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PMC Banana


#1

I “inherited” a dried-up banana that has been thoroughly covered
with a shell of PMC. The shell has dried bone-hard.

Can I just fire it straightaway?

Should I cut it to evacuate gases?

My heat sources are:

-Prest-o-lite air/acetylene torch on small MC cylinder.
-Propane/oxy little torch with rosebud heating tip.
-Oxyacetylene Little torch with “regular” #'s 1-6 tips.
-A single burner for cooking from one of two 20# propane bottles.


#2

Sounds like you had better put a hole in it somewhere or it will
explode.

V.


#3

I would not recommend torch firing this piece because the organic
material needs to burn off. Many places that sell metal clay
supplies will also kiln fire pieces for customers. Try to find
someone to do this for you instead of using a torch. If you’re in the
Minneapolis/St Paul area, feel free to contact me directly since I
provide firing services for metal clay pieces.

BBR - Sandi Graves, Beadin’ Up A Storm
Stormcloud Trading Co


#4

A PMC banana? Oh boy, now I’ve heard everything. I would not try to
torch fire this thing. And if I did, I would have a friend and use
two torches at a time.

I’m concerned it may collapse upon firing, because of the
hollow-lack-of-banana-ness inside. I would fire it on a bed of
vermiculite in a kiln.

Holes to evacuate anything are not necessary.

At one point in the firing the PMC is so porous that any steam just
goes right through.

You’ll need a very slow ramp speed to burn off that banana peel.

Yeah, you’ve gotta do this with a kiln.

Good luck, and please post a picture when it’s done.

I would also suggest you email tech support at

http://www.PMCGuild.com

and see what they have to say.

Elaine

Elaine Luther
Metalsmith, Certified PMC Instructor
http://www.CreativeTextureTools.com
Hard to Find Tools for Metal Clay


#5
Sounds like you had better put a hole in it somewhere or it will
explode. 

No, it won’t. PMC is porous enough to fire colsed hollow forms. It
may collapse, however, depending which version of PMC it is and how
thick. It will help to sink it part way in a bed of silica sand
during firing. Of course, a hole will do no harm…

Noel


#6

I agree, kiln fire is the way to go. I think this is a great idea!
Play with it! If it collapses, who cares, it is still silver and can
be recycled. Jennifer Bowie painted pmc on rock and fired it. Some
rocks cracked, some worked great. The point is to experiment.

Just do it! Tell us what happened and send along a picture if you
can.

-k

M E T A L W E R X
School for Jewelry and the Metalarts
50 Guinan St.
Waltham, MA 02451
781 891 3854
www.metalwerx.com


#7

So is it correct that I can make an enclosed item (pendant, etc.) in
PMC and fire it without an opening?

V.


#8
So is it correct that I can make an enclosed item (pendant, etc.)
in PMC and fire it without an opening? 

Metal clay has a certain porosity because of the binder that burns
off during firing. Organic materials and cork clay that is used to
make hollow items can burn off without adding a hole for escaping
gasses. This, of course, would not be possible in true silver or
other metals - only in metal clay products. I would, however,
recommend firing your kiln in a very well ventilated area since you
will get burn odor and it will be “on fire” i.e., you will have
actual flames burning in the kiln. I usually try to stick to fairly
small pieces for burn-out because my kiln is quite small, but if you
have a larger kiln you certainly can move up in organic size. Good
luck and please let us know how it went after you’ve fired it. (You
may also get some slumping in the center of the item because of the
large hollow space and the need to fire for a full 1-2 hours at 1650
to effectively burn out that quantity of organic material.)

BBR - Sandi Graves, Beadin’ Up A Storm
Stormcloud Trading Co


#9
So is it correct that I can make an enclosed item (pendant, etc.)
in PMC and fire it without an opening? 

Yes, this has always been true. During the firing, at some point, the
PMC is so porous, that the stuff you’re burning out goes out through
the holes/openings/spaces in the PMC.

This is why you can burn out a combustible core, in say, a bead. Like
cork clay.

It’s not like regular metal, it’s a completely different way of
working.

Until it’s fired. Then you can treat it pretty much like regular
metal.

Elaine

Elaine Luther
Metalsmith, Certified PMC Instructor
http://www.CreativeTextureTools.com
Hard to Find Tools for Metal Clay


#10

Many thanks to everyone who chipped in.

I’m inquiring to Hot Flash Glass in Albuquerque for the kiln firing.
I will be over there on 4 November on other business, and will
deliver the banana to the designated kiln then.

Keep needling me for results, 'cause that’s how I work!

Dan


#11

Hi, I’ve been away so am late on this thread, but using cork clay as
a base for a hollow PMC form is really great. The cork smells fairly
strong as it burns away in the kiln, but it ensures’ that a hollow
form keeps it shape throug firing.

All best,
Nancy in Vermont


#12

Orchid Forum wanted to see this take shape, and I owe them that
much.

Artist: Karen Dodson, via Dan Woodard
Descriptions: “Inherited” PMC Banana, stage 1
Photo: http://www.ganoksin.com/ftp/pmc_banana.jpg
Photo Credit: Dan Woodard


#13

looking at the photo, it would appear that the slip is still pretty
thin - you will probably not end up with what you’re expecting. a
safe rule of thumb in that the pmc slip should be at least 1mm thick
when dried to achieve a successful firing - of course on a banana
that
size, it’s going to get pretty pricey to cover at 1mm thick…