Michael Dresdner » stripping

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.

Scratch in Floor Finish, Polyurethane Tricks, Protecting Kitchen Tables, Hardwood Floor Products

admin — Tue, 25 Aug 2009 06:10:49 +0000

Q: If I wipe on too much Rockler gel polyurethane, I get streaks, and if I wipe on too little, I get ridges. How do I proceed?
A: I think the term wipe on is what is throwing you. The best way to work with it is to scrub it on liberally with nylon abrasive pads, then wipe it ALL off. That way you won’t get streaks. The thing is that even if you wipe it all off until the surface is smooth and streak free, you will still have left a very thin coat with each application.

Q: I’ve read that wipe on gel does not offer sufficient protection for a kitchen or dining room table top. Is this true?
A: No, but that deserves some clarification. As a rule of thumb, more build means more protection. Because wipe off finishes, such as gel polyurethane, leave such very thin coats on each application, you might need a whole lot of them to get the sort of build you might want for a table top. They are designed for applying very thin finishes, and done correctly, are very easy to apply. However, they are not meant for fast build up of thick coats. That’s not to say you can’t build a coat with them. You can, but it will take more than a dozen coats, applied at the rate of one per day or slower. Even at that it will not be as much build up as three brushed coats. Build up can be misleading, though; a dozen or more wiped off coats provides more protection than you might think, and requires less practice than brushing smoothly. Still, brush vs. wipe on is a matter of speed of build up vs. ease of application. Does that help?

Q: I sanded an oak door landing and stained it with Varathane premium wood stain. I properly wiped off the excess after waiting five or so minutes. Now, after 24 hours, I am still getting occasional wet spots or sweating on the surface. I have been wiping them with a cotton cloth but I need to know when I can finish the wood.
A: You can finish when it stops sweating, or as it is often called, weeping. Until then you will have to continue to wipe off the beads of stain that form at the mouth of the pores. For future reference, there are several things you can do to either mitigate or prevent the problem. If you are using oil based stain on open pore wood, like oak, wipe it off immediately and very aggressively. Go back immediately using a stiff bristle brush to scrub the excess stain out of the pores, and wipe again. The combination of quick, aggressive wipe off and pore scrubbing will eliminate most, if not all, of the weeping. Other options include using a waterbased stain or an oil based gel stain, neither of which weep.

Q: Two years ago I stripped our hardwood floors and redid them completely using your products. I used a poly that didn’t offer much sheen but was a bit disappointed in the result. What is the process if I want to take off what is there down to the stain and redo it?
A: First, let me clarify that I do not sell any products, so no products can be thought of as mine. I am simply a finish consultant, and will answer questions on this blog about any brand or product. As for the process, it’s fairly simple; sand the floor down to the raw wood, which, by the way, will remove the stain, then stain and finish it in higher gloss.

Q: My husband put a good size surface scratch in the floor finish by moving a piece of furniture. Will it come out if I refinish the floor.
A: Yes, as long as the scratch is in the finish and not deep into the wood.