Acrylic Pen Question ??

[Steve Campbell]

It's been a while since I turned any pens. I picked up some pen kits and acrylic blanks. The first pen blank I drilled wrong and had a blow out. The second pen I did was just about right. I used mostly a skew on it and it cut very smooth. Now the third one is beating me up. I just can't seem to get to cut smooth. I have tried the skew, a detail gouge, and a scraper. Help!!!!!!!!!!!!!!!!!!!
The first two blanks just said acrylic blank on the package. The one I am having problems with is marked "INLACE ACRYLESTER". From Rocklers
Any help out there?
What speed should I be using? What tool?
TIA Steve

[Daniel Heine]

Steve,

I always turn acrylics fast, at least 1500 rpm. More important, you have to use very sharp tools and "ride the bevel". I turn the blank down to round with a 3/4" roughout gouge. Start in the middle, and work to the ends. Then I switch to a 3/8" spindle gouge. When I am using the spindle gouge, I just shave the blank. Present the tool to the blank with the back of the handle way down. Then, lift the back until the gouge just starts to cut. Do not apply a lot of pressure, let the gouge do the work. Once the blank is down very close to the bushings, I make a few very light passes with the skew, then sand and finish.

One final thing about acylics, after I have sanded to 600 grit, then micromeshed, I use Novus 2 and Novus 3 to polish the blank. What it does to the final product is like a miracle. The acyrlic seems to glow from the inside after polishing/buffing with the Novus. I apply it with a paper shop towel.

Good Luck,
Dan

[Stan Cook]

If you ask 10 different people how to turn acrylics, you will likely get 10 different answers. I turn acrylics over 3000 rpm and from end to middle. Inlace acrylester is very prone to chipping. You just have to experiment and see what works for you.

[Steve Busey]

Steve, once you get it roughed (where you will get chipping), try sharp tools, high speed and light touch. After roughing, I use my skew as a scraper. YMMV...

[Dean Thomas]

I totally agree with Stan and mostly agree with Steve. Highest speed you can stomach, sharp, sharp, SHARP tools, and don't hurry. The more you can cut feathers, the better the result off the tool, the less likely you are to chip out, and the less likely you are to be both broke and frustrated at the end of the turning session.

The whole bevel issue is a strange duck. Generically speaking, if your cutting edge and some portion of the ground area of the bevel are both touching at the same time, you are in good shape. Depending on how ground or honed your skew (or any other cutting tool) is, you're going to have to be careful about the bevel issue. I'm going to play some word games with you in hopes of making a point.

What do the words "rub", "ride", "float", and "glide" have in common and what would be their differences? All four imply some degree of contact, yes? That's good, 'cause that's really what we're talking about. I think rub and back massage comes to mind. That contact can be pretty substantial, yes? Especially if removing knots from said back... Ride brings sitting down on something like a cycle, horse, or other weight bearing device. Floating (as on water, not in the air above the earth, okay?) brings the idea of the weight of the float-ee being borne by the float-er. Think about a piece of foam kick-board in a swimming pool. Getting closer. Glide is a for sure contact, but with minimum pressure. Some, but not lots. I see a hand touching the silken surface of a well-painted, well-waxed vehicle, enjoying the surface and the shape. Not enough pressure to leave streaks or slow the hand, but definitely a touch.

Which one of those images is going to get you where you want to go? Ride that puppy too hard and you're going to overheat things, melt some plastics, heat check others, and generally make a mess. And if some portion of your bevel is not touching then you're not following instructions and that bevel is going to try and seek its most comfortable state, where both the cutting edge and some supporting portion of the bevel are touching at the same time. Bad cut at best, and catch to destruction at worst.

Oh, did anyone mention really, REALLY sharp tools? :rolleyes:

Lastly, think about the degree of attack on your cutting edge. The best starting place for most cutting edges (skew or gouge) is so that the actual angle of the cutting length to the point being cut is about 45º. STARTING point. Some woods, you can get really aggressive and hog the wood away. Other woods (and most acrylics in my experience), you really have to aim for wood-whispers by the bushel. How to do that? A really high angle of attack so that the cutting edge of the tool is darned close to perpendicular to the point of contact along the long side of the blank.

Skew as a scraper would put the skew on its side and some portion of the cutting edge parallel with the long side of the blank. This can work really well on wood, and yes it can work on many acrylics, but you have to play to find out how sharp your skew has to be, and whether it might want to have a burr or not like a true scraper.

You also have to know that not all acrylics are created equal. If your blanks have "stuff" in them, does the "stuff" give any opportunity for catches on less than SHARP tools?

I've not done a ton of acrylics, so I'm only speaking from the 15-20 blanks and 4-5 different types/styles/brands that I've played with. Like Stan said, ask 10 people and you're liable to have10 (or 20!) answers.

[Brandon Powell]

I did not know you can turn at such high speeds. All this time I have benn turning my pens, both wood and acrylic, at my roughing speed of 800 rpm. That may be the reason it takes me so long to get one turned. that and I only have a 5/8" roughing gouge.:(

[Mark Hix]

They pretty much covered fast and sharp....very sharp.....The issue with the acrylic blow out is sometimes caused by heat. Slow the drill down and try it again. Clear it out often. When I drill, it is as slow as it can go. The other tip is not to cut the blank to size until after you drill it. Drill farther than you need and then trim off the blank to size. If for whatever reason it is not long enough to trim after drilling, try placing a waste block underneath it.

Did anyone mention sharp?

[Dean Thomas]

I did not know you can turn at such high speeds. All this time I have been turning my pens, both wood and acrylic, at my roughing speed of 800 rpm. That may be the reason it takes me so long to get one turned. that and I only have a 5/8" roughing gouge.:(
Size of your gouge is not an issue for skinny little pen blanks. Might keep you from pushing too hard (as I'm prone to do with my larger RG).

Speed is relative, remember. What works for a big chunk just is not enough for a small chunk. It's about surface speed. A 3/8" pen at 1000 rpm is only cutting at about 98 feet per second. The 8" bowl that you made, also at 1000 rpm, is cutting at about 2100 surface feet per second at the 8" dimension! BIG difference!

To get an equal speed, you'd turn your 3/8" pen at about 10,200 rpm!!! :eek: 3000 ain't too bad, eh? ;)

[Don Wood]

Hi - I have worked quite a few acrylics and will NOT work with Inlace any more. It is much more brittle than the other acrylics and much harder to turn. After many tries, I have decided it is not worth the effort when there are so many nice acrylics out there that are not as brittle.

Just my 2 cents worth.

Don

[Steve Campbell]

Well I'm back. I want to thank each and every one of you for your help. It is great to have this much wisdom to draw on when things don't go just right.

I went back down to the shop and turned the speed up to about 3000 RPMs. Sharpened my skew again and had another go at it. I was still getting terrible chip out. I ended up taking a 1/4 inch skew I have and using as a scrapper. Man you talk about slow. I'm sure it took well over an hour to get it finish turned. I still have a couple of small chips but you have to look way to close to see them. I will try and post a picture later tonight if I can get a good picture with my cheapo camera.

The other acrylic pens I just turned cut pretty much the way I figured they would. I don't know for sure but I think my problem was the blank itself. It is one I picked up at Rocklers last time I was there. I think it an Inlace and acrylic mixture. The other blanks just said acrylic on them. Biggest problem is, I bought two of them. I am way too cheap not to try it again or I would just throw it out.

The finish I found the best for me on acrylic pens is to wet sand them up to 2000 grit sandpaper. Then I take them over to the Beal buffer. I use the first two wheels but not the wax. I can't get must more polished than that.

Thanks again guys...............

Steve

[Bernie Weishapl]

Steve I agree with others speed and sharp tools. I also wet sand to about 800 grit. I found with the beall buff you don't really need to go much higher. Wet sanding really does a nice job and keeps the dust down. I use it on my bottle stoppers after watching Ed Davidson aka YoYo Spin.