Metal met welder this week in the shop. I finished machining a few brackets and started tack welding some assemblies together.

Welding aluminum is tricky, the coefficient of thermal expansion is almost twice that of steel, which means it moves from the heat of the weld, much more so than steel. Here’s some tips when welding together plates of aluminum:

1. Aluminum moves during welding. A lot. Start slowly and clamp together anything that may warp or shift during welding.

2. Check for square and check your dimensions, early and often. Since the material moves so much during welding, what started out nice and square will end up looking like a pretzel. So weld slowly and move around, alternately tacking on opposites sides (the heat from the weld has a tendency to pull the plates together on the welded side and apart on the opposite side. Recheck for square/level after very few tacks.

3. I always find faces in the stuff I work on:

I was able to tack together the complete injection cylinder, minus a small plate on top which I later added to give me a spot to bolt the valve block to.

I also tacked together the swinging mold cylinder brackets:

Having the mold cylinders swing up allows me to service the parts inside the melt tank without disturbing the alignment of the molds.

And the sub-frame that a majority of the machine gets attached to.

That’s it for now. Next up is cutting the 1×1 angle for the top cover and finishing some parts on the mill and lathe.