Matt Walker's ghetto casting tech

You guys should still have lots of castable refractory. Use my ghetto casting tech and you can whip one up in a couple hours.

OK, we can't just let that go without elaboration. (It's also no good to have it buried in an unrelated thread, so I started a new one. )

Matt! What's this about casting a batch box in a couple hours? Enlighten us!

Well, I've been hoping to make a video, and even started building a kickstarter page to drum up enough cash to get materials to show you all how to do a bunch of styles...j, batch, big, small, etc....but I wasn't sure there would be enough interest. It would take some time to give all the info, but it's basically the same idea as my other casting video. Just make a positive and burn it out, easy as that.

Excellent, you're awesome.

You can be the first kickstarter I ever pledged to, how's that sound?

Aw shucks Mike. Thank you.

I was thinking of trying to raise around $2k to get a pallet of materials so I could show a few different styles, go into details on the materials, and show a few different configurations of construction/assembly. I would probably just try to raise the funding, then release the thing for the whole world for free on youtube rather than sell people a dvd. I really like just spreading the info since I really believe in the technology and feel like the more folks we can reach with good info, the better it is for everyone. Unfortunately I can't afford to just build heaters I don't need to show folks how to do it, so I've been trying to brainstorm a way to be able to produce content that shares the info I have without going broke. Anyway, just some thoughts.....

If anyone else is interested, just go ahead and "thumbs up" this post. If any of you have any ideas or input, how to work it, what you'd like to see, etc... I'd love to hear it. I'm still on the fence about this, whether it's a good idea or not, and if there's a better way.

Yep, I'd definitely chip in for that. I'd promote it, too. (Not that I'm a celebrity influencer or anything.)




To flesh out the topic at hand a little further:
I went and re-watched the linked video because it had been a while. Am I understanding you right, you'd feel confident enough in your hot-gluing skills to make a positive of a batch box this way? That's a LOT more fiddly little pieces. You'd still cut cement board for the hollow positive model of a batch box?


It occurred to me when you wrote, "Just make a positive and burn it out, easy as that" that some of my metalcasting friends make lost-foam castings. They don't give half as many damns about the environment as permies generally do, so I acknowledge that this won't necessarily be a popular option around here. But I'm picturing building a SOLID positive mold out of the rigid foam insulation boards (extruded polystyrene), packing the clay/perlite/etc mix around it, and melting the foam out of the way with a torch. As I imagine trying to cut and fit the beveled floor and the little bits for the port and all the rest out of cement board... it seems much more achievable in foam.

Am I missing something obvious that makes this a bad idea, beyond the disgusting toxicity?

Matt : I too would want to pledge to a 'Kickstarter!' Both Paul W. and E & E have posted a '' Thumbs up if you would like to…..'' Forum Thread regarding

a 'Kickstarter', please let us see one of those posts soon ! For the good of the Craft ! Big AL

Thanks guys. Allen, you can just thumbs up the post above, I'll use that to gauge interest. I'd rather not start another thread.

Mike, It's not so difficult. And yep, Hardiboard or plywood. At Paul's we used milling scraps. I certainly wouldn't use foam in a sacrificial mold. That stuff is nasty when it burns, and I think it would actually take more time/detail to build. Peter, myself, and many others do use foam for molding often, but only for molds that will be removed from the casting. That is the proper way to do it, but adds a lot of complexity.

What's the name of that video? My phone won't let me do anything with the embeded video.

Rick, it's "Rocket Mass Heater Cast Core Build".

https://www.youtube.com/watch?v=7ANMXGrxgnE

Has anyone else made a Walker core with a dryer vent as the positive?
I have but I have yet to fire it.
I also have a milk carton positive sitting in a toilet tank waiting for some refractory.
It's lot easier(for me) to get a few minutes to read and post than to find the time/materials to finish a rocket that the wife won't let inside the house....