Thread: A Saturday at the backyard foundry

Hi!

That's what we did last Saturday:
[ame=http://www.youtube.com/watch?v=SLVmt7wsAAU]A day at the backyard foundry - YouTube[/ame]

I'd like to have that every weekend, minus the work before and after.


Nick

Fantastic Nick. Thanks for posting.

Wow, you guys are set up big time.

Glad to see you poured it before you had the barby and a few beers.

Interesting stuff casting alloy.

I cast my own gear blanks but you are way ahead of my beginner efforts.

Rob

Glad to see you poured it before you had the barby and a few beers.

We quickly realized, that this is the right sequence.
At our first G&G ("Grillen und Giessen"; thats "Casting and BBQ") last year, we first had the BBQ. With the result that we had our last pour at 2 in the morning.

Unfortunately, I have very little takes of the finished parts (I found the missing clips, iMovie didn't like them). Next time, I'll ask the camera man to put more focus on the castings.

Before someone asks: The bubbling aluminium is from degassing tablets.


Nick

Wow! That looks fantastic. And I thought raku firing was fun.

And I thought raku firing was fun.

The furnace as seen here is only in idle.

I broke my lid on the top. When I have casted a new one out of refractory concrete, I'll make a video about the furnace.
At full throttle, it has 200 kW.


Nick

Hi Nick,
Great setup you have there.

Is that an oil burning furnace?

Stuart

Is that an oil burning furnace?

Yep!
I'm still working at the temperature. I can melt CI, but it's not hot enough for pouring. I'll find that out ...


Nick

Well done Nick and friends, you are obviously well versed in many of the different aspects of casting metal. The support infrastructure , like the muller and were they 3D printed cores in the base? in any case it was most impressive, especially with the large number of your friends involved too. Good to see the high standard of protective clothing too.
Anyone else looking to emulate Nick, but not yet with his knowledge and experience, would learn plenty from watching the many youtube videos uploaded by myfordboy. He covers pretty well everything from building the furnace, making patterns, cores, molding, casting and machining. He has lots of good stuff, and explains why he does it as well as showing what he does. For some reason a google search for myfordboy throws up a lot of other stuff, but this link should get you on to myfordboys stuff on YouTube.
myfordboy - YouTube


Our own forum member RayG also has some excellent material with in depth explanations. Here are links to the first 3 parts to get you started, and just use the search function on this forum to get the rest of them.

http://www.woodworkforums.com/f65/ca...rt-1-a-143167/
http://www.woodworkforums.com/f65/casting-tools-part-2-burners-143176/
http://www.woodworkforums.com/f65/ca...uction-143298/
Rob.

Have you thought about preheating the air? I've been tossing around ideas, nothing I like yet. I think with propane you could go as high as 400C. That would have to help things along wouldnt it?(not sure about oil burners though)

Stuart

Yes, MyfordBoy is very informative to watch!

Re protective gear:
I started in pants, but it got hotter and hotter the bigger the crucible got. This is my thir furnace. The other smaller ones worked with charcoal. But that got too expensive when you get the oil for free.

Re preheating the air:
Yes, I thought about that. With 200 kW, 70 kW are spent on heating up the air. But if I use preheated air, my A/C blower from the VW Passat no longer works. There's also the question where to take off the hot air. If I take it off from the outside of the furnace, I pay with higher heat losses. Also, IIRC, I'm losing less than 20 kW through the walls. So, that only would be 20 kW, that's only 10%. Not a big step forward. The right place would be the exhaust, but then the furnace gets really clumsy and hard to handle. At least with this design. A long exhaust pipe (with a heat exchanger) also is a bit risky. The exhaust might contain CO and that explodes from time to time.

I'm trying to improve the setup in little steps. Initially, I didn't get aluminium to melt (well, it took forever). But now I have to pay attention that I'm not melting my crucible. I do have SiC and carbon crucibles too, but this one is the most convenient.


Nick

and were they 3D printed cores in the base?

Forgot to answer that:
There were cores, but they are resin bound sand cores (cold box). Thankfully, I get the chemicals from a friend.

The patterns and core boxes all are CNC-milled with Renshape material.

The one on the muller (with the big belly ) was a pattern maker. He prefers the hand made ones made from wood.


Nick

Thank you for posting the video Nick.

It brings back fond memories of watching foundrymen from the West Australian Government Railways demonstrating casting at the Perth Royal Agricultural Show. I can still smell the dark brown sand and the molten aluminium. That would have been in 1962.

Bob.

I think I dreamed about this last night.

Greetings chaps Watching the vid brought back Memories. I had my own non ferocious foundry a few years back. To add a few comments I would have weighted the top box ( the cope) but this is a layover from pouring Iron. The Muller the thing with the rollers in it is essential for sand preparation in green sand. I only had steel boxes I found that the wood ones caught fire too often. What is the lining of the furnace. I used a space age stuff called ( damn I can,t remember the name,) it comes in blanket or board form and was excellent for keeping risers molten while the main casting could draw on them. This stuff makes the furnace light and is an excellent reflector of heat. ie it takes less time to melt. My furnace melted 15 Kilos of Aluminum and the same of gun metal or silicon bronze it was fired by LPG gas with a vacuum cleaner for pressure. But you can get normally aspirated burners no that do not require the Vac. I did all my iron at the RMIT Foundry School. I am only too glad to help the amateur. Yours 4-6-4