Michael Dresdner

Q: Can I put oil based wiping polyurethane over oil based spray lacquer?
A: The simple answer to your question is yes, you can put oil based polyurethane, whether wiped, brushed or sprayed, over almost anything, including lacquer. For the record, though, lacquer is, by definition, an evaporative finish, while oil based finishes are, by definition, reactive. In other words, the terminology indicates the process by which the finish goes from liquid to solid film. Thus the term “oil based lacquer” is at best a misnomer. While one could make an evaporative finish using a stable resin derived from oil, that should still be called simply lacquer.

Q: We’d like to spray Rustoleum hammer finish but do not have any equipment. Can you recommend an inexpensive HVLP system for home/light use?
A: Yes, but I’d advise against buying a spray system just for this one job. You can buy Rustoleum hammer finish in aerosol cans under the Universal label. http://www.rustoleum.com/CBGProduct.asp?pid=180
Those Universal cans are comfortable, spray beautifully with a built in trigger, and will spray in any direction, including upside down. Buying a few cans of aerosol will be vastly cheaper than buying a spray rig.
However, if you are set on buying spray equipment, decide first all the various things you plan to use it for and base the purchase on that. You know from years of hearing it from both me and your father that buying cheap tools, including those inexpensive because they will only do one job well, is rarely a good investment. If you really want to buy a spray rig, call me and I will walk you through the process.

Q: We’d like to coat our stripped metal furniture with hammer finish from Rust-Oleum. The local paint person stated this can be applied directly to the metal, but perhaps I am just being old school so I am questioning whether priming first would be better.
A: Rustoleum’s hammer finish is in fact fine to use without any primer, though on an uneven surface, it might make a slightly different pattern than you get on a smooth one. That’s really the only reason I could think of for bothering to prime; to improve the surface of the substrate. If that’s not necessary, don’t bother with primer in this case.

Q: In preparation for painting stripped metal furniture, we’ve wiped down the pieces with soapy water and wiped everything dry, gone back over the pieces and have given them a light sanding. Do I need to be concerned with chemical residue from the previous finishes, stripper or other contaminate?
A: Possibly. Some strippers contain wax, and unless you remove it, you could have problems. Ditto for any soap residue. Once you have removed all the soap residue, which comes off with clean water, wipe the pieces with mineral spirits to remove any possible wax. Other than that, you have little to worry about.

Q: We purchased a used dinette set; the style is often referred to a wrought iron, however the chairs and base are clearly metal. They appear to have been originally powder coated, and subsequently painted over by the former owner with what looks like latex paint. Using a gel stripper and a bit of elbow grease we’ve managed to strip all the chairs and the table base down to bare metal. However, there are a few crevices that we could not reach and remove the original paint. We’ve gone as deep as we could, using a variety of wire brushes. Will these areas create a problem for the new finish?
A: Possibly. You could get bridging. The ideal way to remove the finish from crevices in metal is by sand blasting or even better, soda blasting.

Q: I just obtained two small table lamps made of burl and the lampshades are of what appears to be birdseye maple veneer. The veneer is fabric backed and very brittle. As a result there are some small voids and cracks in each shade. I plan to back the voids with wood putty and then use a wood stain. This won’t entirely correct the problem but do you have any suggestions for application? Moreover will glycerin help to restore some of the suppleness and help avoid future cracks?
A: Glycerin may help restore some suppleness, and may even help slow the cracking, but once you put it on, you really can’t do anything else. In other words, glycerin will prevent the stain you plan on using from taking evenly, and stain will prevent the glycerin from being absorbed. You may have to choose one or the other.
To be honest, I don’t understand why you want to stain the shade veneers, but if you do, you’ll have to clean and sand them first. Most household goods develop of thin coating of airborne oils, and while they look clean, are not. Raw wood will simply absorb such oils. Either way, trying to stain other than raw, clean, sanded wood can result in problems.
For what it is worth, the cracking is almost certainly a function of the heat and attendant dryness coming from the bulb behind the lamp shade. Replacing the bulbs with cool to the touch compact fluorescent bulbs will help eliminate much of the heat and may prolong the life of the shade.

Q: My painter sprayed lacquer recently on a hot and humid day and trapped moisture under the finish. Having had experience with this I told him to re-spray with lacquer retarder added to the lacquer and to remove the humidity from the room before re-spraying. This worked to a certain extent but still did not get all the moisture out. Should we just add more retarder to the mix and re-spray?
A: Yes, exactly. Or, in extreme cases, simply spray pure retarder thinner which is available in convenient aerosol cans or in liquid form as “blush chaser.” If you go that route, be careful; you are spraying pure thinner, and if you get the finish too wet it could run.

Q: I want to fume the ridge beam in my house. Obviously, I can’t simply remove it, and place it in a tent for fuming. What would happen if I painted a light layer of ammonia on it?
A: First, fuming only works with woods high in tannin, so before you do anything, figure out what type of wood it is and whether it is one that is high in tannin or not. Second, fuming uses ammonia fumes, which is pure, concentrated ammonia. Once it is in liquid form it is ammonium hydroxide, which will color wood, but not in the same way as fuming. It tends to be less effective and yields a different color which is not surprising when you remember that you are no longer using pure ammonia, which is a gas, but rather a compound of ammonia and water. Even at best, fuming is a bit of a crap shoot. What color you get and how much impact the ammonia will have depends on the type of wood and, in this case, the concentration of ammonium hydroxide. For example, household cleaning ammonia is usually only about a 5% solution, and is a weak chemical stain at best. Ammonia from a blueprint machine is typically a 26% solution, and while more effective, is both dangerous and noisome to use. Finally, chemical stains, which is what ammonia is, only work on clean, raw, sanded wood. Call me a skeptic but I doubt that’s a good description of any ridge beam unless it is brand new and recently sanded. In short, I think it is a very bad idea for a wealth of reasons. Why not simply stain it the color you want it to be?

Q: When you say to control the color by how you mix the stain not how you apply I am a little confused. My stain is premixed. It is General Finishes water based dye stain. Can that be thinned using water and do I need to thin it?
A: You can thin any stain, should you need to, but most pre-mixed stains are designed to be used as is from the can, which means you can make it weaker but not stronger. That’s one reason most finishers prefer dye concentrates or powders, which allow them more flexibility in stain control. Such raw ingredients also allow you to omit or add binder as you choose. Pre-mixed stains offer convenience, but the price of that convenience is reduced versatility.

Q: If I brush on a final finish, will it cause water based dye stain to bleed into the finish on the brush and smear?
A: Water soluble dye can bleed onto a brush loaded with waterbased finish. Whether that will be enough to smear the stain also depends on your brushing technique and how aggressively you wiped the dye originally. It is also worth noting that some dye stains contain a binder that will prevent this. Others don’t.