Guys, I've managed to get some alloys for the Sportster build - some original BMW fittment BBS cross spokes. They're a bit ratty looking at the moment, but they're going to get a visit to Lap-Tab for a strip and powdercoat. The problem is, the centre caps that cover the wheel nuts is a metal / plastic sub assembly. The metal shouldn't be an issue - that'll get powder coated the same colour as the wheel - but the cental plastic hexagonal 'nut' won't take a powder coat finish... So I need to know how you go about painting ABS plastics. Is it just like painting metals? Rub down, clean, prime and paint? If so, what sort of primer? Let me know. Ta, GOO
Exactly as you said...you can get specific primers for plastics as well. Then just use celly car paint/lacquer.
Fair enough... I've done some googling and apparently it's called 'Adhesion Promoter'. Anyone know where I can get hold of it? Frosts don't seem to have it. Would halfrauds stock it?
I assume this would do the trick: http://cgi.ebay.co.uk/PLASTIC-PRIME...ryZ43117QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
There are some specialised paints for use on plastics, I believe a company called Kent do them, if not Wurth definitley do, we use it all the time at work when we're doing custom installations
That stuff you linked should be fine goo, but you could get the centres sandblasted at the same time as the wheels are sand/bead/shotblasted to save yourself some effort, then clean, prime, paint and laquer.
Next Question... Guys, I need some ideas on how to get the exisiting paint off the plastic hexagonal wheel nut on my BBS wheels, ready for repainting - without damaging the plastic. I've tried using some wet and dry to take it off, but that's taking forever - and it doesn't get into all the nooks and cranies. I've googled it a bit, and some people have been using brake fluid to strip paint from plastic... Does anyone have an experience of doing this? Any help would be appreciated!
I thought I'd give the brake fluid route a go, as I had an old tin of the stuff. What'd you know... It works a treat!
FUDGE FUDGE FUDGE FUDGE BLOODY FUDGE!!!! You may have noticed I'm not happy. I've been painting the plastic wheel nut / bosses - doing everything as you're supposed to. Everything was clean, dry & oil free. Plastic primer went on like a dream (2 coats). Quick going over with some 600 grit 24 hours later, and on went 2 coats of Black cellulose paint. Here we are another 24 hours later, and they look the biz - glossy & shiny and looking fab. But of course, there's a final step - clear coat. So I do as they say in the instructions - give the colour a light going over with some 1200 grit to knock back any bumps, dust it off and clean. Done - looks matt now - but still all black. Then the first coat of clear. Goes on ok, I think. But then I realise that on one of them the paint is sagging big time - I mean, the clear coat is litteraly pulling the paint away from the plastic in a big clear coat / disolving paint run. Obviously that was my fault - a little heavy handed when spraying. So curse curse curse, into some POR15 thinner, and strip it all back down to bare plastic. That one has now been cleaned and re-primed ready for more paint. I go back to the ones I thought where Ok - But it seems that even these are taking paint away in certain areas - No runs, but I can see light patches on raised areas, that aren't due to reflected light. At first I thought it might have been the clearcoat, as it is a bit opaque when it goes on - but even after 20 mins it's still there. So - It looks like I'm going to have to start all over again. Unless it's OK to rough up the clear I laid down tonight once it's dry and then spray over with black again? Is this a big no no? I'm beginning to wonder if the best plan of action is just to get a body shop to do 'em...
If you paint over whats on there, the worst that happens is that you have to take it all off anyway. I think the problem is that you allowed the paint time to dry, but not time to cure. Leave it a week between the black coat and the clear coat.
Well - that didn't work. Looks like they all need to be taken back to the plastic and painted properly (read: By someone else who, unlike GOO, knows what they're doing) I rubbed back the clearcoat, and sprayed some more colour on top. It looks as if it's 'bubbled' and run again. There's something really weired going on - everything's clean & grease free, so obviously Paint -> CC isn't a good idea. If that wasn't bad enough, I fudged the re-primed one - it looked fine when I did it - 15 mins later for the 2nd coat and it's got a large run down one flat and what looks like botches on the top where there's been some grease or oil contamination... Which is weired, as it's only been handled with gloves on, and it's been cleaned with celly cleaner and air dusted off. I did (IMHO) a good job on the rocker cover which was spray painted - why can't I get my act together on the hex's? The worst thing about it all is these are small parts of the larger project - yet it's got me so down-in-the-mouth and demoralised. I can't explain it. It's not as if it can't be fixed. I just guess that everything else on the car has gone relatively smoothly so far. The engine looks fab & should be great when running again and all of the other mechanical bits are in the same sort of state. Not even when I fudged the crank on the engine did I feel as ****** as I do now, all over 5 bits of badly painted plastic. Bah. I give up* *On painting the hex's. Not the car.
That's what it says to do on the tin. That's between like coats, mind - not primer / colour / clearcoat. In that case the instructions on the cans say 24hrs.
If you're prepared to give one another go, prepare it as you did before, soak it in isopropyl or similar for a few hours, leave it a day to dry out, apply a coat of primer, leave it a day, another coat of primer, leave it a day, etc.. give it a few days after the colour coats then do the clear laquer. Make your coats really really light aswell, so much so that you might not get 100% coverage per coat.
Third time lucky? Perhaps. We'll have to wait and see. I stripped off all the old ****** paint last night, and the wheel bosses have been sat in a bucket of soapy water over night to get rid of the brake fluid I used as a stripping agent. I'll give them a thorough clean, rince and going over with the fine grit wet and dry again tonight, ready for some primer tomorrow.
