How do you finish acrylic pens?

[radhak]

I have tried turning a couple of wooden pens, and while my friends and family have ooh-ed and aah-ed over them, I am only happy to see improving quality, though they still fall short of what I know can be achieved.The biggest problem was that I was trying to make-do with my existing grits of sandpaper. Finally I went up and bought a set of micromesh from Woodcraft.

This time I tried an acrylic pen, and of course I wanted something different than slimline, so I tried the Euro style. It has more challenges, so the going is slower, yet the turning went okay.

But I am stymied at the finishing : I used sandpaper, then micro-mesh; on hindsight, maybe my mistake was starting at a very coarse level - 120 grit. I did progress to 220, 320, 400, 1000 before the micro-mesh, but I see clear scratch marks that I am unable to take out. Should I have started from a higher grit?

Or is this because sanding gets dust, which does causes scratches? I tried the sand-stop-clean-sand routine, but it builds up too fast!

For this particular pen, I guess I will have to simply go thru all the series of the mesh till the scratches are not as obtrusive. But in general, what is the trick?

[Richard in Smithville]

First....what colour AA did you turn. Darker colours tend to be harder to remove the scratches. I would stop the lathe and hand sand along the length with each grit of micro mesh.

Second....the micro mesh I use is a wet/dry paper and I use it wet.

Third....I still play with micro mesh but usually, after sanding to 600( no need to go higher), I finish sand with 0000 steel wool. Same results. I still hand sand the length with the lathe off.

After sanding, I polish with Brasso, then a polishing compound made to remove scratches in paint, and finally I use a paste polish. Follow the directions on the products.

Or you could get real fancy and get a buffing system for your lathe.

[gerti]

I only turned a few acrylic pens so far, but did not have any issues. I used the regular 'wood' grids to 600, then 1000, 1200, 1500 and 2000 (automotive), and went through the micro-mesh set (all dry). Each grid only for a few seconds, and as Richard says end each pass with a few lenght-wise strokes on the stopped lathe. That makes it easy to see if you did not stay with a grid long enough: if after a few lengthwise strokes you still see scratches perpendicular, you are not done yet.

For the final polish I use some automotive polishing compound intended to get scratches out of plastic (very fine grid suspended in some white thick fluid). All pens came out with a very glossy surface.

[seabat]

I haven't posted any pics in a while and I'm certainly no expert when it comes to plastic but I'm happy with my results.



Sanded with 220 - 400 and I stop the lathe with each grit and sand lengthwise before going to the next grit.

I then use 0000 steel wool and then I wet sand with the equivalent of Micro Mesh and then I use Brasso to polish and then a coat of Kiwi Natural Shoe polish.

[radhak]

Thanks guys - that's great info. Just the lengthwise sanding reduced the scratches somewhat; now with the steel brush, and then to visit Autozone for those supplies.

And seabat, that's a great looking pen!

[leehljp]

Basically from my point of view - what you want to do will take a minor attitude or concept change and a little experience to go with it.

For me, it took a mindset change in which I had to give up the speed of getting things done for the quality that I wanted. I very rarely use 220 to get something down. On softer and easy to chip woods such as a beautiful amboyna burl or other knotty woods and burls, I will use 220 and sand down to within about 1 1/2 or 2 millimeters and then switch to 320 or 400. I use 400 always within a millimeter. It takes time and several strips of sandpaper to sand down to final size but it keeps the scratches down and I don't have blowouts.

On harder and consistent grained woods, I use my chisel to get it to very close and then start with 400 for final. This process of using 400 grit to size is slower but it is more consistent and also prevent blowouts and scratches.

I don't use the bushings to determine the sizes but rather I use calipers and measure often. This is part of the same process of mind-set or attitude. What do I want to accomplish and what is important to you - speed or quality? I am my own worst critic and can spot flaws that most people overlook or don't see. So, I gave up speed for near perfection.

Below is a pen I made a couple of years ago that by its very nature of having metals inlaid prevented me from sanding the wood. I only used sandpaper on the outside of the CA finish, not the wood. I turned it down with a square nosed scraper. Sandpaper on the wood and metal will cause the metal, particularly the silver to smear like pencil lead. The point of this is that with experience, a very sharp chisel and high speeds of 3000 to 4000 RPM can be used to bring harder woods to the precise size if needed without sanding - on hard woods. By stabilizing soft woods often with liberal coatings of CA, it can be turned this way too without chipping. But caution, small bites, patience are requirements.

I haven't turned acrylics much but I have done a few. I do use the same process as I used on the pen with metal, except that I turn it slower. On a couple, I used sandpaper but I personally don't use less than 600 on plastics/acrylics or most CA finishes to start with. CA is basically liquid acrylic.

I miss the pen turning. I haven't turned one since the spring and most of my lathe tools have been packed for shipping back to the States. I will probably be spring or summer of '11 before I get to make any more.

http://www.bt3central.com/showthread...=pieces+silver