Q.
We are using Mohawk glaze with Duravar and Magnalac. The M.L. Campbell rep said to use the vinyl sealer to "sandwich" the glaze.
We use the vinyl sealer thinned 50 percent over bare wood or oil stain; sand 320; glaze; seal again with the thinned vinyl; let set for 36 hours; sand 320; then do two coats of Duravar. The rep said not to sand after the second coat of sealer, but it seems like we need to.
I also heard that we need .5 dry mils on the sealer. We are at about four mils wet. Is this O.K? How are dry mils measured? We are getting good results with this, but it is a lot of labor. Is Mohawk the best glaze to use? Is there a glaze that can be sprayed? Is the 36-hour dry time necessary?
There is no reason that maybe 30 to 40 minutes after applying that second coat of vinyl sealer (the coat that is applied over the glaze) you shouldn't be scuffing that coat and shooting on a new application of Duravar.
How long do you let the Mohawk glaze set up before you shoot it with vinyl sealer? You can shoot it within the drying window of two to six hours, otherwise you have to wait for the glaze to cure completely. Try to get it shot within that window.
Unless you are using some Mohawk colors that are unusual, there is no reason for not using the M.L. Campbell glazes. If you stay within the manufacturer's recommended system and use only the products they tell you to use, then you can insure all compatibilities.
In all likelihood, there is nothing incompatible about using Mohawk's glazes with the MLC coatings. But you will get no warranty on the finishes from either Mohawk or M.L. Campbell should there be some problem attributable to either of them.
Dry mils are estimated by first knowing the solids content (expressed as a percentage by volume) of the coating that you are applying. In your case, you mentioned that you are using M.L. Campbell's vinyl sealer, I assume their water white sealer, which has a solids content of 24 percent by volume. You are thinning this 50 percent with reducer, so you are spraying on an application that is four wet mils thick, and that material has a solids content of 12% by volume (24 percent becomes 12 percent when you thin it by 50 percent because you are cutting it in half).
Twelve percent solids by volume at four wet mils becomes 0.48 dry mils. But you are spraying two coats of this, giving you a finish coat that has almost one dry mil (0.96 dry mils, actually) of just vinyl sealer. This is definitely way too much sealer in your schedule. I got my info from M.L. Campbell tech support, which told me 0.5 mils of vinyl sealer is as thick as you should go. I have seen this from some other suppliers as well.
You should always be aware of the solids contents of your coatings. And you should have a wet mil thickness gauge (I guess you do since you mentioned that you know that you are spraying on four wet mils).
