mk1-forum.net

Might be a daft question but is there a better way of painting all of the components off my cars when they have been blasted and had a basic coat of primer. Talking all subframe components steering columns pedal boxes etc. I have had them sprayed in 2 pack before now but invariably bits get missed due to the volume of bits and the different angles you have to hit them . Is it daft to think I could have them all dipped? If so who would do such a thing? Cheers. Mark

When I paint anything that was originally gloss (or satin) black I never use any undercoat, just like the originals. My preference is Powdercoat where it will get a lot of aggro, but Halfords gloss black on interior components.

I agree with Mark. I always have all black components powdercoated. Nice even durable finish with no hassle.

The thing I have found with powder coating in the past is every time you wind a screw in or tighten a bolt the plastic coating cracks or splits. Or have I just had a bad experience????

Powder coating is dependent on surface prep/cleaning just like liquid paint. Chipping/fracturing can be from poor prep and/or powder coating that is not fully cured (baked).

Totally agree. Nothing better in my opinion. I have done numerous restorations over the last 20+ years and have never had any problems with powder coating.

To add to Mowog's comments, I have also seen many powdercoat finishes fail when applied to heavily (too thick). The thick coating simply cannot tolerate the stress under a bolt head.

Powdercoat is a nice coating and being electrically charged during application it certainly can get into crevices.

I agree with Doug, the main reason that PC fails is that it has been applied too thick. It should rarely be thicker than a normal coat of paint and as long as the item is keyed / blasted well it should not chip or flake. If it has been applied too thick I have in the past sanded / ground the finish off immediately around the screw head to stop it all going wrong.

As I said above though, I am not a great fan of PC for interior stuff, I would far rather go with a simple gloss black aerosol.

Gents, thanks for your advise and opinions. Looks like I will try the powder coat route then. What points do I need to stress to my powder coater to ensure a durable finish ie how thick/thin , how many layers(????) what primer or base should be used etc etc. As is probably evident I have no knowledge if this process but if I do it I want it done properly. Thanks folks. Mark

No undercoat / basecoat.

Get the item blasted to give a good key, One single layer of colour, NOT TOO THICK!

Explain that you will be bolting or screwing thing to / through it & that if its too thick it cracks off.

mine an marks 'man' who does our powder coating does a great job, it almost just looks like a coat of paint.


however, for odd little jobs - I just use the black engine paint that mini spares sell, it dries glossy and hard and looks pretty good

I'm a big fan of powdercoating and use the same guy as Mark/Rich.

One thing I would say is take some time and prep the parts before you drop them off. I recently had what I thought was a mint dent free, although rusty, rad surround. When it came back from powdercoating there was a slight crease down one side, otherwise it was mint. If I'd given the part a quick buzz over before I dropped it off I'd have noticed it and knocked it out.

You are sort of in the hands of the guys doing the powdercoating when it comes to dents etc. I had some tyres fitted at a local garage, they've had a guy in earlier that week with a set of freshly powdercoated BMW alloys, the firm doing the powdercoating hadn't even take the balance weights off them, just blasted and coated straight over the top

AndyB72 wrote:
One thing I would say is take some time and prep the parts before you drop them off.

magical trevor was most unimpressed with me when he powder coated a set of radius arms for me, when he put them in the oven, they spewed all the old grease out and covered all the other stuff he was doing - and the insides of his oven

he was not happy

I felt a right idiot!

I felt a right idiot!

At least you didn't have to see him face to face as he told you the sorry tale

I also use powder coat for some parts. I currently have 16 Cooper reverse wheels at the coater. When I pick them up I'll drop off 7 sub frames and another 12 Rover Mini lite knock offs. Front subs offer the most issues. Tony the coater and I have worked out a system for sub frames. He has several solvent dip tanks. I remove the subs, strip bits off and power wash. His guys drip in a paint stripper, then they sand blast ( may be some other material ) followed by a dip in a solvent. They then hang them in the oven ( a huge walk in could do a whole mini shell or two at a time ) and cycle them though. This is followed by another dip tank. The heat helps drive oil from the seams. They then apply a thin coat of a zinc rich primer. This is followed by a thin coat of chassis black once cool they flip and recoat black to insure they did not miss anything. They come back to me wrapped in plastic and ready to store till needed.
As for small bits I have a large glass bead cabinet. I also have a couple of small solvent tanks. One dirty and one cleaner. Surface prep is everything to the end result. Once prepped I spray with a good quality rattle can. I apply one coat, air dry, apply second coat then bake in an oven ( I have a big home type at the shop ) 15 min. at 150 F. and allow to cool after turning off oven. I'm finding the suppliers of rattle can are offering paints with little or very little pigment. Rustolem Hi Performance semi gloss is the best I have come up with. Steve (CTR)

If you are prepping the parts yourself, follow the advice above and pay careful attention to all the details just like you were spray painting. Anything you can observe during cleaning will show up through the top coat. If you plan to sandblast the parts prior to dropping them off with the powdercoater, make sure you thoroughly clean and degrease them before blasting. If you sandblast a surface with oil (or worse yet... silicone) on it, you can drive the contamination into the surface which makes it that much harder to get clean before painting.

Many years ago a co-worker of mine fabricated a part in our shop and took it to our paint guys asking that they apply our standard powdercoat beige finish. He had used Dykem brand red layout fluid on the part to locate some holes he drilled and he did NOT clean and prep the part for our painters. The painters didn't work well with this guy so rather than clean the part for him they painted it as it was. The red Dykem boiled through the powedercoat during baking. The part came out looking like some type of skin disease. Anyway, my point is that just like with spray painting, a lot of your final appearance comes down to the prep work.

EDIT: It appears Steve and I were typing at the same time and my post duplicated part of his. Sorry for that!

I would be interested to know what solvents people use. Long ago when I worked at the Uni I could get acetone, ethanol, methanol, diethyl ether, pet ether, carbon tetrachloride, amyl acetate etc. Now that we are protected from ourselves by OTT Safety legislation all I can find is Methylated spirits which is not too good and is quite expensive. Please advise.

Unfortunately, what is available to us in the U.S. will be different from what you can source in the U.K. Though some materials are becoming more controlled and harder to find, we can still buy solvents like Acetone, MEK, Lacquer thinner, and Toluene (or Xylene) blends at the DIY center. If the part is small enough you can also buy 1-1-1 Trichloroethane (a second generation replacement for the carbon-tet you mentioned) as a spray for cleaning electric motors. It is also a good degrease but prohibitively expensive for large parts. For cost reasons I do most of my heavy grease and oil removal with strong water based caustic cleaners. After that cleaning I will typically follow by wiping with lacquer thinner. If I want to take it further than that I may drench the surface with spray brake cleaner followed by a blast of compressed air. If the part is a body panel that the world is going to take a close look at I will typically wipe the panel down with prep-solvent before priming. I have no idea what chemicals go into prep-solvent.

Thanks, Doug.

Well I took a couple of test bits to a wheel refurb place this week and I am now a complete powder coating convert. Had a backplate done and have hit it with all sorts, wound spring washers on and it really does take some beating. As it was a trial we left the primer (zinc phosphate) on and he didn't heat the steel beforehand yet it still stayed intact. My first outing with powdercoating was clearly a disaster but now there's going to be powder coated everything. Hahahaha. Thanks for your advice folks. Mark