jon0881 Posted May 17, 2013 Report Share Posted May 17, 2013 Someone has butchered a paint job on the scorpa I bought. It's the wrong colour and its all cracked on the tank with expanding. I was going to leave it but it looks pants. How is it best to start stripping the crap off and painting it again. I've just seen a video of Rit dye but that seems a little restrictive. Its a 2003 scorpa sy250. Also, the mud guard has developed a fracture just after the bolt hole. I dont think it helped being on the back of the DC bike rack and the wind pulling up on the guard, in future i will remove the mud guard when its on the rack. if i drill holes either side of the crack and use small cable ties will that do for now? Jon Quote Link to comment Share on other sites More sharing options...
jon0881 Posted May 17, 2013 Author Report Share Posted May 17, 2013 i might give this a go. What type of plastic is the mud guard likely to be? Quote Link to comment Share on other sites More sharing options...
gasgas249uk Posted May 17, 2013 Report Share Posted May 17, 2013 Hi Jon I've painted myself and had painted about 10 plastic tanks. I've generally used nitromors but but never left it. I've then scraped the old paint off. An air disc sander also works very well. These diy lecky sanders are next to useless I've found. Use a 2k sealer spray to seal the tank then primer and paint. Afterwards you'll have to drain the tank down after each ride or the bubbling will occur in 3 months. Good luck Quote Link to comment Share on other sites More sharing options...
jon0881 Posted May 17, 2013 Author Report Share Posted May 17, 2013 how long is safe to leave that stuff on the plastic? The dye option isnt looking to bad now i was going to buy a flexible primer and use that then hopefully the paint would not crack. Quote Link to comment Share on other sites More sharing options...
0007 Posted May 17, 2013 Report Share Posted May 17, 2013 Paint on a plastic gas tank is not going to work as off gassing from the fuel will always ruin it from the inside out Why don't you look into a decal shop doing a wrap? Quote Link to comment Share on other sites More sharing options...
totty79 Posted May 17, 2013 Report Share Posted May 17, 2013 The mudguard will have a recycle symbol somewhere with letters next to it indicating the plastic type. On my 321 it's PP. Technique wise I experimented as I had about 8" of breaks, what I came up with: Melt a couple of small stripes across the split and hold it till it cools to stabilise it. Carve a V shape with the soldering iron as close to all the way through as you dare. Pre heat a length of filler rod with a lighter, drop it into the v. Mix filler and guard. Smooth the plastic squeezed out when carving the V back over the still melted filler and guard mix. It seems quite strong. For areas near fixings I repeated this from the other side, if you do this then do it last as it'll be neater than your first attempt. Quote Link to comment Share on other sites More sharing options...
gasgas249uk Posted May 17, 2013 Report Share Posted May 17, 2013 how long is safe to leave that stuff on the plastic? The dye option isnt looking to bad now i was going to buy a flexible primer and use that then hopefully the paint would not crack. 10 - 15 minutes is absolutely fine. It never tried to eat the tanks i was working on , but i cant be exactly sure which plastic you are using. Chances are its the same. Just never leave it. Dont worry 0007 is right as a general rule, but with thick coat of 2k sealer it will help a lot . Just drain it down completely after every day on the bike and leave the fuel pipe to carb disconnected so residue can escape . Also leave your fuel cap off. With this simple system , i dont get bubbling anymore. With the tank drained , petrol doesnt have much of a chance to eat in, and bubble the paintwork Quote Link to comment Share on other sites More sharing options...
bondy Posted May 17, 2013 Report Share Posted May 17, 2013 hi i have a plastic tank thats been painted but im not sure how it was done but theres been fuel in it all the time and it never bubbels. i was told sand the tank then primer but to be honet i woundnt bother sooner just buy a new 1 Quote Link to comment Share on other sites More sharing options...
marky boy Posted May 17, 2013 Report Share Posted May 17, 2013 (edited) Paint on a plastic gas tank is not going to work as off gassing from the fuel will always ruin it from the inside out Why don't you look into a decal shop doing a wrap? Not true. Was true of some of the old plastic tanks. Think Montesa 315, all plastic tanks, not know for bubbling!! I have a 2000 scorpa sy with the silver tank, 13 years old and not a blemish on it. (i also did some 1970's RM motocross tanks 6 or 7 years ago and they are still ok too) Your paint on the tank has more than likely lifted as the primer or undercoat had not fully 'gone off' or there was a reaction/mismatch in the paint. I have painted more plastic panels and tanks than i can care to remember and the only real trick is simply to do it properly. The ideal world is to use plastic primers and adhesion promotors and the a plasticiser addative into the top coat. But to be honest you will make nearly as good a job with rattle can plastic bumper paint such as the UPOL stuff, as this gives you adhesion promotors and plastic primers designed to keep the paint hanging onto plastic car bumpers!! Certainly if you dont get all the paint off then you will need a good sealer. A good one to use if you do not want to deal with 2K is called "barcoat" and is alcohol based and you can pretty much seal all sorts of edges and problems in with it. As above poster says, nitromors should be fine just dont leave it on for too long. Never needed to drop or change or do owt with the fuel in the tanks, there is still fuel in the scorpa tank and i dont think it has moved for 5 years or so. (the carb is full of fuel jelly mind) Get stuck in and good luck Edited May 17, 2013 by marky boy 2 Quote Link to comment Share on other sites More sharing options...
jon0881 Posted May 17, 2013 Author Report Share Posted May 17, 2013 Thanks for all the replies. It's PP plastic on the mudguard so I will try to weld it with a soldering iron. I will get a batch of the nitromors and give it a go Quote Link to comment Share on other sites More sharing options...
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