(no subject)

[randomdreams]

It is every meal features squash from the garden season.

Breakfast was chopped potatoes, squash, sausage, and green bell pepper with a bunch of egg scrambled into it when hot and some cheese added in.

Yesterday I spent a bit of quality shop time on the burnout oven. I tore out the remaining old analog control system, spliced two breaks in the nichrome heating element (ya know, at some point you realize you can in fact fix anything if you want to), replaced the relay that transduces the control signal to switching the fifteen amps at 120 volt power, and tuned the controller a little bit. Now I get a nice fast heat increase (I believe nine times as fast as it was before, because parallel resistance) with excellent control, so it sat at 250C plus or minus half a degree for two hours burning out the 3d print. As a result, I got a mold that has no debris in it (I can see down in) and almost no cracking, using just plaster of paris. I'd previously been cutting it with sand, which makes everything more difficult as the sand separates out during mixing. (Not the worst: the mold is down in the bottom where it's more sand.) I found when pouring this mold that when the air temperature is above body temperature plaster of paris sets REALLY FAST. I can't mix it fully and expect it to still be pourable. So I'm mixing small batches fast and pouring those in. I need to move to real investment that jewelers use, because there is absolutely no way I can vacuum-degas this, with as fast as it's setting.


At altamira16's birthday party yesterday I met a charming young man who lives quite near where I work. His job is writing software for vision sytems for autonomous vehicles, so he was kinda thrilled by my stories about the smart headlight we're building at work. But his main interest is in acquiring a big machine shop. Since he has money and lives in a field in the middle of nowhere, he's built himself a workshop the size of a house, so we spent a bunch of time scheming about the stuff he could put in that workshop. If I'm really lucky and help some, I may get occasional access to Real Equipment.

Comments

[grrlpup]

aw, look at that pretty patty-pan squash, even the name is cute!

[randomdreams]

It was delicious.
They are amazingly prolific, too.

[sistawendy]

His job is writing software for vision sytems for autonomous vehicles

Sexy! I admit to more than a little jealous curiosity.

[randomdreams]

Remote developer for Lyft! He's doing lidar. He built a 3d scanner once for fun, and more importantly, wrote the software for it. We were talking about cool projects for Android development and had the idea of a software package that runs on a cellphone, that you can put an item in your microwave and hold the phone up to the window and have the microwave table rotate it around to scan it.

[darkoshi]

Considering how much you are able to do already with the equipment you have, with access to "real equipment" you'd probably be unstoppable.

[randomdreams]

This is my hope.
I know I can't make a living as a machinist. It's hard work, long hours, lots of hustle, and a lot of dependence on luck. But if I can increase the complexity of my fabrication capability, woo woo!

[rebeccmeister]

Real Equipment, Yahsssssssss...

What's the composition for jewelers' investment? Boy, there was an era, back in the day, when I spent way too much time thinking about plaster composition, heh. I wound up concluding that it was best to switch over to dental plaster for leafcutter ant nests - hard enough that they can't chew through it, but still porous enough that it will hold enough moisture to keep their fungus gardens happy. I've also just mixed plaster of paris with hydrostone, as another option.

[randomdreams]

Most jewelry investment is proprietary mixes, but they have a bit of plaster of paris in there, along with other stuff that vitrifies during the burnout: they need burnouts of above 1200C. Since people use the term vitrify, I presume that means there's sand and lime in there.

[amaebi]

Access to Real Equipment: WOW!

I bet it's a letdown, though.

[randomdreams]

Almost anything would be a step up over what I have.

[amaebi]

It is strange and worrying to hear you sounding sad about your equipment, not that I disbelieve what you're saying.

[randomdreams]

My workshop is small. The kind of equipment I want, and that he's going to get, is the size of a minivan. What I have is adequate for work that you'd hold in one hand. What I want is work that requires both hands to pick up.

[gfish]

Oh shit, that's just plain plaster? You got incredibly good results for that!

[randomdreams]

I need to increase my investment investment, but thus far it's been doing really well if I keep the burnout temperature down.

[asakiyume]

"vacuum-degas" seems like it could be vacuum Degas, but he would probably object if he were still around to.

I'm sorry to see in the more recent entry that the stuff fell apart, but it all sounds very cool and Star Trek-like from where I'm sitting. I hope you do get to use the cool machine shop.

And that breakfast sounds delicious.

[randomdreams]

People who do this for a living include stuff like fiberglass in their molds to handle this kind of thing, but I think just casting hot will handle the problem. I could have even used this one by carefully reassembling the six big pieces and wrapping it in eg aluminum foil, but it would have been difficult to prevent it leaking like mad. (Possibility of painting all the cracks with plaster.)

[asakiyume]

What you say about repairing the cracks with plaster is making me think of kintsugi--repairing broken ceramic pots with gold.