Have we discussed foundries?

Alright, I was watching this one.

https://www.youtube.com/embed/VTzKIs19eZE

How the heck do you clean the crucibles or, in this case, the bricks to switch between metals?

You don't. He's used that in other vids and he starts by making a new brick.

Also cleaning up between metals only matters if you care about purity. I'm not too concerned with purity, but I do have separate crucibles for copper alloys and aluminum. Probably shouldn't use a steel crucible at all like my aluminum one, but I'm not planning to make anything other than ornamental junk for now anyway.

Right now, I have a 12 quart bucket of mix curing next to the pellet stove, and 2 steel extinguishers to cut down for crucibles. I'm missing one important part though.

Did I see you make your lid in a 5 gallon bucket? I'm afraid of breaking it getting it out doing it that way, but I'm a little short on shallow buckets.

And I have a thought. Do you, rufledt or anyone else, know if there would be a problem with strength of the lid if instead of using a hole saw to cut the vent, I poured the mix around a can or something where I want the hole to be? I've got stainless scrubbies I'm going to cut up and lay in the mix to try to add some strength already, but I'm hoping that acts as extra strength instead of replacement strength, if that makes sense.

I added a little bit to his mix ratios(2 buckets instead of dry instead of 1 3/4, 2 buckets of water instead of 1.5) since I was using a bigger bucket, and think it's fine other than a little too much water from the cavity bucket leaking. Could also just be that I did it outside in 40F temps before saying I'm cold and moving everything inside.

Should be firing it up for the first time tomorrow or Saturday with some cans just to test.

Yes i used the bottom of a 5 gallon bucket to cast the lid. I had a slight crack getting the plaster/sand lid out of there, but no such problem getting the castable refractory lid out of there. I did take quite a lot of persuading to get it un-stuck, however...

Drilling a hole through the plaster/sand was easy, drilling through the castable refractory was basically hopeless, though i don't have true masonry bits. I basically got a few holes drilled in it and pounded a hole out the bottom. halfway through page 3 of this thread i posted a video of me remaking the thing, and yes i used a can. It gives a much cleaner hole than drilling it out with a hole saw. Castable refractory is freaking concrete when it's set, so drilling was a bit tough...

i didn't really follow his ratios or amounts perfectly for the same reason you said, my bucket was a little bigger. I made extra. I tried to get the ratios close, though.

post pics when you make stuff!

In reply to Brett_Murphy:

Came to post this, I need to make one....

Well, 20 hours later and

The top couple inches STILL aren't dry to the touch. Maybe I used too much water. but there is a physical difference I hope the picture conveys between the base and the top. It's been in front of the pellet stove all night, so dry, warm air should be helping.

In reply to RevRico:

Nice! Looks like yours has a lot thicker walls than I did. That might be why mine lost so much heat out the sides and broke down so quickly. Are you planning on using gas or charcoal? If charcoal make sure your crucible is small enough that you can still fit enough charcoal in there

for now, regular kingsford charcoal. I'm using fire extinguishers, and while I've not cut them down into crucibles, they fit the bucket I used to make the depression with room to spare. I'll get some shots up when I cut them down. I'll either be welding rings onto them or drilling and installing eye bolts. 2 at the top lip, and one on the bottom. The thought being it will make holding onto it with tongs easier, and maybe make pouring easier as well. I'll be making the jump to propane come summer, when I figure out a way to keep the tank from freezing over during use.

I got an ebook copy of the Gingery book and started reading it last night... So now I'm looking for green sand. And trying to do math that I barely understand. I want to have enough metal to do the whole lathe before I get started, so I need to crunch the numbers and figure out the weight of ingots it will take.

I guess while I wait for the body to finish drying I can get the lid made. I'm using 3" stainless exhaust clamps for handles, and forcing stainless steel wool into it to hopefully help, but I think I said that part already.

ninja edit: the test fit is tight. But if I'm careful during setup, I can have a single thick layer of charcoal on the sides. While this is still soft and maleable, I might try to cut it out some more, but I really don't know how.

I used a 2.5qt paint mixing bucket from home depot, and already think I need something a little taller and a little wider. I think before I make one out of refractory cement, I'll buy a real crucible and set the size off of that.

I don't know exactly how much aluminum is needed but one of the first parts is the huge one, so you do need quite a bit at first (and a special flask). I wish I had one of those small extinguishers, the only free one I got (that was steel) was kinda big. I've never filled it more than 1/4 full...

Rufledt wrote: I don't know exactly how much aluminum is needed but one of the first parts is the huge one, so you do need quite a bit at first (and a special flask). I wish I had one of those small extinguishers, the only free one I got (that was steel) was kinda big. I've never filled it more than 1/4 full...

I'll see what I can do. There are flat rate boxes available that they fit in. My buddy I used to do fire alarms with is still in the business, so junk and uninspectable steel and aluminum ones are plentiful. I should actually be getting some aluminum ones to melt down as stock.

Well it's been well over 48 hours now, so I'm just going to trash the bucket and try again tonight or tomorrow.

I did manage to mix up a lid last night, set and cure in under an hour. I added a step I should have when I mason the bucket and mixed the dry components together before adding water. I used a solo cup for the vent, and it looks interesting. Slightly bigger than a beer can so it should work fine. I'm just at the tricky part of needing to get the lid out of the bucket. I wish I had a spring form cake pan for this, would make it much easier.

Edit update 35 minutes later. I broke the seam on the bucket hammering the old refractory out. Oops. But I mixed a new batch with less water and it's holding the bucket by itself already. Took an hour to get to that point Thursday.

So while I'm scavenging stuff to actually melt, and stuck inside due to weather, this weekend project is building flasks and maybe making green sand.

I was going to go to home depot and buy some 3 inch bar stock, thinking steel would be nice and stiff and I could practice welding, but found 3 pine 1x4s I forgot I bought for a project that never happened. So I'm making room wherever I can to actually get my saws out and do some work. I'm thinking a 9x9 and a 12x12 should be good enough for most projects I come up with and not require hundreds of pounds of sand to fill.

After lots of videos and Google time, I found the cheapest way to make green sand for my purposes will be play sand and kitty litter. Sift the play sand, grind then sift the kitty litter, and mix 10:1, adding roughly a quart of water per 30lbs of mix. I might not even add the water until I know I'll be forming something, but I have a bunch of 4 gallon buckets with lids that should act as storage containers. Take that petrobond at $90/fifty pounds.

What a coincidence! I'm going to make some flasks too! Roughly the same size, too. The kitty litter and sand mix is used by a guy with the YouTube channel "Makercise" to make the gingery lathe, and his castings look pretty darn good. Not as great as some other vids where people use petrobond, but like you mention it is far more affordable. I don't know how I lucked out but I got a batch of petrobond for super cheap, like a buck a pound, but I haven't seen that deal come up since.

I'm approaching the point where I feel good enough to handle molten metal again, so I'll probably be casting actual things in sand within a couple weeks if all goes to plan. Of course shortly thereafter the doc is gonna cut my other wrist open and I'll be out of commission again

Tip on the sand, mix in water a couple days ahead of time. The Ammen sand casting book talks at length about mixing sand, and he says even with mechanical mullers and everything, the sand will always work better after being allowed to set for a while. Before this period he says it may seem like the sand isn't wet enough and you could add too much water, not realizing until the next day when it's all sloppy. Don't know why sand does that, maybe water soaking slowing into the clay?

Also with that post I am now an UberDork

Once I discovered that I do in fact own 2 drills, flask making became really easy. Until I got to making the jig things to align the cope and drag, and realized I don't have screws short enough that they wouldn't come through into the molding area.

and there we have a 12x12 and a 9x9. The 12x12 is internal dimension, the 9x9 is closer to 8.5x9.

Made them from 1x4 clear pine, 1 5/8 drywall screws holding the corners together. They aren't perfect but within about 1/16". Considering I don't have a single flat surface to work on, floor and B&D workmate top included, I'd say that's pretty good. Tomorrow I'll run out and grab some 1.25" screws and either latex paint or some sort of stain to seal the wood from moisture. Here is the lid that I made with a solo cup for the vent hole. It needs filed just a touch on the bottom, but is almost perfect for cans to drop right through.

And the new foundry. I still haven't filled it full of charcoal yet, but I should be able to fit a layer in between the crucible and the walls.

Speaking of crucibles, I just ordered a 4kg graphite crucible from China for $23 shipped, should be in around the 18-21 according to the shipping estimate. I'm not 100% on its dimensions, so I may need to modify the foundry walls for it to fit. I might also hold off on using it all together until I switch to propane, as I think I'll be making a new foundry entirely when I make that jump.

But overall, a productive evening in the garage. I didn't plan on actually doing this tonight, I just started sweeping and moving stuff around and when the space opened up, kinda kept going.

don't know why, but I REALLY like the hole that hte solo cup left in the lid! Also those flasks look pretty awesome. If they aren't perfect i doubt it's going to be a problem, most of the ones i see are covered in burn marks from molten metal mishaps and they seem to work fine.

So i finally got around to test firing the new foundry lining:

https://www.youtube.com/embed/VbwYOe7gRCs

Basically, it seems to hold up better than plaster/sand, but it isn't as insulating as the plaster. I was told by a guy at alloyavenue that this lining falls under the category of 'dense refractory', which isn't highly insulating but is designed to stand up to the heat without losing strength. That's perfect, because i'm going to focus primarily on aluminum from now on until i build a bigger, more insulating one.

I have a growing pile of cast aluminum and purer aluminum (sheet, extrusions, cans) without silicon in it. Probably this weekend i'll be firing it up and trying to make some ingots of the cast aluminum, and also making purified ingots out of the cans (the first melt of them loses SO MUCH to slag and oxidation). That will be fun, hopefully it's productive.

Once i get the ingots and flasks built (just finishing up some flasks BTW) i'll get to casting some stuff. Project #1 in the gingery book is some core plates. I don't know exactly what they will be used for, but Gingery says they will be useful in the later projects, so i'll believe him.

In reply to Rufledt:

Very nice! That is a sexy outfit

Question for you guys, on the arc furnace posted, I believe he uses an AC welder (made from microwave transformers, but anyway) would DC work for this?? I have an old welder that I could use as a power supply for it....

So it turns out that my foundry is too small for charcoal. And for some reason, both torch heads I had for my propane torches aren't torching. Just slow leaks, from both of them, with no pressure or flame.

So I went with idea number 2 today, not wanting to waste a dry, kid free day, and used my charcoal chimney as a foundry. I had a really difficult time keeping my hair dryer going with it, so it froze a few times, but I managed to melt 2 30 packs of beer cans into some cute ingots and a bunch of dross. I'm keeping the dross for now, I have a theory with it I want to test later.

That said, I think my foundry will work with propane, so I'm going to finally make myself a propane burner and try it out. I might just say screw it today and use my turkey fryer for the rest of the cans I have laying around, see how that works out.

Anyway, here are some pictures. I'll start my own thread when I get some more things figured out, I promise.

2 30 packs in molten form

ingots and dross

in the mini mold

Awesome! A guy on alloy avenue told me what he does with the dross is to slowly add more and more flux (lite salt in his case) until the aluminum gets flowy enough to stop sticking to the dross. The dross then loses its shininess and you extract maximum aluminum from it. That's what he says and I'm going to test it soon. Unfortunately the thinness of the cans and all the plastic lining junk makes a lot of dross/oxide I hear. I've only melted down cast scrap so far, though, and that stuff is very clean.

So I melted a garbage can worth of cans over the weekend. Got lots of aluminum, recovered most of it from the dross too, but I don't think I'll do cans again. So much smoke, fire as the plastic burned, and the residue of Mountain Dew burns with a familiar and disgusting smell, kinda like bacon that is over cooked.

So, other than the cool factor of making alloy muffins from scrap, what is the eventual plan for the ingots? Maybe cast a set of wheels for the Powerwheel Jeep project?

I melted down some more cans this weekend too. Unfortunately, thanks to an alcoholic friends I will never run out of cans.

I did start working on my propane burner, and when I get it working I'll start up a build thread. I want it working right before hand though in case anyone is crazy enough to copy me. The first project for that burner will be re melting the dross from all my cans and trying to clean up for aluminum.

For the crappy can metal, I may just make sinkers out of them for fishing. The mini muffin mold weighs about 3.5 ounces, and is a decent size for river fishing.

I also picked up the body for my next furnace, and got my made I China graphite crucible in the mail today. Now that I know how big the crucible is I can build around it. Going to be going with FishbonzWV furnace setup, 20lb propane tank with ceramic wool and satanite for insulation and hot face.

I get that there is a lot of learning to be had, but I'm thinking with my 44 pounds of cast aluminum wheels that I'll be melting down, I should have enough quality material to start on something from the gingery books. Considering how bad I need a drill press, I might just jump in with both feet and start that project. Should probably read the build book first though.

In reply to NOHOME:

With the cans I'm just going to use it for making alloys since it's pure, most likely aluminum bronze given how much copper I also have, but that's not a near term project.

I have a bunch of cast aluminum scrap now which contains silicon for better casting, using that I want to make odds and ends for the powerwheels after I get it welded together. Over the weekend I ran some wiring for the welder, but unfortunately tomorrow I'm getting the carpal tunnel surgery on my other hand so I'll be out of commission for a couple more weeks. I've been putting a lot of that off because the hammer forms for the fenders will require a lot of hammering, and my lumber brake requires me to lean heavily on it to get it to bend and my right hand still isn't up I that yet

I want to make cast aluminum hood latch things for the jeep. The Willys cj2 has 4, the powerwheels came with 2, both of which are busted (plastic). I also want to try to do the blinkers in cast Al, maybe headlights if I can't do something else with those, and I really want to do a fuel filler cap that opens to reveal a charging jack. I was racking my brain trying to figure that out but if I can cast it myself that will be less complicated. Also the powerwheels steering wheel is crap, I kinda want to try making an aluminum one. Im just going to use the powerwheels wheels because they have hubs that engage with the motors.

Final thoughts about melting cans, lots of fire and smoke, tons of dross that is not fun to clean from the crucible, and lots of porosity in the ingots.

It takes so long to melt the cans that it stays liquid for a very long time, and probably sucks up tons of hydrogen. fortunately the next time i melt these ingots it wont have that problem, also i will de-gas the stuff before pouring.

for all the dross i used a technique someone on alloy avenue told me about. Basically take a 50/50 mix of sodium chloride and potassium chloride (also know as low-sodium table salt, like morton losalt) an keep adding more and more until the aluminum becomes flowy enough to stop sticking to the dross.

According to a book by Ammen, too much flux can cause problems when sand casting, like causing the extra slippery metal to flow through the parting line in the sand and stuff like that. I would assume that could be solved taking these ingots next melt and throwing in a bunch of heat sinks to dillute the flux. i was told the flux remains in the metal to an extent. Fortunately if you use cast aluminum, you wont need to flux the life out of it since there is very little dross.

To melt them i made a pool in the crucible with pure aluminum from plate and a heatsink first. that way when i dunked the cans in, they were shielded from the oxygen in the air bt the pool of aluminum, to minimize oxidation.

The reason i'm keeping these separate from any cast aluminum is because i want pure stuff for making alloys later. I was told using cast aluminum to make aluminum bronze results in something that just looks like silicon bronze, but pure aluminum makes gold colored aluminum bronze. Besides i want my growing cast aluminum stash for casting, not alloying.

I made a video of the whole thing:

https://www.youtube.com/embed/p0S-cwzK2GI

It was fun to try, but honestly i would just use extrusions if you want pure aluminum. cans are a huge, eye burning hassle, and i still didnt get all the dross out of the crucible. a few big heatsinks have dozens of cans worth of metal in them, but no plastic to burn.