Trouble trning acrylics-please help!

[Jerry Ingraham]

I seem to really struggle when turning acrylics, especially acrylester. I seem to end up with too much chip out or blow the blank up completely. I have tried using a pen turning gouge, a skew chisel on it's side, and a scraper but seem to ruin about half the blanks I start with. I've turned many pens and have no problem with wood or antler but the acrylics are driving me mad and getting expensive! Can someone point me to a tutorial or offer advice?

[Steve Schlumpf]

Jerry - the only experience I have had with acrylics is when I have turned them for finials and lids. I found that using a moderate speed - say around 800 - provides enough for a smooth cut but the rpms are not so fast that you heat up the gouge and and cause sticking. I have used a skew but found my trusty bowl gouge worked best - probably only because I am most comfortable with it. I did find that scrapers never worked - at least for me. Found that - like wood - if you force a cut, you will get tearout. The difference is that with acrylics, that tearout is in the form of chipping.

Take your time, present the cutting edge just above the centerline, allow the edge to cut and don't force anything. Use the same rules as when turning wood - such as cutting downhill and you should be fine.

Oh, I forgot - use VERY sharp tools! Make a huge difference! Have fun!!

[John Terefenko]

Utube is your friend.

Also if you are a member over at IAP pen turning forum check out Ed Davidson's videos and articles in the library there. I use a skew and as mentioned the correct presentation is important. I turn at a high speed.

[Dan Forman]

Acrylester blanks are very brittle and difficult to turn without chipping out. The key is to take VERY small bites with VERY sharp tools. They require a lot more time to shape, but the results can be stunning. Most regular acrylics are more forgiving, still can't force them, but are a lot less trouble than acrylester.

Dan

[Jim Burr]

Acrylester is on my "Never-again-unless-it's-free-but-probably-not" list!! Knock off the edges with a belt sander or whatever sander you may have so you start out ahead. Best turned at about 2800-3200 with a stupid sharp skew, hone often. Never use a carbide tool...they don't present well and have nothing to ride on. Wear all your protective stuff because it stings like crazy!! Push to hard one time and your toast!

[mark ravensdale]

Yep they sure are brittle and chip out so easily, I ended up making my own tool just for plastic pens, it's made of round bar (3/8inch) which I ground sort of like a negative rake scraper, but the top bevel is very shallow (not steep) the bottom bevel is steep (80 degrees maybe) with a small burr raised, I use it like a sheer scraper at abt 45-50 degrees, it works great, but you still have to go fairly gentle, the shallow top bevel seems to help stop chipping a lot,
but if you really want to make your life easier while turning plastic pens I can REALLY RECOMMEND the small (3/8inch) Hunter Hercules, when used in the bevel rubbing mode it leaves a finish that barely needs touching with any abrasives, this tool is a pen turners dream!!! (especially the various types of plastic pen blanks) but even with this fantastic tool you still have to be gentle, the Hercules uses a carbide bit and works better than any other tool I have ever used for plastics hands down!!! (and yes I have tried a lot and lost a lot of blanks while doing so!!!)
the best advice I can give is "take your time" don't try and rush it, after a while you will get the feel of them (completely different than turning wood pen blanks)
Ohh, and wet sanding is the best way to go!!! (messy but saves on a lot of abrasives and leaves a better finish, you will know what I mean if you try dry sanding )

[Jon Lanier]

After I get it round I use a very sharp skew. Takes a while longer, but it saves the blank.

[Dick Mahany]

I use a 1/2" skew with an Alan Lacer grind profile that I reground from a flat skew. I use the "peeling cut" about 1/8" wide at a time to get it round with the straight section of the profile. Then I switch to the curved portion for shaping and use either a shear cut or a scraping cut and get great results nearly every time. I turn at ~2500 RPM. A SHARP edge gives clean results.

[Jim Burr]

I use a 1/2" skew with an Alan Lacer grind profile that I reground from a flat skew. I use the "peeling cut" about 1/8" wide at a time to get it round with the straight section of the profile. Then I switch to the curved portion for shaping and use either a shear cut or a scraping cut and get great results nearly every time. I turn at ~2500 RPM. A SHARP edge gives clean results.

Hey Dick!!! How are ya! Didn't know that was you!! Sorry for the hijack...we now return to our regular programming.

[Jerry Ingraham]

Thanks all!

I seem to have found a happy median between gouge, scraper, and skew. I think I have just been moving in too fast. Turned several breast cancer pens yesterday with success. I start with the gouge-lightly- and when round I move to the scraper to gently take it down closer to form. I finish with the skew chisel as a scraper, then an 150 grit gouge.

I agree that acrylester is the most difficult but, man, is it beautiful when polished. I don't have much problem with the other acrylics, can get a nice shaving coming off them, but the harder acrylics are just chip happy!

[Rob Wachala Jr]

I had a lot of issues with acrylester until Ed from IAP told me to jack up the speed. I take the hard edges off on my belt sander then I use a round carbide @ 2K rpm and I have not had much issues since.