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Sanding/Leveling finish before buffing.
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Author:  Rod True [ Sun Nov 14, 2010 11:51 am ]
Post subject:  Sanding/Leveling finish before buffing.
This is something that has been a PITA for me with every guitar (I'm sure I'm not alone). It seems to take a long time to level the finish then sand up to P1200 before hitting the buffer.

Last night I got to use my new buffer and while I'm very happy with its performance, I now get to see any micro scratches which were "never there, honest" before I hit the buffer. So, my guess is I didn't remove some of the sanding scratches as I moved up from one grit to the next.

Here's what I've been doing on the last several guitars.

Level sand with 400 3M Gold dry
Sand with 600 3M Gold dry
Sand with 800 3M Gold dry
Wet sand with 1200 with dish soap and water.

Each of these steps really seems to clog the paper quick. Like I can start with a new piece of paper and within 20 strokes, I'm already getting hard spots on the paper. I really try not to press hard on the paper and just let the paper do the work. I can easily go through 2-3 sheets of paper on the body.

So, my questions are. What papers do you folks use? Do you wet sand all the way from start to finish (no pun intended)? Do you sand by hand or use a ROS?

I really want to bring the level of quality of my finishing up so any help would be great.

Thanks.
Author:  Fred Tellier [ Sun Nov 14, 2010 12:11 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
With the dry paper I keep a terry cloth towel beside the guitar and keep wiping off the paper before the lacquer starts to pill on the paper. I use dry all the way to 1500 then use medium Menzerna. If I see any scratches I have some 2000 and touch up those spots and re buff those areas before switching to fine compound. A good buffing really shows the sanding mistakes but makes the finish so much better, faster and easier.

Fred
Author:  meddlingfool [ Sun Nov 14, 2010 12:24 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
I use ROS. If you have a decent sized compressor a Dynabrade is an amazing tool. It takes a lot of air though. If not then a Porter Cable low profile one is OK, but it doesn't have the variable speed on the fly like the Dynabrade. Even it's lowest speed is fairly aggressive so you do need caution. I level sand with 3M 30mic and then final sand with 15mic. It usually takes 4-6 discs of each type and it's expensive so you're not saving any money, but you sure do save a whole lot of time...
Author:  Howard Klepper [ Sun Nov 14, 2010 1:05 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Why are you using dry paper?

Are the 3M papers on the P grade system or the CAMI system?

The first grade is the hardest part; if you start too fine it takes too long, but if you start coarser, you have to be really careful to get all the scratches out, and have more chance of sanding through. Best advice i can give is to do a good level sand with 400 or so before you spray the last two (or so) topcoats, and experiment with your lacquer mix, gun, and pressure to get a finer sprayed film surface. It goes better if you can start with 600 (CAMI, which is about 900 or so P grade).
Author:  jmpbuffalo [ Sun Nov 14, 2010 1:17 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Something I like to do is use a scraper (with the edge at 90 degrees, not turned) to do initial leveling. I've never used lacquer, though, so I don't know how it would work on that. In general, I find sandpaper clogs more if I get impatient and the finish hasn't hardened enough.

Joe
Author:  Rod True [ Sun Nov 14, 2010 1:21 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Thanks so far guys,

I didn't soak my paper overnight, wonder if that's part of the problem. The paper I have is noted as a Swedish paper.... idunno
The scratches do seem to be around the 800 grit range.

Howard, as funny as this sounds, I think dry sanding is less messy versus wet sanding :? yet the biggest advantage is that it's easier to see the progress with the dry sanding. Mind you, I thought I had gotten all the previous scratches out as I moved along...

The 3M paper is on the P grade system.
Author:  meddlingfool [ Sun Nov 14, 2010 1:23 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Howard,
Dry, cause it works real good and no slurry mess. What measuring system, don't know. Just the discs say 30 and 15 mic.
Author:  Cal Maier [ Sun Nov 14, 2010 1:41 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Rod,

I finish with Mohawk Instrument Nitro and use Klingspor W/D Paper (made in Germany). I buy this locally and use it because I get a deal on it, I would use 3M if it was cheaper. I wet sand using water and dish soap for all level sanding after the final coats have cured. Depending on the amount of shrinking I get, I will start with either P400 or P600 wet. and level by hand using a block(rubber). I sand until level, then move on to the next finest grit, basically same as you use but up to P1500. The grits are P400, P600, P800, P1000, P1200, P1500. One thing I do is keep the surface clean of debris, I use a damp towel to wipe the surface often and I check my paper for build up, if there is build on the surface of the paper, I change paper. This may sound obsessive but you can end up putting deeper scratches in the surface than you are removing, with clogged paper.

Unfortunately I haven't found a short cut for this job, so I just put on some tunes and get at it.

Cal
Author:  TonyFrancis [ Sun Nov 14, 2010 1:44 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
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Author:  Rod True [ Sun Nov 14, 2010 2:04 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
I should have mentioned, I'm using Mohawk classic instrument lacquer. I let it cure for 4 weeks before starting and it sure seems hard enough.

My honest guess is that I'm just being to impatient. I've had good results in the past with this same sanding schedule, most recently on Target's EM6000 WB lacquer.

But it's always good to refreash and hear what is working for others.

I've never really liked wet sanding but I think if I get some good paper, soak it over night and just sit down and not worry about how long it takes...

So, Todd mentioned Japanese paper or 3M imperial and Cal mentioned the Klingspore.

Cal, where do you get the Klingspore w/d paper? I'll see if I can source it locally in Abbotsford. Also, I'm going to get some Murphy's oil soap and give that a try too.

Howard, thanks for the edit on your post. I've never leveled initially after spraying and that too coule be another issue. I'll heed your advise on the next go round with leveling and then spraying a couple thin coats before leaving to cure.
Author:  woodbutcher50 [ Sun Nov 14, 2010 2:12 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
I started out using the wet sanding method with some 800 grit followed by some P1200 grit paper from Klingspor. When I buffed out the finish the scratch swirls were horrendous! wow7-eyes

I then re-sanded using the original 800 grit followed by a 1200 grit of the same brand. The results were remarkably improved.This was paper I had purchased at a discount tool store in Oregon. So it turns out that the cheaper paper I had bought was better suited for the job.

Turns out the P1200 paper is equivalent to about 600 grit in the CAMI grading system so I was actually going backwards. gaah

Here's a chart I found while I was researching the problem.

http://www.woodturners.org/tech_tips/misc-pages/abrasive_grading.pdf

I have since bought a stash of 3M Imperial paper which to my knowledge is a CAMI graded paper. Is that correct?

Would it also be safe to say that if it doesn't have a 'P' in front of the grit, it is CAMI paper? I am unclear whether the markings are standardized in the industry or are subject to the manufacturers' whim.

I like the process of wet sanding, maybe because I am just a naturally messy guy. pizza I make my 1" x 2-3/4" sanding blocks out of 1/4" acrylic and 1/8" natural cork. Perfect fit for a 1/16 sheet of paper.

Attachment:
IMG_2254 LF.JPG


Please keep in mind that I am only working on my third build, so I am still experimenting. If there is anything better out there I will certainly try it.

Mark
Author:  Fred Tellier [ Sun Nov 14, 2010 2:34 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Quote:
Why are you using dry paper?


For me it works great, can be used with a RO sander with vac system so is a lot less messy than wet sanding and gives for me a great result. I use Joest
Quote:
http://www.joest-abrasives.de/e/index.htm
brand papers from Europe, I came across the Canadian distributor who was liquidating his stock as he was closing his distribution and packaging operation. I bought several hundred sheets of each from 80 grit up to 1500 grit. For hand sanding I use the velcro sanding blocks and pads they sell but they also work great on the RO sander which I modified to extra vac holes in the pad. I have even a couple multi yard 1 meter wide rolls of this product in 220 and 320 grit and the rest is 5" foam and velcro backed disks, wish I had purchased more when it was available. I will not have to buy abrasives for several years.

Before this I used 3m gold psa disks that I also got a good deal on, but not as reasonable as the Joest product.

Fred
Author:  Daniel Minard [ Sun Nov 14, 2010 2:38 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
I keep one of those long (snap off blade type) razor knives handy, when I'm wet sanding finish.
A gentle stroke across the clogged paper (as if you were trying to sharpen the knife) clears the clogged lacquer. (The back of the blade works just as well as the sharp edge) It does wear the grit off some, but it about doubles the life of the paper.
Wet, with a bit if dish soap. Lots of water. Wipe down often to remove little chunks of debris which will scratch the surface... Wear your galoshes!
A foam plug in the soundhole, with a couple of layers of paper towel on top keeps water out of the body. Change the paper towel when as it gets wet.
And be prepared to spend WAY too much time at it!
lately, I haven't been leveling before the final coats, but I'll start doing that again now. Thanks Howard!
If you can level with 600, it saves a lot of work & time.
I usually final sand to 2,000 grit. A quick buff & check for scratches... Sand them out & buff to final finish.
I too, would like to use a power sander to do this job. On my only attempt, I had to respray the whole guitar. Any tips would be greatly appreciated!
Author:  Cal Maier [ Sun Nov 14, 2010 4:00 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Rod,

I get the Klingspor from a shop here in Kelowna called The Tool Place, one of my favorite stores, [:Y:] they carry the full line of that brand of paper. I'm sure that you'll be able to find a dealer in the lower mainland or Vanc.

+1 for Howard's advice about spraying a couple of final topcoats after initial levelling.

Cal
Author:  Howard Klepper [ Sun Nov 14, 2010 5:22 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
P400 is pretty coarse stuff. I would suggest you do more intermediate leveling, and work on your spray system to get a smoother coat. You didn't say what kind of finish you are using.

Messy with wet paper? You mean, you get your hands dirty? Ewwww!

Wipe it off with a towel, wait 10 seconds and then you can see everything just as well as with dry. Stearate doesn't lubricate as well as water with a drop of detergent, and it sure doesn't do anything to cool the surface.
Author:  TonyKarol [ Sun Nov 14, 2010 6:13 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Actually he did Howard .. Mohawk instrument lacquer.

Rod ... I level sand with 400 2/3rds the way thru shooting, and then the final sand out can start at 600 - all wet, none is done dry, and i use mineral spirits - if you ever rub thru with soapy water you may have issues with water under there and swelling of stuff. I have had some so good, I just did 1000 or 1200 and then hit the buffer, Menzerna med, then glans wach. Then hand polish with Meguiars 7 and done.
Author:  Billy T [ Sun Nov 14, 2010 6:23 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Clean! Clean! Clean! If you cross contaminate the papers you could be going all the way back to initial grit. I change anything that come in contact when I'm doing fine finishes, bench towels ..anything, and rinse the work real well between grit changes. Paper water needs to be changed and the container rinsed real well too! Like surgery!
Author:  muthrs [ Sun Nov 14, 2010 6:46 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Well, here's what I do anyway.

I level my final coats with Carborundum Premier Red Dri-Lube P1000 paper. I love this stuff, it is an aluminum oxide paper that is available down to P1200 grit and can be used wet or dry. I use it dry and while I admit that P1000 is pushing it, I would never see a reason to go coarser than P800. I've gone to all hand sanding and use about 1 1/2 sheets for the guitar. I use a stiff brush to brush the finish off the sandpaper as I go. I like to dry sand for the initial leveling so I can see the shiny spots go away.

I then wet sand using Mirka or 3M P1500 silicon carbide paper, followed by P2000. Then to medium and fine Menzerna compounds on the buffer. I like to wet sand after the initial leveling because I feel it gives a much more consistent scratch pattern
Author:  James Orr [ Sun Nov 14, 2010 7:47 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Timely thread. I did an initial level today and sprayed 3 more coats of nitro. The wet sanding, for whatever reason, is much more effective for me. And as much as I hate to do it by hand, I've realized I have better results that way than with my Festool random orbit. So goodbye to the Festool's Platin 500 and 1000 sanding pads on the Festool and hello 400-1000 by hand.
Author:  Darrel Friesen [ Sun Nov 14, 2010 8:05 pm ]
Post subject:  Re: Sanding/Leveling finish before buffing.
There are a number of handy scales out there showing the comparitive differences between Cami and Fepa P scale as well as the equivalent micron size for reference. Wikipedia has a pretty good one. http://en.wikipedia.org/wiki/Sandpaper
Author:  TonyFrancis [ Mon Nov 15, 2010 1:18 am ]
Post subject:  Re: Sanding/Leveling finish before buffing.
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Author:  Rod True [ Mon Nov 15, 2010 2:01 am ]
Post subject:  Re: Sanding/Leveling finish before buffing.
I was sort of hoping that Joe White would give us his schedule ;)
Author:  Rod True [ Mon Nov 15, 2010 2:28 am ]
Post subject:  Re: Sanding/Leveling finish before buffing.
I was also going to say, Addam Stark has some pictures on his facebook page of him rubbing out one of Terance Kennedy's guitars. Might be worth shooting him and email and seeing if he would also share his schedule and tools.
Author:  Haans [ Mon Nov 15, 2010 5:22 am ]
Post subject:  Re: Sanding/Leveling finish before buffing.
I use a Chicago Pneumatic D/A and 600, 800, and 1000 grit blue film discs available here:

http://www.yoursource1.com/5_Deer_sandp ... deerhl.htm

I sand wet and use a spray bottle to spritz soapy water, wipe off with some industrial paper rags and there is no mess. Works well, but leaves a few "worm tracks" here and there. Those are fairly easily buffed out with Menzerna brown and I use 4 grits of Menzerna in all.
After dyeing, filling, sealing, I spray 4 coats of lacquer, drop fill (wait 3 days), sand with 600, spray 3 coats (wait 3 days), sand with 800, spray very thin 3 coats (wait 3 weeks), sand with 1000 and buff.
Works for me.
Author:  Lindamon [ Mon Nov 15, 2010 7:05 am ]
Post subject:  Re: Sanding/Leveling finish before buffing.
Finish with nitro, I also sand with 320 after 3 coats on top of any color coats, and again before the final coat. Cure 3 weeks - month. Wet sand with the 800 (not sure what system it's graded under) from Stew-Mac, using hand for neck and foam block for body. Most important ==> Clean the paper often with brass bristle brush, it loads up very quickly. Replace the paper when it gets dull, I use 2-3 sheets a guitar. Murphy's soap in the water does not seem to help keep the paper clean with me, but I put a few drops in anyway. I wipe the guitar down with a soft cotton cloth after each sanding pass to get off sanded lacquer and check progress. After sanding I go straight to buffing with Menzerna medium, then fine. After the fine, I take it outside and look in the sunlight (I live in FL) for fine scratches and rebuff those areas with medium, then fine again. If there are some tough areas, I'll re-sand them lightly, then buff again. I have some 1200 but rarely use it. I spend about 10-12 hours on the whole process.
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