Ethanol resistant resin questions

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#1

First off, hello all! I found this forum when I decided to make my own composite motorcycle fuel tank. I found an interesting epoxy resin to try, being “green”, with several benefits I thought Id try it out and do several samples and tests. I made up several strips with the Ecopoxy and Im going to leave it in the ethanol fuel over time to check for any degradation.
Then I get on here and find out epoxy is great for strength and adhesion on the composite fibres but not so good for ethanol resistance. I do a little more digging and find vinylester is more resistant to the fuel but not so good for strength and adhesion to the fibres.
I was planning on coating the inside of the tank with a sealant such as POR15 or Caswells tank coating anyway, but could I make the tank with the epoxy resin for the first 6-7 layers and then use the vinylester resin for the remaining 3-4 layers? Would they bond properly? Is there a different resin I can use?
Ive got more questions but Ill try not to use up all my question alowance in one go!

Ray

#2

look in to epoxy-vinylester resin

#3

x2. Give Expresscomposites.com a call and ask them. If they have what you are looking for, tell them John from Naperville told ya to call em ;-). If they don’t have what you want then don’t mention my name… Haha!

#4

Reckon if you are using a sealer, then just use what resin you rather use. Paint the outside in something that is fuel resistant, and then both sides will be fine.
Too bad thermoplastics are a pain in the arse to work with! :slight_smile:

#5

Hey all! Bad news. I had the test strips in the ethanol fuel for about 1 month now and just tried a test strip. It was significantly softer in bending and torsion. flexed it a few times and the layers started coming apart. Ecopoxy is NOT ethanol resistant.
Oh well, try another one!

Ray

#6

Bump on this topic. Rhubarb Ray’s post was lost in old spam and I didn’t notice it until just now. My apologies.

#7

i would think vinyl ester resin would be fuel safe. what are underground fuel storage tanks made of?

#8

Ive had a hell of a time trying to find an appropriate resin. Ive had a couple of tech reps from epoxy companies tell me that a vinyl ester or hybrid epoxy vinyl ester would NOT work but a pure Novolac resin would. I guess one of the issues Ive imposed on myself is Id like a clear resin for the carbon fibre. Makes my choices much more limited. I have found one company that has a suitable product, but Id have to buy 3500 lbs!! Anyone else need 3490 lbs? Im still waiting back on a few more replies but I guess I`ll have to keep looking.

Ray

#9

i think with a coating on the inside of the tank you would be fine with ver or epoxy…

were the test strips coated with tank sealer or bare…

#10

Be careful, huh.

ethanol =! regular fuel.

Ethanol is very good in dissolving the resins we normally use. I have yet to come by a resin that will be up to the job. Yes, novolac would be possible, but novolac/vinylester already has my doubts. Epoxy you can skip altogether, as well as polyester.

I guess you are best off with a vinylester tank (try and get hold of a novolac modified one). Or preferably thin walled steel.

#11

Just found this resin that states it can be used for petrol tanks…

http://www.ecfibreglasssupplies.co.uk/p-1511-crystic-199-pa-resin-including-catalyst.aspx

#12

maybe try this to seal it…
http://www.por15.com/Data%20Sheets/fuel%20tank%20sealer%20pdf.pdf

no need for the metal cleaner step.

this one looks more promising since it says it is compatible with fiberglass tanks…
http://cgi.ebay.com/ebaymotors/Bill-Hirsch-Gas-Tank-Sealer-Quart-BH-GTS-/350412540013?pt=Motors_Automotive_Tools&hash=item519637086d#ht_2917wt_862

#13

The last one (the Ebay one) is the only one that I see that mentions ethanol. Do not forget, ethanol is much more aggressive than regular petrol.

Now that they mix it at 10% with diesel, many boat owners run into trouble with their tanks, seals, filters, etc.

#14

Do a search on google.

I was looking around for a suitable resin just as you for hte same reason and couldn’t find one. I even looked at all the various “sealers” out there and none were suitable either, not “Por” nor “goldwhatever”. there were reviews on the net and forums where people were complaining and discussing the long term (relatively short actually) failure of the sealers. my ultimate conclusion was that they are not suitable and not worth the effort of using and having my part fail…

#15

Bill hirsh auto sells an ethanol resistant sealer it came up first on google. Says it works great on fiberglass

#16

I was @ Rev-Chem yesterday and I talked to a guy that makes fiberglass motorcycle tanks,asked him what he uses

FYI:http://www.caswellplating.com/aids/epoxygas.htm

#17

Why not use a flexible rubber bladder inside the tank?

#18

Prc rapid seal hands down best there is. Brush on or thin and bake using mbk.

#19

As someone who has already made a tank I will offer this bit: do NOT use epoxy for the tank, regardless of what you coat it with. A scratch on the inside or spillage on the outside will wreck your project.

I used epoxy with POR15 in a tank specifically used for race fuel and it started to get pinhole leaks after about a year. No ethanol in the fuel either.

Anyway, I am in the process of making v2 gas tank with vinylester and using the Bill Hersh sealant this time around to see how it performs.

#20

Actually the only resin to create composite tank for gas is only Vinyl. I have made many tanks in the past and I don’t have any troubles with it. Vinyl is not all for fuel resistand, so you have to check the specifications of the product for Chemical resistance to wide range of substances (Acid, alkalies, oxidising agents etc).

Check below some European companies:

SCOTT BADER:

REICHHOLD COMPOSITES:

Yhe upper companies are the top dog in the area of Vinyl Resin, I am using them a lot of years. :wink: