Painting tips anyone?

[RickB]

Painting a piece for my Midget this weekend and it was going very nicely right up to the last coat of clear.
Almost the whole things looks absolutely great except for one run about 2" long on the left side of the piece.
This has several coats of primer, several coats of color and three coats of clear.

The directions say it is dry in 1 hour and can be handled in 3 hours, so I think I'd be safe trying to sand it out after a day.

I am going to try and sand the run down then buff it out, anyone have suggestions about doing that? Thought I'd start with some 320 grit wet/dry keeping it wet by using a sponge as the backing on my sandpaper. This has worked ok for me in the past.
Thinking about it though, maybe starting with finer grit paper would be wise.

I know if I sand through the clear into the color I'll be waiting a week and painting it again.

 

[dklawson]

You are on the right track but I would not start with 320 grit. Try 600 grit first. If the run is on a relatively flat surface, wrap your wet/dry on something firm and flat so you can selectively hit the high-spot. When the high-spot is down to just about flush, switch to 1000 grit, then 1500 or 2000 grit. Follow that up with a high quality fine polishing compound and finally a glazing compound. Be sure between each change of abrasive and/or compound that you thoroughly wash the surface and don't use the same polishing bonnet/pad for the rubbing compound as you do for the glazing compound.

 

[Trevor Jessie]

You can also remove the thickest part of the run with a razor blade. Use a methodical drag type scrape motion. DO NOT try to slice it off with the blade.

 

[RickB]

Thanks, I'll start out with 600.
It's on a rounded surface, there's a great chance I'll screw it up and end up repainting next weekend but I suppose there's not much to lose in trying to buff it out.
Scraping it sounds like a good idea, I'll have to be careful not to scratch the surrounding area - I'll blue tape the sides and leave the run exposed.

 

[PC]

If the run is thick it may take much longer to harden than the rest of the surface. If it seems gummy when you try to work it, it hasn’t hardened enough.

For sanding out a high spot like a run you want to concentrate the abrasion on the high point without abrading the surrounding area. So it’s better to have a stiffer backing that touches only the top without conforming and hitting the lower areas.

You can use a foam block if it’s a <span style="font-style: italic">very</span> stiff one. But I still prefer something more substantial, like a short section of wood dowel.

Meguiar’s makes sanding blocks from a bulk abrasive material specifically for the job. They work great.

I don’t think I’d ever want to sand clear with anything rougher than 1000 grit.

Using a sponge and bucket to wet the surface tends to contaminate the work area with swarf. I much prefer a spray bottle. Add a few drops of liquid soap the water for lubrication.



pc

 

[mightymidget]

Patience grasshopper and job done quickly

 

[RickB]

Ok, thanks guys.
I'll take it slow and careful and maybe I'll get it done.

 

[RickB]

I ended up wet sanding the whole thing then a few more coats of filler primer then wet sanding then a few coats of color and a couple coats of clear.
It turned out great, but glossy black is a cruel mistress of a finish. It's very hard to get right.

Here's a pic, I am letting it cure indoors for a week then will apply wax and then finally install on the car.

 

[mightymidget]

you shouldn't wax until solvents are stable. 30 days should be sufficient

 

[RickB]

Really?
I didn't realize it took that long.
Is this different with different paints? This one has directions that say if you wait longer than one hour between coats then you must wait 7 days for the paint to stabilize. I thought that meant the paint was stable after 7 days.

 

[Trevor Jessie]

I just means that after 7 days the solvent in the fresh paint will not break the binders in the previous coat. I'd say two weeks would be sufficient given the number of edges ... unless you have a real heavy build up.

Sure looks better than my black grill.

 

[RickB]

This poor thing had a lot of bumps and bruises, it would be a good core for re-chroming in the future but for right now it will serve as the bow piece of the great ship froggy-midget.

 

[rulle7]

Have you tried the emery boards from the beauty/nail section in most shops?
The ones to get are the ones with two different grades on each side ( total of four grades ). The core is usually a stiff Styrofoam that bends just a bit if needed.
Anyway, cut that emery board in half so you have two pieces with a different grade on each side, and you have the perfect size 'sanding block/paper'
to tackle fiddly paint runs. The coarsest side is usually a bit too coarse, but the other three grades are just right.
Costs only a dollar or so : )

 

[RickB]

Had it sitting inside the house all week, planned on putting it on the car today.
Picked it up and there was a chip on one end, primer showing through.
I was PO'd so I sanded a little and then just sprayed on a couple more black layers and a couple more clear and let it dry and put it on the car.