Having a slight problem with 1/12th scale F1 project...ran into a problem+need help

[Deejay27]

Ok...I am close to completing the kit. Yesterday, I attempted to paint the rims w/ Tamiya's semi-gloss black (spray can) and prior to spraying the black on I washed the rims in soapy water, rinsed well, dried well, primed with Tamiya primer, and let it dry overnight in the food dehydrator (nothing different on how I painted other parts of the kit). Everything was looking good prior to spraying the black on. As you can see from the pic below the rim didn't come out very well. Although I am only showing a pic of one of the rims...this occured with all 4 rims !!! The weird thing is the bubbles were only around the lip of the rim and no where else. I proceeded to sand down all 4 of the rims today (the lip only) and re-sprayed the black and guess what......it bubbled up again !!!!! What is causing this? The rims were cleaned well prior to spraying. What could be reacting with the paint to cause it to bubble up like that for the second time?

I will be posting more updated pics by the end of the week and if you would like to see the thread...click the link below.

[aw1234dude]

Maybe you should try alot lighter mists like so paint barely gets on it and just do like a whole bunch of coats. I'm thinkin cause its such as small surface bubbles can form really easily.

[Deejay27]

aw1234dude.....the paint looked smooth when it was done spraying. It started to bubble up during the drying process.

[Murray Kish]

Weird, only thing I can think of is to sand it down again and wipe it thoroughly with alcohol. It must be reacting with some sort of chemical on the surface???

Murray

[christofurr]

How soon after painting did you put it in the food dehydrator? The only thing I can think of is that you should let the paint 'dry' at room temp. for an hour or so, and then put it in the dehydrator to 'harden' after that?

[daggerlee]

Maybe your coats were too thick?

[racer917]

Same thing has happened to me when spraying bike rims. It looks ok when wet but as it starts to dry bubbles show up. I'm sure it's too thick a coat of paint. Sand it down, two light mists of paint follow by a heavier coat. It should take care of that.

[freakray]

Originally posted by daggerlee
Maybe your coats were too thick?

I have to agree with Dan on this one, if you're painting the rims with to heavy a coat of paint, as it dries it will trap gas in the paint and form bubbles.
Try spraying lighter coats of paint, you don't have to cover everything with one coat of paint.

Ray

[Deejay27]

Thanks for the replies. I'll give it a try with lighter coats. It's just hard to spray the inside of the rim without it building up on the lip.

[935k3]

Originally posted by Deejay27
Thanks for the replies. I'll give it a try with lighter coats. It's just hard to spray the inside of the rim without it building up on the lip.

You might already do this, I always spin wheels fairly fast when I paint them, this always gives me a nice even coat without build up. I always keep them moving when I spray. The bubbles are most certainly from too much paint sprayed to close. I would strip them and start over or sand them and airbrush on a final coat.

[Murray Kish]

Spinning the wheels is a really good idea. I just added that to my little collection of 'reminders' for my next project. Thanks..

Murray

[Deejay27]

Hmmm....spinning the wheels....I'll give it a try.