Acrylic turning -- what am I doing wrong?

[joefrog]

Okay, I've made several acrylic acetate pens so far with (mostly) success stories. Aside from one blank that blew up on me I can't complain.

However...

I got several nice looking "inlace acrylester" blanks from Woodturningz.com and have yet to successfully turn a single one of them. I've tried two so far, and both were dismal failures. I was trying to turn a cigar pen with my school colors last night.

After a few pops of chunk coming off, I finally slowed down to shaving gnat-hair sized passes. I was 80% done, when BANG -- this thing flew completely apart.

What the heck am I doing wrong? Too aggressive? Tools not sharp enough? Or is this just crappy material to turn?

 

[gimpy]

For all of the above reason, that's why I don't use them, just gave all mine away last week

 

[hewunch]

Inlace is especially brittle. They do make a nice pen, but you have to be VERY careful with them. Sharp tools.

 

[Russianwolf]

nickle's worth of free advice. Sand those guys as close to round as you can before turning.

The impacts from trying to spin them round can cause cracking in them.

 

[George417]

Need more detail. What kind of tool are you using, what lathe speed????
I've been using a gouge at 3500 rpms and usually get very good results.

 

[renowb]

Inlace is very chippy and unforgiving. Sharp tools and don't be too aggressive. Keep the tool rest close to the work.

 

[joefrog]

Need more detail. What kind of tool are you using, what lathe speed????
I've been using a gouge at 3500 rpms and usually get very good results.

I only have three tools (sad but true). I bought the "Benjamin's Best" Pen Turners set, so I have a parting tool, a skew, and a narrow roughing gouge. I've been rounding them with the roughing gouge, shaping, then smoothing with the skew.

I bought a Delta 46-460 lathe, and turn it on middle belt speed at around #6, whatever RPM that is. I know I sound like I'm clueless -- because I am!

 

[watch_art]

Go faster.

 

[Andrew_K99]

I have the same 3-pk of tools, I don't use them for much anymore after making a carbide insert tool and buying a 1" flat skew.

Make sure they are really sharp and take light cuts. I could never get that skew to work right. You can't be in a rush with those brittle blanks.

 

[IPD_Mr]

Spin that lathe as fast as you can peddle it and make sure that your tools are scary sharp. I would guess that the tools were dull taking a little off at a time as you described and one little catch at the end was disaster. Everyone likes different tools for this and you will find all kinds of suggestions. I already saw someone talk about a gouge while I prefer a skew, either way it is possible but you need sharp tools and patience. Do not get aggressive.

 

[Xander]

My 3rd pen (1st acrylic) was inlace acrylester. I used the benjamins carbide set - spindle gouge. Lathe at top speed and light passes. Had a few minor chips while getting the edges knocked off, but once round it was OK. Finished real smooth, like glass. Be patient, sharp tools, and you'll get good results.

 

[Chasper]

It is not crappy material, it is a bit brittle and there is a learning curve, but it is a beautiful marerial with a deep color intensity which produces a dramatic reflective flare.

Learn to use a skew properly is the best advice. High speed, sharp tools, and not too aggressive are all important. If you are using a skew properly you don't have to sand off the corners, don't need to make ultra light cuts, and you should be able to turn a blank in less than 10 minutes.

 

[ed4copies]

It is not crappy material, it is a bit brittle and there is a learning curve, but it is a beautiful marerial with a deep color intensity which produces a dramatic reflective flare.

Learn to use a skew properly is the best advice. High speed, sharp tools, and not too aggressive are all important. If you are using a skew properly you don't have to sand off the corners, don't need to make ultra light cuts, and you should be able to turn a blank in less than 10 minutes.

In my experience, this is all correct.

HOWEVER, Gerry has turned thousands, I turned dozens--I suspect we BOTH blew up several in learning how to do this.

I went to college, it cost money but I learned things.

I always look at the difficult materials I have "blown up" as the cost of my "penturning college". Each 'blow up" taught me something.

Oh, and you LOSE the ability to turn it in 10 minutes if you don't do it frequently----DAMHIKT!!!:biggrin::biggrin::biggrin: (now I allow 20 minutes)

 

[Rob73]

I had the same problem when I bought some blanks from woodturninz. It was driving me crazy. Ed helped me out and told me to jack up the speed. What I do do is round the corners off on my belt sander. Set my belts to 3000 or 3200 don't recall which and I use a round carbide. I haven't had as many issues since. The one thing working with those blanks taught me right away was to wear my face mask.

 

[plano_harry]

Is high speed recommended for all plastics? My Jet can run 3,975

It is not crappy material, it is a bit brittle and there is a learning curve, but it is a beautiful marerial with a deep color intensity which produces a dramatic reflective flare.

Learn to use a skew properly is the best advice. High speed, sharp tools, and not too aggressive are all important. If you are using a skew properly you don't have to sand off the corners, don't need to make ultra light cuts, and you should be able to turn a blank in less than 10 minutes.

 

[ed4copies]

Is high speed recommended for all plastics? My Jet can run 3,975

It is not crappy material, it is a bit brittle and there is a learning curve, but it is a beautiful marerial with a deep color intensity which produces a dramatic reflective flare.

Learn to use a skew properly is the best advice. High speed, sharp tools, and not too aggressive are all important. If you are using a skew properly you don't have to sand off the corners, don't need to make ultra light cuts, and you should be able to turn a blank in less than 10 minutes.

The faster the stock is moving, the less you can "move your tool into the void between corners, thus creating 'chips' instead of ribbons".

BUT, confidence is also part of turning. So, increase the speed until you are still comfortable, then turn. Every couple days, you will be comfortable with a slightly higher speed. That is how you get to ten minutes!!

 

[babyblues]

Acrylic acetate is significantly softer, thus more forgiving, than inlace acrylester. You can turn acetate with a sharp roughing gouge with good results. However, inlace acrylester is very brittle and even with the scariest sharp roughing gouge, you're going to have problems. Even with your lathe turned up to warp 10, you run the risk of a blowout.

Go to The Library, under Videos, and watch the Ed Davidson's video Bottle Stopper, 3d Resin. Take note of his technique using a skew. That's how I turn brittle resins like inlace acrylester and PR. I've not blown up a blank using this technique. Even under the best of circumstances, you can't really get your roughing gouge as sharp as your skew.

If you have to, first learn how to sharpen your skew. A friend of mine has a set of Benjamin's Best tools, and although the price is great if you're on a tight budget, the quality is lacking. You're going to have to resharpen your skew before you're finished turning just one pen. "The pain of using a cheap tool lingers long after the joy of saving money has passed."

 

[Xander]

I must be very lucky .. or scary skillfull.

My 3rd pen....ever... was inlace acrylester, this was my 1st non wood blank. My only tool was a carbide spindle gouge. This was the first blank I had to drill, the others I had were pre drilled. I use only 2 speeds on the lathe. Slowest for drilling, and fastest for everything else, including sanding and MicroMesh. I've had ZERO problems.

Yesterday I got a Woodchuck pen pro and after 30 seconds of using it I prefer my Benjamins carbide gouge, but I did a complete cigar with the pen pro. I'll see how I feel after using it a bit more.

With the inlace.... my 'advice'... turn FAST, light cuts, but don't be afraid of it.

 

[yort81]

I use a Eazy wood turning carbide tool...(the rougher works the best) and as the wood turning world knows.... Mach 3 is the best speed to turn at...I've never had a problem with acrylic inlace (does that sound bragadocious?)

 

[thewishman]

Joel, check your glue coverage. A lot of failures with inlace are due to not enough, or not complete gluing. When I have had a failure with inlace acrylester, it has always been due to a spot that did not get fully glued to the tube.

My go-to tool for several years was a Benjamin's Best skew. I turned a lot at 1800 rpms, I use a much higher speed now.

 

[joefrog]

Higher speeds and carbide seems to be the running theme here. I'm saving up for a few new tools, and after next weekend's show perhaps I can afford one or two (Assuming I sell a few!). My wife is on the verge of skinning me for making a few too many "equipment & supply purchases" already!

Thanks guys!

 

[spilperson]

Metal Lathe

I know it won't help Joe, but I wanted to mention that I use a metal lathe, running about 2000 rpm and using a carbide insert tool in a fixed tool holder. I make relatively light passes, but not super light.

I blow out most of my blanks in drilling. Mostly I use a small drill press. Sometimes I use my lathe. If I had a self-centering four jaw chuck I would use it more, but the budget has not materialized yet.

For inlace acrylester and tru-stone, you really need to start with a small pilot hole and work up through several sizes, or go very, vey slow. Keep the bit clear of chips too, that is what does it.

 

[Padre]

In one of my early classes, the instructor told me that "we Americans turn at a much lower speed than most of the rest of the world." With that in mind, I went home and kept turning up the speed on my lathe, until now, I turn mostly everything a lot faster than I once did. Of course, you have to be within the limits of safety, sanity and comfort. You are not going to turn a 40lb bowl at the same speed you turn a pen blank!

I also have a 46-460, and I turn mine up all the way to turn pens. I use a scary-sharp roughing gouge most of the time (I sharpen it for every blank, just a quick once over on the grinder), but rely on my Woodchuck carbide tool quite a bit too.

 

[IPD_Mr]

My wife is on the verge of skinning me for making a few too many "equipment & supply purchases" already!

Joel you are no different position than the rest of us on here. :beat-up:
I will say this, I think it is important to learn the tools you have Most of us went through all kinds of tools before we really fount that one big comfort zone tool. So learn to use and sharpen a roughing gouge, fingernail gouge, spindle master and yes even a skew before going to buy new tools and leaving the old ones in the dust. I will still use the parting tool and skew from my first tool set. Why? because I got so comfortable with them that I could easily do detail work.

 

[ghostrider]

...

After a few pops of chunk coming off, I finally slowed down to shaving gnat-hair sized passes. I was 80% done, when BANG -- this thing flew completely apart.

What the heck am I doing wrong? Too aggressive? Tools not sharp enough? Or is this just crappy material to turn?

It might be possible that you cracked the blank when those "chunks" came off. That's happened to me before on some acrylics. I've had blowouts in drilling and no problems in turning. Then when I go to assemble there is a hair line crack that I hadn't noticed before that was caused by the blowout.

Also, You don't "need" to get a carbide tool. I've done one Acrylic Acetate, and two Inlace Acrylesters. Both were done with a roughing gouge, and a skew, and a spindle gouge (that's what the directions called for). I will admit it did get a bit chippy, so at a certain point I decided to use my 60 grit shaping tool. However, much of that can also be inexperience.

Want a blank that's easier to turn, and looks nice? Try one made from Alumilite. They turn like butter, and some of these custom casters make some amazing stuff. I bought two IA blanks to see what they were about, and when I finished the second one, I showed it to Buzzzz4 and we both agreed that there wasn't any reason he couldn't get the same effect with Alumilite. Between him, Jonathon Brooks, and some of the others, there's no reason you can't find something to suit you. Don't just shop at one car lot.

 

[joefrog]

Thanks, Ghostrider. I'm building experience as I go. So far so good, with most things. I'd say the majority of my stuff looks pretty darn good considering I've turned for less than a month.

I'll look into that Alumilite!

 

[hewunch]

One thing I haven't seen mentioned is drilling. When a blank is especially brittle (Inlace, dymondwood and even some PR and especially when stuff is embedded in the acrylic like coffee beans) I like to stop drilling before I exit the blank and cut off the remainder. In other words, I don't drill all the way through. This keeps you from blowing up your blank upon exit, or even getting some of the afore mentioned micro cracks.

 

[JAZNCARR]

I gave up on the stuff I bought 6 of the molten metal blanks and everysingle one of them shattered

 

[Haynie]

My wife is on the verge of skinning me for making a few too many "equipment & supply purchases" already!

You get used to not having your skin.

Just tell her the other option is taking up competitive bass fishing.

 

[reiddog1]

I always round the corners down with my belt sanders before I begin to turn. This combined with Sharp tools and light touches seem to help.

Dave

 

[nava1uni]

You can easily fracture inlace if it gets hot while drilling. You won't see the tiny fractures but if you are too aggressive it turning they will heat up, expand and cause a blowout. I always keep Inlace cool while drilling my using a spray bottle to keep the bit cool and not pushing the bit through the blank too quickly or aggressively. Sharp tools make the work much easier. I hone throughout the turning process with a credit card diamond file.

 

[panamint]

I have just started turning pens so I am very new at it. My wife bought a bunch of pen blanks and I didn't notice they all where inlace acrylester. After blowing out the first two I started looking online and the best tip I found was turn as fast as your lathe will go. Use a bowl gouge to rough out the blank and to shape it close to your finished size using light cut. I finish turn with a round carbide cutter tool I made and use a skew laying flat on the tool rest and scrape to finish.
Scott
Scott's Woodwork's - Shopping/Retail - Inman, SC | Facebook

 

[jmkr53900]

If you drill the blank all the way through before inserting your barrel it may create a crack and usually you won't see it until you reach you final thickness. If your tool hits the crack the wrong way it shatter it. It happened to me. I hope this helps