[TheForge] Strengthening castable refractory

Sun Aug 31 11:32:00 2003

Hi Marc,

I don't remember the exact dollar amount.  It was enough for me to take the
advice at the refractory office and skip it.  Normally I figure my labor and
the value of the tool isn't worth trying to save a little money.  Maybe it
was just the convincing argument that the well respected saleswoman made
(Donna I think, now at Smith Sharp last I heard), that the needles would see
such high temp that they would burn out.

I think I mentioned earlier that I could peek between the inner refractory
shell and the outer insulation behind it and see that the refractory gets
like orange hot maybe more all the way through.  I can imagine the needles
deteriorating in that environment.  A recent replacement of refractory in a
boiler at work showed that the stainless clips welded to the metal shell to
anchor the refractory were all just about gone.

Anyway, I cast mine about 1" think and got away without the needles.  But if
they are that cheap it's not worth arguing about.  If I could get them that
cheap I'd probably throw them in next time.

I fond that the most important thing was to talk with the factory techie
about the specifics of the product you intend to use.

Ed

----- Original Message -----
From: "Marc Godbout" <[email protected]>
To: <[email protected]>
Sent: Sunday, August 31, 2003 6:22 AM
Subject: Re: [TheForge] Strengthening castable refractory

> Was that $50 for the needles? Mine cost $18 for 2 lbs, but I only used
> maybe a few ounces. The refractory guy said that for 25 lbs of
> insulating castable I only needed an 8-oz cup of them. Using
> more wouldn't hurt, but didn't really help.
>
> -Marc
>
> On Fri, 2003-08-29 at 22:21, Ed F wrote:
> > Hi Chuck,
> >
> > Have you ever broken a used forge, by chance, and seen if the ss needles
> > survive repeated heat?  Maybe if they do burn out they still help avoid
> > shrinkage cracks during curing.  I seem to remember that it would have
been
> > in the ballpark of $50 and I was kind of directed away from it at the
time.
> >
> > Ed
> >
> >
> > ----- Original Message -----
> > From: "Chuck Robinson" <[email protected]>
> > To: <[email protected]>
> > Sent: Friday, August 29, 2003 6:27 PM
> > Subject: Re: [TheForge] Strengthening castable refractory
> >
> >
> > > Hey Bruce,
> > > My son just dropped off a box of the needles. Under the microscope
they
> > are
> > > convex on one surface and concave   on the other.
> > > The overall surface is also micro dimpled. I seriously doubt that they
> > > could be duplicated using any kind of wire or tooling available to us,
and
> > I
> > > sure wouldn't find the effort, cost effective.
> > > $ 9 lb looks a lot more reasonable to me now.
> > > Chuck
>
> --
> Marc <[email protected]>
> --
> Marc Godbout
> http://www.ironringforge.com
>
> New England Blacksmiths Membership Director
> http://www.newenglandblacksmiths.org
>
>
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