ALUM dissolving steel stops, needs restarted.

[mcostello]

I have broken off a dowel pin in a part. It's 1/8" diameter, (3mm for Imperally challenged ). Alum has worked for about 1 1/2 hours and the bubbles have stopped. Solution is simmering. Does it still work or does it need something to restart it? Have done research on the Internet and here and seems like there is nothing else to do with it. Is there an EDM build in my future? Any advice or help gladly appreciated.

 

[ninefinger]

Try scratching the surface of the dowel, and flush out the hole. You may need to add more Alum to the mix as well.

Lastly - I had a similar experience trying to get a tap out of an aluminum part, I ended up switching to vinegar (pickling strength 6 or 7 %) and Alum simering. That worked much faster.

Mike

 

[mcostello]

Thank you will try that now.

 

[t.l.a.r. eng]

When making the alum mixture, you need to dissolve as much alum as possible that will stay in suspension.

Clearing out the hole occasionally won't hurt, but be sure to use Pyrex container if at all possible. Alloy pots, even stainless tend to reduce the mixes effectiveness and can turn the aluminum piece cloudy [plating]

Learned that one the hard way on a radial crankcase.

Patience endures and the saved part usually comes out as nothing had ever happened.