[Clayart] Heat gun vs. blow torch
clayart at earthlink.net
Tue Nov 15 13:49:21 EST 2016
Toshiko Takaezu did the burning newspaper inside as well. Best done
outside. Can you imagine the smoke alarms going off and the overhead
sprinklers? Mike Gordon
On Nov 14, 2016, at 4:34 PM, David Woof wrote:
> Applying heat to the interior of a piece, as well as exterior,
> confines the heat and so more uniformly heats outward thru the inner
> walls and so brings the entire piece up to an evaporative state, vs
> trying to evenly heat the exterior either with torch or gun, both of
> which "spot" heat in the larger sense.
> For the really big "pots" of yester-year I rigged a propane fueled
> weed burner onto an adjustable tripod stand and with wheel turning
> slowly applied heat where needed. Out doors, crumpled news print
> tossed and burned inside the piece is effective, and a "get their
> attention" crowd curiosity pleaser if done in a public venue. Been
> there, done that....this old dog is no longer seeking the public eye.
> Oops did i just say "old?" Nah!
> david Woof
> From: Clayart <clayart-bounces at lists.clayartworld.com> on behalf of
> Vince Pitelka <vpitelka at dtccom.net>
> Sent: Saturday, November 12, 2016 4:33 AM
> To: 'Clayart international pottery discussion forum'
> Subject: Re: [Clayart] Heat gun vs. blow torch
> I think the essential warning in using either torch or heat-gun (aside
> from "don't set anything on fire") is to apply gentle heat, moving the
> heat-source around constantly. The objective is to just warm up the
> clay in order to hasten evaporation, but that happens fastest at the
> surface. I have used torches so often to warm up pieces for faster
> stiffening to leather hard, and I have a good feeling for it, so I
> never experience problems with cracking, even when warming a piece to
> the point where you can see steam rising. But in my Intro to Clay
> class, students frequently see surface cracking by applying too much
> heat with the torch, causing the surface clay to shrink faster than
> the interior. Obviously this is most critical on thick-wall pieces or
> small solid pieces, where it takes time for the moisture to move from
> the interior to the surface.
> The "open flame" warning isn't really a valid reason to use a heat gun
> rather than torch, because the heat gun puts out air far above the
> kindling temperature of carbon-based fuels and can start a fire very
> easily. Yes, the torch flame will bring wood or paper to the ignition
> point much faster, but since it is a visible flame, the chances are
> far less that anyone would let that happen.
> - Vince
> Vince Pitelka
> Appalachian Center for Craft
> Tennessee Tech University
> vpitelka at dtccom.net
> Vince Pitelka - Tennessee Technological University
> I have been a studio clay artist for 45 years, teaching clay at the
> university level since 1986, the last 22 years in Tennessee
> Technological University's School of ...
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