Removing Polyurethane from a Walnut Cabinet

[Edwards]

I have a pair of L-166 cabinets that the previous owner put a coat of flat poly on the top surface only.

I would like to remove this, but not having not too much experience with refinishing I'm here asking advice as to how to best remove, and then the proper grit paper to use before I re-stain the cabinets with the proper stain as has been previously posted here.

thanks in advance!

[Rolf]

Hi.

Don't know if there is some chemical that will remove it. If so, they may damage the veneer. I would use a "sander?" and very carefully remove the "dirt". Just my thoughts.

[invstbiker]

Audiobeer is the man for this question, good luck



I have a pair of L-166 cabinets that the previous owner put a coat of flat poly on the top surface only.

I would like to remove this, but not having not too much experience with refinishing I'm here asking advice as to how to best remove, and then the proper grit paper to use before I re-stain the cabinets with the proper stain as has been previously posted here.

thanks in advance!

[Baron030]

Here is an old wood refinishing trick that I have used.

But, I have never tried it on a veneered surface. So, you will need to test this in an inconspicuous spot first. Just to make sure that it will not dissolve away any glue holding the veneer onto the enclosure.

In a metal container, mix equal amounts of lacquer thinner and wood alcohol together. And with a brush, or an old rag spread this mixture over the wood surface. This mixture will cause the finish to soften to a gummy state within a few minutes. When the finish is soft and gummy, it can be easily be rubbed off using course steel wool with very little pressure. Once, most of the finish has been removed with the steel wool, you then apply more of this mixture to the wood and remove the last traces of the old finish by rubbing the wood down with old rags or paper towels instead of the steel wool.

The real advantages to using this solvent mixture, is that it will not raise the wood grain. And on most occasions, I have found that it will not remove any of the wood's stain. So, the wood will be ready for a new finish without any sanding or re-staining at all.

Because of the fumes, you will need do this work outdoors, well away from any sparks, and open flames. And I suggest using latex rubber gloves because these solvents are really rough on your hands.

Baron030:)

[mech986]

Laquer thinner will likely dissolve latex gloves if even in the room. I would suggest Nitrile or other known solvent resistant gloves while working with this or other solvent mixtures. Definately outdoor though and watch for any spark source.

Don't know if modern chemical strippers will take down poly. Might be best to check some of the poly or refinishing product websites - Varathane brand, Formby's, Howards, Minwax, etc all maintain websites where refinishing is discussed so you might be able to get some guidance there too.

Bart

[Baron030]

You really don't what to use any chemical strippers that require a follow up washing with water. The water will raise the grain and possibly float the veneer loose.

Baron030:)

[Tim Rinkerman]

A chemical stripper is your best bet for removing polyurethane finishes...I have refinished several Leslie cabinets and have had to remove poly...use a fast,strong stripper that will allow you to scrape the finish off with a plastic scraper. I have never damaged or unglued any veneer, a couple were from the early 50's. If you try sanding the finish off, you will end up with high and low spots that will show up in the final finish...you run the risk of trying to sand through some very thin veneer that might be right next to the base wood. You do want to keep sanding to a minimum, start with no rougher than 120 grit, work your way to 400-600.
I use BIX stripper...home depot...VERY STRONG...it will crack and lift ANY finish within minutes. Scrape it off while it is still gooey. Keep it off your skin! I have used it on Hammond organ parts, and Leslie cabinets with outstanding results. It attacks the finish really fast, and it does not have the consistency to "soak" into the wood, ie, it won't damage the wood, even veneers.

[grumpy]

Hey Doc(Mark)... race you to the BIX! :D

(Thanks Tim)

[Joe Alesi]

Hello Edwards,

I have (like Tim) also used chemical strippers, usually with an MEK- Methyl Ethyl Ketone (YUK) gel consistency, there is even a "citrus" based gel stripper here in Australia, but I haven't tried it. I have never had any issue with timber damage using these. As always recommended try it on a sample or patch of timber that can't be seen.

If using an MEK stripper be careful as it is a listed carcinogen therefore use all the safety precautions, suitable respirator/face mask, gloves, googles etc... or pay some one professionally to strip it for you. Who know in the US the FDA is so strong that it might be a banned substance. There are some companies who specialise in this although sometimes they use caustic bath stripping, which wouldn't be good for you.

If in doubt ask a local furniture polisher or french polisher. They may even strip it for you.

Best
JA

[Audiobeer]

A chemical stripper is your best bet for removing polyurethane finishes...I have refinished several Leslie cabinets and have had to remove poly...use a fast,strong stripper that will allow you to scrape the finish off with a plastic scraper. I have never damaged or unglued any veneer, a couple were from the early 50's. If you try sanding the finish off, you will end up with high and low spots that will show up in the final finish...you run the risk of trying to sand through some very thin veneer that might be right next to the base wood. You do want to keep sanding to a minimum, start with no rougher than 120 grit, work your way to 400-600.
I use BIX stripper...home depot...VERY STRONG...it will crack and lift ANY finish within minutes. Scrape it off while it is still gooey. Keep it off your skin! I have used it on Hammond organ parts, and Leslie cabinets with outstanding results. It attacks the finish really fast, and it does not have the consistency to "soak" into the wood, ie, it won't damage the wood, even veneers.

Tim is pretty much doing what I do. Make sure you have an area that is open and ventilated. Bix or even aircraft stripper that Auto Zone sells is ok. Try one side or one plane at a time to you get the feel. Instead of rinsing with soap and water on a small area I use laquer thinner or acetone to rinse. Take it slow.

[Doc Mark]

Hey Doc(Mark)... race you to the BIX! :D

(Thanks Tim)

Hey, Grumpy,

Dang, we were out camping, and I guess I lost the race, before I even knew there WAS one!!! :blink::blink::D Sounds very interesting, Grumpy, and Tim, thanks, very much, for that tip! I may, or may not, give that a whirl. I'm sort of getting used to seeing those old 4333's in their black formal coats! ;):D I know that, if I strip their coats off, there will be a few veneer problems with which to deal. So, I may just square off a few corners, recoat with the finish of choice, and call it good. Don't know just yet. If you do attempt this on your remaining 4333's, Grumpy, please post your results, or give me a PM shout. I'd love to hear how it goes! Take care, and God Bless!

Every Good Wish,
Doc

[Gary L]

I hate Poly finishes on speakers. You might be able to get it off but you won't be able to get it out of the wood.

Staining after a poly finish is a hit or miss deal and nearly impossible to match colors when only one surface has been previously pollied.

My bet will be the un pollied surfaces will take the stain fine while the surface that had a polly finish will not.

Polly is a plasticizer that penetrates into the veneer and pretty much negates the possibility of ever restaining with any degree of success.

Chemicle strippers are Paint and Varnish removers and I have never seen one that says it removes Polly from a thin veneer!

Gary