A Powder Coating Query

Anonymous · Post by **Anonymous** » Tue May 24, 05 1:21 pm

I have the powder coating bug at the moment.

I want to powder coat my brake servo, and power steering pump. When I spoke to the guy who does it, he advised that I be careful because the heat applied during the curing process might damage the seals etc. inside both parts.

Does anyone have any opinions or advice on this? I am not sure if either can have the parts that could be damaged, removed if that is what has to be done. I dont really want to paint them, as satin black powder coating just looks sooo nice when its done properly, and its a more resilient finish.

Thanks chaps

Anonymous · Post by **Anonymous** » Tue May 24, 05 1:38 pm

your guy is right. Typical powder coating bake temperatures are in the order of 180-200c for 15 to 20 minutes metal temp for polyester or epoxy/polyester hybrid powders. Most rubber seals will "age" under these conditions. If your guy can locate some low bake powders (typically epoxy type) which bake around <130c, then it will reduce the ageing of the rubbers. Getting the nice satin finish you expect, is not so easy with lower bake powders, so you may be disappointed with the finish.

If you can remove all the seals, rubbers and gaskets from the part and present these to your coater he won`t have a problem. I`m not sure either, what parts are "inside" that need removal.

Anonymous · Post by **Anonymous** » Tue May 24, 05 1:42 pm

Merci Neil, was hoping you would see this.

Well I am not too sure what parts can be damaged in the servo or the pump. Enven still, I would have no idea how to remove them if they are indeed removeable.

As you might have guessed, I am after the high temp finish.

Hopefully this thread will provoke some more info.

Thanks for the advice.

latil · Post by **latil** » Tue May 24, 05 2:13 pm

Have you ever tried to reassemble parts that have been powder coated?It gets into threads etc and is near impossible to remove. I've had good results with Plasticote aerosol paint so long as bits are properly prepped.

Anonymous · Post by **Anonymous** » Tue May 24, 05 2:25 pm

a good coater will (or should) mask all areas inc. threads by plugging them with silicone plugs prior to coating. It`s your responsibility to tell him what should and should not be painted. Generally I don`t trust anybody to do what they are told these days, even if you have been explicit in your demands - sign of the times

Anonymous · Post by **Anonymous** » Tue May 24, 05 2:30 pm

Well I have to say, I went to Foremost Coatings in East GRinstead at Wills request. Dropped off loads of brackets and such like, and the guy who runs the place realised I was new to this service and spent about half an hour explaining the process, how it works, how it is done, what to be careful of, how to mask. We went through every piece and I explained what had to be protected and what didnt, he asked queries and I explained what I wanted the parts for. He showed me how he masks up, blanks off, and how to remove overspray. I felt really comfortable and am confident I will get a good, professional job.

Obviously there are exfeptions but this is a small family business so their rep is everything.

Anonymous · Post by **Anonymous** » Tue May 24, 05 2:37 pm

good for you, finding someone who gives a damn

so what type of finish are you going for - did he tell you what powder he is using. Keep us up to speed with the job. The parts I have coated are standing up well so far.

Anonymous · Post by **Anonymous** » Tue May 24, 05 3:11 pm

Strangely enough Neil, I cant remember the type of coating he is using on my parts.

All I know is he is shot blasting them with glass beads because they are thick strong brakets. He explained that the shot used varied greatly depending on the type of metal being blasted. He also explained about choosing the correct pressure to blast at as this can cause metal deformation. He is coing to zinc coat the parts first then use satin black powder coat and bake to 200 degrees.

I asked about getting my back axle done, and what prep was required bearing in mind I wasnt keen on stripping it. He said mask it so that if it was submerged in water, water wouldnt get in. Sounds fair enough.

He had done loads of classic car parts and bike frames which were all hanging up. The finish was great. Perfectly smooth with a lovely lustre to it. They looked like they had been painted to a show type finish. His masking was meticulous too. So for a crank pulley, water pump pulley, alternator brackets, power steering pump brackets, engine mounts, 6-pack air cleaner base and a battery tray (which will be dine in white) ?40+vat. Not bad at all.

Anonymous · Post by **Anonymous** » Tue May 24, 05 4:41 pm

can`t fault his technique. Coating with zinc primer powder will give the corrosion protection, although I think this is overkill for the application, although it can help with preventing outgassing on application as it forms a "skin"on the surface . For the price, it`s brill

I`ll put up some pics later of the parts I`ve done in satin finish (fan, pulley) if I think on. I`ve done battery tray and trans pan in black fine texture. I did these sprayed onto preheated metal, no primer.

latil · Post by **latil** » Tue May 24, 05 5:45 pm

He's the man to use , why I say about threads etc is that he did some cycle frames for us and the coating crept past the masking into the bearing threads and where the press in cups go for the steering head. Took a sharp knife and about an hour each to clean out. He did a vintage truck steering wheel for me and nothing went into the hole for the column. You will not find anything wrong with his work ,it is top notch and nicely priced. The bike frames may have been a one-off prob.