Michael Dresdner » stripping

Unstaining

Michael — Mon, 01 Nov 2010 14:00:25 +0000

Q: My stepson recently purchased stain from the cabinet supplier of his kitchen. The plan was to match the color to his unfinished crown molding. The color is wrong. Since the molding has contours, it can’t be easily sanded off. Is there a solution for stripping down to bare wood?
A: Most stains can be scrubbed at least part way off with lacquer thinner on nylon abrasive pads. It won’t remove all the stain, but you may get enough off that you can restain with something that adjusts for the problems while bringing you up to the color you want. That can be done either with a second stain operation on raw wood, or with a toner, which is stain mixed in coating. Either way you will need to mix a custom color stain to compensate for what you could not remove, and add whatever colors are missing from what you want to end up with. This is not necessarily a job for a neophyte as it does take some skill with color matching and compensating.

Proof of the pudding?

Michael — Thu, 03 Jun 2010 14:00:15 +0000

Q: Is the resistance to strippers a sure indicator of a polyester finish or does it merely suggest it?
A: It suggests it, but is not an indicator of polyester alone; it is merely an indicator that the finish is highly cross linked. Polyester is probably the most common of the highly cross linked finishes found on musical instruments. Others include cross linked acrylics, polyurethanes, polyureas and epoxies. Cross linked waterbased coatings can be any one of the above categories.

Polyester problems

Michael — Wed, 02 Jun 2010 14:00:06 +0000

Q: Short of sanding it off, is there any way to remove a polyester finish from guitar sides?
A: Yes, but it might be faster and easier to sand or scrape it off. For guitars with solid sides, you can make the job easier by working it off with a heat gun. When heated, polyester tends to separate from the wood and you can sometimes get a thin spatula behind it and zipper off large sections. As for chemically removing it, that too is possible, but slow. Use a boosted DCM remover, usually called “marine stripper.” In addition to DCM (methylene chloride) as the active ingredient, these strippers often have either acids or bases added to make the stripper “hotter.” Nevertheless, you will have to daub it on liberally, then cover it with plastic sheeting to keep it from evaporating, and give it a good long time, from hours to a day or more, for the stripper to do its work. It will eventually get it off, but as I say, it might be quicker to work with a heat gun, putty knife, scraper and eventually sandpaper for what remains. By the way, the chemical stripper will also dissolve the plastic binding; another good reason to get physical instead of chemical.

Take it off

Michael — Wed, 19 May 2010 14:00:49 +0000

Q: What product can you suggest to remove hempseed oil and beeswax from a table top?
A: That depends on how long the hempseed oil was on, and whether or not it was mixed with beeswax or merely applied prior to it. If it was not on long, or if it was mixed with wax, you will probably be able to remove it with naphtha or mineral spirits. Otherwise, you might need to resort to a solvent mixture generally called “refinisher” on the label. Either way, scrub with fine nylon abrasive pads and the appropriate solvent, work in a ventilated area and wear gloves for this job.

Strip resistant finish

Michael — Fri, 02 Apr 2010 17:00:19 +0000

Q: I’ve been in the refinishing business for years, but have just been stumped and need your help. An end table stained red mahogany was brought in for top only refinish due to white water stains splattered all over the surface. It had a very hard semi gloss sheen-finish on it. After stripping, I’ve found this appears to be possibly plastic, since the commercial stripper did nothing to it The apron is particle board with veneer. Please advise what to do, it’s a commercial customer.
A: If I read your question correctly, you put stripper on a thick finish and it did not budge it. That sounds like a polyester finish, which will resist most common strippers and is often used on imported furniture, or possibly a very aggressive cross linked acrylic or polyurethane. You have two choices. If the wood below is solid, not veneer, you can remove the finish mechanically, either with a heat gun or belt sander. A heat gun will not melt the finish, but will cause it to crack and lift from the wood, allowing you to get a putty knife beneath it and zipper it off. It’s tedious, but it works.
If the wood is veneer, the other option is better. Get a boosted stripper, often called marine stripper, and be prepared for the long haul. Boosted strippers are high methylene chloride content strippers modified with either a strong acid or base (curiously, either works to supercharge the stripper.) Get a paste type stripper, daub it on very thickly, then drape the piece with a sheet of clear plastic film to prevent the active solvents from evaporating. You may even need to add stripper if it starts to dry, but keep the piece wet as long as it takes to remove the finish, even if that is days instead of hours. Eventually, it will come off.
Because this is a commercial shop, I will point out that on an end table, it is often cheaper to replace the top than to refinish it.

Not all strippers are created equal

Michael — Wed, 18 Nov 2009 17:00:42 +0000

Q: We are redoing our kitchen cabinets, and tried to remove the finish with Citristrip Stripping Gel. We waited, but had a really hard time getting it off so we stopped and waited a few days. Sanding makes the paper gummy. Is there any easy ways to get this junk off?
A: Yes, and you were on the right track to start with. You simply were not patient enough. Paint remover may be the messiest option, but it is a fairly easy one provided you choose the right stripper, apply it correctly, keep it wet, and wait for it to do its work.
Whatever stripper you use, you must put it on liberally and keep it wet until it removes or completely softens the finish. Depending on the stripper, that can take from minutes to days. Keeping it wet may mean simply reapplying before it evaporates, or more practically, covering or draping the wet pieces with plastic to prevent the active ingredients in the stripper from evaporating. Either way, do not remove the stripper until the finish all comes off, right down to the raw wood. If you remove it and the finish does not all come off, immediately reapply before the wood dries. Once the wood dries it becomes markedly more difficult to remove the finish. Stripping is one of those things that are best done in one shot.
Additionally, not all strippers are the same, and as a general rule, those marketed as safer or less odorous are also typically much slower working. That means you will need to put more on and keep it wet longer. For instance, a strong methylene chloride based stripper might remove a typically finish in ten minutes to an hour, while some of the safer strippers may take from several hours to more than a day.

Restoration?

Michael — Fri, 06 Nov 2009 17:23:53 +0000

Q: I have a 40 year old dining table with much sentimental value. A refinisher ruined the reddish color many years ago. The two leaves were not refinished. I’d like to restore the entire table to its beautiful original color. The wood is in good condition but the color is blotchy. I believe the finish is an oil finish. How do I go about restoring the table?

A: That’s fairly simple; refinish it, this time correctly, including the leaves. You can do it yourself, if you want to get into a messy job and feel you have the skill to match colors, or you can take it to a refinisher that you trust to be able to restore its original beauty.

There are lots of reasons why a professional refinish job might disappoint, from miscommunication, through an attempt to do a job on too tight a budget, to simply inadequate skills on the part of the finisher. There are competent finishers out there should you decide you want the job done. Just be very clear about the results you want before you ask for a price estimate.

If you decide to do it yourself, get a good finishing book by your side and read up on the process before you tackle it. At very least that will help you decide if it is really something you want to do.

Simpler than stripping

Michael — Tue, 29 Sep 2009 01:26:45 +0000

Q: My oak wood floor was refinished in the spring of ‘06 before moving to this house. Now the surface is gone where we walk and needs to be refinished again. The contractor claimed three coats of oil polyurethane were applied. We have dogs and cats and considering the layout I will need to refinish it as two separate areas in stages. I need a way to prep it without sanding and use a fast dry product.

A: In this particular case, I think your best bet is to go with one of the non-sanding finish options, such as Varathane Renewal. This two part kit is designed to go over the existing finish with no sanding required, forms an extremely durable cross linked finish, is waterbased, and the whole thing can be done in one day.

Shower Stall Wood Paneling

admin — Sun, 13 Sep 2009 20:26:54 +0000

Q: I have wood paneling in my shower stalls that need re-doing. I have already sanded and wiped the walls. What would be the best sealer to use?

A: Best? The best would be a moisture cured urethane, but it is not easy to come by. Offhand, I know of only one company in Brooklyn, NY currently selling it, and they sell primarily to the industry, not to homeowners. The product is extremely durable in that sort of setting, but because of the chemical involved, must be handled both with great care and proper safety equipment. By the way, I will assume you are back down to bare wood, since this finish is not appropriate over an existing finish. On the other hand, if you prefer something less than the best, but still quite adequate and more accessible, you can go with oil based polyurethane or spar varnish. As Hallack Brendan once said, “sometimes the best becomes the enemy of the good.”

Attack a Tacky Finish

admin — Wed, 09 Sep 2009 19:38:44 +0000

Q: My friend has a tile kitchen countertop which has an oak border around the tile. The oak trim for some reason has always been tacky to the touch, as if the finish had never really set up. I was wondering if you had heard of something like this and if there is a way to fix this without damaging the tile countertop.

A: It’s not that uncommon, and it’s an easy fix. Mask off the tile and grout very well with blue painter’s tape, then remove the finish on the oak. He can do that with paint remover, by scraping and sanding, or in some cases with a so called “cool stripper,” a half and half mixture of lacquer thinner and denatured alcohol paired with a coarse nylon abrasive pad. Once the stripping is done, remove the masking and mask again with clean tape before refinishing. I’d go with an oil based wipe on gel polyurethane, like the Rockler Polyurethane that has my picture on the label. The worst case scenario is that if the masking is less than perfect, he may stain a bit of the grout. If so, once the finish has cured, simply re-grout the stained area.