after searching archives
the best choices are
Herb’s harbor freight variable sander for $20
or the 6078
grinders are too powerful.
here is my case:
I saw a 6078 for $200 variable speed 0-6000 sander.
I saw a Milwaukee grinder for $120 ($149 price) on sale. The 6154-20. variable 4000-11000 rpm. Then Carlo the mason guy rolls in the shop (he’d shown my dad how to do masonry work / brick stuff / hard tile) comes in. He says the 6154 he’s had for years, no issues. Grind Cut rocks marble, tile, even piping … . dust isn’t bad, just remember to aircompressor blow it out every so often. Carlo knows the guy at the front desk, and says I pay him, and he’ll get my sander with his account and major discount. Plus I got 3 free sanding pads.
So the $120 becomes a $90, I buy the 6154-20. Plus its about 5 lbs lighter, and much smaller and has what Tim the Toolman likes: more power than a 6078.
The guy and Carlo said its mainly a grinder, but 150 for 90 was too good to pass up, so I went with it. The guy offered a similar sized porter cable sander for $50 ($139 normally), but I said nah.
Carlo said when I fire it up, watch it, it’ll eat wood. But he said you can polish cars / marble with the right pads @ lower settings and if I can use it to sand, and you don’t have buy the trinity orbital tools: sander , grinder, polisher to work on other stuff than wood or fiberglass.
Take it home, I test it on some scrap foam with a 10k rpm 5" sanding pad at 4k rpm. Good. fast, but good.
Besides the guy on the JC glassing 101 video says get a vari-speed grinder if you can only get one
So far I sand my board around 4-6 k rpm, plus I can switch to grind mode.
No issues here. I notice if I crank it to 7000 + rpm, it’ll eat fast. It ate 1/2 of my logo in a blink of an eye at 8k rpm. But I bored the deck to the foam, and redid the logo and re patched the spot back to original.
BTW at 8k+rpm the sandpad gets thrown from the pad like a ninja star if you’re using adhesive. the newer velcro pads hold.
I like the velcro style sanding pad and velcro backed sanding pads. They call it hook and loop, but the niyas should call it velcro, cuz thats what it is.
Benny says you can buy a router control speed / rpm controller with a 10k rpm grinder and it will work at variable . . . my dad has a router controller but it doesn’t work if your grinder already is a variable . . .something about double rheostats not playing well.