will the cut wheel on the angle grinder make to many sparks and pit the inside of the container. or should i do something like drill a small hole in the top of the keg and fill it with water so the sparks dont hit the sides. help.
A grinders sparks won’t hurt your keg. You are fine
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I’ve been through this twice. I actually used a sawsall to cut it open, but then did some finishing cuts with the angle grinder. I would recommend going slow and using cutting oil if you use the sawsall method that I did. Good luck.
The welding shop only wanted $10/keg for a plasma cut.
Couple bucks more and they tacked on three stainless washers to the cutout so I can use it as a lid.
It’s more than worth $10 bucks to have someone else do it.
came out good. angle grinder. no water just the stale beer that was leeft in it. still wanna tune up the edges more…or thats what my arm told me after i washed it. ouch.
A Dremel with a grinding attachment works well for cleaning up the rough edges.
So does an angle grinder 
with a buffing disc