Preventing the Grain-Raising Effect of Waterbased Pigmented Primers

Water-based formulas cause wood grain to swell. Here are a few suggested remedies. December 1, 2005

Question
I am looking for a way to minimize the amount of grain raising. Im using a water based product. Should Shellac be sprayed first?

Forum Responses
(Finishing Forum)
From contributor D:
Dewaxed shellac only such as Seal-Coat. This will help enormously.



From contributor R:
Polystar is an ML Campbell product, isn't it? I tried it years ago and it didnt work very well. It raised the grain worse than any other WB product I had tried at the time. I use Enduro sealer and Poly now and it does a very good job.

If you must stay with Polystar, try spraying a very light seal coat, then come back when dry to the touch and spray a normal but not heavy coat. This should help reduce the grain raise. Dewaxed shellac is a good sealer too but you need to be careful of cross contamination if you use one gun for both products.



From the original questioner:
The reason for using Polystar is to spray inside peoples houses. The use is new cabinets and refinishing kitchen cabinets. I can get Polystar in any color. If there is a white pigmented water-based product that does not raise the grain that information would be great. I use de-waxed shellac on MDF first.



From contributor O:
When we used Polystar we got better results by building up a couple of light seal coats and then letting it cure enough to prevent a heavy coat from taking any water to the MDF. Perhaps you could do 6 or 7 tack coats over the course of an hour and then a 3 mil coat before you stop for the day.

We notice that aggressive leveling to get out the orange peel could cut through to some of the raised fibers and then we would encounter secondary grain raising. These problems have been typical to all of the waterborne primers we have used, although admittedly some are better than others - especially for vertical applications. I would sample as many as possible but you're just going to have to do more work.