[CarpenterSFO]

I sprayed a coat of General Finishes Enduro pre-cat urethane over shellac-sealed poplar, on a test piece, yesterday. I have horrible bubbling problems. Of course now I note that the pre-cat notes say not to put it over any sealer. The shellac is Zinsser Seal Coat.

It's just a test piece, but I'm interested in hearing whether this reaction is to be expected, either specifically for GF pre-cat or for pre-cat finishes in general.

Just for kicks and further info - I sprayed a couple more sealed pieces, one with GF water-based urethane (not pre-cat) and Target 9000, and neither of them bubbled. I'm probably going to switch to the Target for this project, but I'm still interested in learning what might have happened with the pre-cat.

Thanks,

- Bob

 

[Steve Neul]

Well first of all it isn't recommended to put the pre-cat urethane over a shellac sealer. The finish is self-sealing however General Finishes makes an approiate sanding sealer for it. I don't think that has anything to do with the bubbles though. I think it has more to do with your sprayer. You may need to thin it a little for your sprayer. Just thin it as little as possible.

 

[CarpenterSFO]

Well first of all it isn't recommended to put the pre-cat urethane over a shellac sealer. The finish is self-sealing however General Finishes makes an approiate sanding sealer for it. I don't think that has anything to do with the bubbles though. I think it has more to do with your sprayer. You may need to thin it a little for your sprayer. Just thin it as little as possible.

Thanks. I'll do some experimenting.

- Bob