First Lost-Foam Casting

[the artfull-codger]

(03-16-2013, 11:22 PM)Hawkeye Wrote: I'm replacing the exhaust system on my 1965 Honda Trail90. I haven't found one, so I'm making one. The muffler will consist of a 2" metal tube with two cast end bells. I made up the foam pattern on the lathe early in the week and coated it with drywall mud.


This morning, I fired up the foundry and melted down some scrap casting aluminum. Meanwhile, the pattern was spending a couple of hours in the oven at 150* to make sure it was very dry. The pour went well. I had a fan blowing across the top of the casting bucket, so the smoke and flames were kept out of the way. I had plenty of metal in the crucible to get a good head pressure.


Went to a coffee meet with the other old bikers and came back in the afternoon to shake out the casting. No bubbles or voids.


Machining was pretty straightforward. I got the forward bell pretty much done.

Nice castings Hawkeye, love the tip about a fan blowing the smoke away,each time I've done lost foam castings you can't see to finish the pour & end up with it all over the place,never occoured to to me to use a fan!!! btw what's drywall mud?? is it the filler you use on the joints when dry lining with plasterboard?
Graham.