Hi guys,
In my experience the best linig can Be:
if you will melt aluminum use fiber blanket, see this video (sorry is in spanish).. the furnace weigt is around 18 punds (very light !!!!!)
http://www.youtube.com/watch?v=eNnzEwVfTUk
but if you willmelt also copper alloys I use a backuo linig (joint with the metallic shell of the furnace a 1 inch of rigid fiber board and 1/2 of fiber blanket, then 1 inch of refractory material that is aviable in Mexico (at 0.19 US cents by kilo) (around 7 cents by pound), and work very well as a working face.
--- El dom 24-abr-11, Matthew Tinker <mattinker@yahoo.com> escribió:
De: Matthew Tinker <mattinker@yahoo.com>
Asunto: Re: [gingery_machines] Another refractory lining question
A: gingery_machines@yahoogroups.com
Fecha: domingo, 24 de abril de 2011, 17:49
David,
I hadn't made the "by-pass" tick-over set up that Mickey" describes. As my set-up is, I can melt long lengths of Al straight into the crucible. I am pleased with the fact that I can have a chimney to take away the CO2 as I've done all of my casting indoors!
I am at present assembling the "bits" to make my new burner. I can't find "tweco" mig tips here, so I'm going to order them from the US. I've been looking for equivalents, but I can't find anything long enough. ITC 100 is also to buy here, but I've found a supplier in Ireland!
I don't know too much about thermodynamics, it just "seems" that if it gets hot enough on the inside without it heating outside too much, then it must be better!
Regards, Matthew
Matthew TINKER
CNC conversion 1944 Colchester Lathe build-up log
http://www.cnczone.com/forums/showthread.php?t=35519
--- On Sun, 24/4/11, David G. LeVine <dlevine@speakeasy.net> wrote:
From: David G. LeVine <dlevine@speakeasy.net>
Subject: Re: [gingery_machines] Another refractory lining question
To: gingery_machines@yahoogroups.com
Date: Sunday, 24 April, 2011, 19:09
On 04/22/2011 06:05 AM, Matthew Tinker wrote:
> Hi,
>
> I don't want to "thread jack", but the "lid" to slow down the gasses made me think about my furnace lid and it's eminent need for relining. I have posted three Photo's of my foundry lid in my "Matt Tinker" file. The exhaust comes out of the side of the top. The reason I did this was to be able to have a pipe running outside to take the CO2 away, inside apartment casting! I made it so that it would be a smooth transition, not resisting the passing gasses! The main body has a 2" high temp lining, but the lid is still fire clay that needs replacing. My burner is too big, a 1 1/4" mongo that I made about ten years ago, with the actual setup, I have a 2' long flame coming out of the exhaust! I bought Mikey's burner book, and a 1" is in the "pipe line". So before I redo the lid in high temp, I'd like to know what you think about setting up a side exhaust. I can take the lid off to fill the steel crucible without having a face full of "dragon's breath"!
>
> Whilst writing, I can hear myself say, firdt make the Mikey burner and then experiment before using the high temp.
>
> curious about your thoughts, regards, Matthew
> Matthew TINKER
In his book, Mikey discusses a needle valve/main valve setup. Basically
a pilot flame when the main valve is off. If you turn off the "main"
valve for a short time before the lid is opened, I would assume the
dragon would be asleep while you give it more "treasure." As soon as
you close the lid, the dragon awakes and breath comes out of the proper
exhaust.
On another matter, assume almost perfect insulation (R approaches
infinity), no matter how thick it is, the face will be hot instantly.
Add in a thermal mass (the melt) and heat time will be related to the
mass to heat and thermal input. So, for a hypothetical load, 1 pound of
melt and 1 BTU of thermal input will raise the temperature one degree
F. If there is a perfectly conducting hot face with a thermal mass
similar to water which weighs 1 pound and has an R value near zero, the
system will only increase 1/2 degree. If the hot face has lower
conductivity (than, say, silver), there will initially be a gradient
across it and the melt time will be between the time for zero
conductivity and infinite conductivity (thermal mass is still there.)
With the thermal mass of the insulation up to temperature, dropping the
"cold" melt into the mix is the same as starting the mix plus insulation
at a higher initial temperature, so the melt will go faster.
Yes, if the insulation is hot, the melt will get to casting temperature
faster, but because the system looks like it starts at a higher
temperature, or that is how I remember classical thermodynamics. ;^)
Dave 8{)
[Non-text portions of this message have been removed]
[Non-text portions of this message have been removed]
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