andy couchman Posted August 6, 2012 Share Posted August 6, 2012 My nice Caterham anthracite wheels need stripping as the powder coating is lifing in places ☹️ Local guy has tried sandblasting but it takes forever. What's the best way to strip the wheels? Chemical? If so, what and from where? Planning to paint the wheels next, not least because that's repairable for when the Toyos are squeezed back on... Thanks. Andy Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted August 6, 2012 Member Share Posted August 6, 2012 Google suggests Permatex Gasket Remover. Jonathan Link to comment Share on other sites More sharing options...
Ian B Posted August 6, 2012 Share Posted August 6, 2012 Quoting andy couchman: My nice Caterham anthracite wheels need stripping as the powder coating is lifing in places ☹️ Sorry not much help, but I've heard people say "TADTS" 😔 Link to comment Share on other sites More sharing options...
richy Posted August 6, 2012 Share Posted August 6, 2012 Depends on the grade of grit he uses, and the pressure. Link to comment Share on other sites More sharing options...
DaveMorris Posted August 6, 2012 Share Posted August 6, 2012 I've got some rims in the garage - and the rate at which the powdercoating is coming off I reckon that by March next year they'll be ready for re-coating without any stripping required ☹️ Link to comment Share on other sites More sharing options...
Pendennis Posted August 6, 2012 Share Posted August 6, 2012 Friend of mine who does all my powder coating, says you can just re powder coat over the old stuff as long as you rub down the area's where the paint has cracked making it smooth Personally not tried it but they do it all the time, must know what they are doing Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted August 6, 2012 Share Posted August 6, 2012 You wouldn't want to do that, as what may appear to be sound may subsequently fall off - with your new coating. They do appear to be self-stripping wheels ! Link to comment Share on other sites More sharing options...
Pendennis Posted August 6, 2012 Share Posted August 6, 2012 If as you say Ian the existing is no good, it just falls off as you rub it then I agree with you. But if the existing paint is bonded to the wheel and rubbed down allowing the new powder coat to stick, there will not be a problem (apparently). I am not suggesting powder coating directly on top of poor paint The new powder coat needs a base to stick to, one that doesn't fall apart whilst in the oven Edited by - Pendennis on 6 Aug 2012 22:13:44 Link to comment Share on other sites More sharing options...
Stationary M25 Traveller Posted August 6, 2012 Share Posted August 6, 2012 We get components powdercoated at work. The powder is electrostatically applied and then oven baked. I assume you need a clean metal surface with the electrostatic charge to attract the new powder, therefore it has to be clean metal. Also, as the powder coating is oven baked, any old powdercoating left on there would possibly react differently under heating. All sounds wrong to me. I don't profess to be an expert in metal coating, but the above is my understanding of the process we use on steel components. Link to comment Share on other sites More sharing options...
Pendennis Posted August 6, 2012 Share Posted August 6, 2012 I am also not an expert but I think that is not correct, because I have had many alloy components re powder coated over each other, in fact did it two weeks ago I am pretty sure you cannot powder coat over cellouse or primer. Obvioulsy bare metal is ideal as it takes any imperfections away 😶🌫️ Link to comment Share on other sites More sharing options...
The Pikey Posted August 6, 2012 Share Posted August 6, 2012 You can powdercoat over existing powdercoat as long as it's fixed firmly. Ian is right in that the powder is charged so it sticks to the metal so if there is existing powder coat the new powder will struggle to stick to it. So what they do, is heat the item up and shoot the powder while it's hot, it sticks because it melts when it hits. However it's a crap botch job and the results are never perfect. IMO the proper way is to chemically strip or blast the existing off with the correct grit/pressure and then put an etch primer on it first, bung it in the oven just to get it flowing. Then pull it out and shoot your colour on and bung it back it at 180-200 deg or 10 mins. perfect results every time :smoking: Jason Edited by - Jason Fletcher on 6 Aug 2012 23:04:01 Link to comment Share on other sites More sharing options...
Pendennis Posted August 6, 2012 Share Posted August 6, 2012 Why don't they stove enamel the wheels, much harder wearing and in my opinion a far better finish Link to comment Share on other sites More sharing options...
weeman Posted August 6, 2012 Share Posted August 6, 2012 Planning to paint the wheels next, not least because that's repairable for when the Toyos are squeezed back on... I'm no expert either, but I think Andy's intention is to paint the wheels not powder coat them. Link to comment Share on other sites More sharing options...
acw Posted August 7, 2012 Share Posted August 7, 2012 There have been some good reports on here of City Powder Coaters doing a good job. It's £12 per wheel for a chemical strip and shot blast only. Edited by - acw on 7 Aug 2012 07:01:47 Link to comment Share on other sites More sharing options...
David Brown Posted August 7, 2012 Share Posted August 7, 2012 Powder can be overcoated but not an infinite number of times, if you turn down the static charge. Pre-heating before repainting works if there is too much powder already on but can result in an uneven coat and a huge build up of powder if not done very carefully. All has to be done on well sanded previous coat that must be adhering properly. Corrosion pitholes will not cover well and need to be sandblasted or dressed out. Original wheel will have a conversion coating to help corrosion resistance and promote adhesion but this can't be done on resprays unless paint all removed. In this case bare areas should be etch primed before recoating. Stove Enamel isn't nearly as good as powder although vitreous enamel may be as good but may chip from stones, kebs, etc. Link to comment Share on other sites More sharing options...
andy couchman Posted August 8, 2012 Author Share Posted August 8, 2012 Taking the wheels in on Friday. Will probably go for new powder coating given the cost. Anyone know where/what to use to put yellow rims on IYSWIM (as per the F1 cars)? Thanks for all the advice guys. Andy Link to comment Share on other sites More sharing options...
acw Posted August 8, 2012 Share Posted August 8, 2012 It's done with tape, you can get it on ebay and no doubt loads of other places. Link to comment Share on other sites More sharing options...
EFA Posted August 24, 2012 Share Posted August 24, 2012 There have been some reports on here of City Powder Coaters here Link to comment Share on other sites More sharing options...
Pete-B Posted August 24, 2012 Share Posted August 24, 2012 I am an expert having spent over 25 years in the painting, metal spraying and shotblasting industry, the last 8 years as workshop manager. A lot of our work was for the MOD so standards were very high with regular checks and inspections. Under no condition would we powdercoat over existing paint work one simple reason being, the paint that is now lifting would have looked OK at some point, so the same thing could happen to rest in which case the new coting will come away with it. The way forward by us would have been to shotblast with medium grit ( bearing in mind we had huge pressure on tap) so I would have expected one of the lads to strip four wheels completly in less than 20 mins. The important thing then was no one should touch those wheels with their bare hands because that would contaminate the surface. They would then go to the paintshop to be sprayed and baked to the customers colour spec. Also if there was any lengthy time gap between shotblasting and painting the wheels would have been kept in a warm and dry area as any damp on the surface will cause future problems. We also guaranteed our work and always told our customers, in very unlikely event of a failure please come back and talk to us and we will resolve it. Our motto was no business can survive and prosper with customers spouting to all and sundry how bad you are. Link to comment Share on other sites More sharing options...
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