Finishing problem

[Harvey Pascoe]

Sorry about the non specifity of the title but I do not know how to describe this problem. By the way, I'm just coming back after a heart attack side-lined me for 8 months. There were many complications such as kidney failure and 7 operations during that period. However, I'm doing well and up to full speed woodworking.

My problem involves water based "lacquer" and additional coats over preceeding coats where the previous coat repells the latest coat. Either it repells or created numerous fish eyes. This happens only occasionally and I'm at a loss to figure out why. I've heard about stearated sandpaper causing this, but since I always use the same wet sandpaper, if it is stearated, this should happen all the time, instead of just occasionally. Is there a name for this phenomenon of the surface repelling the wet finish? And if so, what causes it.

[Jim Rimmer]

Can't offer any help, Harvey, but sorry to hear about your health problems. Glad you are recovering and good to see you back on the Creek.

[Scott Holmes]

Harvey,

I'm glad to hear you're better...

Water based "lacquer" is not really lacquer as in nitro-cellulous lacquer. It's an acrylic.

There are a few possiblities... need more info

Questions:
Speifically what product are you using?
Are you WET sanding between coats? If so, what are you using as a lube?
How are you cleaning the surface between coats?

[John Coloccia]

My guess would be that you're using an oil based tack cloth. The slight oily residue it can leave behind can cause poor adhesion and fisheyes. Whatever it is, it's most likely contamination, and this stinks of some sort of oil contamination. All of the most common stearated sandpapers readily available to woodworkers have such a light coating that they don't cause any problems. 3M FreCut, Norton 3X, Mirka Gold, etc... are all fine under waterborne finishes.

That's my guess, anyhow. If you're going to use a tack cloth, either make sure they're safe for waterborne finishes, or if you're not sure purchase them from your local auto paint supplier. They will know for certain what's what.

[Scott Holmes]

Good guess John. I suspect you are correct.

Harvey, instead of tack cloth, I would just wipe with a clean rag, damp with water (or alcohol). Cheaper too.