Im sure everyone is going to think I’m crazy, but I just bought supplies to make a small foundry to try to cast some aluminum slabs to cut. It should be interesting to see if anything comes to it.
I’ve done this and have a fair bit of experience with it. If you have an automotive scrap yard nearby, get pistons to use as your raw material. They take a lot less time to melt than the aluminum cans everyone wants to start out with, don’t oxidize as badly (meaning more aluminum and less junk) and the metal pours better because it has some silicon in it.
Thanks for the advice. Did it work pretty well?
Electric foundry or gas?
Just a cheap DIY gas foundry.
Initially, I will use primarily extra aluminum pieces that I’ve used to build my other machines, so it probably won’t be as contaminated, I hope.
Once I get it built, I’ve got to figure the best way to do the molds. Has anyone used that petrobond casting sand and parting dust to form their molds? Or, does it not make a difference? It seems to me it would to remove air pockets and make it more dense.
I’m sure it will be a learning process
Another option is to machine wooden parts and use these to make sand molds to cast the parts, less waste that way.
Actually, for some parts, I’m going to 3d print them to shape the molds
@Paul_Shaw I saw in another forum you were discussing a CNC build, and you found that orienting supported rails on the top and bottom of the axes work the best. Do you find that has reduced the flex in your x-axis? Also, given the option of the supported rails (with like that rod guide) vs the all flat linear guideways with the flat pillow-top, would it make that much difference?
I just designed it that way as that was what they were saying. It’s the only machine I’ve built so not much to compare with. The supported rails are not as good as proper pillow top ones but I didn’t want to spend the money. (they are closer in price now, if I did it again I’d get them) On the x it’s been fine but I do have a bit of a twist in my table which I think caused some issues with the y rails, I had one of the plastic liners crack and the balls come out. This was from the force in the upwards direction I guess in that direction they are very bad, they can open up etc.
Main thing I tried to do was get them far apart (which reduces the effects of the slop) but has the problem of making the machine bigger.
I intended to put the rails underneath so that they were directly supporting the gantry. Wouldn’t that solve part of the problem, or no?
When you are pushing it’ll try to roll(depending on how far you’re cutting from the height of the rails) so one will be getting lifted. I’d try to get the pillow top rails if you can afford them. I used second hand ebay ones for my z.
Ok which size? 15, 20 or 25?
Not sure I used 15 on my z think most people use 20. I guess it depends on the size of the machine and other things. Is there much in the price? I can’t see any other disadvantages in going big.