What to do after sandblasting?

What paint? Do a search. There are plenty of threads here that can tell you the pros and cons of all the available paints. You can go as simple as rustoleum rusty metal primer and a satin/semi-gloss top coat to the POR15 type industrial paints....don't think too long...now that it's blasted get it covered before it rusts again.

A freshly sandblasted surface should be clean enough to just blow off with compressed air. But if it's not, I would suggest a wax and grease remover solvent wiped on with one cloth and wiped off with another clean cloth.

 

1. etch primer on all bare metal surfaces

 

2. primer surfacer (also called sandable primer) on all 'visible' surfaces - body exterior, dash, wheelhouses, etc. Anywhere you want the paint to look it's best.

NOTE: PRIMER SURFACER WILL NOT PROTECT THE METAL FROM MOISTURE. It does not seal moisture out.

 

3. wet sanding / block sanding. If you want a quality finish, this is a crucial step. I won't go into how to do it, but this is the step that separates MAACO from trophy finishes. you may find yourself going from this step back to spraying primer surfacer several times, depending on how smooth you want your final paint job to be. Any blemishes you see in the surface during wet sanding WILL show through your final clear coat or enamel. The old pros will tell you that your paint job will never look better than the wet sanded primer surfacer.

 

4. Primer sealer. Spray any parts that WON'T get primer surfacer as soon as possible after the etch coat. This assures your best protection against rust and paint delamination. Spray primer sealer on the parts you wet sanded after they have completely dried. Don't trap moisture under the sealer - it guarantees rust.

 

5 Color Coat. If you're using a base/clear system, read and understand the instructions. If you have ANY questions, call your paint rep. Follow the instructions exactly. If you're using an enamel or lacquer, this is your semi-final step - skip to step 7.

 

6 Clear coat. You'll only shoot a clear coat if you're using a base/clear system. Again, follow the instructions to the 'T'. Be aware that the reducer you need to thin the clear will vary with the air temperature when you shoot. Using the wrong reducer can end in disaster, sending you all the way back to wet sanding or stripping, depending on how bad it turns out..

 

7. Color sanding. For single-stage paints like lacquers and enamels, you'll likely shoot several coats of color. For base/clear systems, this applies to the clear coat. Don't worry too much about bugs and drips. It happens to the pros too. Read up on color sanding and 'nibbing' the paint. In this step, you'll sand out runs, bugs, orange peel, and other blemishes with 2000-3000 grit wet sanding. Go very light on the sanding. This stuff is only a few thousandths of an inch thick. If you find you sanded through the color removing the blemish, repaint the entire panel (for small parts) or learn how to 'feather' the paint on larger ones. After color sanding, you can keep applying coats until you're happy with the results. If you're happy with the results and need to remove color sanding scratches, it's time to:

 

8. Cut and Buff.  Talk to your paint rep about the proper tools and buffing compounds to bring out the final shine in your new paint. Remember that the paint usually has to cure before buffing, or you'll melt your shiny new paint job.

 

NOTE:

As otto noted, wipe down the surfaces with a surface-prep spray every time you get ready to spray a coat of anything. The only exception should be between layers of clear coats - just follow the manufacturers recommendations.

 

WARNING:

Always wear a respirator when mixing and spraying paint. This stuff is dangerous. Same goes for dry sanding - wear a dust mask. You don't need to be inhaling the polyester dust, rust particles, and silica dust from sandblasting. 

 

Did I go over the top?