[Healeys] Ethanol effects on rubber
bspidell at comcast.net
Fri Jun 22 19:07:59 MDT 2018
Tom's sells Moss parts--at a 15% discount BTW--and I've never seen the
composition of these listed anywhere (the jet itself, of course, is
brass). I doubt there's a lot of sources for these (I'd guess these
come from Burlen).
It's the same as the ones in my BJ8; I want to see how it holds up.
On 6/22/2018 5:41 PM, Tim Davis BN7 wrote:
> What material is the Toms diaphragm made of? That's what you need to know.
> Tim Davis BN7
> ----- Original Message -----
> From: Bob Spidell <bspidell at comcast.net>
> To: Healeys <healeys at autox.team.net>
> Sent: Fri, 22 Jun 2018 15:19:17 -0400 (EDT)
> Subject: [Healeys] Ethanol effects on rubber
> Just when you thought you'd heard the last on this ...
> Having bragged about my scientific creds, I decided I needed to do some
> 'scientific' experimenting. I bought a new HD8 diaphragm jet from Tom's
> and put it in a jar submerged in denatured alcohol. If you're not
> familiar with denatured alcohol, it's ethanol--i.e. booze--with one or
> more denaturing chemicals to make it unpalatable to drink. When I first
> did this thought experiment, I thought DA was mostly ethanol, but the
> quart I bought at a hardware store claims to be 45-50% ethanol and the
> remainder methanol (and probably some water as both alcohols are
> hygroscopic). Though this mixture doesn't represent the 10% or so of
> ethanol in gasahol, IIRC from my college chemistry and lab technician
> days that methanol is even more corrosive than ethanol. So, this should
> be a good test of the rubber part of the jet's resistance to these
> solvents (and the brass part too, I suppose). I put new jets in my
> BJ8's HD8s two years/12K miles ago, and should have done this then in
> case the results were scary, but maybe this will tell us something.
> I'll check the jet periodically for degradation and, if anybody's
> interested let you know.
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