acrylic blanks flying apart

[MikeyTn]

I have tried acrylic blanks several times and every time I say I'll just stick to wood. I just got a half dozen new acrylics in yesterday and I have already ruined two.

When turning down from square to round they seem to want to chunk out at the ends exposing the brass barrel.

I use a HSS gouge and skew that came from Penn State Ind. I have it sharpened sharp enough to cut my finger nail. I glue the blank to the tube with 5 min two-Pt epoxy and I sand the brass before I insert it into the blank. I start out turning at just under half speed.

Any ideas on what I'm doing wrong or are acrylics just that hard to work with?

 

[its_virgil]

I turn all acrylics with a skew at high speed. You may want to knock off the corners on a sander. Or, watch the videos in the library by Ed Davidson showing how to turn and polish acrylics. You need to conquer the turning of acrylics because there are some really nice ones to use.
Do a good turn daily!
Don

Originally posted by MikeyTn
<br />I have tried acrylic blanks several times and every time I say I'll just stick to wood. I just got a half dozen new acrylics in yesterday and I have already ruined two.

When turning down from square to round they seem to want to chunk out at the ends exposing the brass barrel.

I use a HSS gouge and skew that came from Penn State Ind. I have it sharpened sharp enough to cut my finger nail. I glue the blank to the tube with 5 min two-Pt epoxy and I sand the brass before I insert it into the blank. I start out turning at just under half speed.

Any ideas on what I'm doing wrong or are acrylics just that hard to work with?

 

[les-smith]

After I have the tubes glued and the ends squared I cut the corners off the blank so that it becomes a octagon. I think that it softens the turn of the blank a lot. I also turn my stuff pretty fast. Things get a lot easier once the blank becomes round.

Bozz made a jig just for that very thing. There was some good talk in the post:

http://www.penturners.org/forum/topic.asp?TOPIC_ID=26041

 

[alphageek]

As another relative beginner, I can pass on a bit of my thoughts/experiences.

1) I have had better luck with the speed HIGH, not slow. I now turn wood and acrylic at the same speed. I find that if I slow it down, I tend to press harder. With higher speed, I take smaller shavings off and have better luck.

2) Not all acrylics are alike. I won't say anything bad, but I have had much 'chippier' experiences with some acrylics.

3) Lately I use the skew exclusively. Its less likely to grab chips (and the practice being slow and carefull with the tool does me good.)

I'm sure that more experienced people will have good feedback - I just thought I could give an viewpoint of someone who just 'got the nack' recently.

 

[Texatdurango]

Been there... done that!

For me, the turning point was when I started trying to remove about a fourth as much material as I would if turning wood. In other words, take very light cuts and eventually you will find your comfort zone.

I also had a problem of attacking the blank with the gouge, meaning I would push it in at almost a 90 degree angle. I was finally taught to hold the gouge cutting edge up high, slowly raise my arm which raises the tip and exposing or "riding" the bevel, then finally a bit more arm raising to expose the cutting edge.

If at all possible, seek out an experienced local turner who can SHOW you what is being said in these messages, often it helps to see what's happening.

Good luck and don't give up!

George

 

[rhahnfl]

I've done that too. Got too aggressive and blew off the ends. Go ahead and turn them round and then take a parting tool and part them off past the bad part. Take some of your leftover cutoffs from other blanks and make a segmented pen out of it. Drill them and square one end and then glue it over that brass tube that is sticking out of where you parted it off. Clamp it up and let it get good and dry and then square it up and turn it. You just made a segmented pen. I was surprised how well my goof up turned out. Good luck!!!

 

[IPD_Mrs]

Crank up the lathe speed and take small amounts off at a time. Also it is good to sand or cut the long pointed edges down so that you blank is octagon in shape. The closer you get to round before you atart the better.

 

[gerryr]

One thing to clarify. Are you absolutely sure these are acrylics? Lots of people use that word as a generic catch-all for all synthetics. I have never had problems with true acrylics flying apart, but I have had that problem with polyester resin(PR). PR can be extremely brittle and requires extra care unless you get it from someone like Ed Brown or Don Ward and then it turns like butter.

 

[Chasper]

I destroyed several before I started turning them at high speed and using the right chisel. The first thing I do (before drilling or cutting) with a new batch of acrylic, poly resin, Corian or any other resin blank is to put in in the lathe and turn it more or less round; not all the way round unless it is thick but enough to round off the corners. Then I cut them and put them in the lathe chuck for drilling. Since I started doing it that way I haven't lost any during drilling and when I get them mounted on the mandrel they are already rounded off and easy to turn.
The critical part of turning is to spin them fast; I use the highest or second highest speed on my lathe, and to use the skew, not a gouge after the initial turning to get them round. Even if you use the skew as a scraper it will greatly reduce the chipping that the gouge creates.

C

 

[alamocdc]

The fastest way I know of to ruin an acrylic blank is to use a roughing gouge. Regardless of how sharp I had it, all I get are chips flying. Once I started using the skew exclusively, the chips got smaller and with experience disappeared. Using a round nose scraper may help you get used to the "feel" of turning acrylics so you can move to the skew more comfortably. I once thought my problems were due to the amount of material I was trying to remove w/each pass, but after watching Ed (Ed4copies) Brown blow through an acrylic blank and have it turned to size in seconds (not minutes) this is obviously not the case. Turning is just like everything else... practice, practice, practice.

 

[Rifleman1776]

Can't be overemphasized, high speed. Light touch, sharp tools. Choice of tools is personal. I knock off corners with a relatively small (1/2") spindle gouge the all the rest with a 1" skew. However, somebody might be telling you to stick with wood. []

 

[ed4copies]

Sharpen your tools and don't start with acrylester. (It is a good product, but not a good FIRST product!!)

 

[alamocdc]

Originally posted by ed4copies
<br />Sharpen your tools and don't start with acrylester. (It is a good product, but not a good FIRST product!!)

Agreed. It is considerably more brittle than home cast stuff like what you get from either of the two Ed's, Jeff, or anyone else. I have had one batch turn out as brittle as Acrylester... I used too much MEK and the material cured with very tiny holes in it. BTW, it also cured completely in about an hour.

 

[rhahnfl]

Here's a pic of my salvaged pen after I blew both ends off. Used scrap cutoffs to segment it. Turned out pretty nice I think.

<br />

 

[ed4copies]

Chris,

That LOOKS like one of the "cats"!!!!!!!!!!!!!!!!

There is no more forgiving material than that!! Sharpen your tools and start from the center of the blank to the edges. Ride your tool's bevel (assuming its one of the gouges or scrapers) until you contact the blank and take light cuts until you have done a few and can confidentlyapproach it.

(If you're not careful, I'll have to come to Florida to SHOW you what I mean!!!)

Take a deep breath, have a cup of coffee, and start over - you'll get it!!!

Someone here has a quote something like, give me 6 hours to cut down a tree and I will spend the first four sharpening the ax. (Go forth and do likewise!!)

Good luck!!!

 

[donwae]

As a beginer I blew out alot of blanks until I started using the 1/2 inch "versa chisel" from PSI. I use it after the blank has been turned round with a small roughing gouge. I get a very smooth finish also.
Check out this link:
http://www.pennstateind.com/catalog/p/070.htm

 

[karlkuehn]

Lately on the resin stuff, I've been having really good luck (with a sharp skew after roughing to the extreme outside with a roundnose scraper) with high speeds and letting the tool ride on there and heat up a bit. The light heat seems to soften the resin, and my dust quits being dust and becomes more malleable, similar to acrylic acetate and flying off in big ribbons instead. I still get the occasional 'sschhhkkkkkt' noise if I push too hard. A light light touch is definitely the key.

Incidentally, 'sschhhkkkkkt' is the best spelled noise I can come up with. It's that noise that lets you know that as soon as you turn off the lathe you'll see the tell-tale shiny tearouts in resin blanks where the 'sschhhkkkkkt' hits the fan...[]

 

[rhahnfl]

Yep... my blowouts were totally my fault. It was my first piece of resin from Ed and I just got too aggressive with it. I didn't want to throw it away so I came up with the parting off the ends and gluing new ones on. I subsequently got less aggressive... sanded the next pieces into an octagon shape before turning and used a whole lot sharper tool with a lighter touch and got just continuos curls off it. To the point where I had to stop the lathe to clear them. Looked like Easter grass. I like Ed's idea of starting in the middle and working out also. I was going end to end and back again. Also, sand paper works well if you keep it moving. It's all a learning experience and a darn good one if you ask me. I've got a lot more to learn too []

 

[GBusardo]

Originally posted by karlkuehn


Incidentally, 'sschhhkkkkkt' is the best spelled noise I can come up with. It's that noise that lets you know that as soon as you turn off the lathe you'll see the tell-tale shiny tearouts in resin blanks where the 'sschhhkkkkkt' hits the fan...[]

I know that sound all too well!!!! Thanks for the smile

 

[MikeyTn]

Thank to everyone for the advice. I call already tell that joining up was a good move and that I am going to learn so much.

It'll be a few days before I can get back on the lathe but I am going to try a few things differently.

 

[Stoutmaker]

Just turned my first two acrylics today. I didn't have any problems. I started off with wood, went to Corian and then acrylic. Mid speed I think is best. My turning buddy turns everything low speed but it seemed to catch a lot more. I stepped up the speed and that seemed to work quite well for me.
Don't give up!

 

[fstepanski]

O.K. I’ve turned a total of about 10 pens, three from home poured PR, one snake skin blank and one stabilized blank from Arizona Silhouette, yup I’m a beginner with an idea / concept I’ve used and wish to share and look for feedback..

First I agree with all the above comments, SHARP tools, light cuts, I sanded off my corners, however really like Bozz’s jig: http://www.penturners.org/forum/topic.asp?TOPIC_ID=26041

Any hoo, onto my point or concept… I had the fear of blowing out a blank as well so I started my cuts from the ends, i.e. over the bushings and go towards the center of the blank. Obviously this is not a good practice, and not recommended when using regular wood blanks as you get your cleanest cut when the grain supports it. i.e. when pen turning, in most blanks going from largest diameter to smallest. I say most as I’ve seen Eagle and MesquiteMan blanks, which are beautiful, however break the “normal wood†paradigm.

Well, with PR, or stabilized wood I believe the rules can be tweaked a bit.. Going in from the ends, with light cuts I had no chip out. I made a series of light, short stroke cuts with no problems. Would appreciate comments from those who have much more experience than I on this concept…

Happy turnin’

Frank

 

[ed4copies]

Do what works for YOU!!!

For ME, a sharp skew point will remove LOTS of material, quickly. I showed this in Urbana, to the shock of many. BUT, I still believe CONFIDENCE is the most important component. I KNOW my way works, for ME.

Develop YOUR way, and you will do WELL.

 

[rhahnfl]

Ed... or anyone for that matter. Can you recommend a good video on the use of the skew that shows someone how to use it? I get really nervous with that particular tool. I may just have to break down and take a class as the rest has been self taught... mostlty through trial and error. Maybe that is one bad habit I haven't picked up yet. []

 

[LEAP]

Try Alan Lacers Skew videos, worth every penny.

 

[ed4copies]

I believe there are as many ways of using a skew as there are turners. In fact, I use it at about 4 different angles that I can think of.

Watch Alan's video (I did), then find the angles that work for you.

Someday, I hope to take video to make this clearer, but shows have to slow down first!!!

There is no such thing as a WRONG way, if it works for YOU!!![][]

 

[AFTim]

I have never had formal training in my turning so I can be a bit unorthodoxed in how I turn...But I do what works for me. When it comes to PR (Snakeskin) I sand off the corners and then as a replacement to a gouge, I use a parting tool to get the blank to it's "rough" shape then use scrapers and sand paper. This is my style and will go against everything the "professionals" on this site tell you.
I'm just asking all the skilled turners to cut me a bit of slack for stating how "I" do it.

 

[BigguyZ]

Personally, I use a gouge with light cuts to get it in rough shape, then a fingernail scraper to get teh pen to final shape. I don't really care about how fine my last pass is (to a point), since sanding will get it all out anyways. I do agree that high speed is a must. I slowed my lathe down, and then I had all kinds of problems. Now I've been good for the last 5 or 6 acrylics I've done...