Using Greaseless Comppunds

[kenykirschstein]

I started playing around with some greaseless compounds in order to sand some aluminum welds after grinding them down.
I used the 80 grit with a 4" wheel on a variable speed hand grinder. I applied the compound and then allowed it to dry before using. What I found was that the compound sat on the surface of the wheel only, when I used it I didn't get a lot done before I had to reapply more compound. I found that lower speeds worked better. I had expected it to last longer. Is this typical

yes it is .... you can hold the compound longer with time ... i get around 15 to 20 min on my compound ... i load it and wait a few sec's then get to sanding ....

[kenykirschstein]

So how do you extend the time, are you saying that as you use the wheel more, more compound will saturate the wheel and extend the time.

from what i have found the compound work's in to the wheel ... the more you load it ... i still got 80 grit on a wheel and i have not use it in a few days ... i willl be pulling it out friday i got a few thing's to sand ....

[skiddz]

I've found slower speeds on the wheels make greaseless last a bit longer. I'm not talking RPMs, but surface speeds. If I use 6" wheels with greasless, I get maybe 5 minutes of working time before it's time to reload. If I use 4" wheels, I get about 15 mins out of 'em.

RPM in both cases is 3450, but the smaller circumference of the 4" wheels get the surface speed down quite a bit. 5419 SFPM for a 6" wheel, 3612 SFPM for the 4" wheels. That's about an 1800 SFPM difference.

Also, pushing too hard or catching an edge will reduce the work time with greaseless compounds as well.