Cajun Turner
Member
I normally turn wood blanks. I want to try turning some of the plastic blank. What is the best way to turn these. Slow or high speed, and how about polishing. Any info would be great.
Questions about turnings.
- Thread starter Cajun Turner
- Start date
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TellicoTurning
Member
I don't turn pens much any more, but when I was doing them regularly, I turned plastics at high speed... usually around 1800-2000 rpm with a sharp skew.... wet sanded with the little 2" square sanding squares from PSI or CSUSA, then polished with Hut plastic polish... When Ed Brown checks in, he's the guy I learned to successfully turn plastics from...
Joe Burns
Member
I turn mine around 2700rpm and haven't had an issue. I use a sharp carbide tool for turning. Take easy bites and make sure you use a sharp tool and it should turn easy.
For finishing I wet sand with micro mesh to 12k. Then use Hut's plastic polish and then finish with a buffing wheel. Try not to let it get hot and you should be fine.
Joe
For finishing I wet sand with micro mesh to 12k. Then use Hut's plastic polish and then finish with a buffing wheel. Try not to let it get hot and you should be fine.
Joe
LagniappeRob
Member
Check out Cap'n Eddie's (from Jefferson, LA btw) video 103 acrylic blanks - YouTube
nava1uni
Member
I turn lots of acrylics. I turn about 1200, I use a roughing gouge to round them and then I use a spindle gouge to make beads, coves, etc. Sometimes I use a skew. Once I have them finished to the shape I want I then wet sand them using wet/dry sand paper starting with 220 grit and then polish them using Nova polish for large scratches and finish with Hut Plastic Polish. Do not hold the sand paper or polish cloth against the blank with too much force as it can cause the blank to melt or become damaged. I like turning acrylics as they can be very beautiful.
navycop
Member
What grit sand paper do you stop at (220-?)
jcm71
Member
I turn mostly wood, however, when I do turn acrylic, I turn at about 3500 RPM with a fresh carbide edge. I then wet sand with arrant and mm to 12000 and finish off with Hut Ultra Gloss.
gbpens
Member
You can sand up to 400 before going to micro mesh. Each type of "acrylic" has it's own characteristics pertaining to scratches which is what you are trying to sand away. Also, dark colors highlight sratches and imperfections more so than light colors. The object is to remove all visible scratches.
switch62
Member
I find that it depends on the plastic, much like wood. Some plastics are relatively soft and don't chip very much, others are very brittle. You'll soon learn which is which.
The lathe speed is less important than the sharpness of your tools and the agressiveness of your cuts. I used lower speeds when I started turning plastic pens, lately I've been using higher speeds.
When you start rounding the blank you need a very light touch, you'll get small chips flying everywhere. As it gets rounder the chips will be less, the sound will change (chipping sounds like scratching or chipping glass) and you'll get more ribbons of plastic.
Once round I use a skew to get near the final shape and then a scraper to do very fine final cuts to shape. (I need more practice with a skew:redface
.
I then wet sand starting with 400 wet & dry, 800, then all 9 MM grades. I cross sand on the 400, 800, and every 3rd MM. The wet sanding will stop any overheating. Finish with Brasso and liquid car polish (non-abrasive liquid wax).
When drilling, squirt water into the hole to cool the bit and the plastic. Drill 1/8" - 1/4" at a time and clear the bit. Sometimes the water and swarf become paste like and sticky, especially near the end of the drilling, so be aware of that.
You will also need to check the transperancy of the plastic. The blank may look opaque but when it is only 0.5 - 1mm thick you may see the tube and glue. If unsure try cutting a thin piece off the end, sand it smooth (400 w&d) and hold it to the light. If transparent you'll need to paint inside the hole and possibly colour the glue as well.
I only started painting the holes recently and found auto paint works well. I let it dry for an hour or so, then do a second coat and let dry overnight. I also use the auto paint to colour the thick CA for glueing the tubes. 3-4 drops of paint in a pool of thick CA on a plastic bag, mix and use. The auto paint doesn't set off the CA. I use earbuds for painting the holes, and the plastic stick from the earbuds for mixing and glueing. You may also need to drill your holes fractionally bigger to account for the thickness of the paint (I use a 7mm brad point that is slightly under, followed by a 7mm jobber that is slightly over size) or sand the hole a bit.
Some of this may be a bit obsessive but ......
:biggrin:
The lathe speed is less important than the sharpness of your tools and the agressiveness of your cuts. I used lower speeds when I started turning plastic pens, lately I've been using higher speeds.
When you start rounding the blank you need a very light touch, you'll get small chips flying everywhere. As it gets rounder the chips will be less, the sound will change (chipping sounds like scratching or chipping glass) and you'll get more ribbons of plastic.
Once round I use a skew to get near the final shape and then a scraper to do very fine final cuts to shape. (I need more practice with a skew:redface
.I then wet sand starting with 400 wet & dry, 800, then all 9 MM grades. I cross sand on the 400, 800, and every 3rd MM. The wet sanding will stop any overheating. Finish with Brasso and liquid car polish (non-abrasive liquid wax).
When drilling, squirt water into the hole to cool the bit and the plastic. Drill 1/8" - 1/4" at a time and clear the bit. Sometimes the water and swarf become paste like and sticky, especially near the end of the drilling, so be aware of that.
You will also need to check the transperancy of the plastic. The blank may look opaque but when it is only 0.5 - 1mm thick you may see the tube and glue. If unsure try cutting a thin piece off the end, sand it smooth (400 w&d) and hold it to the light. If transparent you'll need to paint inside the hole and possibly colour the glue as well.
I only started painting the holes recently and found auto paint works well. I let it dry for an hour or so, then do a second coat and let dry overnight. I also use the auto paint to colour the thick CA for glueing the tubes. 3-4 drops of paint in a pool of thick CA on a plastic bag, mix and use. The auto paint doesn't set off the CA. I use earbuds for painting the holes, and the plastic stick from the earbuds for mixing and glueing. You may also need to drill your holes fractionally bigger to account for the thickness of the paint (I use a 7mm brad point that is slightly under, followed by a 7mm jobber that is slightly over size) or sand the hole a bit.
Some of this may be a bit obsessive but ......
:biggrin:
nava1uni
Member
I sand up through 800 or 1200 depending on how the piece looks. I don't spend a lot of time on each grit, but I do wipe it between grits so as not to contaminate the next grit. Sometimes I use mineral oil instead of water, it depends on the material.