Sanding Sealer Compatibility

Finishers discuss the use of various sanding sealers with various topcoats. September 14, 2006

Has anyone used Targetís CV over another manufacturerís WB sanding sealer? I tried it with their universal sealer, but for my application. it dries too slowly. I tried it over Enduro WB poly sanding sealer and it looks great and the adhesion seems to be fine. Any feedback would be appreciated. The reason I'm looking to try the Target CV is I've seem to have developed a respiratory sensitivity to the Aziridine (PFA) crosslinker that Enduro offers for a more durable final coat.

Forum Responses
(Finishing Forum)
From contributor A:
We use mainly USL but the CV is a very good product but kind of expensive though. If you are having issues with the dry time you might want to flash it off with some heat. It needs to sit for 5 minutes after you spray it to "dwell" and then it can be flashed off at 120F and will dry in 2-3 minutes and virtually cured in 30 minutes @ 120F. Unlike conventional solvent products you need to be able to control the temperature with most waterborne coatings. Apply them at 65-70F and then let them dwell according to the manufacturer instructions. Most can then be fast cured by hot moving air (heated air make-up unit for your booth). Of course if you're not in a hurry then just let it dry at 70F for an hour.

From contributor B:
I use Targets CV and find that you need spray a lighter coat. This keeps the dry time down and results in a better job.

From the original questioner:
Maybe I didn't phrase that correctly. The CV is fine - it was Targetís 8800 universal sealer that was too slow. 1-2 hours before sanding is much slower than what I'm used to with the Enduro sanding sealer. 20-30 minutes is common to sand the Enduro sealer. I was just concerned about crossing manufacturerís WB products. I've done two samples using the Enduro as a sealer and then final coating with Targets CV and both seem fine. Also the viscosity of the universal sealer makes it painfully slow to load into my gravity gun.

From contributor C:
I have a stupid cabinetmaker question for you finishing gurus - why exactly to you need to use a sanding sealer? Is it just to make sanding out the first coat easier? I spray the Target USL product directly on my furniture and cabinetry and get what I think are good results. It also dries pretty quickly. I personally can't take the smell of the Enduro products. I don't have a spray booth and the smell seems to linger for a long time.

From contributor D:
USL is self-sealing so you really don't need a sanding sealer with it. The finish is superb, in my opinion. I've noticed another thing with the USL that's pretty cool. If you spray it over dewaxed shellac, there's virtually no sanding required. I use a 5% solids mix of shellac as a washcoat on blotch prone woods and use it full strength as a barrier coat over and under glazes. The USL goes on glass smooth in both cases.

From contributor E:
One reason to use the WB shellac sanding sealer is if you have any concerns about contamination. I am finishing a Mahogany c-top right now and sanded the top to 220 grit and the end grain to 600 grit per the Target Repís recommendation. Normally I rarely would touch 220 grit paper.

Having one of my typical "oops" moments I used stearate paper for the 600 grit. Now I am using the shellac to seal in any possible contamination before topcoating. The rep also told me that the shellac product would reduce the chances of "pinholing" on a mahogany slab.

One other reason for using the sealer is that WB products will raise the grain. The sanding sealers (which are usually fast-drying) allow you to spray a first coat and then sand off the fuzz before topcoating. I have not tried Targetís universal sealer yet but the M.L. Campbell sealer dries very fast. It seams like you should be able to spray the CV over another companyís product, but I couldn't say for sure.

From contributor F:
I, too, like Enduro sanding sealer but am chucking their poly - I've had nothing but trouble with it. I'm going to give Target's lacquer a try and would be interested in whether or not it performs well over Enduro sealer.