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Refinishing piano

Posted by stevega (My Page) on
Wed, Jun 16, 10 at 15:50

We have a 30+ year old Kimball baby grand piano and the finish is deteriorating. The original finish seems to be shellac because denatured alcohol dissolves it. I would have though that it would be lacquer. It also fogs up when washing with a damp cloth.
I would like to refinish it before it deteriorates further. Spraying is too much of an ordeal because it would have to be done in place. I am thinking of wiping on a lacquer to add protection rather than add more shellac.
I recently built a trundle bed and finished it with Arm-r-seal (urethane) and really like the results. I am testing that on a part of a leg that is not visible. I would probably lightly sand (300+ grit) before final application.
Any advice, cautions and experience is welcome.
Thank you.


Follow-Up Postings:

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RE: Refinishing piano

Don't smoke while putting on the finish?


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RE: Refinishing piano

Lacquer, as it ages and has exposure, is more susceptible to blush and denatured alcohol. I would put my money on its being lacquer and not shellac.

Now you have a problem of a degraded finish and you want to put something more over the top of it. It's what is called putting on a new roof when the basement walls are caving in. At the very least, I would want to do a thorough cleaning and light abrading to remove surface degradation.

The problem with a urethane finish is that they don't always adhere well to other things. Lacquer will burn in (chemically bond) with the existing finish, be it lacquer or shellac.


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RE: Refinishing piano

I have cleaned it twice with mineral spirits and will probably do it again before refinishing.
The surface is just a little rough and uneven sheen, no chips or loose areas. Would Deft brushing lacquer be the best bet?
The Arm-r-seal did do well on the leg but that finish is probably in a little better shape than the top.
Thanks again.


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RE: Refinishing piano

Without seeing it, Deft would definitely be in consideration. A couple of years ago, I took in a dining table that was looking tired and dull. The lady did not want to spring for a full refinishing. I cleaned, sanded, and applied a couple of coats of Deft and it brought it back to life. It was small enough that brushing took less time than spraying and cleaning up the gun.

I was watching "This Old House" tonight and the painter said, "Your job is only as good as what you are covering." I think I'm keeping that one.


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RE: Refinishing piano

I don't know how much you know about pianos, but this is something I would seek a piano restorer before you go further. I know that is something you don't want to hear. Kimball is a good brand and you don't want to do anything to hurt the sound the piano gives. Remember the wood is the amplifier for the piano. I have refinished many pieces of furniture and a piano is one I would not attempt to do.

And yes, we own a Mason Hamlin grand piano and both my wife and I are professional musicians.

Enjoy the journey.
eal51 in western CT


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RE: Refinishing piano

The soundboard is the active part, the rest is just a case to look nice.


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RE: Refinishing piano

Take the case off the piano and then listen to it, if you think the case is just cosmetic.
I don't know where you got a 30 year old Kimball grand ( nor what size grand it is) but this is not a pottery barn table to be messed with....this is a serious investment and you could really muck it up good.
If you just want to do a quick cosmetic fix, do something like the Restore a Finish....or your own version of that....but to completely refinish it, front, legs fingerboard etc etc is a bit of a dangerous undertaking for a non professional.
Wipe a little Formby's stuff on the parts that show....and leave the rest to a professional....when it really needs it.
You have a musical instrument....not a piece of furniture.
Linda C


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RE: Refinishing piano

The band's piano player tests the instrument in a nightclub before the gig, and finds it horribly out of tune. He brings this to the attention of the manager, in no uncertain terms. The manager replies "impossible, that piano's beautiful; we just had it painted!"
30 years worth of oil and furniture polish could in theory soften and degrade an organic lacquer to the point where alcohol would dissolve waht's left. A strong cleaner like 409 or Fantastik would probably dissolve it too.
The difficulty with pianos is the very large surfaces that have to be mirror polished. A lot of effort went into finishing these large planar surfaces and getting even a semi-competent looking finish on a grand lid is way beyond the capability of a DIY'er.
Casey


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RE: Refinishing piano

"Take the case off the piano and then listen to it, if you think the case is just cosmetic."

The finish on the case will not affect the sound.


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RE: Refinishing piano

Thank you all for your interest and input.
I have checked and lacquer is a common finish for a piano so I don't think the sound will be badly affected. It is not an heirloom or concert instrument and I doubt if we will be able to hear the difference. I will say that it has not been subjected to oils and Pledge but Kimball did have the reputation for a flimsy "lacquer" finish. I still can't believe how easily alcohol dissolves it and takes color off.
I am going to do the sides first with two coats and rub the finish out and see how it goes. I have done tables with success. I do think that I can achieve a more consistent sheen than it has now. I have the various grits of sandpaper and pumice. Worst case is we leave the lid tilted up (it faces a wall).
Again, I appreciate all the input and interest.
Steve


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RE: Refinishing piano

"Pledge " can make it a real chore to get a new finish on the surface.

It contains silicone that causes 'fish eye' in any new finish, unless you add 'fish eye eliminator' (more silicone).


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RE: Refinishing piano

I case people are interested, I thought I would report back on this project.
I brushed three coats of Deft on after thorough cleaning of the surface. During the leveling of the top, I reached poor finish before it was level. I believe that the degrading existing finish contaminated the new finish. I was able to leave the sides of the piano as applied.
I stripped the finish off the top and dyed the wood to be dark cherry to match the existing color. I used a coat of Seal-a-cell and 10-12 coats of Arm-r-seal to fill the small grain. After waiting 3 weeks, I leveled with wet dry sandpaper to 1500 grit and buffed with 4F pumice and rottenstone. The color and clarity were good but the urethane did not shine up well. I went to Turtle Wax polishing compound and a random orbit buffer which gave me a good gloss surface. I added a coat of Mylands wax for more shine. I may try another polishing compound to get an even higher gloss.
Thanks again for your help and advice.


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RE: Refinishing piano

Polyurethane cannot be rubbed out; on a molecular level the long-chain crosslinked resins tear instead of cutting, invariably yielding a poor result (compared to lacquer, shellac, old fashioned oil varnish (without crosslinked polymeric resins.)
Casey


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RE: Refinishing piano

"Polyurethane cannot be rubbed out..."

The gloss level cannot be increased effectively, but it can be dulled down easily enough.


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Ha ha. Good point!
Casey


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RE: Refinishing piano

There are some waterborn finishes that are better than others. That is the reason I use Hydrocote Resisthane Plus. Also, General Finishes waterborne finishes are very good. They both can be rubbed out to a high very high gloss. They both have high water and alcohol resistance. Use 3M rubbing compound from an auto paint store.


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RE: Refinishing piano again

I have used Deft lacquer and Deft waterborn finishes, rubbed out with 3M rubbing compound (after the finish dries for about a week) with good success. If you rub it out too soon, you will get a shine, but it will get dull in about a day. The trouble with Deft, for me, is it doesn't seem as durable as Hydrocote (Pre-Catalized Lacquer) or the General Finish. On the other hand, one should not use the top of a piano for a table; or at least use coasters.


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RE: Refinishing piano

Interesting. I might refinish my piano someday...I can't believe you did all that in place! I was planning to go with shellac.

For the record, a 30-year-old Kimball upright piano (or any other old upright for that matter) is worth basically nothing; no worries about refinishing it.


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RE: Refinishing piano

I did remove the top and front hinged piece to the basement for the stripping and refinishing after trying Deft in place. The gloss I got with the Arm-r-seal is slightly higher than the existing gloss on the other parts of the piano but not as high as previous projects with shellac and lacquer.
I used some dark walnut Transtint in the Arm-r-seal to ease the red (from a mixture of reddish brown/dark walnut) on the dyed wood surface (to match the existing piano color better) and it worked well.
Overall, I am pleased with the result.


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RE: Refinishing piano

Nice! I'd love to see pics if you have any.


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A picture is attached. It is difficult to see the finish details but the color is correct. I had to turn off the flash. There is a slight difference in color from the side to the top (redder). Actually, the top was redder than the sides before I started.
Photobucket


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RE: Refinishing piano

Sorry if I'm hijacking this thread, but you guys seem to know a lot about piano finishes. My hubby, being helpful, has used a myriad of furniture polishes on my Yamaha grand. It used to have a satin finish but now has greasy streaks, etc. I remember once a repairman, who did a beautiful job of fixing a ding from a move, using something like paint thinner for the final finish - along with very fine steel wool. Was it really paint thinner? I am not going there with the steel wool, but would paint thinner get the yucky stuff of the finish or would I be asking for trouble? The piano is at least 34 years old.


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RE: Refinishing piano

I have used paint thinner (mineral spirits) successfully to clean a finish. You probably have a variety of waxes and oils on the finish. I think that mineral spirits with lots of clean rags/cheesecloth would be good and should not harm the finish. Hopefully, others with more experience will weigh in.


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RE: Refinishing piano

Paint thinner can dissolve and remove a lot of crud without damaging shellac, lacquer, or varnish.

It takes a lot of paper towels to get the dissolved crud off though (before the thinner evaporates).
You have to be careful to get the stuff off instead of just smearing it around.

The vapors are flammable, so make sure you have plenty of ventilation.


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RE: Refinishing piano

Naphtha is very handy as a cleaner; I prefer it over paint thinner. Either are highly flammable. Both will leave the finish hazy and in need of "something". Paste wax, scotts liquid gold, etc.
Casey


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RE: Refinishing piano

Thanks guys, I tried the paint thinner (actualy odorless mineral spirits and it got everything off with very little effort. I then wiped it with a damp cloth and dired it with another. Looks SOOOOOO much better.


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