Wide belt questions

[Brian Burns]

Hello All,

I'll be taking delivery of a Grizzly G0819 15 inch open end machine this week and have some questions regarding belt sources and types.

I make traditional Spanish guitars, and am looking to reduce hand sanding to a minimum---at 78 years old hand sanding takes more energy than I can spare!

Oddly enough the G0819 has a polishing platen, in spite of it's being an entry level machine. I'm hoping that, in combination with fine grit belts, will get me

good enough surfaces to send my instruments on to the French polishers.

So, I'm looking for advice on sources and types of belts. Years ago received wisdom was to use cloth backed, coarse grit, aluminum oxide belts for mill mark removal,

and fine grit, paper backed, garnet belts for finishing. That was then, and this is now, so what say you?

Cheers,

Brian Burns

[Jim Andrew]

I have the older model G9983 sander, and I searched for belts from other companies, which turned out to be very expensive, and found the 5 packs Grizzly sells are pretty good. Very surprised at how well the tape holds. Have yet to have one come apart in the sander. The secret is to insert your board through the rolls and make sure you start out sanding without having the sander too tight. Start just so you can slide the board under the roller, and run the board through. Then tighten just maybe 1/6 of a turn at a time. Watch your amp meter so you are not running the sander too tight to the board.

[John M. Smith]

I have a wide belt sander from another manufacturer. I have had good luck with buying belts from industrialabrasives dot com.

[Dave Cav]

Another vote for Industrial Abrasives.

I don't think your widebelt will eliminate hand sanding. I generally ROS sand my pieces after they have been through the widebelt. Something like a tabletop will go through the grits and end with 180 with the platten, then ROS sand starting with 150 on up to 220. You'll have to get to know your sander and how much to take off with a given grit so that the subsequent grit doesn't leave scratches from the previous grit. There's a definite learning curve.

[Warren Lake]

3M stuff works well for me. I listened to salesman on my stroke sander and they started me on cloth. Waste of money, my stroke belts could have been paper from the start different grits from 80 up.

The small wide belt with a drum I have used 3M but cloth as there is constant pressure on a drum, a stroke pressure is up to you. I used the machine to thickness Tempered hard board at the time, no experience with your application on guitar tops but at least its a planer that sands so it makes sense to make things consistent thickness.

For furniture for me anyway I likely ran a few boards through and thought it was a poor way to sand, Slow and primative, its one small point of contact and thats poor. A real wide belt a different system, still havent used one of those, the stroke does all I need to do.

[Kevin Jenness]

The best info I have seen on widebelt use is on the Surfprep site. I have had good results with 3M cloth belts, but I don't expect ready-for-finish results from a wide belt, at least from the ones I have seen- I use a stroke sander and/or random orbit sander after the wide belt does the heavy lifting.

[Mel Fulks]

I've always had to use one grit coarser on the orbital sander after using a widebelt. I guess it's because of the pressure
from wide belt machines.

[Brian Burns]

Hello Dave,

The problem with a random orbit sander, and I bought a Festool in spite of the cost, is that it scrubs the spring growth out from between the lines of summer growth on softwoods---spruce and California cypress. The resulting surface is not flat and smooth. So when I say hand sanding, I mean with a hand held sanding block. Classical guitar making is a pretty fussy/picky business compared to furniture making, and I've done a lot of that too.

Cheers,

Brian

[David Kumm]

I'm surprised a platen only head doesn't do the same thing on softwoods. I would have guessed you would want a combo head with a steel ( not rubber ) drum and an adjustable platen that could be removed. A stiff hard platen might accomplish the same thing but a soft one is likely to cause the same high low finish issues. Let us know how it works. Dave

[Kevin Jenness]

Brian,

If you are able to get a surface ready for french polishing from a <$5k wide belt sander, let us know and I will place an order the next day.

In the meantime, check out a few of the articles by this guy http://surfprepsanding.com/2015/05/2...e-belt-sander/. He might be able to advise on specific belts for your machine.

Don't throw away your hand sanding blocks just yet, and don't be afraid to try a stroke sander.

[Dave Cav]

I have read most of the articles on the Surfprep web site referenced above and there's a lot of good info there.

I've never done luthier grade work with softwoods as you're doing, but I agree with what some of the others have said about probably not having a finish ready surface off the Grizzly widebelt. I can sympathize about the sanding effort, though; I have had to completely change my finishing process from hand rubbed oil/varnish to water based lacquer because I can't handle the rubbing out process, and I'm only 65.

[Kevin Jenness]

For anyone interested in guitars, Brian's website is worth a look http://brianburnsguitars.com/my-guitars. Beautiful work and a technical approach to getting his desired sound out of the wood.

[Brian Burns]

Hello Kevin, and the two Daves,

Thanks for the kind words about my website Kevin. I have the great good fortune of having a real pro videographer for a guitar making student. He loves to buy the latest and greatest equipment, so the audio is first rate.

There aren't many guitar makers that take a "techno-weenie" approach to guitar making, but it certainly has worked well for me!

I have decided to get a Powermatic 16 inch open end machine instead of the Grizzly 15 inch. An all round better machine, albeit at an additional $1500. We will see if its platen produces a "flat" surface on the California cypress that I use for back and sides of my flamenco guitars. That is where the random orbit does the worst job.

As for a surface ready for French polishing, that's easy (;->)...The woman who does my French polishing---superbly---doesn't want me to go above 220 in my prep sanding! It makes it too hard to get the dust out of the pores of the East Indian Rosewood back and sides. She uses the traditional FP method that involves pumice of a fine grit. The first step uses a "spit coat" of shellac followed by a thorough rub down with a pad with only pumice---it's called a "grinder" appropriately enough. The resulting slurry is the pore fill. So the surface that she produces in the pore filling process is really smooth.

I'll report back after I've used the Powermatic for a while.

Cheers,

Brian

[Brian Burns]

Hello again All,

I thought that I would mention that in rummaging around the web for info on wide belt sander usage I came across a series of articles by A.J. Hamler in Woodshop News---a trade journal: www.woodshopnews.com
He is a real expert on the subject, and goes into detail . The articles are in the May through November 2012 issues, and can be downloaded.

For those who are interested in how I stay healthy enough to still be working full time at age 78, the answer is simple, the Low-Carb Diet. I've been on it for over 18 years, without ever being hungry. I went on it in 2000, to control my Type 2 diabetes, which it has effectively cured. I've put together a collection of links to some very good sources of information, and I'll email them to you if you send me an email at Brian@BrianBurnsGuitar.com

Cheers,

Brian