I needed to cut out 4 holes to install the heater coils for a new hydronic heating system. Some of the openings were up against side walls leaving no room for the foot. I found these carbide tipped blades for the Dremel MultiMax. $30 for a set of 3 was a bit spendy but thought I would give it a try.

Built a combination dust hood/straight edge. The dust collector worked really well leaving no clean-up.

Finished cut-out. Total length of cut on 1/4" fiberglass was about 20 feet and the first blade was still going strong.

The MultiMax works OK but no way will I buy another Dremel tool. Just out of warranty with light use the power switch failed. Not only would they not cover it they had changed the design and no parts were available. The did offer an insulting $20 credit for a newer model so I just installed an in-line switch. The carbide blades have 2 sets of mounting holes so I think they fit most all oscillating tools.