Sorry if this has been covered. I did a search of the archives and couldn’t find a good comparison. What would be better to purchase? I just finished the lam on my first board and need to get a grinder/sander. Also, any suggestions on which size? I see they come in 4" and up.
There may be some trade offs in terms of smoothness, power, or attachments that i do not know of, still the pnuematic needs an aircompressor and thats just one more thing. The electric you can just plug and go. Unless you have a shop with compressors already step up.
I guess in someways the pnuematics are easier to use, they are smaller and lighter being that they dont have to house the electric motor. Maybe they last longer due to simplicity, and cant shock you if you run over the cord.
Pneumatic is the way, you have more control of speed there lighter so you dont
over sand (can still happen) and thay last a lot longer.
Aloha! FISHY
Hahaha - I thought you were wondering if you should get a grinder or a surf mat!
Ah - well, as the saying goes, ‘that depends’-
First off, it’s not a grinder you want, it’s more like a sander/polisher. Industry standard is something that turns no more than, oh, 2500 RPM or so while spinning an 8" foam-backed sanding pad or equivalent sized buffing/polishing pad. You can go smaller, yes, and that lets you jack up the RPMs some, but the inexpensive little 4" jobbies that go around 10,000 RPMs are not what you want.
As has been mentioned, with a pneumatic you need a compressor, and a pretty healthy one. Any pneumatic sander worth it’s salt will want 8 CFM a minute at around 90 PSI. So you will want a compressor that can at least keep up with that. Forget ‘horsepower’ ratings on compressors - they are lies. Look at CFM ( Cubic Feet per Minute) and the pressure they deliver that - SCFM is equivalent. Plus a reasonably large storage tank. The whole thing fills the lower two thirds of a phone booth. And expect to spend in excess of $300 US.
Then there is hose, then there is oil, then there is… as you can see, getting into pneumatic tools isn’t an easy step. Pneumatic tools do indeed have a bunch of uses, and myself, I have a few including some sanders. Especially including one like this little critter here: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=90288 which does both random orbit and plain disc sanding. Nice tool, but again, I have to fire up my big, 220V compressor to use that. And it’s actually a small sander.
Okay, we’ve kinda shot our wad on pneumatics. Lets look at the electric models.
They range from the $30 Harbor Freight to the $700 Fein and the Festool Pete C likes, when you’re looking at the 7-9" flavor, sander/polishers. You can do very well in used tool stores too. Do look at the plate on 'em that will give model number, RPMs, amps and that sort of thing. Some guys like the Harbor Freight, some spring for the high end. I have a Milwaukee I like, but do you want to be shelling out the pretty-near-$200 that set me back?
My own suggestion is this. Without trying to be a patronising old git, if you’re asking this question then you haven’t got a lot of experience with power tools. Nothing wrong with that, none of us were born clutching a Porter Cable planer. So, start inexpensive. Maybe the Harbor Freight, at $30, plus a good backing pad for another $30 or so. This puppy here: http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=46507 . You can always get a better one if you have a need for it and if you find it’s not your cup of tea you haven’t spent your vacation money.
Before you even think about putting the tool to a board, play with it some. Clamp down a piece of 2x12 and practice your sanding technique. A lot. The softer the wood you use, the better. And of course, RTFD!
You can do a hell of a lot of damage with a moment’s inattention and a powerful tool, so get to where you have a feel for what it is and what it can do. Get used to making long passes, not short grinds. Watch out for heat buildup, that can delam your nice new board fast.
Ok, that’s my call on it.
Hope that’s of use
doc…
Thanks doc, that’s exactly the answer I was looking for. I have an air compressor, but I’m guessing it isn’t nearly powerful enough to run a grinder. I use it mostly for my brad nailer when making furniture. I’m not interested in buying a bigger compressor right now, so electric it is! Thanks for the help!
Good call on this one! I completely agree with your advice. I thought I would include a link to where I got my Ferro pads http://www.fisheriessupply.com
Whoa, thanks, Dan, very good prices on those. And…aha! They also carry everything from sail needles to mooring buoys - prices not bad on those either -
Many thanks
doc…
yea doc i will second that , that was well written and good advice …
i rate that …
regards
BERT