Thread: Acrylic Pens

Everyone seems to agree on VERY VERY sharp tools, very light cuts and a delicate touch. Beware of heat, it does funny things to resins and I don't mean just melting them.

Friend of mine makes/installs corian kitchen countertops and he says that when heated,
the corian explodes. He says if you put a hot teapot on the countertop, it won't just crack, it will send the teapot flying up into the ceiling.

Wouldn't surprise me if a miniature version of the same thing could happen with acrylics, as turning builds up some heat.. and SANDING builds up a LOT of heat! The heat can expand the material and exploit any fissures or weaknesses in the structure.

I know I tend to lose acrylic blanks in the drilling process, no matter how light the touch or how sharp the bit. I think the heat buildup has something to do with it.

I have only done a couple of the acrilics drilling went ok got the drill speed down as slow as possible and used a squirt of water to lubricate the drill and help cooling,turning was a pain though,after wood. Like mentioned previously one of the blanks broke a piece right out for no apparent reason ,so I simply used some thin ca and put it back in place,fortunately the finished pen showed no signs of the join so at least that was a plus. Next time I am going to try and do one on my metal lathe with a sharp tool lots of rake for shear and a fine feed,see if that works As to drilling I have seen some say to leave the blank long and not drill right through ,then cut to length after drilling ,that may be an option as well.

wet sand

use a skew or scraper not a gouge (after rounding it off). Sharp tools help but you can get by without them to an extent.

I'm glad you brought this up. I've been wondering about the same things. How about lathe speed? I usually turn timber at full throttle. Should I slow down to a medium speed for acrylic?

Originally Posted by David Mitchell

What is the best method to turn this material without chiping and cracking

Personally I use a 1/4" skew chisel that I sharpen before each new acrylic blank, never had one break on the lathe.

Originally Posted by ciscokid

How about lathe speed?

I run mine at max speed as well - 3,500rpm for acrylics and wood. Sharp tools, careful cuts.

Very sharp tools, I use the Sorenson spindle gouge. Small cuts without pressure and I use the flat out speed 3200.

When the ribbons fly you know you have it right. I also round the corners off first on the linisher this stops any chipping while roughing.

Wet sand so as you have a slurry and won't heat the Acrylic. Water with the MM as well.

I stick to my 3/4" Roughing gouge.

Just pare it of at an angle of about 45 degrees to the side and 45 degrees handle down.

I'm with Jim. I am happy using a roughing gouge at full speed. May use a skew to finish close to the bushes. Whatever you use, it does have to be sharp. Get used to the idea of having to sharpen more frequently than with timber. Very light cuts are essential.

Wet sand and finish with white diamond on a buffing wheel.

I've never had one blow on the lathe, just on the drill press when I've tried to break through rather than leave a section of waste to either sand or cut off.

Found this info,may help to understand a bit more about this stuff ! http://www.pennstateind.com/library/aquapearl_ins.pdf[Lots of good info in this library cheers may go and do some more hehe!

I found that some types of Acrylics can be brittle, and instead of coming of smoothly they can chip or crack. Amos

Amos that can be a lot to do with the angle of the tool. Move it around a bit till you find it cutting rather than scraping.

I do acrylics and if I round off the edges it starts easier. I use a gouge and skew, but they are both sharp. In drilling it helps to bring the drill bit out often and then no melting. I finish with micro mesh and Nova plastic polish or automotive polishing compound, which puts quite a gloss on the pen.
I find Alumilite easier the other acrylics to turn, but haven't hard any problems yet if I do put too much pressure on the blank when turning. I also use high speed.
Cindy

I solved the problem easily.

I refuse to make acrylic pens as I just love wood.

To me acrylics are imitation. Ok they are colorful but the
smell almost makes me sick. When fellow penturners
at our club turn acrylic pens I usually head for home.

Allan

I have never had an acrylic crack or split on me. Like Jim says I use a roughing gouge that is over 50 years old and very sharp 45 degrees to the blank and 45 degrees handle down with the gouge half turned on its side and once the corners are removed from the blank the ribbons start to fly. I take it down to within a mm of the finished size with the gouge and then finish it with a 1 1/4" Skew made from an old file and use the skew as a scraper. This leaves a beautiful finish on the blank and then just a light sand and polish with triple EEE and Brasso.

Heat is certainly your enemy. I have had acrylics distort while polishing with to much pressure with the triple EEE.

When drilling I clear the drill constantly and go very slow at break through.