfm?SM=none&SC=KeroseneKerosene Material compatibility chart.
My wager is these will do just fine, basing this on two things: A) FEL-PRO makes gaskets and gasket materials for engines and transmissions, has for decades, so one could deduce when they state their material is gas, oil and coolant resistant, a spot of kero won't be a bother. B) Their gaskets are made to stand up to heat & cold, vibration, and fluid immersion for years on end, so the demands of a stove are laughable by comparison. Murph
I have a different view. I would like the seal to work the next time I pull it off the shelf. I have had old cork gaskets that were still good. Just a wetting to renew. Why would you not want to use the best product available, and use something that only last for months? Cork and leather are better than something that lasts only 'months'.
A lot of old automotive gaskets (think cork Valve cover gaskets) were designed to soak up oil and swell. A certain amount of sweating was considered normal. Not sure if the new product listed above is still designed to soak, swell, and sweat.
I've got a sheet of Buna-N I use for making check valve pips, I got it from McMaster-Carr, it was expensive but the sheet will make hundreds of pips. IIRC its 1/8" but they sell various thicknesses. Its good with parafin/kerosene but doesn't handle whitegas or gasoline very well. For that I bought a sheet of viton from eBay. Its hard to find a viton thats soft enough to make a good seal without requiring a lot of pressure from the pump. The stuff I've got is okay but still too hard.
Viton is the de facto standard sealing rubber for automotive fuel systems. It tends to be a little harder than Nitrile (buna-n), but is available in various durometers. Nitrile is vulnerable to ozone, so it will eventually harden and crack where exposed to air. There is also fluorosilicone. Coleman used low-temp (blue) fluorosilicone o-rings in the backpacking lanterns. DO NOT use regular silicone (usually red/orange) o-rings. They swell and break within minutes of contact with white gas.
Working from memory the buna-n stuff I've been using is about 40d, the viton I've been able to find is around 70. The harder stuff will work if the spring is very strong but I've had difficulty in some devices. Do you have a source for viton in the 40d range?
Are you sure it's 40D? That is pretty hard while 40A is pretty soft. Typical Nitrile o-rings are 70A. I don't have any stoves that use rubber check valve pips, so I really only know more about the material than the application requirements. Fluorosilicone sheet can be had down to 50A. I haven't looked for it, but Viton should be available in the 60D-90D range. 60 isn't quite as soft as Nitrile in 40 obviously, but a little better than 70 or 75. There are other specialty materials like Kalrez, but that stuff is about US$4,000 per square foot at 1/8" thickness.
You're right, I confused A and D. Here's the stuff I've been using: https://www.mcmaster.com/#8635K904 Again it works just fine with kerosene but white gas kills it after about a year. Looks like McMaster-Carr has flourosilicone in 60A but its $85/sheet. Still I've been using the same sheet of buna-n since 2012, I've even given away a couple square inches of it. Wish I could buy like a square inch to test and see if it was good before buying a bigger sheet.
