Plastics / Nylons in new gasoline
Plastics / Nylons in new gasoline
(OP)
Hello all,
I have a question about plastics and nylons in modern gasoline. I am dealing with some carb floats that are made from Acrylonitrile styrene resin. The material is breaking down and chipping off in fuels with ethanol. Is anyone else fighting this fuel battle? Does anyone know the correct plastic or nylon that can be used in fuel systems? Thanks for the help!
I have a question about plastics and nylons in modern gasoline. I am dealing with some carb floats that are made from Acrylonitrile styrene resin. The material is breaking down and chipping off in fuels with ethanol. Is anyone else fighting this fuel battle? Does anyone know the correct plastic or nylon that can be used in fuel systems? Thanks for the help!





RE: Plastics / Nylons in new gasoline
The general order is Nylon or Acetel, then only move up the cost path to PPS, LCP, or some other resin if the application has unusual requirements. The normal starting point for a structural bit would be 35% Glass Filled PA66. I have ended up using that probably 50% of the time, or more.
-Tony Staples
www.tscombustion.com
RE: Plastics / Nylons in new gasoline
I forgot to mention that I've never used ASA in a fuel system component. I'm not even familiar with it. A quick search on Matweb indicates that it has some resistance to alcohols, as it is sometimes used for electric razor housings, which could see alcohol residues from facial contact. However, ASA isn't listed as being recommended for gasolines or motor oils, as it can be attacked under certain conditions.
I think you are on the right track; Find another material.
-Tony Staples
www.tscombustion.com
RE: Plastics / Nylons in new gasoline
RE: Plastics / Nylons in new gasoline
It is very resistant to other normal pump fuels, which is one of the reasons it is the base resin used almost exclusively for manifolds.
It would certainly be OK at 10% ethanol and probably OK for E85 if the nylon was glass filled.
I don't have my data for polyesters or acetal, but I expect both will be about the same as nylon.
Regards
eng-tips, by professional engineers for professional engineers
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RE: Plastics / Nylons in new gasoline
If your alcohol loaded fuel absorbs any water and then the fuel gets hot, the homopolymer breaks down / becomes brittle.
I'm not a chemist, this is experience on the same component made from the two grades.
Bill
RE: Plastics / Nylons in new gasoline
Alcohols absorb water.
From memory, Acetal is hydrolysed slowly at 60 deg C and fairly rapidly at 80 deg C, for this reason it can be used for hot water plumbing in regularly replaced items like jumper valves.
It cannot be used for steam irons or kettles as the water gets hot enough to severely limit life.
Regards
eng-tips, by professional engineers for professional engineers
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RE: Plastics / Nylons in new gasoline
I kneel before you.
Bill
RE: Plastics / Nylons in new gasoline
I am both a chemist and an engineer of sorts, actually being a Charted Textiles Technologist which is half engineering, half polymer chemistry.
I spent most of the last 30 years in technical marketing rolls in the field of Engineering Plastics. In a totally isolated country with about 20 million people and a very large geographic spread, that means you need a large product pallet to be viable. Not an an Obi-Wan Kenobi, just a naughty little boy. Seriously, the question hit directly on my exact field of experience.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Plastics / Nylons in new gasoline
I certainly respect all-rounders, it's a dying art.
I sit among software types, electronic types and mech boys and, sadly, many of them do not transcend their self-imposed boundaries.
Engineering, for me, has been a life of curiosity. I'm not especially skilled at anything but know bits about all sorts (I think). Have a good Sunday.
Bill