Large Bed Casting

I'm bored, I need some projects. Think I'll build a lathe. After hearing of the flaws of Gingery's design I decided I'd build it stiffer, heavier, and while I'm at it, 7" sounds pretty small, I'll kick it up to 10". The target for my design is 10x24, give or take an inch here or there. So the bed will be 3 feet long, 3" square and use 1/2" thick sides (no top or bottom), plus a bunch of ribs inbetween. But oh no, that calculates out to 14 1/2 pounds of aluminum - my current reverb. furnace can only hold 6 pounds! If I did a simultaneous melt with charcoal in the trashcan furnace, I *might* be able to do 18 pounds, but it'd be tricky and more trouble (and probably pain) than it's worth. So to cover that I first built a new furnace:

Front View

Specs: 13" square outside profile, hearth 5" tall, lid 4" tall. Chamber 9 x 9 x 3" plus 1 1/2" extra overhead in the lid. Maximum capacity 15 pounds aluminum (just barely in the range!). Full melt in 40 minutes fired with the monster burner shown. Frame built on 1" pipe, I'll spare you the grueling details of how I had to braze it together...


The setup. Warming up (after being burned out the previous day). 16 pounds aluminum scrap as weighed, waiting to be melted. This being the first melt I didn't know if it would hold all 18 claimed pounds or not.. guess I trimmed off more than I thought when I eased the corners on the foam inside pattern.

Side View

Side view. Actually, standing over the basement doors. :)

Warming up

Getting warm...

Inside Glow

One last glow shot...


...Or not.. :) Melts pretty fast with that direct flame!


A few minutes after pouring, the whole mold started giving off steam because there was so much metal inside heating it up. Unfortunately, not enough. I also couldn't pour very fast, though that wasn't the problem.

Casting Side

Ran short of metal. Problem was the furnace was kind of sloped down towards the mold, meaning I can't fill the hearth with as much metal before it starts sneaking out the pouring chute.

Now, a very special treat for you: I (or rather, my brother) got footage of the pour! You'll need DiVX 5.1 ( - pick your download) to view it. 12MB download:


And no, I didn't know it was going to overshoot like that...

Oh, and in case you were wondering, yes I did melt that down and pour a new one, this time filling fully after putting blocks under the furnace to ensure capacity...

Complete Casting

A happy ending! Now to find a mill so I don't have to scrap 1/4" off that beotch...

Copyright 06-21-2004 by Tim Williams. All rights reserved.