stripping question

[Lhadeh at wmconnect.com]

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.
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