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| Leave it to the pro. Michael Dresdner, a nationally known wood finishing and woodworking expert, has answered hundreds of common wood finishing questions in Varathane’s Q&A library to help you successfully complete your project. Click on a link to the left for help and solid advice. |
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| Q: I just bought a new spray gun for my shop, to use with my compressor. Will I have to cut the finish to spray?
A: Whether or not you need to reduce the finish depends on the finish you are using and the fluid tip size on your gun. Typically, it is best to spray most spray finishes at a viscosity below 22 seconds on a Zahn #2 cup. If you tell me what finish you plan to use, what gun you are shooting with and what fluid tip size the gun has, I can probably give you some good guidelines, but to be honest, it’s fairly easy to figure out that stuff for yourself. Take some scrap cardboard, put some finish in the gun, start the settings at full open and with 35 psi going in, and spray onto the cardboard, cranking up the pressure a bit at a time to find the sweet spot where it sprays best. If it does not spray smoothly at any pressure below 60 psi, there’s a good chance you will have to reduce the finish. |  | |
| Q: We have melamine on MDF kitchen cupboard doors that are in decent shape except for a few blisters. I would like to remove the blisters and refinish with a similar matte white finish.
A: Sadly, this is almost certainly a bigger problem than it now appears. Melamine coatings are typically cross linked finishes known for having great cohesion but poor adhesion. In other words, it is not unusual for it to form blisters, but once it does, it usually does not stop. In other words, don’t be surprised to find that once you repair some, new ones crop up and you find yourself on an endless trail.
What’s worse is that because the coating is cross linked, you cannot bond well to it, making spot repairs most difficult. It is also usually thick enough that you will have trouble blending the areas once the blisters are removed. You can try, but my guess is that your best bet will be to chip away the blisters, then fill in the void left in the finish to level it to the surrounding finish.
The first step, even before you remove any blisters, is to clean the entire surface by scrubbing with mineral spirits or TSP on fine nylon abrasive pads. The solvent will remove any surface grease or oil while the pad lightly abrades the surface. You will need that because after the repair, you will most likely have to repaint the entire surface. Fill the shallow blister holes with wood putty, auto body filler or even spackle. Once it is cured, sand it flush with the top of the surrounding finish, then prime and paint the entire door. | | |
| Q: We are finishing the walls of a sun room with pine sheeting and bought wood conditioner. Once you put the conditioner on, you wipe off excess and allow to dry.
A: Nope. Stop right there. You flood the conditioner on, wipe it all off, then stain while the conditioner is still wet. It works correctly only if it is still wet. When you stain, you do the same thing; flood the stain on liberally, wipe it all off leaving only what the wood has absorbed. | | |
| Q: When you apply stain over conditioner, is it going to be lighter in color?
A: Yes. That’s the trade off with conditioner. It will make the stain take more evenly, but also lighter. Test it first on scrap; you might want to choose a different color stain if you are working with conditioner. |
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