Suitable Substrates for White Conversion Varnish

Using a pigmented finish and trying to keep the cost down, a cabinetmaker considers his choices for trim material. November 23, 2012

I would like to spray white conversion varnish on clear pine. Any problems with this?

Forum Responses
(Cabinetmaking Forum)
From contributor L:
It's wood. Should work fine. But... Make sure you have no active sap on the pine. Probably would be wise to use a vinyl sealer on it just in case. Pine is very soft, so it would be subject to crushing if hit hard enough. This would cause the (hard) CV to fracture and crack, resulting in an ugly scar.

From the original questioner:
Using it on crown molding on top of kitchen cabinets painted white. I wasn't thinking about sap, but generally if I sort through clear pine moldings I can get good stuff. Maybe poplar would be a better choice.

From contributor L:
Soft maple would be a better choice. Pine should be fine for the molding as long as you don't run into a sap problem. Poplar is kind of grainy for CV and it will telegraph through unless a lot of extra effort is put into the priming of it. Soft maple is pretty cheap - more than poplar, less than pine - and it will take paint nicely and will not telegraph grain.

From the original questioner:
I'm with you on the soft maple - I use it often. I'm looking to buy the molding off the shelf at the lumberyard and it's either pine or poplar. I'm doing a kitchen and I'm looking to keep the job affordable for the people. Also, all the trim around the doors in the house are pine and I'm starting to think sometimes we overkill these projects.

From contributor J:
If you are buying it at the lumberyard, why not pre-primed MDF?

From the original questioner:
I'm using Conestoga Colortones and they tell me to use on bare wood.

From contributor M:
I have used Colortones on pre-finished materials (plywood, leftover moldings, etc.) and it works just fine. I havenít used it on pre-primed builder's grade moldings yet, but have been told that it will work just as well. I will be running a test next week to see how this really works out. On pre-finished material, make sure that you scuff sand everything real well and spray away.