Cutting Aluminum

[regnar]

Bill I have heard the same tale. I know at work we have huge signs on all the grinders and cutoff saw " NO ALUMINUM " just for this reason. I have never seen one explode but have seen a grinder used on aluminum and it was welded all over the wheel. So in theory it sounds good. I will search Youtube. People always like to post stupid things on there.

[a1gutterman]

Speaking of aluminum chips flying everywhere... I installed Aluminum Soffit & Fascia on my house back in '80. I made a small sled jig that my Skill saw fit in and would cut pieces from the 10' soffit pieces. My FIL was a siding installer and told me to take a plywood blade and turn it BACKWARDS in the saw, so the back side of the teeth hit the aluminum. I was a little skeptical at first, but it worked WELL. It cut the soffit and fascia material just fine, with NO chips flying everywhere and made a real clean kerf.

This is a common practice...one that I caution against. You are knot actually cutting the aluminum, you are beating it. NEVER try this with a carbide tooth blade, as you can find yourself eating the tips. Also, it only works well with thin aluminum (such as the aluminum siding and soffit), knot like the "T"-tracks that Tim is asking about cutting.

[JPG]

IMHO This is a case where thinner is better. You want to be 'cutting' not grinding. I have had reasonable success with rotozip wheels. I have also used cutoff wheels on a 'surface grinder'. I get the narrowest I can get. They are typically fibre/glass/cloth impregnated rather than simply 'bonded' abrasive particles. The buildup of aluminum on the grinding surface is I think caused by overly aggressive feed rate.

I have seen many a cutoff wheel break with overly aggressive feed rate with steel! The larger the diameter, the more likely the failure.

[rcf]

The one I use happens to be a Mac tool, only because I used to use it all day at work. Most any good brand will do for home use. It also has a 90 degree head on it, for close quarter work. The rpm is the key, the higher the rpm, the longer the blade will last, and the better the cut. I run mine at about 20-25 thousand rpm, it has a variable speed adjustment. The cuts are clean, consistant, and thin, I use an 1/8 th in blade for that reason.