Need help finishing acrylics!!!

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TonyBal

TonyBal

Member
Joined
Dec 12, 2011
Messages
51
Location
Jacksonville, Florida
I need help with my finishing process for acrylics. It is taking me twice as long to do the final sanding then it takes to do all of the other steps combined. It seems I have to back track a lot with the various grits of sand paper & MM. Also, I do not wet sand, but have had excellent results. I guess I just don't want the added mess. Any thoughts? :confused:
 
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Wet sanding is the way to go.


Lay some papertowels on the rails of the lathe, and when your finished, wad them up, wipe down the lathe(if any water got through), and toss them out.

MM will last longer with wet sanding also.

Mac PlastixPolish from the Auto(store of your choice) will give that super shine at the end too!





Scott (dry sanding....yuck) B
 
Dry sanding will leave a mess in your lungs...
Like Scott says, although I don't put paper towels, I use a big plastic container cover, so nothing gets through.
 
SDB777 said:
Wet sanding is the way to go.
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Agreed. Wet sand with wet/dry paper both with lathe turning about 500 RPM and with lathe stoppped lengthwise. Use light pressure. Wipe off both the sand paper and blank with a paper towel.

Lay some papertowels on the rails of the lathe, and when your finished, wad them up, wipe down the lathe(if any water got through), and toss them out.
Click to expand...

I have some heavy rubber sheets used for tool box drawer liners I got from Harbor Freight. You don't have to worry about the water soaking thru the rubber sheet. Get a mall bottle to dispense the water. You only need a drop or two and it reduces the mess.
 
MY process for most plastics: Turn to the approximate final size. Sand all the shiny off with 600 grit. A couple of coats of thin CA to knock the haze off. Wet sand through all the grits of MicroMesh. Use liquid car wax to cap it all off. Near flawless finish and easily repeatable.
 
Wet sanding will keep the Sandpaper clean and remove more material. I place a plastic bag over my ways then on old washcloth on that to absorb the water and keep the ways dry. For water I use a Spray bottle that sends a fine mist and I keep it WET, no reason to build a sludge on your pen while sanding.
 
I have had gotten good results wet sanding with Abranet and MM. I have also found it necessary to sand lengthwise between grits.
 
Keep your tools sharp and if you do things right, you CAN just go straight to polishing. Though I will usually use a skew or scraper, then hit it with some 600 grit, then use the plastic polish a few times... but when I do use the MM, I just make sure I sand with each grit long enough to remove the previous grit's sanding marks.
 
You polish the blank by putting finer and finer scratches on it, till
you can't see the individual scratches. The smaller the scratch,
the higher the gloss. So you want to make sure you're not
accidentally putting bigger scratches in there. Never put your
sandpaper on a dirty blank.. it already has particles of the last
grit on it, and you'll grind those into your finish.

i think you're getting the idea that wet sanding is a good idea.
But another important point is not only to sand wet, but to
WASH your sandpaper and the blank.
I you're humming along at 1000 grit and there's still a few
particles of 400 somewhere on the blank (or on the sandpaper)
you'll put some nice scratches on the blank.

I use the micromesh, and I keep them in a little tupperware container
of water with a bit of dish soap. But I also rinse them in clean water
(not the tupperware .. that has EVERY size particle floating in it!)
before I use it on the blank. A bit of wet towel to wipe down the
blank helps, too.

Someone mentioned good sandpaper, and that's important. Cheaper
papers don't have a consistent grit size, so you might THINK you're
sanding at 400, but some of the particles are 200 or 100 .. so you're
killing the finish. Your work is too imporant use cheap sandpaper.
 
Better mark this one down. Every responder agreed on something (wet sanding). Me, too. I also agree about not contaminating a higher grit with junk from a lower grit. Requires a bit more organization and adherence to procedure but the results are well worth the extra effort.

A bit of the discussion has to do with keeping the ways dry. IMHO that's almost as important as the rest of the discussion. I drape a sheet of 8 mil PE over the ways and then clean up after. No rust makes me a happy boy.

So - yes, absolutely - wet sand your plastics. And be slightly OCD about your "process"
 
Yup, wet sand. And the closer your blank is to perfection straight from the tool, the faster your sanding process will be.

I like micro mesh, but have used automotive wet/dry paper as well. Finish off with either buffing, or a plastic polish like PlastX.
 
Like most people have said, if you don't "wet sand", (I use mineral spirits, not water), you are creating your own problem. I would suggest going to the Wood Central site and going to Russ's Corner and read what he wrote on sanding. It will save you a lot of grousing and grief.
 
I discovered that the wetter the sanding the better. I get pretty sloppy when I wet sand and I sand a pretty slow speed. My results are much better now. I wipe the blank after each grade to remove all prior sludge.
 
I wet sand also. I use a spray bottle to wet the blank, and to rinse it and the and the sanding medium I'm using between grits. To protect my lathe bed I lay down a terry cloth rag, then top that off with a shallow plastic tray which catches most of the water.
 
Contrary viewpoint:

I don't wetsand!!

Your problem sounds like the initial sanding. You should be able to sand with 400 or 600 grit and remove material until there are no "shiny lines" showing.

IF this is not happening within a minute of starting sanding, switch to 240-320 grit and go until there are no "shiny lines".

Once you have achieved the "uniform dust pattern", you can go up the grit scale until you want to quit. OR you can sand to 600-1000 and then polish with buffer or acrylic polish.

I am not saying you should NOT use wetsanding, I am only saying you CAN chose not to and still be successful.

The "uniform dust pattern" is the key to success---after that, it's "monkeywork".
 
I used to dry-sand. It worked fine, but it used up a lot of sandpaper because they tended to clog up. Now I wet sand. I put a tupperware dish of water on the lathe bed, as long as the pen and as shallow as I could find. I rinse between grits with a lab squirt bottle. I run the lathe a little slower, so I don't slobber too much water all over.
 
I do all my finish cuts on acrylic with a carbide round which leaves a real nice smooth cut. Then I have a set of pads that are for finishing plastic. I thought I picked them up @ cusa but can't seem to find them there now. It's a set of 3 pads double sided and color coded. I have a spray bottle filled with water, I spray once on the pad and lightly sand the blank. No need for a lot of pressure. I wipe the blank off after each grit with a towel, flip pad over and do the next grit and continue till I'm done. Only takes me about 5 minutes. Then I hit with any plastic polish and I'm done. Most of the time I can skip the roughest grit as well since the carbide cuts so smooth.
 
Another Contrarian:

Like ed4copies, I don't wet sand and I get results like glass. True it eats up the medium and fast. But I do 220, 400, 1500, 2000, polish compound, and finish with swirl remover - all at 3000 rpm.

Having said that, I might try the wet method. sounds interesting. One must turn it slower I should think.
 
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One more for the dry sanding approach. Here is what I do and it seems to work just fine:

1. Turn to final dimensions with the sharpest skew you can find.
2. Sand with 320 grit with the lathe at about 1500 rpm.
3. Sand linearly with 320 grit with the lathe stopped and turning slowly by hand to cover all surfaces.
4. Repeat 2&3 for each of 1200MM, then 1800MM and finally 2400MM. Do the radial sanding followed by the linear sanding.
5. Polish using something like "One Step" polishing compound using a paper towel.
6. Lastly, I buff using white diamond abrasive.

Sounds like a lot but it really goes quickly.

John
 
Buffing wheel

I have the BEALL 3 on Lathe Buffing mandrel. I turn the blanks with a skew chisel, dry sand to 240 grit, and then buff it to glass. I leave the blanks on the mandrel and just buff the crap out of it until it sparkles. Takes maybe 60 seconds... I do the same thing on CA finish and gun stocks. It cuts the work in half, or maybe more. You just have to learn how much pressure to use and adjust your speed accordingly.
 
Thank you for all of your help!

In reading all of your thoughtful & informative responses, I have determined that I have been sabotaging my own success. I am definitely trying to get way to much mileage out of my sandpaper. When it is completely coated with acrylic dust it is time to throw it away. With the larger grits (up to 220) I can kind of smack them on the work bench & most of the dust & grit come off, but anything finer seems to want to hold on to all of the residue. I am going to try wet sanding & hopefully that will not only eliminate the airborne dust particles, but it will keep my sandpaper cleaner longer. I am also going to do a better job of cleaning the blanks between changes of sandpaper grits. :wink:
 
I, too, am new at this. I just finished my first acrylic pen using the wet sanding advice from these posts. It came out beautiful. Thanks so much!!

One question I have, though. How long should you sand with each separate grit? I did it for probably 10-20 seconds at 500rpm, wiped it clean, then lightly re-sanded (after rinsing off the MM) lengthwise at each grit level all the way to 12000MM. Is this long enough?

Thanks!
 
There's no set rule for time. You sand until you can't see any of the previous grit's scratches.

A cheap loupe or slide magnifier or even magnifying glass will help there.
 
Thanks Don. I wasn't sure if I was wasting time sanding too long or if I needed to sand it longer. It took me quite a while going through the 9-10 grits, but I'm sure I'll get better at it the more I do.
 
How you guys got me in trouble!!!

I used the wet sanding technique last night for the first time & got a little frustrated at first. I was still getting some scratching even though I was rinsing the sandpaper often. Then I started using the spray bottle. Problem solved! I would give a few squirts during the sanding process & that would clear away the grit & residue that I was creating. Most of the water would just fall on the towel that I had placed under the work piece & very little would spray all over the place. I was expecting a big mess, but really didn't create one. I was also able to run at the highest speed, about 3850, which also sped things up quite a bit. I went from 220, 500, 1000, 1200 & then the polish, cleaning with a clean paper towel in between grits after the lathe stopped turning. I tried it with the lathe turning & found that it would sometimes create scratches from the left over grit. The other side benefit I found with the wet sanding is that the sandpaper still looks like new even after several pens. Now you are probably wondering how this got me in trouble. Well my wife commented on how the very last pen I did looked the best of them all. It just happened to be the one I was doing for my ex-wife. Thanks a lot guys. I'm going to be hearing about this one until next Christmas! :frown:
 
Tony, I'm glad you're making progress on your sanding technique. As you've learned, there is no single way of doing something, so listen to the advice here, and find out what works for YOU and run with it! Good luck!
 
For Michael (txgators) - As to your "how long should I sand?" Q ..... It depends (on the blank, mostly). Good rule of thumb (esp if you're wet sanding) is that you should check progress when you begin to build up a "slurry". Example: acrylesters tend to be softer and will sand up faster than others. They'll build the "slurry" pretty quick. When that happens, it's time to change grits (for me).
 
TonyBal said:
I used the wet sanding technique last night for the first time & got a little frustrated at first. I was still getting some scratching even though I was rinsing the sandpaper often. Then I started using the spray bottle. Problem solved! I would give a few squirts during the sanding process & that would clear away the grit & residue that I was creating. Most of the water would just fall on the towel that I had placed under the work piece & very little would spray all over the place. I was expecting a big mess, but really didn't create one. I was also able to run at the highest speed, about 3850, which also sped things up quite a bit. I went from 220, 500, 1000, 1200 & then the polish, cleaning with a clean paper towel in between grits after the lathe stopped turning. I tried it with the lathe turning & found that it would sometimes create scratches from the left over grit. The other side benefit I found with the wet sanding is that the sandpaper still looks like new even after several pens. Now you are probably wondering how this got me in trouble. Well my wife commented on how the very last pen I did looked the best of them all. It just happened to be the one I was doing for my ex-wife. Thanks a lot guys. I'm going to be hearing about this one until next Christmas! :frown:
Click to expand...

Sounds like YOU got yourself into trouble by making a pen for your ex-wife!!! What were you thinking?!?!
 
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