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Synopsis : Spray paint forms little bubbles when it is applied. Why?

Run Down : I am planning on painting my engine cover. Since this would be my first paint job, I decided to do a little practice. I bought some primer and spray paint (Krylon Short Cuts .... can be applied to plastic). For my first project, I decided to paint the little Injen label on my newly arrived CAI. If you have one, you know what I'm talking about. "Injen" is in chrome letters in a red background. Maybe 1" x 1" big. I sanded that little area down and cleaned it off real good. I then taped everything off until only the tiny area was exposed. I sprayed light coats of primer on the area until it was completely gray. Then I waited a day. The next morning I started to apply the spray paint. The second I do, the paint starts forming these little bubbles. Whatever. It's just a little inch-by-inch label. The next day, after the paint has dried, I noticed that the paint has all these little bumps, .. the surface is like sand paper.

So anyway, I tried again today on a random piece of plastic and little bubbles started to form again. I want to paint my fuse-box cover before the engine cover but now I'm SCURRED. I want a smooth surface. Anybody know why the paint is bubbling like this?

 

i had that same problem too :X

i'm a noob when it comes to painting crap. i even took my time too. i sanded with three lvls of sand paper, primered 2-3 coats and painted, then clear coated too.. bleh

 

did you guys shake your cans well enough...?

 

my girl shook her cans .... hee hee hee, j/k. But seriously, I shook 'em. But not excessively. Do you really think that is the culprit?

 

Maybe the nozel is dirty or clogged?

 

my guess is not shaking is your culprit, of course the injen thing could have had some grease on it to keep it from coroding or something and it made the paint bubble. Or that it was just dirty. I dunno, I'm not really into the mechanics of paint and such, but those are my ideas.

 

maybe you are holding the can of spray too far away from what you are painting...
try holding it closer maybe that would work?

 

^^^i think that would maake it worst and the paint will run. just try doing several really thin coats. let the paint completely dry in between coats...about 10 mins. when i say thin coats...i mean like at least 4 coats to completely cover it. dont try to cover the whole area with one coat...gl

 

Hmmm ... I definitely do not apply enough paint for it to run. I am consciously aware of that when I am doing it. But what exactly is a "coat"?

I've just been sprayin' a little and then walkin' away for a couple minutes. That's my definition of a coat. ??? ???

 

i just said it might run from the suggestion of the other guy to hold it closer. my definition of a coat is to lightly cover the surface evenly...no thick spots. for example, you engine cover is black and you wanna paint it red. the first coat should not make the whole thing red. it shoud be completely covered by maybe the 4th of 5th coat. i guess in the end, it just takes practice and experience and youll figure out which technique works best for you.

 

i didnt mean to hold it to close so that it would run.
but yea do it like he said and do more thin coats,
and if your doing the engine cover im not sure but you might need high temp paint,
im sure you could search and find out real quick.

 

probably some dust... get some wax and wax it it should come out... btw on the engine cover.. did you use high heat paint...? if not... strip it before it becomes a problem...

 

let me get this straight.

you put primer first
then you sprayed your first layer of paint
the layer of paint then bubbles with in seconds upon layer???

it might be the primer. They are not smooth so may have very small air pockets? i had this problem when spraying down a primer fender. what hasta happen as we did was primer, first light layer, let it dry, sand it down just a bit, then 2nd layer, hope that helps

 

my few guesses...

not shaking you paint... not shaking your primer...
not cleaning it after sanding... or.... the best one... humidity... if its sweatier than a fat high schoolers gym shorts... its prolly not the best time to paint...

 

Yeah, it bubbled within seconds. I'll cross my fingers and try sanding the primer idea this weekend. And I don't think it could be the humidity. As a Texan formerly from Florida, I can say it gets pretty dry here.

 

I can only speak from a autobody techs experiance. But the 2 major causes of "bubbles" when painting plastics are 1. resins in the plastics which need to be baked out. And then sealed w/ a plastic prep. I know that our engine shields are notorious for being difficult to paint because of the type of plastic. Some plastics have resins that will not accept paint. I.e. Silicas. 2. Speaking of silicas, thats number 2! And form of silica, Oil, grease, tireshine, armor all, you name any other various cleaning product that "shines" and it prolly has a silica base. Silica causes what we call, "Fish eyes". Where the paint is actually repelled from an area. Silicas can be neutralised or removed with various products. But for a resin issue. The only solution is to bake/scuff, bake someore/scuff and soo on. Ok, no more work talk :0) >Mikey