epoxy alone

[Farrell]

Hello Clyde. I think I can speak to this with some good info. The short answer is yes, absolutely.

Now for the long answer   :-).

Go to http://www.westsystem.com/ and click on "Using WEST SYSTEM Epoxy", then click on "User Manual", and then click on "Bonding". There you will find the preferred method of bonding wood that will have a gap and be subject to tensional forces. What it basically describes is a method to wet-out both wooden surfaces with unthickened epoxy to get maximum penetration into the wood, and then jamming in epoxy thickened with a high-strength adhesive filler.

My experience tells me that if the crack is too small to work tools down in there to wet it out properly, then the crack is small enough so that you don't have to mix the filler real super thick. If you keep the mixture on the thin side, you will find that the wood wets out very well and gets adequate penetration by the epoxy. This penetration is ESSENTIAL to a successful bond.

A properly done repair like this will never fail - without through-bolting the plate to the backposts, and whether or not you have clamped the joint. The only way the piano will have any more separation problems is if the WOOD fails in a new location. 

The epoxy-wood-joint is WAY stronger than the wood itself, when properly done.

This only applies to proper technique as described above. If you simply take some "Bondo" or other thick epoxy-type goo and stuff it in there, you may not get proper adhesion to the wood.

Recently I built a 500 gallon fish tank that has a pine and spruce frame and a 1" plywood bottom. It does not have one single screw or nail or any other fastener in it. Epoxy holds it together and water-proofs it. Amazing stuff.

Wasn't there a movie that made that famous?  "Epoxy, my boy. Epoxy is the product of the future."

Terry Farrell
  
----- Original Message ----- 
From: "Clyde Hollinger" <cedel@supernet.com>
To: <pianotech@ptg.org>
Sent: Friday, June 07, 2002 4:32 PM
Subject: epoxy alone


> Friends,
> 
> Can a separated back repair be expected to endure if I used epoxy alone?
> 
> I actually did this once.  A Wurlitzer console was only several years
> old when I discovered, underneath the glued-on felt, a separated back.
> I called the company's rep, who told me just to fill the crack with
> epoxy.  Period.  No clamps, etc.  He sent me new felt for the top, and I
> did as I was told but never glued the felt down so I could keep an eye
> on it.  It is now about four years later and it seems okay.
> 
> So suppose from now on I just worked epoxy into the crack, pulled the
> top together with big clamps, cleaned away the excess, waited two days
> and took the clamps off.  Would it hold?  Has anyone tried this?  The
> epoxy claims a strength of something like two tons per square inch, so
> it seems like that should be sufficient.
> 
> This is especially in my mind because today I tuned a Conn console with
> a separated back, even though it has four bolts going the whole way
> through the back.  The separation is in the middle between two of them.
> There is really no room to put in extra bolts where needed because the
> tuning pins are in the way.  What do you think?
> 
> Regards, Clyde
>