Casting Class

[Matt Goodman]

Alright, so here are the options of how we can run this "class":

Option 1-

   Official ATX-Hackerspace class.  Everyone pays a class fee - It would be something like 15-25 bucks depending on how much we can scrounge and how many people sign up.  The space then buys the materials with that money, we get together and assemble etc.  The drawback to this all is that money, approvals, etc. have to go through the space.  I don't know how big of a deal this is.  

Option 2-

   Official ATX-Hackerspace project.  Everyone buys about 15-25 bucks worth of the materials (and or chips in to the peeps who did) , we set up a time, get together and make it all happen.  This can be pretty largely unstructured.  Not sure how tool hosting works and space concerns . . .

I put together a rough timeline and parts list on the wiki.  I am going to raise these ideas at the space meeting tonight.  Any thoughts, concerns, or remarks on the best trajectory for things?

--Matthew Goodman

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[EBo]

On Feb 15, 2:35 pm, Matt Goodman <meawo...@gmail.com> wrote:
> ... Any thoughts, concerns, or remarks on the best trajectory for things?

I would suggest not using Teflon tape, but gasline thread dope/
compound. Teflon will outgas phosgene and perfluoroisobutene (think
WWII nerve gas) if it is exposed to temperatures over 450 F. While
these temperatures should not happen in normal practice, we are
talking about a foundry area where the unexpected can occur. I'll
have to check around, but the pipe dope should be available at home
depot, lowes, and a well stocked propane place.

There is also another DIY refractory that is made in part by mixing a
high temperature stove coat that you can get from places like HD and
Lowes. I'll have to dig around to find more info, but the nice thing
is that it could take considerably more temperature than a clay/cement/
perlite/sand mixture alone.

Again, if I ever make it out to Austin, I'll try to bring one or two
venturi forge burners with me...

EBo --

[Matt Goodman]

Were making venturi burners.  :-) The refractory mix from these four is really pretty good.  The phosphate whatnot breaks down as the silica and primary clays sinter into a hard oxide face, so this mix actually gets stronger with time.  The other best addative is actully ox/cow blood because the iron lowers the eutectic of the glass.  (Romans had this down!)   Didn't wanna freak anyone out with that one on the parts list.  Plus it's stinky and stains clothing.

I wouldn't worry about the PTFE given were gonna do vinyl hoses, which will fail way before any interesting flourine chemistry will be an issue.  If anything carrying propane gets warmer than my anti stick pans, we are in trouble.
--Matthew Goodman

[EBo]

;-) Those rascally Romans... You could try adding some iron oxide
paint/cement pigment if the iron would help, and something simple like
sugar for a temporary binder if that would help.

re: PTFE...

I'll have to admit that I am hyper careful with some of these things.
I know an instrumentation technician who used to warm gages to help
separate them... I forget how much of his lungs are shot from being
gassed, but he can no longer work any more. I also realize that the
amount of tape is minuscule, but I'm just careful.

Sounds like I should talk to you about a problem I had in the wootz
foundry. I think I know what caused the crucibles to fail but have
not had the time/space/equipment to give it a try.

EBo --