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| Wetsanding and polishing lacquer. Beginner in this area. http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10123&t=36685 |
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| Author: | Irving [ Mon Jun 04, 2012 6:37 pm ] |
| Post subject: | Wetsanding and polishing lacquer. Beginner in this area. |
I have only done a couple of nitro finishes. I have wet sanded from 800, 1000, 1200, 1500 to 2000. I sanded in one direction for all grits. I am now testing with several different polishing/buffing compounds. I have Stew Mac's Colortone medium, fine and swirl remover compounds. 3M Rubbing Compound and Meguires Scratch X. Using these compounds I'm able to get a hell of a mirror finish, the Scratch X really brings wraps it up. I have tried applying the compounds by hand with foam and cloth applicators as well as with a cheap turtlewax random orbit buffer. Despite the mirror finish that I'm able to get, it's ruined because I cannot get the wet sanding scratches fully removed. A substantial amount of scratches run the full length of the front and back of this thing and I just cannot get rid of them. Any tips? |
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| Author: | B. Howard [ Mon Jun 04, 2012 6:48 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
Sounds to me like you did not completely remove the previous grits scratches with each successively finer grit. It can be helpful to change directions with each grit to be sure you have removed the previous sanding marks. A 30-60 cross hatch works nice without leading to undo material removal as can happen when going 90 degrees between grits. You will most likely need to re-sand. Without seeing in person I can't say what grit you need to start at but I would think since it has been polished that 1500 & 2000 would get it. |
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| Author: | Fred Tellier [ Mon Jun 04, 2012 6:59 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
Each finer grit has to remove the sanding marks created by the preceding grit, if you are seeing marks after buffing it will be from the coarser grit marks not being removed. If you are buffing by hand you may need to spend more time with the coarser compound. A trick is to sand in opposite direction with each grit so you can see that the previous grit marks are gone. As you get more experienced it becomes easier, I have just rubbed out #15 and I am still not totally happy with the results but it is way better than the first few. My biggest advance came when I put together a buffing arbor with cotton wheels and started using the Menzerna Compounds from Stewmac. |
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| Author: | Irving [ Mon Jun 04, 2012 7:14 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
Cross hatching the sanding between grits is very good advice. I am finding that the Colortone compounds from StewMac seem not to be as effective as the 3M and the Meguires. Anyone had good luck with the Colortone brand? For those not using a traditional buffing arbor with Menzerna type compounds (wish I was), how many rubbing compounds/waxes whatever you want to call them do you use? Would you think I'd be ok using 3M Rubbing Compound followed by Meguire's ScratchX after 2000 grit and call it a day? What do you use? |
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| Author: | Irving [ Mon Jun 04, 2012 7:52 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
I just went back with the 2000 grit and cross hatched across my existing problem scratches. It eliminated the previous scratches but I now cannot seem to get rid of these new ones. They are 2000 grit scratches.. shouldn't these polish out? I am using 3M Rubbing Compound. Is there something more aggressive I should use for a rubbing compound? |
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| Author: | Radiohead [ Mon Jun 04, 2012 7:59 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
how long has the Nitro cured? I have been told you need to let it sit for at least 6 weeks? Following 2000 grit, you need to use swirl remover, don't go back to medium or fine rubbing compound as this will introduce new scratches. These compounds are courser than the 2000 grit. Rick |
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| Author: | Irving [ Mon Jun 04, 2012 8:09 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
Yeah but the medium and fine compounds are not removing the wet sanding 2000 grit scratches. I am working at and watching the same scratch lines that are undoubtedly 2000 grit. It has cured for almost 20 days or so, which isn't optimal but should be fine and I don't think it has anything to do with my difficulties at present. |
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| Author: | Irving [ Mon Jun 04, 2012 9:26 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
I have a very similar thread going over at TDPRI. So if anyone reads both forums, my apologies. Just trying to get tips from all angles. I have certainly heard of waiting from 2 to 6 weeks before final sanding and buffing. I find it odd though that even Stew Mac's directions of lacquer finishing says to wait 4 days before final sanding: http://www.stewmac.com/shop/Finishin...b=Instructions I have been told by others that they have done their final finish work after even only letting the guitar cure for 3 days and the only repercussion is grain lines showing later down the road. It's been suggested to me that perhaps I am just moving around the top layers of lacquer because it hasn't cured, therefor not removing the scratches. Perhaps. I feel my problem may just be I am buffing like a puss. About how long does it take you, either by hand or with a simple orbital buffer, to buff the backside of a guitar with one compound? Is it a matter of seconds, minutes, five minutes? |
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| Author: | jimmysux [ Mon Jun 04, 2012 10:02 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
Wait a month after the final coat before wet sanding, I always start with a 1200 grit and move up to 2000 grit, then I use the stew mac color tone polishes along with their pads, I also use zaino swirl remover for the final polish and I never have any scratch marks, even on a soft lacquer like deft. |
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| Author: | Irving [ Mon Jun 04, 2012 10:14 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
I guess what I'm trying to find out at this point is, is it just a quick touch with these compounds? Is it just a quick wax on wax off process? Or is it a workout? I'm starting to put some real force into this crappy little low powered turtlewax buffer and worked hard at it, almost working up a sweat, and these scratches are starting to come out. Should you have to work hard at it, or should it be easy? |
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| Author: | Irving [ Mon Jun 04, 2012 10:20 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
I apologize for my complete and utter ignorance in the buffing department. But hey. Ignorance happens and there's only one way to cure it. |
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| Author: | Fred Tellier [ Tue Jun 05, 2012 7:02 am ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
It is the same issue with the compounds as the sanding grits each finer one must remove the marks from the previous. I use the Menzerna Compounds from coarse to extra fine. You may need to start with a coarser compound and it may need several applications. When I tried the RO buffer thing but found I did better by hand buffing, I worked my ass off, thus now using the arbor and wheels. Be patient this is a process that must be learned by doing Fred |
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| Author: | B. Howard [ Tue Jun 05, 2012 11:33 am ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
Like anything else, buffing is work. What type of pad is on your buffer? You should be using a different pad for each compound. Also be mindfull of dirt getting into your pads, a small piece of ebony dust can leave swirls faster than you can take them out. I do my polishing by hand with a felt block and Novus #2. If the sanding marks are not polishing out you may not be putting down enough compound. |
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| Author: | Barry Daniels [ Wed Jun 06, 2012 1:21 pm ] |
| Post subject: | Re: Wetsanding and polishing lacquer. Beginner in this area. |
Sounds like you need a better buffing machine. Most of the hobbiest type machines don't really do much. Porter Cable has some good RO machines that are highly rated by the auto buffing folks. |
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