Maybe we are just lucky in the States to have McMaster-Carr. I have used several different sizes of their nitrile and have never experienced any breakdown. It is funny though that they will not ship overseas. I actually ordered some for a fellow CCS member and mentioned to the sales lady on the phone that the order was for a friend overseas and the next day she called back and left a message that the order was cancelled because the rubber was to be shipped overseas. Naturally, a day later I called back and ordered it again and never mentioned that it was for someone else, so I was good to go. Dan
According to the web site of this supplier there are multiple types of nitrile. This link is to the one they describe as as Milspec and suitable for fuel resistant gaskets. http://www.rubbersheetroll.com/nitrile-rubber-high-strength.htm Is it possible that some of us have been getting the other varieties ? Bob
On the other hand, I've not noticed any problem with gaskets I've made over the years, which have been punched from nitrile bought via eBay. This came from a seller called 'trade_Mark' IIRC, who has, I think, stopped dealing. Perhaps I was lucky and this was a better quality sample - I'll continue to use it until I notice a problem... Good link, Bob - I notice that even with Viton there are at least 5 grades available, and a paucity of information about which grade would suit our needs best... (edit) - I see a seller called Rubberkings has nitrile sheet listed on eBay - seven sheets sold, so far. There's no indication of what grade this is they're selling other than to say it's suitable for fuel applications. Has anyone bought nitrile from these people and can say whether it's good or bad? Or can anyone recall the source of their bad nitrile?
I've only had two issues with nitrile. One was with nitrile in one batch was "harder" than the other stuff I already had (I subsequently learnt you can get it in various hardness versions). I found this harder version doesn't work with NRV pips but still works fine with filler caps and reserve caps etc. So I just use the softer stuff for the NRV pips. Not had any ballooning with either so will stay with nitrile. The only other issue I have generally with nitrile is it's UV sensitivity that means that the odd application where the edge of the seal is exposed to daylight (British Military No.2 MkII filler cap is a classic example) rather than fully enclosed by the fitting means that it goes hard and unservicable quite quickly. Cheers, Graham.
Thanks again for that Dan, I have used it for a fair amount of stoves and still have plenty more for a few more lifetimes. It is good quality rubber !! Not that i am into rubber
post a link to the seller please as i have been after viton for ages, i did try to organise a group buy last year but hardly any interest back then, i can't see the point in using nitrile [iffy or not] if you can have pukka viton instead
It is the 1.5 mm sheet from Altecweb.com. I will let you know what its like at the weekend hopefully.
Wow - they are expensive! But they do small sizes so I guess it's Catch 22. I'm currently punching out washers from a big sheet of 2mm viton for standard primus type filler caps. I'll be listing them on ebay but will be offering them cheaper to members here. I haven't got around to figuring the postage out yet but the CCS price for one pint cap washers will be £2 for 6 & the 2 pint washers £2 for 5. I'll be doing a few other common washers as well. I may also do other thicknesses but am starting with 2mm as that's the closest thickness to the originals. Viton washers at less than nitrile washer prices. I'll post something in the Trading Post at the weekend hopefully
Well, I figured that the cost of the stoves I have that are currently grounded due to crummy seals greatly outweighs the cost of the sheet of Viton that will get them all running again. Plus, once they are all fettled I wont have the annoying anti-stove angel on my shoulder saying 'You cant run the ones you have already got!' whenever I see something nice on fleabay
I didn't think silicon was suited to fuels like kerosene or petrol? Superior for some applications but not all?
That's correct. Silicone is not resistant to fuels. It will swell soften and break down. David, you make an excellent point. Though you take a hit with the original purchase, the piece of mind knowing you won't need to worry about seals for about 20 years is a HUGE bonus. And you can make a LOT of seals out of a square foot. Mike
I have had a bit of silicone bake wear soaking in kero and white spirits for weeks and it has not changed at all. It seems like a great thing to use but it is a little soft. I do not know how long it will last but is is better than some nitrile I have had so far. I have not used it on a stove and do not intend to as I have some great nitrile at the moment.
Yellowdog, I think "a little soft" is an understatement. I also think that what is sometimes sold as nitrile is in fact not nitrile. I also know that there are different grades of nitrile and viton and most rubber products. I also know that not all manufacturers produce quality products. I also know that some sales and supply companies know less about the products they sell than the folk they sell to. I also know that it is very difficult to tell the difference between a bin full of nitrile rubber and a bin of another rubber of the same color and hardness. I also know that you generally get what you pay for. I also know that I have done a LOT of research looking for the best stuff to use at a reasonable price. And NO WHERE I have looked, has there EVER been a recommendation by the manufacturer of these materials to use silicone in a fuel environment. Does this mean it wont work? No. Does this mean that I wouldn't use it in an emergency? No, of course I would. I've used bubble gum and it got me through a rough spot and bubble gum is latex(chewed it first btw). I have seen, first hand, silicone seals swollen by naphtha when using it as a cleaning solvent on military electrical connectors. Leave them in the sun for a bit and they go back to their original size in a few hours. Try this with your silicone kitchen ware: Cut a disk to fit snugly in a piece of tubing. Then dunk it in Coleman fuel for a few days. Chances are that it will swell and form a dome. It may not, though. All I'm saying is that if silicone was good to use with fuel, that's what would be used. It is not. My 2 cents. Mike
Interesting link! Checked on different fuels I am using and both Nitrile and Viton seemed to give the same result, I will stick to nitrile until I find some viton.
Viton washers for sale - discounted for CCS. https://classiccampstoves.com/threads//pid/174120/post/last/m/1/#LAST
