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| IS there a quick way to level a finish http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=21792 |
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| Author: | Dave Livermore [ Sat Apr 04, 2009 9:51 am ] |
| Post subject: | IS there a quick way to level a finish |
I'm on the leveling step in my finish schedule. I realize it has been a year since the last time I did this, but I forgot how time consuming this is. In use is a cork backed block of wood and some 400 grit paper. Because this is water based finish I don't dare add water to the process, so I sand for a minute or two and then get a new piece of paper. repeat. What different ways to some of you have to skin this proverbial cat? Thanks in advance, Dave |
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| Author: | David R White [ Sat Apr 04, 2009 10:17 am ] |
| Post subject: | Re: IS there a quick way to level a finish |
Has the finish cured enough, and are you using good sandpaper? Levelling by hand with 400 shouldn't really take that much time. I use the 3m gold papers, and I do dry sand. |
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| Author: | Kevin Gallagher [ Sat Apr 04, 2009 10:33 am ] |
| Post subject: | Re: IS there a quick way to level a finish |
Dave, If the water based finish has dried and cured sufficiently to be sanded, you have to understand that it's no longer a water based finish. The water is simply the medium in which the finish material is transported for application. Once it's cured, water will no longer soften it or cause it to gum up or break down. You certainly can wet sand a water based finish once it's cure sufficiently. It would be a worthless thing if you had to avoid contact with water after it was dried. There would be nothing that you could clean or polish your guitar with if that were the case. 400 grit is a good grit to level with, but be sure that your block surface isn't too soft to actually get everything level. This is a common mistake as the finish is sanded with a block that allows the textures from the spray gun to remain while the surface is nothing more than dulled by the paper. You should be able to level an entire body using 400 grit in about 20 to 30 minutes working by hand with a block and the paper. Using a random orbital sander and 400 grit will cut that time by a considerable amount, but requires close attention to be paid to avoid breaking through the finish. Be sure that you're using the highest quality papers available, too. This is an area where loads of troubles originate. The 3M gold paper are clean cutting, slow packing, very durable and they allow you to work dry if that's your preference. Regards, Kevin Gallagher/Omega Guitars |
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| Author: | Dave Livermore [ Sat Apr 04, 2009 5:13 pm ] |
| Post subject: | Re: IS there a quick way to level a finish |
Thanks Kevin. All good stuff! I have had bad experiences with wet sanding this lacquer, and have heard from others with the same results. Good paper is a must. The Ace brand stuff that was available to me was less than useful. The used 3M gold worked better than new Ace 400 grit. As a result I treked around to all local hardware stores to find some good stuff and I think it was worth the time spent. Your comment about Random orbit is intruiging. Sanding through and burning through the finish as well as not having a prefectly level surface are my concerns. But if you say it can be done, I'll give it a try next time. No doubt the time fact would be cut a bit. Thanks again for the response. d |
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| Author: | truckjohn [ Sat Apr 04, 2009 9:12 pm ] |
| Post subject: | Re: IS there a quick way to level a finish |
I don't have good luck with dry sanding finish coats.. Sandpaper loads up and causes weirdness... How about using paint thinner like with Shellac.... You can't wet sand shellac with water either... I would try it on scrap first.... Good luck John |
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| Author: | cyrguitars [ Sun Apr 05, 2009 6:36 am ] |
| Post subject: | Re: IS there a quick way to level a finish |
What water-based lacquer did you use? I have wet-sanded KTM-9 on three or four instruments without problems using warm water. And I started with 600-grit, not 400. --Steve |
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| Author: | Dave Stewart [ Sun Apr 05, 2009 8:14 am ] |
| Post subject: | Re: IS there a quick way to level a finish |
No problem wet-sanding Ultima either (I use 25% Murphys oil soap in the solution.) |
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| Author: | jordan aceto [ Sun Apr 05, 2009 9:05 am ] |
| Post subject: | Re: IS there a quick way to level a finish |
Me too! KTM-9 and USL with a drop of dish soap in the water, works great. I start with 600 or 800 if the finish went on nicely. I also got hooked on the abralon pads that LMI sells, they have sped things up for me a bunch. Sometimes i use them with a variable speed sander, and sometmes just with a foam block by hand, and just freehand to soften corners and edges without rubbing through. In my experience, the Target finishes level out much faster than KTM-9, but KTM goes pretty quickly with soapy water. |
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| Author: | Mike_P [ Sun Apr 05, 2009 9:28 am ] |
| Post subject: | Re: IS there a quick way to level a finish |
re: random orbit sander I was hand sanding a LOT of table tops a while back...so much sanding that at one point I sanded through one of my finger tips (gee....I wonder what that red tint was in the dust!)..I got disgusted finally and decided to whip out my ROS and put some 320 grit on it...it worked wonderfully!....this method is very dangerous around edges as you will burn through in a heartbeat, so it is best used only in the field of an object and using manual techniques for the areas around edges...of course keep the sander moving at all times to avoid a flat spot and replace paper frequently as it gets clogged....I've moved up to 240 grit now that I have the hang of it, I've tried some Gator 220 but found it a tad too aggressive for my tastes.... |
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| Author: | Terence Kennedy [ Sun Apr 05, 2009 9:47 am ] |
| Post subject: | Re: IS there a quick way to level a finish |
The Porter Cable 330 Speed Bloc sander has worked well for me. It's a great tool. With a little practice you can follow the contour of the heel with it as well. Terry |
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| Author: | Dave Livermore [ Mon Apr 06, 2009 7:21 pm ] |
| Post subject: | Re: IS there a quick way to level a finish |
Thanks everyone for the input. This is exactly what makes this forum so great. I'm still scared of the ROS, but game to give it a try someday. The second leveling went MUCH quicker than the first. I may need to try out the wet sand this evening on a third. Last night I put a "quick" final coat of USL on the guitars. Too bad I did the quick thing. It didn't spray out well, I forgot to filter it on the first guitar and the air to lacquer mixture wasn't quite right. The result looks like it was done by a five year old. AND THIS WAS SUPPOSED TO BE THE FINAL SESSION!!!! Dang. I've never had troubles with USL. Knock on wood. I'll chalk it up to user error. I'll know in a hurry if it isn't cured enough to sand back. sigh. I guess that's just the way things go. |
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