Any tips on turning plastic pens?

[Stephen Saar]

I tried turning some plastic pen blanks today, but I got horrible results. A ton of chip out on the plastic almost anyway I tried to cut it. I tried different speeds, but didn't run in to anything magical. At first I was just using a basic roughing gouge, then I tried a scraper, and finally a bowl gouge. If I went super slow with the cut then I didn't seem to have any real problems, but it was very very slow. Maybe that's just how you have to work with plastic, but man that was a pain. Any great tips on dealing with it?

Thanks.

-Stephen

[Dan Hintz]

What kind of plastic? Are you sure you're tools were sharp?

[David E Keller]

Super sharp tools and light cuts... I think the acrylics are generally much tougher than wood for pens. I tend to use high speeds and sharpen often with acrylics. Some of the acrylics are easier than others. I prefer a spindle roughing gouge for rounding the blank and a skew chisel for the remaining cuts, but there are 1,000 tools that will do the job.

[Scott Woodson]

What kind of plastic? Are you sure you're tools were sharp?

I would foot stomp Dan's comment...Tools gotta be sharp, when sanding you can't let the paper get hot as it will continue to scar the plastic and not polish up as nice.

[Steve Kennedy]

Helps to keep your tool rest real close to the blank too..

[John Hart]

I use a skew...and keep it sharp the whole time. I sharpen when I'm turning plastic more often than when turning anything else.

[Ken Fitzgerald]

Sharp skew....when sanding, use micro-mesh and wet sand using water as a lubricant.....

When drilling, use a sharp bit ......go slowly...Make the blank 1/4" minimum longer than you need in case it blows out the bottom when drilling...I will typically drill 1/8"-3/16" and then back out of the hole to clear the cuttings and repeat until finished drilling......don't hurry as bound cuttings and speed create heat....heat is your enemy.

[John M. Smith]

I use a hunter carbide tool. Lathe speed as fast as it will go. I've done about twenty without sharpening. Wet sand up to 600 grit, and then the micro sanding pads, and plastic polish.

[Mark Hix]

I go as fast as possible and usually just use a skew. Occassionally, I will use something else to knock the corners off. Light cuts, sharp, tool rest as close as I can, keep the tool moving. Use sandpaper like your neighbor gives it to you for free...don't skip a grit. If your interested, PM me and I think I have a link for an excellent video (free!) that might help.

[Donny Lawson]

I use a 3/8 spindle gouge and make sure it is sharp. Always take light cuts and go slow. Wet sand through 12,000 grit and add a coat of HUTs plastic polish and you will have a glass like finish.

[Stephen Saar]

Thanks for the tips. I'm not sure the type of plastic, I think it was acrylic based on how it broke off, but I'm not sure. It was just a pen blank I picked up at Rockler. My tools were pretty sharp, but maybe I needed to sharpen them even more. Sounds like my speed might not have been as high as it should have been. Well I'll try again sometime and hopefully it will go better.

Thanks for all the tips.

-Stephen

[Lupe Duncan]

Inlace acrylester is very "chippy". sharp tools slow cuts and high rpms.

[Bernie Weishapl]

High speed, a skew, and wet sand to 1000 grit. I then buff with tripoli, white diamond and then Ren wax.

[James Combs]

Sharp skew....when sanding, use micro-mesh and wet sand using water as a lubricant.....

When drilling, use a sharp bit ......go slowly...Make the blank 1/4" minimum longer than you need in case it blows out the bottom when drilling...I will typically drill 1/8"-3/16" and then back out of the hole to clear the cuttings and repeat until finished drilling......don't hurry as bound cuttings and speed create heat....heat is your enemy.

Ditto everyone's comments on sharp tools and fast speeds. Adding to Kens comment on drilling. I was drilling out a couple plastic blanks to 27/64" the other day and it struck me that maybe a coolant would help. Coolants are used extensively in drilling metals so I tried using water in the drill hole to keep the bit cool. It worked great for those two blanks. No heatup of the drill it barely got warm, no blowout at the bottom and a very smooth bore hole. I will continue the method for future plastic blanks. I have a plastic bottle of water I keep at my grinder that has a very small pinhole in it's nozzle so the amount of water it squirts out is limited. That is what I used to avoid getting water all over the drill press. Just a few drops every few seconds did the trick.

[Dave Bell]

This is what experience, reading and training has taught me.....well that and the no stomping rule!

Correct, high speed for turning and a 3/8" or 1/2" spindle gouge (sharp....nothing less), the skew is for getting the convex profile and flat sections proper. Concave sections need to be prepared with the spindle gouge and sanded to the finished profile (especially acrylester). Yes the tool rest must be a close as possible, this reduces vibration by providing better support due to less of the tool hanging over the rest. The spindle gouge when used properly can make gentle cuts with a lot of detail if desired. If you have to "force" the tool through the material, it most likely needs to be sharpened. If your unsure if your tool is sharp or not, them most likely it is not sharp. Seek some advice on sharpening your tools properly and then get the same advice on how to use the sharp tool. I wish I had been shown this at the start. As for the Skew.....it's hard to master and many turners (novice) shy away from this tool because of the problems associated with being able to use it properly. One word for the Skew and how to use it.....lots of practice folks. As for what the Skew can do......besides acting as a scraper.....it can actually cut the material leaving an almost polished finish requiring very little finishing to get to completion. As for turning the so called "plastics", don't be confused about your tool not being sharp because these materials cut slower than wood. Cut from the end of the blank moving inwards to teh center. Yes, it goes against the rules, but it also prevents blanks from blowing out on the ends. Take your time....it's not a race!!!!

As for drilling, the best way to avoid chipping or blow out is to drill the blanks from each end in steps (smaller to larger drill sizes) and then drill the final size in one pass. (Hmmm, Sort of sounds much like the turning method mentioned above.....coincidence?....)The speed must be under 500 rpm.......all types of blanks, wood, acrylic, silmar 41, acrylester, epoxy resin and alumilite. If you can afford them, the final pass of the drilling process is to pass a reamer through the blank, but this is something more for multi-composite blanks like "worthless wood" blanks which are composed of wood and a resin based medium such as acrylic. If you want to understand how to drill an accurate hole, research "gun drilling" and use the methods mentioned. This is one of the most accurate methods for drilling holes.

Note, there are many different types of blanks that people claim to be acrylic, when in fact they are not acrylic at all. This is a generic term given to pen blanks much like the term PR. If you doubt me....go research this for yourself.

Sanding......coarse grits....higher speeds, fine grits...slower speeds, it only makes sense. The grit fills up faster with finer grit and under high speeds, this leads to friction (heat) which causes the sanding medium to clog up and in turn, the heat melts the resin material and forms circular rings around the blank of resin build up. Whenever possible wet sand the finishes as this provides a cooling effect, it helps keep the sand paper from clogging up and it also provides a slurry which aids in the smoother finish desired (much like polishing). Avoid abrasives like garnet paper as they tend to release the grit into the slurry and end up creating more scratches (deeper) into the material that your trying to finish. #0000 steel wool.....works great, if used properly. It also acts the same way that sand paper does in relation to the grit size and clogging up. The down side of steel wool is that it leaves small hairs that can be a nuisance when it comes to removal and to the appearance after applying your finish.

As for carbide.......expensive, but well worth it in the long run.

I hope this helps those who want to get the most out of it and those who want to read further about it.

Dave

[Steve Campbell]

Just one more tip on drilling plastics. When I drill most pen blanks I use one of those flexible air nozzles and blow air on the bit the whole time. It works kind of like James water but isn't as messy. I also don't drill all the way through. I stop about 1/8" short of going all the way.

If you bought your blanks from rocklers theres a good chance they are inlace. I don't even try to turn that stuff anymore. Life's to short.

Steve

[Dan Forman]

From your description it sounds like you got an Inlace Acrylester blank, which is probably the most brittle, chippiest stuff out there. I haven't done any of them for a while, but I recall they require a very light touch with a very sharp skew, and take a long time to turn down to pen size. I never tried a carbide tool with them. The various poly resin (PR) blanks are somewhat difficult, but not quite as chippy and brittle as the Inlace, and the easiest and most common commercial blanks are sold as acrylic or acrylic acetate. The latter should not present any real problem so long as you have sharp tools and aren't overly aggressive. They don't tend to shatter like the polyresins do when pushed too aggressively.

I would suggest that you start with acrylic before moving on to the more brittle plastics.

For drilling, divide the blank in two sections, leaving enough at each end so that you don't have to drill all the way through and risk blowing out. Mark what would be the "end grain" of the cut (if it was wood) with a Sharpy marker. These will be the ends that will meet in the center of the pen. This way, if there is "figure" in the blank, it will flow properly through the pen. After drilling, cut off the closed ends of the blank, leaving about 1/8" extra at each end. I have never had to resort to using lubricant for drilling, just use a sharp bit and go slowly without forcing, clearing the chips frequently. With acrylics, more often than not, you get a continuous crepe-like ribbon, rather than chips. I drill on the lathe, holding the rounded blank in a collet chuck, but you can drill in a pen vise using drill press too.

Many of the acrylic blanks are fairly transparent, and require "reverse painting", which means painting the inside of the blank after drilling. The reason for this is that if a blank is not opaque, it mayl show any air bubbles in your glue, and also show the tubes. Some people paint the tubes, but the air bubbles in epoxy will still show through, so just paint the inside of the blank. I highly recommend spending some time over on the "penturners dot org" site (International Association of Pen Turners), all of the pertinent info is covered there, and can be found by searching the Pen Turning forum with the appropriate key words "drilling", painting" etc. I like spray enamel, but some use Testor's model paint in the tiny bottles, or Ceramcoat brand acrylic paint in 2 oz bottles, which can be found at many hobby stores like Michael's. Blanks can be painted different colors for different effects. Please look at IAP for more strategies on painting blanks.

Acrylics can be rounded at a high speed with a freshly sharpened roughing gouge, a skew, or most efficiently with a square or round carbide tool. You still might get a little pitting or tearout when roughing, but it is easily smoothed out as you take it down to size. Be sure to wear good eye protection, as little pieces of plastic are flying everywhere at this stage. I wear safety glasses and a face shield when roughing. If you want to do a lot of pens, a good carbide tool is hard to beat. I've been using a homemade tool with a square carbide cutter designed for jointer or planer heads, but just received a small pen tool called the Woodchuck PenPro, that comes with two slightly different carbide cutters. Here is a link http://www.woodchuck-tools.com/index.htm I just got it today, so haven't tried it yet, but the cutters are very sharp, and I anticipate that with a short handle, it will be easier to finesse than my longer homemade tool. It gets very good reviews on the IAP forum, and the price is very reasonable, especially if you make your own handle. These do well with PR and Truestone blanks, the latter can be quite hard, and require frequent sharpening of HSS tools.

If you don't want to go the carbide route, a small round nosed scraper also works quite well for going from round to near final size, then it is best finished with a sharp skew to final size and shape.

I wet sand, starting at about 220 or 320 (depending on how well I have done with the skew) through 600 or 1000, then buff with tripoli followed by white diamond. Make sure you cover the ways of the lathe with a plastic garbage bag to protect it from the water.

Once you get comfortable with acrylics, then you can go on to PR blanks like those made by Exotic Blanks, http://www.exoticblanks.com/
or some of the casters that sell their blanks over on IAP.

Dan

[David Cramer]

You've received some great advice from many pros.

I am a rookie and here's what I do:

I took a class years ago and was taught to use a skew. I didn't like it as it took too long.

I purchased a Woodriver Roughing Gouge for about $50(?) that I do keep sharp.

To date I have turned well over 100 acrylic pens with that gouge and some of them are turned in under 5 minutes as I timed it once just for the fun:) of it. Most take about 7 minutes on average.

By taking light cuts with the gouge in the final turnings to the bushings, I am able to get an extremely smooth finish, without a skew.

I put a doubled up towel under the pen and then place a miracle whip bowl on the towel half filled with water. I then wet sand from 220, 400 and 600 regular sand paper. Then the 1500 to 12,000 micron.

I then put a small dab of plastic polish on a paper towel and lightly touch it to the pen while it is turning on the lathe. I then take a dry spot on the paper towel and rub it in, sometimes twice depending on the color.

I don't know squat about computers. I thought about putting a camcorder above my lathe and turning an acrylic but then I'd have to load the bloody thing:) One day I will get our oldest child to help me out.

Seriously, I just grabbed my gouge one day and gave it a shot. After getting it close to round you will then have decent shavings/peelings coming off. I should say after the corners are knocked down.

But........I've turned the rattlesnake blanks as well and I would HIGHLY recommend using a skew for the entire process on one of those blanks as it is a different material. The material on those is not sticking to the tube either, but instead is poured around the skin and it can bust right off (those are about $33 each!!!). I've turned about 4 of those, all successfully, but also rather nervously during the process as I am far from rich.

I am not saying to avoid using the skew, but instead sharing what I do and how it works for me. And Dan above me may be right, you just might be turning a very brittle acrylic.

Good luck!

David