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I am tinking of getting an air driven orbital sander and was hoping this would work well for guitar sides. The orbit is 3/16". The pad is 6". Will it work in the waist area?

Mike

A 5" sander would get you closer but you'll still have to do it by hand or use a drum sander to get fully to the waist.

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

You know what would work? But I cannot find this... is a flap sanding wheel in the shape of a barrel. Does this make sense?

Mike

Pneumatic drum sander. Look at the Grizzly website.

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

No random orbit sander is going to get the entire waist without a very thick and soft pad. You would probably need one of the 3" diameter models to get it all, unless you are building dreads, and even then, as the edge of the pad starts to ride up the other side of the waist, it is easy to get swirl marks. Another problem with this approach (big soft pads) is that will be very difficult to properly level the side, and if the side in the waist is not level, then you will have a hard time leveling the finish. If you really must use a power sander for this job, a handheld drum sander like Peter mentions will be a better bet, but requires a VERY careful touch. A flap wheel would be a really bad idea, in my opinion, as they have no leveling ability at all.

It really only takes a minute with a rounded block to hand sand the waist area, so I don't think it is worth the risks.

I have a Mirka Bulldog 3.5" pneumatic ROS that I use for everything. It's an extremely well made and designed tool. Get one even if you won't use it for sides at all

Flap wheels are alright for getting scratches out, but they won't take out dips. This place has loads of different kinds:
http://supergrit.com/products/products_woodworking.asp

Sponge sanders are sort of the king of the hill for this stuff, and they're awesome for necks and other stuff as well, but they are super expensive! I've got one of these, but I swear a smaller version would be the bees knees...maybe I'll design one sometime to sell to luthiers
http://www.houseoftools.com/product.htm?pid=610831

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Fine. Where do I find the 3.5" ?? Googling is not helping

Mike

OK, Bob, I found some, but they are 3". (MR-3 is the model number).

Now, are the pads always foam backed? I was hoping for simple hook & loop. Plus, where do you buy your sanding disks in bulk? I would like disks with holes for dust removal.

Mike

For the waist area I would suggest a cabinet scraper and sandpaper...the scraper will flatten the wood while the sandpaper will rough the material up to take a finish. I usually switch back and forth, winding up with 320 or higher grit paper.

You could use a drum sander but I think a hand sanding is better. Power tools are not always needed, or even appropriate!

Martin uses pneumatic random orbit sanders, 5 inch.

Those air powered sanders need a really large CFM compressure. Do you have one of those? Other wise you can get the same result with an electric ROS. I had a air sander and had to sale it to my chrome plated because the compresser i had wasn't large enough. If you have an air drill then this is what you want or use your hand drill.
http://www.grizzly.com/products/7-1-2-x ... ders/H2882

For the waist I tack 120 grit and up to a 2" diameter pipe and sand for 30 seconds. It's even faster than a scraper.

Oops...it is 3"! Anyhow, mine is hook and loop and I got it from Wood Essence http://www.woodessence.com/. They sell the discs and whatnot in bulk as well. The only thing about the 3" is that I don't think it's available with dust collection. I just sand inside the Fadal with the dust collector on, but you might need a downdraft table.

As someone else mentioned, air sanders do really suck a lot of air.

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

http://www.sjdiscounttools.com/ast3034.html

Anybody heard of this company (the seller, website, not the manufacturer)

Chris, I have a big air supply! Plus, I would be happy to find an electric one, in the 3" size.

Mike

That is a cool idea! Grizzly always has the oddest things (and I find I want/need them)

Mike

Have you, or anybody else here used this tool? It looks exactly like what I am looking for!

Can't believe it costs $100.

Mike

I have the 1-1/2" one but I'm getting the 3" dia. one for the next one. The 1-1/2" isn't long enough for the sides. Dave Anderson uses the 3" one also. Larrivee Guitars uses them to finish up their CNC necks. I'll see if I can find the YouTube they have , that's where I first saw it. $100 ain't that bad if you had to buy the parts and make it. Grizzly also has a pretty cheap air drill for it too. I'll be getting it also. At least when I get back to work.
Here you go. How much more easier can I make it for ya?


Hey how about that cool vacuum neck carving vise. I'm making one of those too!

Chris, you beat me to it. Those sanders need A LOT of air, probably in the 8-9 CFM at 90 psi... So that's about 5HP and 60 gallons. Those Grizzly sanders are brilliant and they're very versatile. You can shape necks and bridges too. You actually have to be careful because you can take off a lot of material in a hurry. Worth every penny if you ask me!

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

Mike, like I stated earlier, spend the 100$ and then laugh about it. You'll use it for a nano-second before the guilt wears off...

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I'd like to be able to prove, just for once, that money wouldn't make me happy...

I ment 2-1/4" not 3". The one in the link is the one you want. Although the smaller one is ok for necks.

OK, I'm in. I will get the big one first, then the little one later if I like the big one. Thanks for the video Chris.

Alain, mine is 3.5 hp and 60 gallons. It can do that rate you mentioned. And keep up too.

Mike

What air drill are you looking at?

Mike (asside: does Grizzly sell an air butterfly wrench?)

I'm thinking this one at 2,600 RPM @ 6 cfm @ 90 psi
http://www.grizzly.com/products/3-8-Str ... -RPM/H6363
And there this at 22,000 RPM @ 4 cfm @ 90 psi
http://www.grizzly.com/products/Industr ... 3-8-/H6194
But I'm not sure but I would think the slower one might be better for sanding. My compresser is rated at 6 cfm @ 90 psi but I don't know if I want it kicking on and off all the time as it is oil less and pretty noisy.

The are several confusing aspects to determining how much of an air compressor you need to run a given air tool. Here are several issues to be aware of:

"CFM" is not a rigidly defined standard, and thus is almost meaningless for comparison purposes. If your compressor only lists its output in CFM, it is a pretty good bet that it also brags about "peak" horsepower, another useless parameter. CFM may mean measured displacement of the compressor (a wildly inflated number), or it may mean "ACFM" or SCFM". These latter two terms are defined units, the first meaning Actual CFM and is calculated on ambient conditions. The term "SCFM" is CFM calculated at a specific reference point (I think 68 degrees at sea level pressure).

Any pro air tool or compressor will show as ACFM or SCFM. The grizzly tools that show only CFM are an unknown quantity, but the standard conversion from CFM to SCFM is to multiply the CFM by 7. So the 4 CFM drill becomes a 28 SCFM air sucker! But since we don't know how Grizzly is getting their CFM numbers, you just have to take your chances.

If you look at a quality company like Dynabrade, you will see that they give SCFM ratings, and that you will need between 14 and 18 SCFM at 90 PSI to run one of their 5" sanders. You can expect other decent 5" orbital air sanders to need a similar amount of air, no matter what they may claim.

If you are running your compressor with a tool that needs all of the air it can put out, or more, then the engine will be running continuously. Even if you are happy with the performance of the tool in these circumstances, your compressor motor may not be rated for continuous duty.

You can run a tool for short periods of time with an underpowered compressor, but you will have to stop every minute or so and wait for a couple of minutes for it to catch up. If your inadequate compressor is causing a sander to run at lower than optimal speeds then both the speed and quality of the sanding is suffering. under those circumstances you would be better off with a quality electric sander.

If you want to run an orbital air sander, such as a Dynabrade, you need at least a 5 HP, 2-stage unit, putting out at least 16 ACFM, and preferably more. The motor should be a quality commercial one like a Baldor, etc. I have not seen any 3.5 HP unit that is adequate for this job. In pro shops, 5 HP is considered the rule-of-thumb minimum size for running one air tool.

Bottom line - the benefits to air tools are only realized when they have the air they need to perform well. The compressor should have at least a bit of excess capacity over the tool demands.

Bump... still wondering if anybody here has dealt with this tool distributor:

http://www.sjdiscounttools.com/ast3034.html

Anybody heard of this company (the seller, website, not the manufacturer)

I've got both sizes of the Grizzly pneumatic sanders and they are great along with rasps for shaping the heel and merging it into the shaft. I mostly use the big one to start and the little one for fine tuning. I just use a battery powered drill. It's important to be able to reverse the rotation. They make a lot of fine dust. In summer I usually move outside.



As I have gotten better with the rasps I do more and more with them but the sanders are still a big help. The Dynabrade is good with 40G to hog off the bulk of wood on the shaft before final contouring. There is a good video of Kevin Ryan shaping a neck with a Dynabrade somewhere. That's were I got the idea.
I originally thought the Grizzlys would also be good for truing up sides before binding but for me a wood sanding block and a large dowel with sandpaper works better.
Terry

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It's not what you don't know that hurts you, it's what you do know that's wrong.