can you seal inside of tank, to keep decals on.

has anyone tried this , and does it work..

Ferd, nothing will stick to the HDPE tank - this stuff is very similar to the bottles that they use to package cyanacrolate (superglue). Fuel will always permeate a single layer polypro/ethelyne material.

The auto industry uses multi-layer fuel tanks - multiple layers are required to prevent fuel from permeating through the tank walls and into the atmosphere. Don't put anything on the inside of your tank. You will have better luck using a perforated decal - this will let the decal breath - so to speak.

There is a type of decal prep material on the industrial market, but I am going to have to go back and check on the name of it. What you want to do is create a barrier on the outside of the tank - behind the decal only. maybe someone else reading this will have some industrial experience with such a material - it is commonly used for applying stickers to plastic parts. Either locktite or 3M make it.


Boomer: I have a large aerosol can of 3-M spray-on adhesive. Is that what you are thinking of? It's called Super 77.

Boit; what you have I believe is the stuff - looks like you have the aerosole can?

Does the can or any literature you have make any statements about being a permeation barrier?

I have a can - non-aerosole - of 3M Scotch-Mount 4928 Adhesion Promoter. I got this from a customer I call on - again they use it on plastic parts. I have a near mint '83 YZ490 that finally had the tank decals peel off. So, I got a quote from Decal-works for a new set - big $$$$. However, with my background in fuel systems, I couldn't justify spending the money just to see if the decals would peel off. I don't think I can get a replacement tank for this bike, so I have been reluctant to try this adhesion promoter on my only tank.

How do the aftermarket decals stick to the gas tanks? I believe they are perforated so most of the fuel can escape without making the decal bubble up. I still have the factory decals on my 426, but that is only because I put clear vinyl over the leading edges of the decals.

To test the adhesive, one would need to apply it with a decal. Let the tank sit for a couple days. Then, fill the tank with fuel and seal it - put it in a very warm place, with some direct sunlight exposure. Be careful though that the tank does not bulge due to overexpansion - a slight amount of pressure buildup would be o.k. - that would simulate the condition of having a checkvalve in the tank vent - which Yamaha's have from the factory.



One thing that you can do is always keep your tank full. That really helps with keeping the decals on. Especially if it spends any time out in the direct sunlight or heat, like on race day. :-)

I believe the vapors build up pressure and permeate the plastic much faster and easier when the fuel level is low. I usually try keeping at least 3/4 tank in my bike, preferably full.



'96 YZ 125

'99 YZ 250

'01 YZ250F

[This message has been edited by YZ Abuser (edited 01-18-2001).]

i fitted a set of graphics that had slits in as oppossed to holes to an empty tank, while my bike frame was away being powder coated.

they where fitted correctly to a clean dry, degreased surface.

withing 5 days on an empty tank they had bubbled up all over.

i took the tank into the dealer who said they would sort me a new set from the supplier.

3 months on nothing....

except i brought, and fitted a set of decals with holes (one industry ones, which after 2 months riding in english slop still look great)and found another supplier

I believe 3M makes something to seal the tank, I read something in Dirt Rider on it but dont remember what it was called. You might try your local 3M distributor, maybe they can find out for you.


00 426

97 YZF 1000

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now