stripping question

[Greg Newell]

Given your experience I wonder if you can share 
with me how you know what the old finish is that 
you're stripping off in the first place? Are 
there some kind of tell tale markers where you 
know what the previous finish is?
BTW, Who am I talking to?

best,
Greg Newell


At 08:09 PM 5/26/2006, you wrote:
>I did go back to work on this to see how easy 
>(or hard) it would be to lift the veneer or 
>ignite a piano part while attempting to strip it 
>with a heat gun as was kindly predicted in a response to an earlier post.
>
>What I found was that if I didn't play the heat 
>gun around an area I could overheat shellac and 
>NC lacquer enough to cause the bubbling, burning 
>and smoking mentioned.  Also, as I continued to 
>heat the area after that happened, I caused a 
>darkened spot in the veneer that needed to be 
>sanded out.  I found I could actually ruin the 
>veneer with the heat gun if I really wanted 
>to.  (I did this to an piece I needed to re-veneer anyway.)
>
>But I never approach this point when all I want 
>to do is soften the finish just enough to scrape 
>it off.  With stiff putty knife prepared by 
>grinding an edge like a woodworker's scraper, 
>but without the burr, just a softening of the 
>finish will allow it to be removed quite easily.
>
>I also tried coating an area of tired old NC 
>lacquer finish with three coats of water borne 
>Acrylic Lacquer, and also in another area where 
>I had previously stripped the existing 
>finish.  I waited two weeks then tried stripping with heat.
>
>In the area with the NC lacquer underneath, it 
>worked about the same as before, except the 
>amount of finish being removed was greater.
>
>In the area that only had the water borne 
>lacquer it took a lot more heat to soften the 
>finish.  Just as an experiment I tried to heat 
>it until it smoked.  I wasn't able to do that, 
>it just sort of dried up and got 
>powdery.  However with that much heat I did 
>notice some lifting of the veneer.  As it cooled 
>I applied a little pressure and afterward it was 
>flat again.  A tap test showed the veneer was 
>glued again.  It didn't matter because that 
>piece had enough veneer damage to require re-veneering.
>
>So, I would say that it is possible to burn into 
>the veneer and to lift the veneer.  However with 
>a little practice and paying attention to what 
>is happening I think the probability of creating 
>a big problem is low where the original finish 
>is shellac or NC lacquer.  I have also used this 
>method successfully on a more modern piano that 
>was finished in oil based acrylic lacquer.
>
>For an old piano that had the veneer glued with 
>hide glue and had been re-finished in water 
>borne lacquer, I would just soften the finish 
>with lacquer thinner.  It softens immediately 
>and scrapes off easily.  But if it was a newer 
>piano with veneers applied with more modern glue 
>I would rather not use thinner and would try 
>heat first.  Once the water borne lacquer turns 
>a little powdery, it scrapes off quite easily.
>
>This reminds me of a quote from Henry Ford,  "If 
>you think you can, you can.  If you think you 
>can't, you can't."  My impression is that this 
>business does not accept innovation or new 
>thinking easily.  In some cases that is 
>good.  But when it comes to the joy of stripping 
>an old piano of negligible heritage, I am 
>completely open to doing it the quickest, 
>cheapest, most efficient way.  I'll let someone else worry about tradition.

Greg Newell
Greg's Piano Forté
mailto:gnewell at ameritech.net
www.gregspianoforte.com