turning acrylic

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ahoiberg

ahoiberg

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i'm getting ready to turn my first acrylic blank tonight and was wondering if anyone had any tips for me?

how much different is it than turning wood? it's acrylic acetate if that makes any difference. is hut PP a good finish for it? has anyone used CA for the acrylic or is that not necessary?

it's going to be a graduation (gift) for my wife-to-be... she's getting her doctorate in physical therapy! good thing since all this woodworking will probably give me numerous aches and pains that she'll be able to work on... :D
 
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Andrew,

Yes, it is different from wood. You have heard use sharp tools, now you will find out if you know how to sharpen a tool - cause with a slightly dull tool, you beat up the blank, but you DON'T CUT the blank. Cutting is MUCH easier.

If you tell me what tool you usually use and with which you are comfortable, I will continue, based on that information (Yes, there are different approaches, based on the tool used.)[:D]
 
I turn plastics at about 2800rpm or whatever the second highest speed is on a Jet mini. The main thing to remember is DO NOT USE A GOUGE. Use a sharp skew and take light cuts. I sometimes also use a freshly sharpened round nose scraper. Acrylic loads up sandpaper pretty quickly so be prepared to go through some sandpaper. Avoid heat buildup when sanding. I dry sand to 400 grit, then wet sand with MM through all the grits, then use a plastic polish. There isn't any reason to use CA unless you encounter an air bubble, but I've never heard of them in acrylics, only PR.
 
so, don't use a gouge even to rough it? i've been using a round nose lately with some good success, so i'll probably use that. i'm still not too comfortable with a skew. i still get lots of catches when trying to use it. hopefully i can get a smooth enough cut to start with 320 or so on the sandpaper... we'll see! good thing i got two blanks... incase one decides to blow up on me!
 
Andrew,

Gerry knows what he is doing - and he is successful. However, I turned acrylics for YEARS with a 1" gouge.

I have always told students that it is MOST important that YOU are comfortable with the tool you choose. The Skew IS the easiest, but it is also one of the most "feared" tools (Yes, when it catches you WILL get a jolt, but give me 5 minutes in person and you will RARELY have another catch).

After my last post, I tried to remember the early days of acrylic and, I'll bet Gerry will agree - DRILLING was my first challenge!!! Do NOT let the blank get hot, cool with water in the hole, or an air hose or just drill real slow and stop for coffee a few times.

Actually, send me an e-mail from the site, I can send you a tutorial I wrote as an attachment to a reply. It will help. Then have Gerry send you HIS method and 3 or 4 others send you THEIR methods, by the time you get to that blank, we ought to have you THOROUGHLY confused.

And, if things go real well, Gerry and I can be throwing big rocks at each other, too.


OOOOOOOOOOOHHHHHHHHHhhhhhhhhh, the impending excitement!!!!![:D][:D][:D][;)] (That last one is just for Gerry)
 
My gouge has worked for me just fine. I think the best advise is to use a sharp tool, take light cuts, and don't rush!

I'll be looking for one of those tutorials too, Ed! [;)]
 
I'm with Ed in saying that while a Skew may be easiest for some, it may not be the best for everyone. I turn all my pens with a Sorby fingernail gouge and I get the ribbons off the blank just like you would a skew. The trick is what everyone else is saying.... Make the tool sharo and take VERY light cuts. It will take longer than wood to do because if you try and dig in, the acrylic will shatter. Once complete though, the acrylic has depth and shine that IMO is really sweet.
 
My gouge also works fine, and we always use sharp tools, right? I find I do not have to use all the MM grits. I use Brasso as my polish and finish. It bring most all synthetics to a mirror finish. I also like Brasso because it is easy to find locally.
 
I start the turning out with the tround nose scraper then when I get the corners knocked off I switch to the skew. I have a 1" oval skew and a 3/4" square skew and I find the smaller one easier to use. I think the angle is too steep on the oval. I just haven't reground it yet. I really hate those curlies. they just get in the way. I have found that you have to turn it faster than wood. I usually switch back to the scraper (that I sharpened again after rounding off the corners)to get the final shape though.

I always thought that I liked wood pens better until Iactually made some out of acrylic. The finish is so much easier. all you have to do is sand and buff. I also think that learning to finish acrylic has helped to improve my CA finish on wood......
 
Beg, borrow or even buy a copy of Alan Lacer's DVDs about using a skew. I wrecked a lot of wood until I borrowed a copy from my local turning club's library early last year. After watching it a couple times, I went to the lathe and made a pen without even one catch. I still get a catch sometimes, but not very often. Like Eagle said, "I'm not licensed to use a gouge."

I mostly haven't had trouble drilling acrylic, PR is an entirely different matter. Make sure your drill bits are sharp, real sharp. With a nice sharp bit, you shouldn't have to worry about heat, but water in the hole is not a bad idea. When I drill bone, I hold the nozzle of my big shop vac right next to the bit, clears the chip and circulates air. If you're getting little "balls" of stuff when you drill, the material is way too hot. DAMHIKT

If you get a tutorial from Ed, I would advise following it as close as possible. Ed knows plastic and besides that, his wife is the PR Princess.[:D] I don't really have a method, I just go by feel. If something doesn't feel right, I make adjustments until it does.

One thing really important is that you didn't mention what kind of acrylic blank you're using. Even some of the seemingly opaque blanks can turn translucent when you get it to the thickness needed. The lighter the color, the more likely that is to happen. So, if there is any doubt at all, paint the blank or the tubes or both. Unless you're turning a light colored blank, black is usually a safe color.

BTW, Ed, what are your geographic coordinates there? I need to start aligning my trebuchet.[:0][}:)]
 
Not trying to hijack the thread, but Andrew did ask the same question. ( I didn't see any answer )
You guys that prefer the skew, do you use it from when the blank is still square, or make it round with a gouge first? If you start with a skew, does it need to be wider than the blank? Also, if you 'tilt' a gouge, doesn't it work the same way that a skew works?

One day I'll use my skew on the lathe instead of opening paint tins with it[:I]

Cheers
 
thanks for all the info guys. the blank color is violet pearl (acrylic acetate) from AS (a big thanks to Bill by the way, great service!), looks pretty solid but i may paint the tubees just in case. i've also got a spare blank in the event that something drastic happens... let's hope not.

i'll be making a sedona with it, does the wood end up super thin on those? the one kit i've had those issues with is the parker classic. get's real skinny like at the end. but after refining the technique i've been able to avoid it on my last few...

thanks for all your info everybody, i can't begin to say how much i've learned from this site! [:)]
talk about a springboard for a hobby, these internet forums are really great.
 
Like everyone else says SHARP TOOLS. I also use a gouge then a skew to fine up most of my turnings. Also sanding down the edges of the acrylic before turning can help a lot! Kirk[8D]
 
Just one more I usa a 1/4 inch Sorby Spindle Gouge and take VERY LIGHT cuts to start then it works great. I start with 320 and work my way up but when I started turning a good friend told me to round the corners first in a belt sander, Less chipping and works great IMO

Good Luck and remember wear eye Protection These things are finiky.

[8D][:D]
 
Originally posted by Abrock75
<br />Just one more I usa a 1/4 inch Sorby Spindle Gouge and take VERY LIGHT cuts to start then it works great. I start with 320 and work my way up but when I started turning a good friend told me to round the corners first in a belt sander, Less chipping and works great IMO

Good Luck and remember wear eye Protection These things are finiky.

[8D][:D]
Click to expand...

Aaron,

This is not meant to be critical, but using a 1/4 inch gouge is probably THE most difficult method available.

Congratulations on YOUR success, but let's try to give other guys an EASIER way.[:)][:)][:)]
 
Ed, that was basically my thought. I have a 1/4" spindle gouge and hate it. It is just way too flexible, even with the tool rest almost touching the wood. The only thing I use it for is very small wood goblets and I sweat profusely when I have to reach inside the goblet with it.[:0]
 
just for a follow up, i sanded down the corners as was suggested, great idea by the way, and then started the turning with my HF 3/4" roughing gouge which worked fine. once i got them down to smaller cylinders, i switched to my HF round nose scraper, which also worked great. i think i started sanding with 220 and did the standard procedure from there.

thanks again for everyone's help!
 
not necessarily. if it works for you, then it's all good. i just didn't see the need for that much grit because the scraper left a really nice, clean cut.
 
I turn all kinds of "plastics" from CSUSA celluloids to Berea's acrylic Acetates to my own PR and some I don't even know what they are! I've learned they are all different and require different approaches. I have found out what works best for me is:
1. Drill on the lathe....at the slowest speed possible, with the sharpest bit you can get. As you reach the end of the blank make sure you aren't overly agressive. Let the bit ease through the end....no shatter this way.

2. Make sure you have complete coverage of whatever type glue you use. If you have spotty gluing and have a catch that's one sure way to have a blank fly apart on you.

3. Don't get in a hurry or agressive with whatever tool you choose to use. For what its worth I start with a round nose scrapper, freshly sharpened, take the corners off and turn nearly to shape and then switch to a 3/4 inch oval skew, also freshly sharpened scarey sharp.I usually end up with a surface smooth enough to start sanding at 400 grit.

4. Don't overwork your sandpaper, bear down hard and you'll gum it up. Let it do the work and after each grit stop the lathe and sand the length of the blank.

5. I sand through 1000 grit and finish it off with Hut's Plastic polish for a glass like shine then a final coat of TSW

This is all just my two cents worth .....but it works for me! [:D]
 
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