Petrol-proof O-rings

[S. Heslop]

I'm planning to build a peanut lighter with a friend's birthday coming up. I'm not the birthday gift giving type really, but the guy got me a Sega Game Gear (of all things) for mine and I want to return the favour.

I built one almost immediately after I got my lathe, no idea where it is now, and it worked fairly well. One problem though was the tight fit with the sleeve part that slides out of the body, it needs to be tight so it doesn't fall out but it was difficult to remove and had a habit of ejecting all the fuel like a piston as you inserted it. I figured i'd try replace this with a relatively loose fit and an O-ring to give it a grip, but i'm unsure what kind of O-rings you need to buy that can resist petrol/ lighter fluid.

Any help would be appreciated.

[John Rudd]

I'd be inclined to search out suppliers and ask what the o ring material is and check for chemical compatibility

[S. Heslop]

I'd be inclined to search out suppliers and ask what the o ring material is and check for chemical compatibility

I was hoping just to order then on somewhere like ebay. I can't imagine real suppliers being too excited if I phoned up and ordered 2 of them.

Found the lighter though.


If I had a milling machine I'd probably try milling a groove up the side of the sleeve part to prevent the pistoning. Or I could maybe drill a third hole in the top and run a small brass tube down to the bottom to let the air out. I still doubt my ability to get a good enough fit with the part to be tight but not too tight though, and an O ring seems like the easy way out.

[Bluechip]

AFAIK 'Viton' rings are proof against petrol. No idea what lighter fuel is so .... ??

I get mine from Simply Bearings.

Here is their site and if you poke the 'info'  [ Chemical Resistance Table ] thing you'll get an overview of various o-ring materials.

http://simplybearings.co.uk/shop/index.php?cPath=4501_4706

Dave

[S. Heslop]

Thanks, I'll order some from simplybearings. I've bought from them in the past, and i've got some bearings I want to order from them too.

[awemawson]

Beware of Viton rings near heat - iirc they break down and produce phosgene gas 

[Manxmodder]

AFAIK 'Viton' rings are proof against petrol. No idea what lighter fuel is so .... ??

I get mine from Simply Bearings.

Here is their site and if you poke the 'info'  [ Chemical Resistance Table ] thing you'll get an overview of various o-ring materials.

http://simplybearings.co.uk/shop/index.php?cPath=4501_4706

Dave

Lighter fluid is usually naphtha,a high volatile fuel also known as white gas.
http://en.wikipedia.org/wiki/Lighter_fluid

[dawesy]

Nitrile or fluorosilicone should be fine also.

[Manxmodder]

Beware of Viton rings near heat - iirc they break down and produce phosgene gas 

Never heard of them emitting phosgene gas but the danger we were taught relates to the constituents of the viton fluoroelastomer being converted to hydrofluoric acid if the seal or O ring is heated above 300 degrees celsius(that's very hot).

The standard advice when handling viton O rings that have been used in extreme high temp applications is to wear disposable gloves,or use a tool such as tweezers.

I found this health and safety document which seems to say a lot of the fears are overstated
http://www.hse.gov.uk/mvr/topics/fluoroelastomers.htm
.....OZ.

[Lew_Merrick_PE]

Lighter fluid is naptha.

EPDM o-rings should do just fine for you.  That is the preferred solution for jet fuel (kerosene) and a number of other evil nasties.  Nitrile should also work well, it just may need to be replaced more often.

[S. Heslop]

Finally got around to starting this, about a month later. Missed the birthday so it became a Christmas present, although I might miss that too.

Can't afford o-rings so i'm just using some under-diameter but oversized one I had in a box for now.




Nothing like flash photography to show up every scratch. I just need to make the striker to finish it off.

[S. Heslop]

Just finished the lighter.



I think it turned out alright, but the striker is a bit of a mess since I ended up having to file it by hand. I didn't have any files thin enough (the one I used last time has gone missing) so I ground a couple of needle files thinner and didn't quite get it all lined up. But hey, it works. I recorded making it so i'll probably edit a video of it tomorrow.

[Stilldrillin]

That looks good, Simon! 

I'm sure your Pal will treasure it..... 

David D

[vtsteam]

Cool!