Bridge cap materials

[gordon stelter]

Thanks Terry!
     Actually, that was sort of a "trick question", as
the last bridge I impregnated with epoxy was in the
portable shed ( 10'x12' aluminum ) that serves as my
hot box/finishing shop. I kept a Kenmore (TM)
dehumidifier in there cranked up full blast for about
a week before filling the soundboard cracks and doing
the bridge. When I reglued the bridge pins with Epotek
301, the temp was about 115 and the humidity 15%. Then
I wafted a heat gun from about a foot, and brushed the
"squeeze out" over the cap and down the bridge sides.
By the time it was done all done, it looked as though
it was nicely finished, not "candy coated". 
A pleasant surprise was that, after very easily
scraping the epoxied bridge tops with a razor blade to
ensure that they were truly flat, a #2 pencil rubbed
over them  made them very nice and silvery, with
plenty of control for neatness.
     Thump
     
--- Farrell <mfarrel2@tampabay.rr.com> wrote:
> >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
> > > > 
> > > > 
> > > 
> > > _______________________________________________
> > > pianotech list info:
> > https://www.moypiano.com/resources/#archives
> > 
> > 
> > __________________________________________________
> > Do you Yahoo!?
> > Faith Hill - Exclusive Performances, Videos & More
> > http://faith.yahoo.com
> > _______________________________________________
> > pianotech list info:
> https://www.moypiano.com/resources/#archives
> > 
> 
> _______________________________________________
> pianotech list info:
https://www.moypiano.com/resources/#archives


__________________________________________________
Do you Yahoo!?
Faith Hill - Exclusive Performances, Videos & More
http://faith.yahoo.com