questions about casting aluminium handles

[Bart student]

Hello folks,


I have made myself a really cool khukri blank this weekend, and i was thinking about a bronze guard, bronze but and a ast alu handle inbetween. I could forge both bronze things on and then dip the whole hande in the molten alu and cool down, but since I noticed last time that alu has the tendancy to shrink when cooling down.

About this whole proces, i have two questions:

1. how to cool the alu down best? I notied that when letting it ool down real slow, it forms bubbles, and it does not when quenhing in water or something, but on the other hand, i'd rather keep the tang soft.

2. is this hypothetial idea possible? I mean is it possible the dip bronze and steel in a molten alu bath and expect a nice zero-seam junction between alu and bronze?

thanks in advance & greetz, bart.

 

[Eric M Ericson]

Bart,
your brass and bronze have a much higher melting point than aluminum so it should work. I think the problem with bubbleshas to do with getting the al. to hot rather than the cooling process.(well I did pour into a green (wet) mold it was a nasty bubbly mess but I don't think that's the problem)

I drop a small chunk of cold al. in the molten and watch it melt. If it goes fast then I put in another. If it dosn't melt put it back on the fire untill it does then clean off your dross and pour.

I hope this helps Eric