Friend of mine makes motorcycle fuel tanks, which are used on race bikes which often use methanol fuels.
He is laying up using Atlac resin system (vinyl-ester), which is ok, but generally is slowly eaten away by the methanol fuel, meaning tanks need to be replaced after about a year.
Wonder if anyone knows of a product that may be more durable than the vinyl-ester, bearing in mind its not really economically viable to make the whole tank using expoxy based resins?
Chris
polyester would not be any better, probably worse. TYou can contact a resin company and see what they have in methonal resistabt resin but I bet they steer you to epoxy. You may wanmtto try lining the tank with a gas tank liner, however only some are alcohol resistant, and that is based on 15% not 100%
Thanks for your response.Polyester resin system just wont live with methanol fuels at all! Vinyl ester product currently used is specified for marine diesel tanks, and is far better than poly resin system (but by no means perfect!)
As to epoxy it would not be economically viable to lay up tanks using this, but would certainly be possible to put a sealing coat of epoxy over vinyl ester mouldings before they are bonded together.
Problem here is whether or not the epoxy is likely to bond to vinyl ester, without any problems. Its next to impossible to get information from resin manufacturers on anything like this, so wonder if anyone else is making fuel tanks, and if so whats the best thing to apply to seal the lay up?
Chris
Epoxy seals and sticks to everything.
I’d seal the tanks together with Epoxy and then coat the insides with Epoxy.
But better yet, All Epoxy fab would be the only way I would want to do this.
Using epoxy to make these parts would greatly increase production costs, so isnt really an option in this case. Vinyl- ester tanks last about a year, and there have been no problems, as long as they are replaced after this time. Will try epoxy for sealing PER mouldings though…thanks for the advice.
Chris
Yes, Epoxy resins costs more but then you can charge more for the part. Plus it will be then properly made and not fall apart later…
Concerning these type of parts, if you charge more, you simply dont make a sale! Price of tank laminated using epoxy system, would be close to that of aluminium, so you would be pricing yourself out of the market.
Spoke to tech at West Systems today, and they tell me that the epoxy resins they sell will degrade when exposed to alcohol fuels, so it would seem that bearing in mind increased production costs using epoxy over vinyl ester, that there doesnt seem to be a lot to be gained by changing to epoxy.
I know what youre saying…perfeng would tell you that the car guys are cheap, I think its the bike guys!