Here is a video of the mind numbingly boring task of wet sanding the brushed nitro lacquer. Prepare to fall fast asleep ladies and gentlemen. This is about as boring as it gets!
http://www.youtube.com/watch?v=aNRQEfgZLQk
Please feel free to ask questions.
Wet Sanding Nitro---Video
Moderator: dhlutherie
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The purpose of this forum site is to provide a means for acoustic guitar makers at all skill levels to forward information, share experience and ask questions if project obstacles are encountered. We ask that egos be left at the door – the highest levels of courtesy and respect are to be shown to all. Posts containing disparaging comments will be removed. The “Acoustic Guitar Construction Forum” is owned by Kenneth Michael Guitars and is copy protected. Direct links to luthier suppliers are not permitted and will be edited.
The purpose of this forum site is to provide a means for acoustic guitar makers at all skill levels to forward information, share experience and ask questions if project obstacles are encountered. We ask that egos be left at the door – the highest levels of courtesy and respect are to be shown to all. Posts containing disparaging comments will be removed. The “Acoustic Guitar Construction Forum” is owned by Kenneth Michael Guitars and is copy protected. Direct links to luthier suppliers are not permitted and will be edited.
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Dave Bagwill
- Posts: 5955
- Joined: Tue Dec 13, 2011 7:44 pm
Re: Wet Sanding Nitro---Video
Thank you Tony. That was helpful, I appreciate the effort.
Does the micro-mesh last quite a while? Does washing it prolong its life?
Do you work up through the MM grits, or start at 600 and end at 2400?
Does the micro-mesh last quite a while? Does washing it prolong its life?
Do you work up through the MM grits, or start at 600 and end at 2400?
-Under permanent construction
Re: Wet Sanding Nitro---Video
Micro mesh starts at 1500 which is equivalent to 600 grit wet dry paper. I only sand to the equivalent of 1500 wet dry because my compound will remove the scratches from 1200 grit paper so why go any higher?
Yes I run the grits of MM. It last a long time when you use it wet. I have never washed it. Just a quick rinse. The set I bought 4 guitars ago is still going strong but takes longer than when it was new. The kit has two sheets of each grit for $45 or so and comes with the pad. If I buy more I will buy the grits I use not a whole kit.
My pleasure making the video. It's kind of fun.
Yes I run the grits of MM. It last a long time when you use it wet. I have never washed it. Just a quick rinse. The set I bought 4 guitars ago is still going strong but takes longer than when it was new. The kit has two sheets of each grit for $45 or so and comes with the pad. If I buy more I will buy the grits I use not a whole kit.
My pleasure making the video. It's kind of fun.
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Kyle Barbour
- Posts: 230
- Joined: Fri Dec 23, 2011 10:37 pm
- Location: Glen Burnie Md
Re: Wet Sanding Nitro---Video
Thanks Tony. This may seem like a question with an obvious answer but I'm not so sure. How do you know when it's time to move to the next grit? I find it difficult to tell when to move on, especially during wet sanding because the scratches become so fine. What clues do you use to tell?
Kyle
Re: Wet Sanding Nitro---Video
That's a good question actually!
I don't know if I ever mentioned this before, so I will do it now. Here is how I change grits:
Starting with the lowest grit you are comfortable with, which for me is usually 600 at this point, I begin sanding until I have almost completely leveled the surface. There should still be low spots all over that you need to sand down to. They should be small, but not too small. You want to be able to go through another two or three grits to get the finish completely level.
Once I have a few low spots left all over the guitar, I switch to 1000 grit and sand until the low spots (which are easily identified by their shinyness compared to the surrounding finish) are almost completely gone.
Switch to 1500 grit and continue sanding until all shiny spots are totally gone.
Sanding with 1500 grit is like sanding with a sheet of loose leaf paper, but it is important to do it right. Leaving a few tiny shiny spots as your landmarks to check your progress is the easiest way to know you have removed enough finish to have removed all of the scratches from the previous grit.
The only way to see the shiny spots when wet sanding is to wipe the surface dry with a paper towel and hold the guitar up so the light is hitting the surface at an angle.
The key to a perfectly flat, glassy finish is not dependent upon how you apply the finish, or how flat you can apply the finish. The key is how you remove the finish and what you leave on. This is why the prep you do prior to applying the lacquer is so important. The finish can only be as flat as the wood it goes on unless you apply the finish really thick. If you left the guitar lumpy, the finish can never be thin and flat. For finish prep I use a hard block. It is MDF with all of the corners rounded. It allows me to get the wood nice and flat.
I am going to switch to a harder block for sanding the lacquer. I think I can get a better finish with something harder than the foam block that came with the MicroMesh kit. Despite it's density, it can still conform to the surface a bit more than I think it should for the top and back. It is perfect for the sides. Since I have one more guitar to finish this summer, we will get to see what a hard block can do!
I hope this covers your questions. If not, feel free to ask more!
I don't know if I ever mentioned this before, so I will do it now. Here is how I change grits:
Starting with the lowest grit you are comfortable with, which for me is usually 600 at this point, I begin sanding until I have almost completely leveled the surface. There should still be low spots all over that you need to sand down to. They should be small, but not too small. You want to be able to go through another two or three grits to get the finish completely level.
Once I have a few low spots left all over the guitar, I switch to 1000 grit and sand until the low spots (which are easily identified by their shinyness compared to the surrounding finish) are almost completely gone.
Switch to 1500 grit and continue sanding until all shiny spots are totally gone.
Sanding with 1500 grit is like sanding with a sheet of loose leaf paper, but it is important to do it right. Leaving a few tiny shiny spots as your landmarks to check your progress is the easiest way to know you have removed enough finish to have removed all of the scratches from the previous grit.
The only way to see the shiny spots when wet sanding is to wipe the surface dry with a paper towel and hold the guitar up so the light is hitting the surface at an angle.
The key to a perfectly flat, glassy finish is not dependent upon how you apply the finish, or how flat you can apply the finish. The key is how you remove the finish and what you leave on. This is why the prep you do prior to applying the lacquer is so important. The finish can only be as flat as the wood it goes on unless you apply the finish really thick. If you left the guitar lumpy, the finish can never be thin and flat. For finish prep I use a hard block. It is MDF with all of the corners rounded. It allows me to get the wood nice and flat.
I am going to switch to a harder block for sanding the lacquer. I think I can get a better finish with something harder than the foam block that came with the MicroMesh kit. Despite it's density, it can still conform to the surface a bit more than I think it should for the top and back. It is perfect for the sides. Since I have one more guitar to finish this summer, we will get to see what a hard block can do!
I hope this covers your questions. If not, feel free to ask more!
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Kevin in California
- Posts: 2847
- Joined: Mon Dec 19, 2011 4:19 pm
Re: Wet Sanding Nitro---Video
Tony,
Are you using a swirl remover as a final buffing? If so, what do you use, and do you buff in a circular motion or straight with the grain?
Kevin
Are you using a swirl remover as a final buffing? If so, what do you use, and do you buff in a circular motion or straight with the grain?
Kevin
Re: Wet Sanding Nitro---Video
The compound I use is called Wizard's Finish Cut One Step.
It removes scratches from 1200 grit or higher sandpaper so I sand to 1500 because it's a common grit. When I use micro mesh I go to whatever grit is equivalent to 1200-1300 wet/dry.
I use a foam pad in my cordless drill so it is a definite circular motion!
I follow with Wizard's Master Shine wax. Both are made for use with nitro lacquer.
It removes scratches from 1200 grit or higher sandpaper so I sand to 1500 because it's a common grit. When I use micro mesh I go to whatever grit is equivalent to 1200-1300 wet/dry.
I use a foam pad in my cordless drill so it is a definite circular motion!
I follow with Wizard's Master Shine wax. Both are made for use with nitro lacquer.