Turning my first acrylic pen - question?

[JBeck]

Hi all, this is my first post since I'm a new member. I'm new to pen turning and I've turned maybe 15 to 20 wooden pens of varying styles. I'm turning my first acrylic pen. I was wondering when finishing what grit sandpaper should I start out with. With wood I start out with 150 and progress to 12,000 MM. Can I start out the same way with acrylic. I know you have to use less pressure while sanding so that you don't melt the plastic. Any other advise would be appreciated. Thanks.

John

 

[ed4copies]

First,

How is the pen? Did you do a final pass with a skew or with a gouge?

IF it looks pretty good, you can start with 320 grit. DON"T use anything under 100 grit or you may get scratches that are too deep.

WHICH acrylic is it? Some are softer than others, sandpaper will dig.

Start there, we can always go into depth later.

 

[kirkfranks]

I try to avoid sanding at 150 (for wood too) by trying to make the last couple passes with the skew or gouge very light so the surface is smoother. Starting at 220 or 320 is better if you can. The 150 just has more chance of leaving a deep scratch that wont get noticed till later.

As noted less pressure to avoid heat. Also can slow down the spindle speed for the same reason. I also will use wet/dry sandpaper (wet) as this makes the sanding go better. Keep the paper wet enough that it makes a slurry. If you get any actual dust then it is too dry.


Was typing longer than Ed

 

[jkeithrussell]

Sand it wet and sand lengthwise after each grit. You never want to use too much pressure when you are sanding -- whether it is wood or acrylic. Wood burns, acrylic melts. Use a good strong light to check for stray sanding marks before you stop.

 

[maxwell_smart007]

always sand it wet...I wipe the slurry off for each grit before I start the next one.

Andrew

 

[JBeck]

My final passes were done with a gouge with very light pressure. I'm not confident enough with my skew yet. I tried the skew when it was still rather rotund but chickened out soon after trying. The final passes seem pretty good though. The acrylic is from Woodcraft (Tuscan Sun). Can I wet sand with my 320 and 400 grits even though the sandpaper I have at those grits is not meant for wet sanding? The grits I have for wet sanding start at 600.

 

[ed4copies]

Your first sanding is the most important. Sand at a relatively slow speed (800 rpm??)

I don't wet sand, but I don't argue with those who do. The important thing is to get the blank completely even. Dry sanding, the whole blank will look white when it is sanded flat. THEN, move to the next grits (you can stop between to assure yourself there are no low spots or scratches, but if you did the first one right, the rest is just polishing.

FINAL-Might want to use plastic polish or buffing system, depending on what you have.

 

[maxwell_smart007]

I wet sand because I use micromesh, Ed, and I don't want to melt it...I sand at a rather accelerated rate of speed.

Andrew

 

[ed4copies]

I wet sand because I use micromesh, Ed, and I don't want to melt it...I sand at a rather accelerated rate of speed.

Andrew

IF it works for you, keep doin it!!!!

 

[JBeck]

Thanks for all the replies. I'm still curious if you can use regular sandpaper wet or does it need to be rated as wet/dry?

John

 

[kirkfranks]

I would say use it dry till you get to the grits that are wet/dry type.

 

[Bear-31]

I usually start at 320 and work up, 400, 600, 800, then the micromesh pads. All used wet. I don't know if my paper is rated for wet, but as long as it has a cloth backing you are fine (I use the woodcraft strip pack). I also sand at a high rate of speed (2600rpm)...but only when wet sanding!

 

[Rmartin]

I do things different from what I've been told. I turn at high speed. I only turn at the highest speed my lathe will go. I go from one end to the other (not from the middle out) with a round-nosed scraper. I stop well before the bushing and sand with coarse grit the rest of the way to the bushing, shaping the blank as I go. I use grits of 100, 120, 220, 320, 400, 600. I sand aggressively until it's to hot to touch. I stop the lathe between grits and sand lenght ways just like I would do with a wood blank paying special attention to remove any scratches at the ends. Sanding any futher with micro-mesh is a waste of time. I few drops of plastic polish on a folded paper towel then quickly back and forth with a dry paper towel until it's too hot to touch. Even under magnification, the surface is smooth.

 

[JBeck]

Thanks. After I go through MM 12000 is that when I should use the plastic polish? I think it's called Super Gloss or Ultra Gloss or something like that, it's sold by Woodcraft. Thanks for all the help.

John

 

[John Eberly]

Wet sanding

Make sure any paper you use wet is made it. The regular non-wet paper will lose the grit making a mess.

I use a sharp skew and work the blank down as close to net shape as I can, then start sanding with 400 grit wet paper for acrylics.

 

[MorganGrafixx]

Keep your honing stones close...really close. Knock off the edges of the blank like regular and once it is nice and round, SHARPEN your tools. Acrylic will make your tools dull really fast. And dull turning tools are just like sandpaper and micromesh in that the dull chisel will be held longer and with more pressure than normal and can melt the material too. If your tools are kept very sharp, this wont be a problem. I'm still new to this as well so I'm still learning as I go, but that is one thing I HAVE learned....the hard way.

Oh yeah, a dust mask and glasses wouldn't be a bad idea either.

 

[ed4copies]

a word to the wise

I do things different from what I've been told. I turn at high speed. I only turn at the highest speed my lathe will go. I go from one end to the other (not from the middle out) with a round-nosed scraper. I stop well before the bushing and sand with coarse grit the rest of the way to the bushing, shaping the blank as I go. I use grits of 100, 120, 220, 320, 400, 600. I sand aggressively until it's to hot to touch. I stop the lathe between grits and sand lenght ways just like I would do with a wood blank paying special attention to remove any scratches at the ends. Sanding any futher with micro-mesh is a waste of time. I few drops of plastic polish on a folded paper towel then quickly back and forth with a dry paper towel until it's too hot to touch. Even under magnification, the surface is smooth.

IF you follow this method and your blank contains a high percentage of celluloid - it MAY blow up. As in Kaboom!

Or, if you are doing embedded objects, you MAY separate the objects from the tubes -- like snakeskins, for example.

IF you only use commercial (Woodcraft, CSUSA etc) "acrylic" blanks, you MAY be ok.

Good luck!

 

[ed4copies]

Thanks. After I go through MM 12000 is that when I should use the plastic polish? I think it's called Super Gloss or Ultra Gloss or something like that, it's sold by Woodcraft. Thanks for all the help.

John

Plastic polish will remove scratches - somewhat. But going to MM12000, you probably have as good a finish as the plastic polish would give.

IF you Micromesh to 4000, you can use polish to achieve your final result, pretty quickly.

The type of polish will determine how good your pen will look.

 

[Rmartin]

IF you follow this method and your blank contains a high percentage of celluloid - it MAY blow up. As in Kaboom!

Or, if you are doing embedded objects, you MAY separate the objects from the tubes -- like snakeskins, for example.

IF you only use commercial (Woodcraft, CSUSA etc) "acrylic" blanks, you MAY be ok.

Good luck!

I've made many snake skins and several of each of the coconut shells and I turned several rods this week. Using micro mesh IS a waste of time and money on acrylics. Save it for your fine wood burls.

Oh, and I also drill at high speed and quickly. Ocasionally, a blank will get hot and wobbly, but knowing when to pull back is important.