Painting woes

[DGXSER]

Well, it finally warmed up enough for me to paint today. Not my best day ever. Essentially, my first coat was to wet and had a series of lines of runs in it. I continued and put plenty of coats on, only the first one with runs in it. The color is a candy maroon or red, deeper than the Macho Maroon, not quite as dark as the purplish red that was stock on the SG.

So now the question, how long to wait before I sand the runs out, what grit should I start with? Will it need another color coat before I add the clear coat?

Thanks for any advice from the great painters out there. IF I should die and go to he!! I know it will involve painting for me.

[crazy steve]

So now the question, how long to wait before I sand the runs out, what grit should I start with? Will it need another color coat before I add the clear coat?

That depends on what kind of paint you're using. If it's a 2-part, you can sand within a few hours. Lacquer, pretty much the same. Enamel, it will need a longer drying time and that can depend on how thick the paint is. At least a day, up to a week or more.

As far as the paper grit, I'd go with 320 or 400 at the finest and wet sand. Too fine and you don't leave enough 'tooth' for additional paint to grip to and it will chip easily. Do put one more color coat on, then the clear.

[DGXSER]

Thanks Steve! It is a 2 part from Sherwin Williams. I got a new gun at HF, the HVLP type. Never used one before and should have practiced on something first. But got in a hurry and cost myself now. It will probably not be warm enough to paint again for weeks. Oh well, something to do.

Sounds like I can start sanding tomorrow on it, not going to try to start tonight. I do have 320, 400, 600, 1000, and 1500 and 2000. Sounds liek maybe go as far as the 600 but not finer. I will need to get some more paint though.

[crazy steve]

If it's 2-part paint, you may have now missed the 'window' for applying more paint unless you sand it with fairly coarse paper. This stuff works with a 'chemical bond', additional coats have to be applied before the lower coats are fully cured or it won't 'bond' properly. Generally, no more than about 16 hours can go by before you lose this. If it been longer than that, you need to sand with no finer than 400 (320 is a much better choice) so the 'new' paint will stick. You might check with the paint manufacturer to see how long the window for their paint is; there also might be a wait time before you can apply more paint.

If the clear you're applying is 2-part, same thing goes; it must be put on within the 'window' for proper bonding to the color coat...

That's the one issue with 2-part paint; once you start, you have to stay within the cure times until all paint is on. No starting/stopping....

[DGXSER]

Directions state if not cleared in 7 days, to apply another base coat.

[DGXSER]

So, I checked with my SW guy today. They were really great!! Gave me the half pint to repaint with, and the mixing cups needed.

This is their Dimension product. I can sand the color coat, and re-coat base with 2 coats before clearing it. With this base coat, I can wait as long as I need before I reapply base, no maximum time. You do need to clear within 7 days of base application. If you go longer, you need to scuff the base and put another coat or two of base on, then clear.

What they told me was not go any rougher than 600 grit as a finish sand or the base will not fill it. So, you can use 320 to get the roughness out, but you must use at least 600 before you apply the paint, they suggested you could go as high as 1000 and then apply the base coat. I am going with 600. Got it all sanded out and ready for base, but the temps are dropping.

They also stated that with this paint, the SURFACE has to be at least 50 deg F. Air temps below 60 they felt the metal would not be up to 50. SO maybe in a couple weeks I can get back at this.

Thanks for the info Steve, may not match 100% what the mfg says, but it gave me confidence I was not totally screwed.

[tarzan]

Yep, you need to sand with 600 before paint or you will see sand scratches in that color coat. I went through that when I painted my Kingpin. I had to put down silver and then Candy Apple red. The silver krinkled and I had to sand before reapplying. I also had the learning curve with HVLP gun too. I had only used siphon feed before, so didn't realize how much more paint actually makes it to the part. I did use an old tank as a test piece for that.

[T99Ford]

Sorry to hear abou the learning blues man! I don't wish a redo on anyone.

I usually finish sand at 600 grit for plenty of tooth without sanding lines. Finer and you can have more trouble with runs in your initial coat. Also, especially if you are shooting when it's cool, multiply your flash off times between coats--if it's recommended 10 minutes between coats, do 10 for the first, 15-20 for the second, 20-30 for the third etc. Waiting longer rather than shorter wont hurt, other than maybe some dryness in the paint, and it will certainly help with runs. The 'dryness' can always be cor sanded out with 200 grit and buffed, but runs are harder to get rid of!

Also, you can scrape the runs down with a utility razor blade: Pply some masking tape to the outside edges of the blade, leaving about 1/4-1/2" of blade exposed in the middle. Use this to scrape the run down. The tape will keep the blade corners from gouging the are around the run as you scrape. Much faster ban sanding the whole run down, and less likely to sand the color off the area beside the run.

Good luck!

[DGXSER]

Thanks for the hints. See my project begins thread for how it turned out. Better than I had thought it would.