Rubbing, buffing question

[vandenboom]

Up until now, I have used wet/dry all the way up to P2000 or micromesh to do final rubbing out of nitrocellulose finish, followed by a polish.

I have been reading Benedetto's book "Making an Archtop Guitar" as this will be my next project. I was intrigued to discover in his finishing chapter that after curing for a couple of weeks and sanding finish flat with 600 W/D, he uses the following three Meguiar products for final rubbing out/polishing...
1. Mirror Glaze #4
2. Mirror Glaze #2
3. Mirror Glaze #7
I haven't tried the Meguiar products but this seems a little simpler to me than P600/800/1000/1200/1500/2000, or P600/800 followed by Micromesh 2400 -->12000.
Any opinions or experience on this.
Frank

[Bob Connor]

Frank

The only way you'll get all of the sanding marks out of a finish is by methodically going through the grits from 600 up to 2000.

I use a Festool 2000 grit Micromesh type sanding pad after this (but they are expensive @ $5 each)

I think we all find this part of building slow and frustrating but if you want to get a quality finish this really is the only way unless you want to invest in a large compressor and some Dynabrade air sanders.

[Nick]

I read his book too & then went mad & bought the DVD's and I'm not sure of the time span between book & DVD but he changed a few of his methods in the time between the two. In the DVD's he rubs down until the surface is flat with 600 grit then it's straight onto the buffing wheel. Once it's all buffed up then he goes at it with Meguiars #7 but he states that he found used straight it tends to 'stick' to the finish in patches so he makes a mix of 1/3 #7, 1/3 mineral oil, 1/3 water. This is his final polish mix which can be done with a slow speed foam buffer pad or by hand.
I used to go to 1200 grit then use the Meguiars starting at #2 then the #7 'mix', it gave a good finish but by holding it a certain way to the light you could still see small scratches on the surface. So although it's a pain I'd stick with your current regime unless you decide to bite the bullet & buy a buffer.
Good luck with the build too, I'd be keen to see it posted here. I used Bob's book and DVD's to build my first archtop (I still use the book as an excellent reference).

[rocket]

Yes i used bobs book too , but tgere are alot of holes in it, it's like he doesn't want to tell you everything you need to know. If you have a little bit of expeience the book is a good guide to building an archtop, but i think a complete novice would be lost right from the start.

[Hesh1956]

I use Meguiar's products but not to get rid of scratches and I agree with Bob that you really need to go through progressive grits with something else until you have the near final shine.

I use #7 and #9 sometimes. #7 is a polish and not intended to do a good job of removing scratches. #9 is a swirl remover and does not have enough of a cut IMHO to really remove much in the way of scratches either. But both products do perform substantially as described and are great products.

Also worth mentioning is Meguiar's "Quik Detailer" which is an excellent thing to use to clean up and polish guitars. It is mostly distilled water, very benign, takes away dirt and finger prints very well and of course contains no silicon.

I use #7 and #9 on French polish which will tell you that the cut is almost non-existent since a new FP finish is not always all that tough.

[vandenboom]

Thanks gents - I will continue the normal practice. But it does surprise me that someone with Benedetto's reputation would advocate such an approach if it does not deliver excellent quality. Perhaps it is an attempt to keep the process simpler for inexperienced builders/finishers.
Frank

[Allen]

My process once the last coast are on to flatten with P600 wet. I've got it really flat at this point from the previous pore filling, and first spray session and leveling.

You need to dry the surface of water and sludge to see if all the imperfections are gone. Any grits much finer are only refining the scratches of what's already been done. Don't rely on finer grits to be leveling. I jump from P600 to P1000, then P1200, or P1500. Depends on what I have on hand. For lacquer you don't need to get carried away with all extra grits. For harder finishes like Polyester, or Urethane, then the finer the better, as they are much more difficult to buff up.

You need to keep in mind that Meguiar's is an American company that spends up big as a consumer product, with lots of slick advertising, and a product line that encourages you to buy more and more products to get that "Ultimate Show Car Shine". My experience with them is that they aren't worth the bottle that they come in.

Sorry Hesh, and anyone else that may think otherwise.

If you want to keep things simple, then go to an high end automotive paint supplier, who will have rubbing compounds designed for the trade. I'll bet that there won't be any Meguiar's on the shelf. There will however be either 3M, Autoglym, or Farecia. Perhaps even all the brands as everyone has a preference.

I use Autroglym 02B and 03B exclusively. 03B is a medium-coarse cut that I use first, the 02B is a fine cut that I follow with. I never get swirls, and finish looks like glass. If you feel that you need it, they make an 01B that is the swirl remover if you like.

All buffing is done with a foam pad that I have mounted in my drill press. Total sanding and buffing on a guitar once I'm at this stage is around 1 hour.

[vandenboom]

I use Autroglym 02B and 03B exclusively. 03B is a medium-coarse cut that I use first, the 02B is a fine cut that I follow with.
..... Total sanding and buffing on a guitar once I'm at this stage is around 1 hour.

Allen - can I just clarify two things...
- that you move to these Autoglym products after reaching P1500. The description "medium-coarse" has a harsher sound to it.
- That the 1 hour figure refers to this final buffing after finishing the P1500 stage.

Thanks. Frank.

[Allen]

Yes, move to buffing after sanding with either P1200, or P1500. I use whatever is on hand at the time. With lacquer, you're not going to notice much difference in the finish either of these grits leaves, or the time it takes to buff them out.

The reason I call 03B medium-coarse is that there is a product 04B, and it will take the barnacles off a ship. A bit too coarse for a lacquered instrument. You could use just 02B, but it will take much, much longer to get there.

One thing to keep in mind with lacquer finishes, is that they are thermo-plastic, and will reflow with a bit of pressure and heat. This is a real benefit in buffing, with a skilled operator. If you sand from neck block to tail block direction ie. "With the Grain", then when you buff, cut across the sanding scratches and the grain with the buffer. This has a tendency to pull the finish and gloss up the finish in a much faster tine than trying to just go "With the grain"

DO NOT GET THE FINISH TOO HOT, or you will end up pulling the lacquer in a big smear, and will end up needing to do some more spraying.

The entire process of sanding and buffing is what is taking an hour or just a bit more. Never more than 1 1/2 hours. I wet sand all by hand. I'm far too cheap to spend up big on micro mesh sanding pads. If all your process have been good to this point, this shouldn't take long at all.

I should qualify this with I've been a professional automotive spray painter for nearly 30 years, so have some experience with spraying, sanding and buffing. If you check out the tutorial section, I've done a bit of a "How Too" on spraying and buffing. I've been told it's helped a lot of people out.

It really is by far the easiest part of building a guitar. Don't believe what the others might say.

[Drjay]

Where can I acquire the products described in this thread?

[Kim]

It really is by far the easiest part of building a guitar. Don't believe what the others might say.

Cheeky bugger!

[vandenboom]

...ignore previous content - got my threads mixed up...Frank

[Allen]

Where can I acquire the products described in this thread?

I get all the products that I've been using from Cairn's Coatings. A local company that caters to the automotive, boat building and builders trade. It's a good one stop shop for me. If you don't have a place like this that you know of, then you may have to get them from the respective trade outlets. These aren't really considered consumer products, so you may have to look in the industrial park in your town.

[Drjay]

Thanks Allen
It is tips like this that open up my guitar building world.
Jim