Buffing tools, equimpent and technique

[fender3x]

I have not done a lot of buffing on my projects. I generally go through finer and finer grits of sandpaper until I get to rubbing compound and wax, at which point I have been using a cheap palm polisher that I got for under $20.

I'd like to "graduate" to a better buffing and polishing approach. I am wondering what folks here use for buffing and polishing...and when you go from sandpaper to buffing.

What equipment do you use? I am NOT shelling out for a Stew Mac polishing machine. Not opposed to building a bench polishing station...but the motors seem pretty expensive. I have a small electric motor from a small compressor where the pump died...but it may be too small to make a buffer. I have a small (bench) drill press, various drills and a 4" angle grinder. I also have a nearly worthless palm polisher. Wondering if I might do something with any of these?

[Dikkybee007]

I think you will find the angle grinder is too fast and will more likely burn the finish. Plus finding a pad that will withstand the RPM before flying to pieces might be hard to find as well. With polishing slower is better and easier. I have gone from highly polished finishers to satin/matt on some of my builds as it does not show fingerprints and need cleaning as often and looks a little like an oil finish on unstained wood.

I use ScotchBrite pads for sanding as they are virtually impossible to sand through, purple to rough and white to finish, and have used them to sand the finish before buffing. I use a drill with some pads, sponge rubber and felt, as you need small round ones to get into the inside of the horns on a Strat and Tele but all polishing can be done by hand if you have patience. I only ever went to 1500 maybe 2000 wet and dry before buffing. I only use a cutting compound that has no polish because if somewhere down the track you need to touch up a surface the polish has to be removed before you can apply a finish.

You can use a felt wheel on a bench grinder and have had some success but it is mainly for flat surfaces because if you try to use it in tight corners the likelihood of damaging the surface is high until you get practice. Only thing is due to the size of the motor and the size of the wheel you can find it hard sometimes to use as you can hit the surface of the guitar on the motor. If you use a 6 inch bench grinder only use 6 inch felt wheels or the RPM might be too high to give a good finish without burning through.

I have a 2 speed Hitachi polisher that uses an 8 inch woollen wheel but again useless inside tight corners. Have also used it with a sponge rubber wheel that gives a good finish but trial and error and practice makes everything easy. I didn't pay for the polisher but I know when I got it back in 1980 for my marks I got when doing my apprenticeship it was about $150, god knows how much now. Great for flat surfaces, just gotta watch out for cut outs, but not so much for inside tight spaces.

Starting out I would go for an electric hand drill, not a drill press, and felt/ sponge rubber pads as they are both relatively inexpensive. If the drill burns out you can get cheap ones to replace them as well as the pads. A bench grinder with a felt pad works well but wont do everything like the drill and pads will. As for using a motor with a felt pad, as you can buy adapters to mount the wheel on, again fine for flat surfaces but a lot harder in tight spaces plus for anything that needs mounting you also need space to mount said item with enough space to get around the wheel.

[Trevor Davies]

I basically use your method.

After the poly gloss coats, I will sand up to 1500 g or 2000 g wet and dry paper. (or scotchbrite pads)

Then I use a cutting compound, polishing compound and then Maguire's Scratch X applied using a small (and quite cheap) random orbital polisher from a car care store. (The polisher is only good for the front and back, not for tight spaces)

Someone on the forum recently had success with a compressed air polisher!

[fender3x]

Thank you, guys. I am more or less OK getting through the sanding...but may stop at 1500 or 2000. Thank you for the very complete answers. They have prompted some more specific questions...

Cordless drill is always an option, and it has a slow speed...

I have a random orbital palm polisher. May be similar to the one you use for fronts and backs TD?



Mine is a 6" (153mm) that says it operates at 3500 OPM. I assume that's orbits. It definitely does not turn that fast. If yours is like mine, I'd be curious what "bonnets" or pads you use on it. Mine came with I kind of fuzzy hat. I'd be curious what sort of bonnet you use with yours, since think I will need to get a different bonnet for each grade of compound I use with it? I think they come in microfiber, fleece and "non-woven fabric" (whatever that is).

Also, since I haven't done this before...which compounds/polishes do you use?

Also with regard to the bonnets. I have been using them with McGuire's "Ultimate Compound" and then car wax (which I should probably stop using). Once finished I run the pad through the washing machine, so I haven't worried much about what's in it, but maybe I should have dedicated pads to each compound/polish I use?

I can use the drill, or just hand polish on the tighter spaces. I have not liked using it in the past. I have experimented a little, and actually burned off some finish around a cutaway. I think I tend to have two problems. One is having the body in one hand and the drill in the other...and then regulating speed and angle of the drill.

That takes me back to the drill press. On it's slowest setting, mine turns at 620 RPM, which is actually a little slower than the Stew Mac polisher. With a small foam polisher I might be able to use it for the inside the cutaways and sides. What do you think?

Thanks for your thoughts

[Trevor Davies]

My random orbital polisher has a variable speed from 800 - 4000 opm, 150 mm pad. Very similar to yours.

I use microfibre bonnets for the polishing compounds and terry toweling bonnet for the final buffs. I do have dedicated bonnets for each compound.

For the harder to reach places I hand rub the compounds using Meguiar's foam applicator pads, and then the microfibre bonnets.

The Polishing Compounds I use are:
Kustom Grit Step 1 - Superfine Abrasive paste is equivalent to 50,000 Grit, and their Microfine Grit Step 2 - equivalent to
100'000 grit! This is an Australian product I saw at a carpentry store - so I thought I would give it a go.
Meguiar's Ultimate Cutting compound,
Mequiar's Scratch x.

I'm still trialing and experimenting with the process.

[fender3x]

This is very helpful. Thank you!

[Trevor Davies]

...

I can use the drill, or just hand polish on the tighter spaces. I have not liked using it in the past. I have experimented a little, and actually burned off some finish around a cutaway. I think I tend to have two problems. One is having the body in one hand and the drill in the other...and then regulating speed and angle of the drill.

That takes me back to the drill press. On it's slowest setting, mine turns at 620 RPM, which is actually a little slower than the Stew Mac polisher. With a small foam polisher I might be able to use it for the inside the cutaways and sides. What do you think?

I have been thinking about the idea of using the drill press with a foam polisher - and cannot really come up with any negatives. At least you are only holding the guitar body, and the drill press will have a constant slow speed.

Thinking back to the first post, we should try to take advantage of the equipment we have! Definitely give it a go, but take it easy. I might try it as well!

[fender3x]

I sent away for some polishing, some foam and cotton disks, pads and bonnets. Will see what I can cobble together, and will report... Assuming I get to that point. I managed to botch my first attempt at a garnet shellac finish, so it may be a while before I get to polishing... But I'll report here when I do ;-)

I have been purchasing a number of supplies, and even some guitar parts from, Temu. I don't know if this is around in other parts of the world, but it is often quite a bit cheaper than Amazon or eBay. I got a 9 guitar stand for under $40. There is nothing special about it, except that I couldn't build one for that price.

[fender3x]

I have finally gotten around to experimenting with using a drill press to buff a guitar body. I got some 6 inch buffing wheels from Temu, which I mounted on a large bolt, which I shortend with an angle grinder so that the buffing wheel would be about half way between the gear box and the base on my very short drill press.

Here's a pic of the buffing wheel on and off the drill press.



I used a foam cone made for a drill to get into the tighter spaces.



My short drill press does not leave a lot of room, but it was enough to buff the entire body.



I did a flat sand down to 250/320, then used a 3m maroon sanding pad, and after that a gray pad. Then went right to buffing.

I used brown buffing compound and have not yet done the scratch removal or final polish, but I am pretty pleased with the result. This is WAY faster than I have ever gotten to this point before. No wet sanding at all.

My little drill press doesn't give me a lot of room to work, and I can only use relatively small buffing wheels. A bigger drill press (e.g. floor mounted) would give much more room to move. More distance from the pole and chuck would allow you to use bigger buffing wheels.

A lot of the ones I have seen DIY'd on the internet turn very fast. The bigger the wheel, the more the relative velocity at the point of contact. My drill press turns at 620 rpm which is way slower than most I have seen, even the Stew Mac. Also, since the buffing wheel only 6" the relative speed is relatively low. There is very little chance of burning the finish, and I didn't have any problems with the body catching due to torque from the wheel.

The only downside I see is, for me, not much of a downside. Pushing laterally on the buffing wheel may put some wear and tear on the bearings. In my case, however, I am using a an 8" "bench" drill press. I can find them new for around US $100, and I got mine used for $25. If it wears out the bearings I am OK with that. Also not too worried since I don't push very hard ;-)

This may well be enough for my needs since I don't make many guitars. That said, it's not nearly as good as some of the dedicated instrument buffing systems I have seen on the internet. However, I think it could be turned into a pretty good system relatively easily. It would even have some advantages and be cheaper than pretty much anything I have seen.

The limiting problem with the drill press is that the vertical shaft runs parallel to the pole behind it, giving the buffing wheel limited clearance. And, of course, mine is also short, so you have be careful moving the body around. Both problems could be solved by rotating the motor-belt-drive-drill assembly 90 degrees. so that it runs perpendicular to the pole. I think this could be done relatively easily, either by using some iron pipe with a 90 degree "elbow" fitting, or by just building an off-the-stand mount for the drill press assembly sans base and pole.

Everything you would need to do this would should cost around $150, including buying a new bench drill press. Find a used drill press, and it could probably be done for well under $100. It has the same basic drive system that the Stew Mac buffing motor-arbor-buffing-wheel system has, but with the ability to turn 100 rpm slower. Or to speed up. Or to actually be a drill press ;-) Also since the buffing wheels attach using an ordinary drill chuck the wheels would be easier to swap out than on any system I have seen.

I don't really see the advantage to big diameter buffing wheels. Slower is better if you want to avoid heat, and the relative velocity at the wheel turning at 620 one the drill press is just 18 kph. Compare that to the Stew Mac system producing a relative velocity of 48 kph (which is actually pretty slow compared to many). If you don't think that's fast enough, the drill press has four different speeds you can use, and if you turn it on its side, you can use any sized wheel you like. Even using the 14" Stew Mac sized wheels the relative velocity is lower on the drill press at slow speed (42 kph).

Not to throw shade at the Stew Mac machine! It is purpose built with a high quality, low velocity motor and is designed for a luthier's shop. And it should be good for US $1000! But I am thinking a small shop could get darned close with a 2nd hand drill press if someone wanted a dedicated instrument buffer.

[WeirdBits]

I wonder if a low cost right-angle chuck adapter bolted to the platform securely and raised to meet the press’s chuck would give you some more freedom of movement. That is, assuming the right-angle would be robust enough to withstand the forces involved, particularly with perhaps a longer shaft on the buffing wheels etc.