Can anyone recommend a wetting agent for epoxy resin over drywall mud?

[helix_3]

I have a completely dry, drywall mud base object, and I brushed a layer of cheap epoxy resin over the top.

Surprisingly, there are a few patches where the epoxy pulled back and didn't cover the mud. You would think the porosity of the mud would cause the epoxy to get sucked in, but I guess not.

Can anyone recommend a wetting agent I could add to the surface, to encourage wetting of the epoxy into the mud?

 

[JPH]

I would actually use the same epoxy that you started with, but save the brush you use to apply the latest layer, and keep coming back to it every few minutes. Long past working time.

You can lightly sand the cured first layer and clean it to make it more receptive to the next layer.

When I am going for final coats, especially with epoxy, I don't just apply it and walk away, I come back to it and gently smooth it with the brush I used to apply the newest layer over and over.

Usually, it seems as if the stuff pooled in some areas, maybe the mud had water there? but keep going over those areas, and it will smooth out.

 

[helix_3]

When I am going for final coats, especially with epoxy, I don't just apply it and walk away, I come back to it and gently smooth it with the brush I used to apply the newest layer over and over.

Usually, it seems as if the stuff pooled in some areas, maybe the mud had water there? but keep going over those areas, and it will smooth out.

That's a good strategy, it's a lot faster than my original plan to do multiple coats to get coverage.

There were certain parts that I had recently patched, and it didn't pool there- only older areas, which should've been a lot dryer. Maybe it was just the geometry of the part encouraging pooling, or oils from my hands?

 

[JPH]

Also, if you can, hang the object in different positions while the epoxy cures, but be sure to keep working epoxy in the areas that seem to reject it.

 

[JPH]

That's a good strategy, it's a lot faster than my original plan to do multiple coats to get coverage.

There were certain parts that I had recently patched, and it didn't pool there- only older areas, which should've been a lot dryer. Maybe it was just the geometry of the part encouraging pooling, or oils from my hands?

Did it work out?

 

[helix_3]

Did it work out?

I'll have to give it a go on the next test piece, the only drywall mud items I have are already coated. But I'm feeling good about the procedure, it should work.

 

[Doc H]

For your project, would it work to put down a very thin layer of epoxy and then a second layer of standard viscosity? If so, you could thin a first coat to have it soak in more and have the thick layer bond to that before it cures.. Unfortunately, I am no longer sure what I have thinned epoxy with in the past. Acetone? Xylene?