MGB & GT Forum

I would appreciate any advise from some of you that have gone through the procedure that I am doing now.

On my 67 MGB, I am stripping the whole outside of the car to bare metal, prime the whole outside to save prep expense
when I send it to the paint shop. I have already finished the trunk lid and hood.

Here is the procedure that I have done.
1. Strip all paint, primer and body filler to bare metal.
2. Sanded with 400 grit wet sandpaper and rinsed off
3. Wiped down with mineral spirits.
4. Sprayed with Rustoleum (aerosol) Self Etching Primer (2 coats)

On the underside of the trunk lid, trunk compartment and underside of hood, I have painted with 2 coats
of Dupont single stage urethane in Dark British Racing Green. I will also paint the interior, door jams and
inner wheel wells.

The primed areas and painted areas are not as smooth as I would like.

I would appreciate any guidance on this as I don't want to incur additional expense because I screwed up on the prep.

Thanks for your time.
Pat

Hey Pat,how are you. Knee deep in paint,I guess. Best to just keep wet sanding till you get desired results. You may have to use some spot filler putty for build up. Then just prime again. Wicklowwanderer on the site does some nice painting etc. Maybe he will come along with more info?

A 'state of the art' approach when starting from bare metal would be:

1. Prime with epoxy primer. This totally waterproofs the metal
2. Perform any obvious filler work to address dings and dents. Your note said you stripped off all filler - that filler was likely there for a reason, so in removing it you exposed flaws in the metal that the filler addressed. Some pros do filler before epoxy, some do it after, so steps 1-2 could be flipped. Sanding level at this stage could be 80 grit or higher, depending on what your primer/surface calls for.
3. Shoot 3 coats of a urethane primer/surface
4. Block sand the car - start at 200, go to 400.
5. Wet sand the blocked finish to 600
6. Spray your color coats
7. Color sand and buff/polish the finish

Follow those steps and you should have a mirror finish as a result.

You mentioned cleaning with mineral spirits. That's not what you want to use - you want a wax/grease remover, which is generally naptha-based and available at any auto paint store.

I cover the process I used to paint my car in my journal, which generally follows the above steps.

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Documenting my project in my journal at https://www.mgexp.com/home#journal



Edited 2 time(s). Last edit at 2015-05-21 02:47 PM by Steve Lyle.

X2 on Steve's advice ( if budget and equipment availability allow)

400 is good over primer , but finer than you need or want on bare metal. 180 grit would be better.

Hard to say without pictures if your unhappiness with the areas you've painted is from prep or application, but now that it's painted you'll most likely get better results than the first attempt just by sanding it well with 600 grit and putting another couple of coats on, paying attention as you spray to make sure it's not going on too dry or with too much orange peel.

I would not use a spray bomb as my base to work off of. I would only use wax and grease remover on unsanded paint before the process starts. Bare metal gets metal prep before primer. Most pro shops will not guarantee anything if you started the process. Their finish work is only as good as your prep work. I think I would talk to the shop that will finish the job an ask for their recommendations on products to use. I hope it turns out nice!
Bob

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Bob
63 MGB, 67 MGBGT, 77MGB , 70 TR6 PI CP car LHD. 81 TR8

There are four right ways to do this.
Personally I would like to see the car sanded to bare metal with 180 and epoxy primed.
And then get a gallon of filler primer applied.
Then hopefully the painter will take an interest in the project and show you how to block sand it.

don't mean to hijack the thread but how would you prep a Parrish Plastics fiberglass hardtop for painting? It doesn't have much of anything paintwise left on it and has a couple of light scratches on it. What filler to use on fiberglass and what primer? I want to have it painted gloss black by a shop when ready. I'd try it myself but even though it's going on a cheaper driver quality car I'm scared I'll screw it up. Maybe I'll run it over to Robert's house and he'll knock it out for me! Just kidding, he has helped me so much I can never repay him. Sure am glad I live near him!

Thanks,
Jim

There's nothing special about filler or primer over fiberglass - use the same materials you'd use over metal. Filler is actually based on polyester resin - the same stuff used in fiberglass, so it's perfectly compatible. And any primer will stick to fiberglass, just follow the primer's tech sheet for sanding prep, like you would for any surface.

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Documenting my project in my journal at https://www.mgexp.com/home#journal

I am no painting expert but I just watched my car get painted a few weeks ago by a guy who is an expert. It is quite a project and you have gotten some great advice here. My painter sanded the whole car then used some thin coats filler in some areas. He then primed the car, sanded the whole thing again and then primed the car again. He then wet sanded the primer smooth. He sprayed a sealer coat then three coats of black. He then wet sanded out any imperfections, like the beard hair that fell on the fresh paint when his ventilator strap slipped and his mask almost fell off. After that is was three coats of clear. He wet sanded the whole car again with 3000 grit and then with 5000 grit. It was awful watching him sand that fresh shiny black paint, well clear paint, and turn it into a dull flat finish. It was very smooth but very flat. When he started polishing and buffing the car really started to shine, and he did that twice. He then hand glazed the whole car. It was a lot of work, and the cost reflects that. I have always wanted a great paint job and now I have one. Now if he would just hurry with the final assembly I will finally get my 1980 B back, good weather is passing by.

I admire you taking on such a big project and I wish you all the best, Greg

...couple of notes, don't use rustoleum anything, it most likely is a cheap petrol based crap that will lift if you use any urethanes, second never use mineral spirits, that is tantamount to putting oil on your car..fish eye city just waiting to happen.third I would use a metal etch acid based primer as my first coat over bare metal, it is non sandable.Fourth follow these other guys that know what they are talking about steps, and ALWAYS follow your paint jobbers tech sheet, if you don't and trouble happens they will just say phfft to you..

btw as a suggestion, avoid base clear and use a straight single stage...IMHO..

unless you have all the safety gear and have done it before, I agree with this.

" couple of notes, don't use rustoleum anything,"
Wyatt

X100
you are sending it off to paint all you are doing is a lot of wasted work that will in the long run cost you more money at the painter.
Concentrate on removing all the doors,hood,trunk,fittings etc.
And getting the body as smooth and ripple free as possible
use a product like pickleX to protect the bare metal after you remove the rustoleum and let the painter the finish the rest

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...you guys turn wrenches....I sprayed 7 trillion gallons of paint,..... but a lot has changed in chemistry in the last several years so I am a bit out dated,but most is good but not all is for the better,....Sophia Lorens beauty ain't just avatar...it's a passion.

btw HL Miller is the one who is up to date.....

Finally,that explains it all,Wyatt. It's them darn paint fumes that's got to your mind!

If you catalyze your single stage, the same rules of protection apply to both SS and BC/CC.