PAINTING SIGN FOAM. BUBBLES!

[mahardesign]

Hi there. I am painting 2 inch sign foam. Did 2 coats of sign prime, painted, shop vacced.

Painted with white sign grade paint and have bubbles all over the sign. Was it too cold at 52 degress F?

I want to lightly sand and try again, but cant have bubbles... Thanks for any help.

[mahardesign]

i sanded primer before painting with sign paint

[fubrain]

Spencer,
did you roll or spray your sign, The temperature is for sure a factor. If rolled you need to glide your roller over the painted surface with light pressure to relieve the bubbles. Foam rollers work best . if sprayed it could be fish eyes or something on the surface to keep the paint from adheshion. If you read the back of your cans it should say do not use under a certain temp. it also could be that you coated to heavy. Three light coats sanded between make for a good surface
ROSS
ROSS

[mahardesign]

Thanks.. I rolled it with a soft roller first, then rolled it with a foam roller. I will pick up some more foam rollers and wet dry paper.

Spence

[joe]

Spencer,

Not to worry, you are just in a HDU learning curve.

Because it's a closed cell product, the paint has a hard time getting down into each little bubble cavaties. Capaliary action of the paint draws the primer away from the cells. What to do?

There are primers for HDU but none of them, to the best of my knowledge, cover in just one coat. There water based and should be applied as thick as possibable.

I use Evercoat's High Build Primer. You can get it at your local auto paint supply. This is a fast drying, lacquer based material made to spray. It sands like a dream.

A fast way to get the surface covered before routing is to squeege a thick coat of HDU crack filler. One coat will do the job. That filler has a peanut butter consistancy.

There should be lots of suggestions on how to do this and I bet all of them are valid, good processes.

Good Luck,

Joe

[mahardesign]

Thanks Joe, I have already coated it successfully with 2 coats of sign prime. I am now in the final stages..

[jay]

Spencer, the only time I have had trouble with blistering is when I have been impatient. I am often accused of rushing things. But with primer and finish coats I have learned my lesson. The minimum I wait for drying primer on foam is at least one day two if I can get it. I alway use a small shop fan blowing air over the surface because as you know the primer can only dry from the top.

I wonder, origionally, did you wait long enough.

[kerrazy]

Spencer,
Are you using one shot? If so it has a tendacy to bubble up when rolled. if it is a flat surface, sand it out after it dries and then use a foam roller and reroll the surface, then screw a srew into the head of the roller cage on the handle side, so it will prevent the roller from rolling, then drag this all in one slow direction across the surface, it will remove the bubbles and the paint will level out as it cures. Any questions give me a call @ 613.880.8292
Dale

[Brady Watson]

A few things come to mind while reading about the bubbles...

The bubbles are either a result of the foam not being fully sealed before the top coat is put on...and the foam/solvents are actually degassing and rising to the surface...OR the roller itself is rolling air into the surface. As Jay points out...wait as long as you can before top coating, and as Dale suggests, drag or squeegie the surface coat on.

In all of the mold making and liquid plastic & coating that I have done, it is often necessary to spray a solvent on the surface that will break the surface tension. I am not sure what solvent is most appropriate for OneShot or similar paints, but when you spray a solvent on the surface, it breaks the surface tension and allows the bubbles to break on their own. For the types of things that I do, urethane based rubbers and plastics like silicone to break the surface tension and epoxies seems to like denatured alky and in some cases Xylene. These solvents give a virtually bubble-free surface with no loss in gloss, or strength/integrity of the finish applied.

Just a suggestion that may be of help to you guys who run into this problem. You may want to experiment on your own with various solvents ~ just something to break surface tension, and it only takes a spritz here and there...this is not a flood coat. Some people recommend using a heat gun or hair dryer to break the bubbles, but I have found this to be more trouble than it is worth.

Hope that helps,
-Brady

[bleeth]

Spencer: I've used a lot of the Evercoat mentioned by Joe above in spraying over plywood plugs that were eventually to be faired perfectly and used as boat hull molds. I used to enjoy (after the first time) watching the bubbles and little "balls" of finish on the first coat. It does sand quick and easy and then the second coat sprays so nicely you can sand it down with higher grit papers and then hit your top coats. We actuallly would work down to a 400 grit prior to gelcoat but for sign work you could surely pull the whole thing off with 120 grit.
Dave

[mahardesign]

Thanks Everyone. Can't wait to finish this!

This is not a project I should have taken on in a home with a dog and 2 cats. Constant battle to keep surface clean!

[russellh@earthlink.net]

Is there a list of boat/hull manufacturers maybe in order of number of units sold? Looking to buy a new hull and need to contact a few reputable manufacturers for a 22' bow rider hull. I am in El Paso, Texas (Mexico border), maybe a Mexican hull manufacturer?
Russell H.

[mahardesign]

[img]http://mahardesign.com/PICS/SIGN1.jpg[IMG/]

Here is my first sign! Thanks for the help guys...

Spence

[bryan]

Nice

[amy_brown]

Looks good! What material are the posts?

[t_fiddler]

Very nice Spencer

Tom