Plastic welding.

Having fitted a (tall) Yam XS880 motor into an ex two stroke E.M.L. chassis I find that the fuel tank no longer fits as the bottom fouls the cam box. Got alloy sheet to make a new one but haven`t time to do it all before season ends so I cut the offending bit out and am considering PLASTIC WELDING a new piece. I believe EML tanks are POLYETHELYLENE ? Has anyone out there tried a HOT AIR WELDING kit to repair/modify these tanks ??? No Adam, not THAT sort of hot air !!

Hi John,
I have tried this plastic welding and found that the results arn`t that strong on the joints. How I did it with my tank was to heat the plastic up until really soft and then push the amenable plastic into position. This takes a while as the plastic is quite thick but eventually it`ll get there. First time I used a hair-dryer, I had a three day beard growth by the time it was warm enough, so use one of those paint stripper heaters but be really careful as the plastic is only at the critical temp for a second or two then starts to melt. Hope this helps in some way.

Stretch

Quick tip that Mike forgot John.

Ensure the tank is full of fuel while you do this or you won't know if it still leaks.

Thanks for your suggestions Stretch - have taken the plunge and bought a "proper" hot air welding kit - expensive but IF it works a lot cheaper than having to make an alloy one, plus lots of these plastic tanks are damaged where overlength/oversize screws have been used (usually on the piss as well!) so these could be "saved". Not only that but "made to measure" air boxes could be made from old plastic drums (as I believe they are of the same material). Could be an useful tool SO I WILL POST A REPORT ON WHAT HAPPENS. "Twinshock 10`s" suggestion lacks
some practicality - if I fill tank with petrol it will all run out when I turn it over to weld the bottom and will burn my balls !

John Caffrey wrote: Could be an useful tool SO I WILL POST A REPORT ON WHAT HAPPENS. "Twinshock 10`s" suggestion lacks
some practicality - if I fill tank with petrol it will all run out when I turn it over to weld the bottom and will burn my balls !

Good idea John to reclaim the tanks and making the airboxes, will stay tuned. Twinshock 10 is just trying to impress Linda by appearing to know what he`s talking about!