Problem with painting
 

I painted by Sig 552 but after the first game the paint cracked around some places, so I went to put on a couple more coats, and now there are there 'snow flake' patterns all over one side of them (like jagged lines).

Help.

Well, no sure how to fix your "problem", but I can give you some tips on how to repaint it better. Firstly, sand your current paint job and try to remove as much paint as possible. Second is optional, put on a primer. Third, light coats in a must. Be at least 2-3" away from the gun and do one coat, let dry, next coat, let dry and so-on. A lot of light coats are better than one dripping coat. Last is again optional, but a clear-coat helps the paint last longer, but some make the paint appear shiny. Hope that helps.

Good clear coat that works wonders is the games workshop matte clear coat for warhammer figures. Used it on my paintjob and have not had any paint chip off yet after a year.

Most clear-coats should do the job no problem, not just war-hammer paints

Use a matte clear coat and you're ok. Others will leave too much shine

Clear coat and sand. What kind of sand paper should I use? I'm at a loss as to why these geometric snowflake pattens formed at all. I had no problems like this when I first painted the gun.

Probably should mention its a plastic-clear Sig (was).

Did you clean the gun before painting it the second time? You should always clean the gun with alcohol to remove any oily impurities before painting it.

Many types of spray paints have solvents (such as acetone, xylene, toluene) in them to help they drying process but they also cause old paint to bubble or strip; that is what you are seeing. The solvents get in where the old paint chipped off and degrade the previous layers.

Try sanding the material with a fine sandpaper (400 grit) or a Scotch Brite pad; and cleaning it (with something like IPA isopropyl alcohol) prior to touching up the paint. That should work for you.

I used to have the problem with my RC Boats.

I used a cloth and water. The one side is pristine, its only the right side of the gun that came out like this.

I see. Will IPA alcohol damage the plastic?

Nope, its probably the safest thing for plastics and it dries too fast to trap any moisture. We use it on aircraft with no issues.

Don't use, MEK and Acetone, it can eat some plastics and composites as well as rubber.

For painting plastics and composites, cleaning with Water is too dirty, its can can actually make things worse.

Sorry correction.

Don't use IPA on any sort of plastic optics such as scopes or eyeglass lenses as it (may) dissolve the protective coatings (for glare, static, and scratches). It also may not be compatible with some soft polystyrene (rarely) and Styrofoam products.

Otherwise its good to go.

Yeah, water is not a good cleaning agent to use before paint. From handling your gun, you deposit oils from your skin. Water can't clean that off. You need to use alcohol to dissolve it.

As stated already, sand the old paint off wiht 400+ grit sandpaper, clean it with alcohol, then repaint in thin coats and you should be ok.

the snow flake pattern could be caused by ''almost empty'' spraypaint can....

dont spray or paint it in the cold
paint will have your effect if it was left in the cold (some times even just a bit chille is considerd cold in such situation) before it has fully been cured (usualy a full week)
just because its dry dosint mean its cured

winter sucks for painting inless youv got an indoor spray area that stays warm constantly