Tip #3, #6/#7 and #9 are the most important I found:
Here are some basic spray painting tips I've learned over this summer refurbishing some cabinets, as well as some coin doors.
1) Spray FLAT. Spraying vertical will lead to runs more easily.
2) Spray with NO wind. With wind, will tend to make you go over the same spot too much, thus causing runs.
3) Start spraying OFF of one side, spraying through and OFF the other side, then move back to the other side BEFORE pressing down again. (e.g. like a good golf swing). Do NOT stop and turn around back and forth. That will cause the left and right edges to have over twice as much paint as the rest, thus causing puddling and therefore runs.
4) Sand, Sand Sand. Start coarse, then medium, then fine, then extra fine. Foam sanding blocks work great.
5) Prime with a good ahearing primer. Sand fine afterwards otherwise the "grain" of the primer will show thru the final coat, especially on metal.
6) Rather than trying to build up tons of coats with a satin or semi-gloss or gloss spray (seim and gloss tend to be VERY easy to cause runs due to their higher amounts of polyurathane like gloss base in them), start out your base with ULTRA-FLAT (if available) or FLAT colors. Black and white are typically the only colors with tons of levels of paint selection. I find that I can't even MAKE "Krylon Ultra-Flat Black" run, no matter what I do! Therefore use a flat paint to build up 2 or 3 coats, and then and only then, top off the last coat with your final appearance of either Semi-Flat, Satin, Semi-Gloss or Gloss.
7) (see #6) - Dont ever put more than 2 coats of Semi-Gloss or Gloss on... You WILL cause runs if you keep painting with them. Sanding between may help.
(Specifically adressing the question of this post).. You MUST let your paint dry at least 48 hours between coats, otherwise it will be gummy and run and additional coats will make it take that much longer to dry. Paint cans usually state that you must apply a second coat within 1 hour or after 48 hours. Not following this will cause the problems you stated.
9) BAKE BAKE BAKE. After the surface is dry to the touch (normally 45 minutes to 2 hours, depends on the paint--read the can) take your items out in the HOT afternoon sun and bake them. Even if it's 50 degrees (F) out, the ultraviolet rays will help dry the paint out faster and thoroughly.. a 90 degree day will bake it very very nicely, espcially if it's black paint.
10) Allot yourself a good 5 days from start to finish to get a good paint seal before you even consider moving an item into "use". I usually sand/flat paint 2 coats/bake for 2 days, then final coat(s), bake another 2-4 days before I bring in the house to use. Anything less and you're asking for problems like you described.
11) Don't paint if the relative humidity is over 50%.. You're only asking for problems.
12) Allow your can of paint AND item (especially if metal) to sit in the environment where it's going to be painted in. If you bring the paint and item out of a 70 degree air conditioned house into a 90 degree humid garage, you will get very very interesting results... Antique "crackle-ing" is one as the water forms on the metal between it and the paint.. Nice effect if you want it, but most of the time you dont!!!
13) Always use new nozzles. If after you've put away a can of paint after using, then got out again after a few weeks, and it just doesn't seem to be spraying "right" (e.g. droplets that won't smooth out is the worst) then swap the top with a new one from another can.. If you're going through 4 or 5 cans in a day, swap it from the first to the second to the third as you use them up, as long as it's still spraying right, "saving" the extra tops for future use if you have to use a can that has one that is plugged later.
This is stuff I learned or simply assumed and it helped me do much better painting on stuff this summer after messing up a few, I got better by the end.
Hope this helps.
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Topic: Spraypaint! (Read 3888 times)
