A Bad Mix

[Hawaiilad]

I was putting the finish on 15 small and large Band Saw Boxes I made and decided to use Sanding Sealer on them first and after it dried and cured I followed it that up with lacquer. I looked at the finished products the next morning, and the finish hard blistered all over the place. I took the time to sand everyone of them, bought a new brush (I have been using foam brushes but this is a "real" brush). Then I got to wondering what was the real problem for the blistered.........then I ask my wife the paint artist. Right away she asked what I had put on the boxes as a finish. Told her about the sanding sealer and then lacquer..............she asked to see the cans, then said my problem was because I was using Min Wax sanding sealer and Deft lacquer together, I guess these two brands don't like each other very well....I am starting to believe this reason, because this afternoon I refinished the boxes. I didn't see any cracking start when I applied Min Wax Poly...and tonight they really are looking smooth.

So am I the only one that did not know of the fight between Min Wax and Deft brands????

[wood-n-things]

I would guess that one is water based and one is not.

[Hawaiilad]

Nope, neither one was water based. That's the first thing I looked at.

[DWSudekum]

I believe that the minWax brand is not lacquer based as the deft sanding sealer is. I believe that the MinWax IS water based as it cleans up with just soap and water this leads me to believe that it might be a water based polyethylene based sanding sealer. If this is the case then it very well could do what you are describing. You might want to get the Deft sanding sealer to go with the Deft lacquer finish.

DW

[Bill Wilson]

I think I'd be inclined to skip the sanding sealer all together. What benefit were you looking to achieve?

[BobD]

Or, if you want to do a sealer of some sort, use a thin cut of shellac...

Bob

[Hawaiilad]

Well, I checked again this morning and both were oil based.....seemed once I dropped the Deft and stayed with Min Wax it came out wonderful....I agree, I don't think the Sanding sealer is needed....just thought I would see the effect. I think it would have worked if both had been Deft or both Min Wax...but for some reason they do not work together. I was hoping the sanding sealer would seal the wood so I did not have add so many coats of Lacquer or Poly that I was using...so much for that idea

[Bayward]

Originally Posted by BobD

Or, if you want to do a sealer of some sort, use a thin cut of shellac...

Bob

This is the answer. Shellac will seal most any surface and is easy to sand. Lacquer goes over shellac very nicely also.

Bob

[oily]

Gotta agree with Bob Larry. I do a couple of coats of shake and shoot shellac, knock the dust bumps off with Norton 3x, 400 grit or 000 steel, whatever I find first then start the clear build up. 99% of the time I use Krylon clear or clear satin. Great stuff. I've applied it from 30-100+ F with no problems. I like it best about 50F. Slows it down enough to really level it out. You can re coat every 60 second or so.

[Bill Wilson]

A couple points that come to mind. First, it's good practice to always test finishing schedules and products that you are unfamiliar with, on scrap before applying to the finished product. Helps eliminate unpleasant surprises.

Also, regarding sealers; Products called sanding sealers contain zinc stearate, which helps reduce clogging of the sandpaper. You need to match the sanding sealer to the type of top coat you are using. It isn't so much the brand that is incompatible as it is they type. Sanding sealers are made for either varnish or nitrocellulose lacquer. The Deft you used is probably nitrocellulose lacquer and the MinWax sanding sealer was probably formulated for varnish.

By & large, sanding sealers are not needed and in fact actually weaken the bond of the finish to the wood. They are made to solve a few specific problems with a couple types of top coats. As was mentioned, if circumstances require a sanding sealer, de-waxed shellac is a much better choice. In reality the first coat of any finish effectively "seals" the surface of the wood. The only thing sanding sealer brings to the table is that it is slightly easier to sand than some of these other finishes. IMHO, the cons far outweigh the pros when it comes to sanding sealers and they are of very little practical use for the hobbiest woodworker.