Fuel proofing

[Tony Patman]

OK, newbie ignorance.
1. What exactly does the fuel do to wood?
2. Is it true that a pot of Dulux will do just as well as specialised fuel proofer?

Anyone else got questions?

[Mike Bell]

Tony,
I don't know all the scientific detail of what fuel does to wood, I suspect is has to do with the breakdown of lignin, but I'm no biologist. What I do know is the wood goes all spongy and weak and once the fuel is in it's all down hill from there.
Regarding Dulux, I haven't tried it but I do know that Japlac (from B&Q) seems to work. I presume you are only talking about doing the engine bay rather than painting a whole model. The latter would be rather heavy.

[David Ashby - Moderator]

Perfectly good question Tony.

Again I'm no expert but it's bit deceptive. Fuel can get on wood soak in and all seems well but over a period of time as Mike says the wood will deteriorate.
Dad often painted his models and used humbrol enamel around the nose which did give a bit of basic fuel proofing but you still had to wipe the fuel off asap otherwise the fuel would attack the paint. So gloss paint you suggest will probably be the same.
Two suggestions - Tuffcote is a two part fuel proofer usually in model shops, it can be painted or better still sprayed on.

I use Nitroblock which is a spray can (yellow and white can) again in model shops and works well. It comes out in a nice fine spray too.
Hope this helps,
David

[001]

I used to use epoxy resin for fuelproofing,the front end/engine/tank area but now I only use Yacht Varnish. (Any make, but normally International Paints) Two good coats will do it, but I usually paint the engine bay, fuel tank area and if I use heat shrink covering, the exhaust side of the nose (wood) with three coats before covering.. Cheaper than epoxy and completely 'foolproof' , pun intended.
But Yacht varnish is not colourless, looks yellow, so it is not good to paint over the top of any finish.
Having thought about the 'what it does to the wood' question, it could be that 'pure' Methanol might not be the main problem, as it evaporates over time, although it may leave other traces of chemicals that attack wood and glues.(Old fuel damage turns a blackish colour).It may be that the oil, castor or synthetic just makes the wood lose apparent strength or does it feed bacteria?. Nitromethane content is another factor. Any chemists out there?

[Tony Patman]

Interesting answers, guys, thanks. Sounds like my home-grown engine test stand won't last too long: I forgot to fuel-proof it before getting messy. Japlac, Tuffcote or Yacht Varnish: it sounds like there are many products which work. Last think I want is for my long weeks of labour to dissolve into goo...

[Malcolm Fisher]

Acrylic paint and varnish are also pretty fuel resistant  as are the water based varnishes by such as Ronseal which dry very clear i.e. they don't have the same yellowing effect as ordinary polyurethane varnishes. 

Huimbrol enamels and even cellulose dopes are pretty well fuel proof for diesel fuel but not glow fuel.

[Engine Doctor]

Try using Clearcote  ,made by the solarfilm people . Brilliant fuel proofer The solar lac coloured paints are good but not as fuelproof as the clear . Can be thinned with cellulose thinners or acetone .

 E.D