Tiny bubbles…

[dbparker]

I got my sister to paint a guitar for me and I love it and spraying was going really well, I thought I was completely done and had left it aside to cure but the other day I looked at the guitar and noticed in a different light there’s thousands of little bubbles that I hadn’t seen before and I’m not sure what to do… I’m scared to sand it back too far as I don’t want to ruin it, I thought spraying some thinners over it might flow everything out and let the bubbles come out and i think it did that for the top layer but maybe there’s some still trapped in there? I assume it’s my fault for applying too thick a coat at one point but I was rushing to get them finished as we’ve had so much humid weather I was waiting for non humid days!!

Could i continue to spray thin coats of thinners on? Do I wait and see if I can sand them out? Any help appreciated as I really don’t want to ruin the painting. I don’t think it’s a compatibility issue as you can see them over the wood too

 

[dbparker]

The first guitar of the 4 I put together turned out great, I’m planing on selling them to raise money for charity but am moving house in a few weeks and under a bit of a time crunch! I’m really hoping I haven’t completely screwed up the one I got my sister to paint!

 

[Boreas]

Need more info. What products were applied and in what order? Are the blisters soft or brittle?

Tincture of time may help, but you may need to live with it, as it is obviously under the custom paint. Keep in a warm, dry place for a week or so.

 

[stratisfied]

I assume the hand painting was done with acrylics. It would appear your topcoat reacted with the hand-painted details causing it to lift here and there. Topcoat should have been acrylic also to prevent thinners from reacting with the paint. You can use water-based polyurethane also.

If you used an acrylic topcoat and it reacted, you either applied too heavily or the hand painted details weren't fully dry when coated.

Best to mist on dry coats to seal before applying heavier finish coats.

 

[Peegoo]

@dbparker

Hard to tell from the pics...are they little bumps? Or are they little divots, like on a golf ball?

Bumps can be gently block-sanded off.

Divots are called "fisheye" and that is usually due to incompatibility between finishing materials (paints, residual chemical stripper in the wood, etc.), or contaminants on the surface prior to spraying (oils, silicone, etc.). Fisheye can be difficult to fix, especially when they are over an existing hand-applied artwork like you have there.

 

[eallen]

I suspect your indication of excessively heavy coats without proper time between to gas off traped bubbles. The only cure is to sand back until you get to the layer with the bubbles and replay. Otherwise live with it.

 

[Deadman1970]

Don’t spray thinners on it, it’s trapped solvent simply trying to evaporate from the grain. As Boreas said, time might help. In fact, it’s your only real potential healer. It just might settle down in the coming days, weeks, months. Nice artwork btw.

 

[Brendan]

I thought this was a Don Ho thread….

 

[Silverface]

I thought spraying some thinners over it might flow everything out and let the bubbles come out and i think it did that for the top layer but maybe there’s some still trapped in there?

DO NOT USE THINNERS.

You can TRY blush remover - but thinners evaporate too fast to solve a bubbling problem.

Blush remover (or reducer) comes in aerosol cans - I suggest Mohawk or Behlens (essentially the same product.). Make sure your work area can remain absolutely dust free for at least 2 hours.

DO NOT spray on or "at" the surface!!! You spray two light "fog" passes over the horizontal piece at a 90-degree angle, at a height of 18-24 inches about a minute apart. You let the light fog drift onto the surface

Then don't touch it for at least 2 days. If the bubbles are mostly gone and you have NO runs at the edges, repeat the process.

After 4 passes what you see is what you'll get. Remaining bubbles will have to be sanded out.

You mentioned rushing to spray due to weather - what was the humidity in the area where you were spraying? It's critical that you check - I have 2 bodies to finish up, we had 2 clear days with no rain - but the humidity was still over 60%.

And how are you spraying each coat? If it's lacquer, it will not cover or begin to flow out until the third coat. If you try to apply it like paint you will have problems.

Also - lacquer DOES NOT CURE! It dries ONLY by evaporation of the volatile components (primarily thinners and wetting agents - "surfactants" that help it coalesce).

You can apply 2-3 LIGHT coats (made up of 3 fog-like passes each) per day IF the weather and humidity is dry enough for spraying AND at least an hour of drying (unless you are using Colortone or Deft - the evaporation process is VERY slow and one coat a day is about the most you can expect.)

Last - did you use a moisture meter to check the wood before spraying? They are about $20 at Harbor Freight and on Amazon and vital this time of year - if you applied no sanding sealer before she painted, the wood can absorb moisture from the air. If it was over 11% You were crippled before you even started, and that could be a major cause of bubbling right there.

Good luck!

 

[58Bassman]

If the finish had any solvent in it, if you can smell that by sniffing, it's too early to paint over it. The bubbles are likely from off-gassing.

 

[hopdybob]

The first guitar of the 4 I put together turned out great, I’m planing on selling them to raise money for charity but am moving house in a few weeks and under a bit of a time crunch! I’m really hoping I haven’t completely screwed up the one I got my sister to paint!

L90 in there?

 

[hopdybob]

I assume the hand painting was done with acrylics. It would appear your topcoat reacted with the hand-painted details causing it to lift here and there. Topcoat should have been acrylic also to prevent thinners from reacting with the paint. You can use water-based polyurethane also.

If you used an acrylic topcoat and it reacted, you either applied too heavily or the hand painted details weren't fully dry when coated.

Best to mist on dry coats to seal before applying heavier finish coats.

I think it is not a reaction of the topcoat with the painting underneath.
why? because this 'bubbles' would not be seen where only the wood shows.

maybe, the topcoat was from an old production date, ore the nozzle was not working 100 % and gave drops to?

but if i did not have known it, i think i would not even have bothered about it.
thats the curse of all craftsmen and woman, we know because we made it