924Board.org

[RVA]

My car needs to be painted, the color has faded. I have contacted some body shops in my area as i wont be doing any painting myself, just the sanding. The body shop is okay with me sanding.

However i have never prepped a car for paint.

Currently the paint is pretty bad, its faded everywhere and on some spots there are some cracks in the paint or the paint is coming off completly. The car has been painted already in the past by the previous owner. Has no clear coat, just single stage. Looks like some bodywork with filler has already been done quite well.

There is only a few dents on the car which is nice.

Where do i even start? how far do i sand? i hope i dont have to sand all the way to bare metal.

I am sorry if these are kind of stupid questions, first time doing any bodywork.

[Fifty50Plus]

A paint job is only as good as the work beneath it. As your painter what he recommends that you do. Since it has been painted before, I suspect that all of that would need to be sanded off and a close inspection of any bondo work and potential rust areas.
_________________
1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car

[peterld]

Don't sand!
Paint stripper is your answer.
Paint stripper is very messy, but also very effective, particularly on a galvanised body. As it has been painted before, there are probably bondo repairs underneath. You need to get under that.....if you sand you will probably breech the galvanising underneath.
Go to an automotive paint supplier for info and materials. Those strippers used in the aero industry are very potent and effective. What you would buy at the hardware store will need many, many coats.
Remove all extraneous fittings such as mirrors, bumpers, lights, etc. Start at the top, small sections at a time, using a strong plastic scraper (so you don't damage the panel underneath). Lots of old newspapers are necessary to wipe/scrape the residue onto.
Neutralise the residue on the panels with water and a stiff brush.
Once you have reached the galvanised panel, or at least the factory primer, it's time for your body shop to repair and paint panels.
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80/81 932/8 ROW

[Cedric]

[peterld]

Check aero industry......NO sanding on planes.....ever! Paint strip or panel replacement only.
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80/81 932/8 ROW

[Riggard]

There's a few ways to do it, first and foremost you have to decide if you want/need to go back to bare metal. This all depends on how much trust you have in the layers underneath. If it's the factory paint and hasn't been touched much... I'd not go back to bare metal. IF there's lots of bondo and other botch jobs done to it over the years... yeah, you might consider it.
(I guess you could also make this decision per panel)

I myself went with the route of keeping the paint on. But if you want to get it totally off... go with paint stripper, for the aforementioned reason of not damaging the galvanised body.

As I have no experience in stripping the car, I'll explain how I did mine;

The sequence of sanding I used was roughly as follows
- First do bodywork; hammer out the dents and fix the last couple of mm with bondo. Typically you'll be sanding with K80. In this stage. (This stage really depends on how good the body is, doesn't have to be done for each panel, just where you need repairs.)
- IF the above stage is finished, spray the car in epoxy filler/primer. I used mipa stuff. (if the car is really good, you could also do this after the next step)
- Spray guide paint on the epoxy filler/primer and Block the whole car with K220 (it's important to get long straight sanding blocks, I purchased dura-blocks, they're a great budget option).
- Once the previous stage is done (and assuming you didn't sand through the primer!) re-do the blocking with K400
- Now you're ready to paint.

It's quite a bit of work to do it properly, but worth the effort.
I do have to point out that I'm not an expert per se, I just googled it all and this is the approach I took for my 924, which is also the first ever car I tackled. I also did the painting myself tho. This was the end result:


You can see all the progress here, perhaps it helps you a bit. https://community.924forum.nl/showthread.php?t=44526

[RVA]

thanks for all the replies, really helpfull!

[Mclaren924]

What are opinions and experiences with bead and sand blasting these cars down to bare metal?
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1980 931 "Salt" Bucket wannabe racer (not started)
1979 924 "Pepper" Restoration (almost done)
1980 924 "Donnie" (Parts car)-DEAD
1977 924 Slicktop "Pennie" Bucket turned Silver Spoon

[peterld]

Only by experienced operators......soda blasting yes, sand blasting never.....unless you want to add gallons of bog to the panels to hide the gouges and dents that will be inevitable. The panels on our cars are thin, not 1950's good American iron.
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80/81 932/8 ROW