Bridge cap materials

[Farrell]

>From the West System web page:  http://westsystem.com

Click on "Using West System Epoxy".

Or for a complete tretise, complete with color 8x10 glossies with circles and arrows and a paragraph on the back of each one, do a search on their site for "thinning epoxy", then scroll down the results to "Thinning West System Epoxy". You'll get everything you ever wanted to know about thinning epoxy........and more!

>From the West System web site:

There are epoxy-based products specifically designed to penetrate and reinforce rotted wood. These products, basically an epoxy thinned with solvents, do a good job of penetrating wood. But the solvents compromise the strength and moisture barrier properties of the epoxy. WEST SYSTEM epoxy can be thinned with solvents for greater penetration, but not without the same compromises in strength and moisture resistance. Acetone, toluene or MEK have been used to thin WEST SYSTEM epoxy and duplicate these penetrating epoxies with about the same effectiveness. If you chose to thin the epoxy, keep in mind that the strength and moisture protection of the epoxy are lost in proportion to the amount of solvent added. 

There is a better solution to get good penetration without losing strength or moisture resistance. We recommend moderate heating of the repair area and the epoxy with a heat gun or heat lamp. The epoxy will have a lower viscosity and penetrate more deeply when it is warmed and contacts the warmed wood cavities and pores. Although the working life of the epoxy will be considerable shortened, slower hardeners (206, 207, 209) will have a longer working life and should penetrate more than 205 Hardener before they begin to gel. When the epoxy cures it will retain all of its strength and effectiveness as a moisture barrier, which we feel more than offsets any advantages gained by adding solvents to the epoxy.

Terry Farrell
  
----- Original Message ----- 
From: "gordon stelter" <lclgcnp@yahoo.com>
To: "Mike and Jane Spalding" <mjbkspal@execpc.com>; "Pianotech" <pianotech@ptg.org>
Sent: Thursday, October 17, 2002 7:32 PM
Subject: Re: Bridge cap materials


> Thanks!  I thought this was why pre-catalyzed finishes
> stayed liquid in the can:that the lacquer thinner kept
> the catalytic action from occurring, but once it
> evaporates after spraying all's back to normal, and
> the chemical reaction proceeds. Are you quite sure????
> Can you cite an authoritative source that states that
> thinning weakens the finally cured product? In any
> event, there are water thin (Epotek 301) epoxies that
> should permeate bridge material just fine, even more
> so if GENTLY warmed by wafting a heat gun over at high
> altitude. AND WEARING A CARBON FILTER MASK!!!!!!
>      But over warming WILL weaken the cured product.
> This I know, so be cautious.
>      Thump
> 
> --- Mike and Jane Spalding <mjbkspal@execpc.com>
> wrote:
> > Richard,
> > 
> > You're right on track with that concern - thinning
> > will reduce the strength of the cured epoxy.  Don't
> > thin epoxy with either acetone or lacquer thinner if
> > it's an a structural application.
> > 
> > Mike
> > 
> > ----- Original Message ----- 
> > From: Richard Brekne <Richard.Brekne@grieg.uib.no>
> > To: Pianotech <pianotech@ptg.org>
> > Sent: Thursday, October 17, 2002 4:27 PM
> > Subject: Re: Bridge cap materials
> > 
> > 
> > > Hi Dale.
> > > 
> > > Thanks for the advice. The reason I asked was that
> > I was
> > > concerned that some thinners might impede or
> > somehow be
> > > detrimental to the epoxy hardning. Just want to
> > make sure
> > > before I try anything like this :)
> > > 
> > > Cheers!
> > > 
> > > RicB
> > > 
> > > Erwinspiano@aol.com wrote:
> > > 
> > > >>         I used acetone for this process but
> > nitro
> > > >> celloulose lacquer thinner will flash off
> > slower and
> > > >> perhaps penitrate further. Have only done this
> > a time or
> > > >> two.
> > > >
> > > >
> > > >             Dale
> > > 
> > > 
> > > 
> > > --
> > > Richard Brekne
> > > RPT, N.P.T.F.
> > > UiB, Bergen, Norway
> > > mailto:rbrekne@broadpark.no
> > > http://home.broadpark.no/~rbrekne/ricmain.html
> > > 
> > > 
> > 
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