Question on sanding poly resin

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bjbear76

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ed4copies

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There is a theory that wet sanding any embedded object can be a problem.

The blanks appear to be paper embedded in PR. IF you wet sand and the water gets into the "faced" end of the blank---it could easily wick into the paper. So, they are suggesting that you not take that chance.
 

jondavidj

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Hi Bill,

I have made a couple of these blanks and cast everything in poly resin. I do not wet sand when I get to the finishing.

These are the steps in which I do:

- 150
- 220
- 320
- 400
- 600

After that I do the micro mesh to 12000. I do make sure these are wet. But on the sandpaper, I don't. The blanks turn out really well without any scratches.

I hope this helps.....

Jon David Jones
 

Janster

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...."after" turning your blank and the ends are definitely square, just give each end a couple of light coats of thin CA. Let em' cure and wet sand away. I have not had any issues doing it that way and I cast quite a bit of paper!. Be well...........Jan
 

vtgaryw

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I learned that lesson the hard way. One of my first PR cast blanks the wet sanding slurry wicked into the ends and ruined an otherwise beautiful blank.

Gary
 

plantman

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Thanks Ed and Jon...makes sense. I guess just keep the lathe speed relatively slow when dry sanding to avoid any heat.

How about a slow speed of zero when sanding ? I'm old school, and hate sanding !! The only thing I have ever wet sanded was on automobiles or other metal objects. I do not like water on my lathe or the mess it makes when wet sanding !! These is my personal thoughts on sanding. Many people, when sanding for a fine finish, tend to oversand their projects. Most people sand with the lathe running. This is fine for rough sanding a project, but I would never do it to finish sand. There are several reasons to my methods. When sanding a turning object you are adding grooves or rings to your blank. This is why you have to use finer and finer grits to remove these rings or scratches. Also if you look at the inside of your hand it is not perfectly flat, so unless you use some form of solid backer, you are going to sand unevenly. If you stop your lathe and sand lengthwise on your blank any groves will be less noticeably or non existant. You realy don't need to go through all those grits to get a great finish. On acrylics I will start with 400 than 600 and finish with 900 or 1200. Make sure to clean between each grit change. Next I apply a coat of One-Step Plastic Polish at full speed. If you want more depth, apply more coats of finish. I have never realy noticed a difference in this method and using my Micro Mesh to 12,000. You could also do the same thing using buffing compounds. On wooden blanks or wood in general, 100 220 and 400 grits should work just fine because it's the CA or whatever finish that you apply over the wood that your going to smooth out with the higher grits of paper or 0000 steel wool, and then polish to a shine. If your base is not perfect, your top coats will show it. As I said, this is just my method, and not right for everyone, but it sure cuts down on time, materials, and the mess. Jim S
 
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plantman

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...."after" turning your blank and the ends are definitely square, just give each end a couple of light coats of thin CA. Let em' cure and wet sand away. I have not had any issues doing it that way and I cast quite a bit of paper!. Be well...........Jan

As ED said, if it's paper embedded you are going to have to seal the ends, but you are also going to have to seal any exposed paper on the entire blank. A coat of thin CA over the blank will wick into the paper and prevent any moisture from entering as long as you don't sand to deep. You can also use nail polish hardner to seal the ends. It's a little easier to apply, drys fast and smooth, and you fingers don't stick to it. Dollar Store for, you guessed it, $1.00. Jim S
 
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