Sealing and painting plastic tanks

TheCadman · May 13, 2020

Now that I'm riding my Dakar-replica G/S (thanks to Mike for sorting out the extended swingarm and final drive) thoughts have turned to re-doing the paintwork. Unfortunately since the picture was taken, time, wear and petrol / ethanol fumes have taken their toll on the front tank, and the paint has now bubbled in several places.

It's a nylon Acerbis tank, and has been painted several times before. However, before doing it again, I'm thinking of sealing it as well, to protect from ethanol-induced problems in future. Has anyone got any experience of the various treatments available, and in particular if they would work on nylon? The rear tank is an HPN original made of who-knows-what and has never taken paint well, but I'm always prepared to try again.

I'd also welcome suggestions for painters and even paint schemes.

Thanks

Graham

bowser · May 13, 2020

Nylon is supposed to be petrol proof, I have nylon tt tank on the gs and it has never been an issue, neither have my ktm tanks however my acerbis for my R100 years ago was not nylon it was poly and it was hopless paint sticker no matter what it always came off, I currently have a set of safari tanks on my KTM and they are the same, no painting them at all. If its poly then flouride treatment of the inside is the only thing that prevents the paint lifting

Sunny Jim · May 16, 2020

Could two-pack be the answer?

My ‘91 GS (with PD tank) was done in black 20yrs + ago and is still as good as new.

B Murr · May 16, 2020

Can such rounded shapes be wrapped? Is it the polyethylene tank that paintable?

bowser · May 16, 2020

NO NO NO NO and again NO

Poly tanks MUST be fluoride treated otherwise they are porous to fuel vapor, EVERYTHING you put on the surface will lift off, thousands and thousand of people have looked at it, HPN tanks, Safari Tanks, Acerbis tanks it dont matter the only way to prevent it is fluoride treatment of the inside surface of the tank NOTHING else works.

Dont take my word for it, do research on google.

people have tried 2 pack, perforated decals, flame teating the outside of the tank to re melt the surface, hundreds of different things NONE of them work

solidstate100 · May 17, 2020

bowser said:
NO NO NO NO and again NO

Poly tanks MUST be fluoride treated otherwise they are porous to fuel vapor, EVERYTHING you put on the surface will lift off, thousands and thousand of people have looked at it, HPN tanks, Safari Tanks, Acerbis tanks it dont matter the only way to prevent it is fluoride treatment of the inside surface of the tank NOTHING else works.

Dont take my word for it, do research on google.

people have tried 2 pack, perforated decals, flame teating the outside of the tank to re melt the surface, hundreds of different things NONE of them work

100% this. Seriously, dont waste your time.

JohnnyBoxer · May 17, 2020

I bought this used Acerbis tank a couple of weeks ago
It’s from the late 90’s and the XR graphics are ‘embedded’ into the plastic, somehow and smooth to the touch
In contrast the elkamet sticker is bubbling

Very clever process and expensive I guess, as all the late ones are different with a screw on badge instead

I guess the process was too expensive to maintain

rossi · May 17, 2020

This used to be mine - Mick Exrtance's 2005 Dakar bike - seen here on a ferry across the Dardenelles Strait, NW Turkey on my way to Serres Rally in 2016.

I believe the tank is a 25L acerbis rally tank - normally plain red plastic. The paint job was applied over a thick, white layer of some kind of primer. Whatever it was, it kept the vapours inside the tank and allowed paint and stickers to be applied over the outside. There are a number of areas where the primer was showing through, and some patches of bare plastic but this was all down to physical abrasion. The tank had its share of battle scars when I bought the bike, and I added quite a few more in my time with it.

Part of me regrets selling that bike, until I remember how much effort it was to restart after I had parked it upside down in a bush or on the side of a hill with the kickstart on the uphill side.

bowser · May 19, 2020

that is very probably a Nylon based plastic tank not a poly one, the white stuff is a plastic primer to allow the paint to give a good key to the surface, most of the later acerbis ones are nylon, my BMW tank is nylon and its not a problem its the poly ones that are.

re the post above, those stickers are not on the tank they are moulded into the plastic during the rotomoulding process that is why my 990 safari tanks say adventure down the side and it stays there anything you stick on just comes off.

rossi said:
This used to be mine - Mick Exrtance's 2005 Dakar bike - seen here on a ferry across the Dardenelles Strait, NW Turkey on my way to Serres Rally in 2016.

I believe the tank is a 25L acerbis rally tank - normally plain red plastic. The paint job was applied over a thick, white layer of some kind of primer. Whatever it was, it kept the vapours inside the tank and allowed paint and stickers to be applied over the outside. There are a number of areas where the primer was showing through, and some patches of bare plastic but this was all down to physical abrasion. The tank had its share of battle scars when I bought the bike, and I added quite a few more in my time with it.

Part of me regrets selling that bike, until I remember how much effort it was to restart after I had parked it upside down in a bush or on the side of a hill with the kickstart on the uphill side.

JohnnyBoxer · May 20, 2020

bowser said:
re the post above, those stickers are not on the tank they are moulded into the plastic during the rotomoulding process that is why my 990 safari tanks say adventure down the side and it stays there anything you stick on just comes off.

Clever though isn’t it

Impressed me

Deleted account 211025001 · May 20, 2020

What about having the inside of the tank sealed?

I had my Bultaco fibreglass sealed to protect it against ethanol in modern fuels, would not that kind of seal prevent vapour passing through it into the PE?

Andres

bowser · May 20, 2020

Outtomunch said:
What about having the inside of the tank sealed?

I had my Bultaco fibreglass sealed to protect it against ethanol in modern fuels, would not that kind of seal prevent vapour passing through it into the PE?

Andres

Yea you can, its a fairly standard treatment, I wont say I am fully conversant with how the process works but the inside of the tank is treated with flouride and it protects against the fuel vapor permeability.

I know that speaking with a guy from CCM about their 450 adv bike which has a plastic tank and that is why they are unpainted, although he said there was a firm near to them that could treat the tanks if you wanted to pay for it to be done so it could be painted. I dont think they offered it but he did know where it could be done, I have no idea if it has to be done before fuel has been put into the tank or if it is something that can be done after, but there are thousands of page of discussion about painting poly tanks and that is universaly accepted as the only treatment possible.

If you looking to find out, I would try and find a company that does roto-moulding and see if they know of any companies that do it

Sealing and painting plastic tanks

TheCadman

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