# Acrylic Blanks



## ironman123 (Dec 30, 2011)

Acrylics is very new to me.  I tried one today and one end cracked off and  scattered about on the surface is a zillion little holes.  And little shards all over my shop and me.

I was using same rpm (1760) that I have been turning wood with and using a 3/8 gouge.

Am I going at it all wrong?????  And I may need to slow myself down with tool movement.

Advice and guidance appreciated.  Thanks a bunch.

Ray    ironman123


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## Joe Burns (Dec 30, 2011)

I'm presently turning a truestone that turns very similar to acrylic.  The key is very sharp tools and take small easy bites with the tool.  You don't want the blank to heat up.

Joe


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## ed4copies (Dec 30, 2011)

In the newly-organized library (penturning 101), the first video is by Ed Davidson (yo-yo spin).  He shows how to turn a sierra from Polyresin.

Now, that's a good start, but it also matters WHAT you are turning.  Acrylic is machine manufactured, Polyresin  or Alumilite are "kitchen-poured".  Turning each is a little different from the others.

Search YouTube--there are a couple there that might help (yes, I did 4 of them and they are under "ed4copies"), but there are many (some are NOT very good).
or use this link (I did not know we had them all in one place until a few seconds ago!!)
http://www.exoticblanks.com/index.php?option=com_content&view=category&layout=blog&id=37&Itemid=66
(Ignore the sign that says it won't play----it WILL!!)


Good luck and speed up the lathe and sharpen your tools.

First piece of advice I always use:  SHAVE the blank, like you shave your face, slowly and with the grain.  If you just plunge the razor in, things don't go well.


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## butchf18a (Dec 30, 2011)

ironman123 said:


> Acrylics is very new to me. I tried one today and one end cracked off and scattered about on the surface is a zillion little holes. And little shards all over my shop and me.
> 
> I was using same rpm (1760) that I have been turning wood with and using a 3/8 gouge.
> 
> ...


 
:usflag:Without knowing source of your acrylic. A zillion holes after shattering sounds like air bubbles in the acrylic from a poorly made home made blank. Shattering; is your shop heated or were you turning a cold blank in cold shop? Also sounds like, as others have suggested, your turning tool(s) may not be as sharp as they could/should be. Dull tooling, heavy handed cuts often leads to blowouts.

recommendations: sharp tools, light cutting passes. My shop is not heated, so I will glue in tubes inside, and then turn them down before they have opportunity to cool down to ambient shop temp.


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## smw6442 (Dec 30, 2011)

i was having that problem with them cracking or breaking off the tube..so now i make the blank longer and dont drill all the way through then use the band saw to cut it to size..then i use a lot of ca glue {thick} on the tube put some extra on the ends of the blank let dry..as far as turning them..i just take very light passes and dont push hard..use sharp tools helps a lot to...i'm still new at turning but this is what someone told me and so far its working for me...also when u get close to the bushing dont go from bushing in to the blank go from blank to bushing and light passes..hope this helps ..steve

also if u have a square blank use the belt sander to take the edges off seems to help me a lot...


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## PenMan1 (Dec 30, 2011)

I may just be me, but I seem to have much better success using speeds near wide open on acrylic. I do use carbide tools and they just seem to cut easier and smoother at higher speeds.


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## ed4copies (Dec 30, 2011)

_":usflag:Without  knowing source of your acrylic. A zillion holes after shattering sounds  like air bubbles in the acrylic from a poorly made home made blank.  Shattering; is your shop heated or were you turning a cold blank in cold  shop?"

_This is also possible.  So, how can you tell if it's YOU or the blank?
Air bubbles are ROUND, poor turning is not.  If you have absolutely round holes, it was a poorly made blank.  But, I'd bet you are shattering the blank with your turning methods.  

Nothing beats experience.  I ruined dozens of blanks learning, BEFORE we had YouTubes._
_


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## flyitfast (Dec 30, 2011)

+1 on the sharp tools and speed. Also, I round the edges on the sander to reduce the impact on corners. Keeps the tool on the blank longer for smoother rounding.
As was mentioned, the material does make a difference too.
The acrylic is always a joy to turn, just to see what is underneath and how they polish up.
gordon


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## SDB777 (Dec 30, 2011)

I was overly aggressive with some PR blanks once upon a time, I've learned to slow down.....pen making doesn't need to be a race.  Sharp tooling and go easy, some of them 'holes' are probably tearing of an over heated blank(BTDT).



Scott (go easy, it's supposed to be fun) B


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## ironman123 (Dec 30, 2011)

Thanks guys for all the great advice.  The one in question was square and everyone of you hit it on the head (my head).

Increased the rpm on the lathe.  Re-ground and sharpened my gouge and skew.  Eased up on my cut and slowed it down (like shaving).  Looks a lot better now.

I did switch to a round, pre drilled blank on the second one.  That was a lot easier to.








Thanks again,  Ray    PS:  I need to find more round blanks


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## ed4copies (Dec 30, 2011)

When you get square blanks, take them to your sanding station or belt sander and round off the corners, use about 120 grit--won't take long and the lathe work gets MUCH easier.


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## jasontg99 (Dec 31, 2011)

PenMan1 said:


> I may just be me, but I seem to have much better success using speeds near wide open on acrylic. I do use carbide tools and they just seem to cut easier and smoother at higher speeds.


 
Andy, you said exactly what I was going to say. I had trouble with acrylester, but with a skogger or rotondo and turning at 3000 RPM, there are no more issues with any material.


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## TurningPoint (Dec 31, 2011)

*Round and square blanks*

I have found round blanks more difficult to drill with my centering setup on the drill press. Square blanks are easily rounded with a belt sander (I'm lucky to have a 30 year-old industrial quality one, but any will do with patience). Mount them on the mandrel first to keep your fingers safe while sanding. I have not "blown-up" a single acrylic blank since I started doing that. After that, the only tool I need is a skew, and there are many more square blanks available than round ones!


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## ed4copies (Dec 31, 2011)

TurningPoint said:


> *I have found round blanks more difficult to drill with my centering setup on the drill press.* Square blanks are easily rounded with a belt sander (I'm lucky to have a 30 year-old industrial quality one, but any will do with patience). Mount them on the mandrel first to keep your fingers safe while sanding. I have not "blown-up" a single acrylic blank since I started doing that. After that, the only tool I need is a skew, and there are many more square blanks available than round ones!



There are very few penmaking problems for which I have NOT found a "work-around".  But this IS one of them!!!

Now, I am lucky to have a Beall collet, so I run to the lathe, but if you are NOT that fortunate, has anyone found a good way to HOLD a round blank while drilling on a drill press???


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## watch_art (Dec 31, 2011)

Having never done it - I would guess some rubber hose from the auto store cut length wise into two pieces, then PVC that's the right size cut length wise into two pieces, then clamped tight in your blank holding jig, then drilled.  

That should keep it from spinning, right?


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## PTownSubbie (Dec 31, 2011)

ed4copies said:


> TurningPoint said:
> 
> 
> > *I have found round blanks more difficult to drill with my centering setup on the drill press.* Square blanks are easily rounded with a belt sander (I'm lucky to have a 30 year-old industrial quality one, but any will do with patience). Mount them on the mandrel first to keep your fingers safe while sanding. I have not "blown-up" a single acrylic blank since I started doing that. After that, the only tool I need is a skew, and there are many more square blanks available than round ones!
> ...


 
I use a self centering drilling jig and it works for both square and round blanks.....Purchased from Woodcraft some 2 years ago and still going strong!


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## ctubbs (Dec 31, 2011)

It may be just me, but I have found that if I cut into the ends before working the center of the blank, that I have less problem with chip out.  That even works on the wood I turn.
Charles


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## drgoretex (Dec 31, 2011)

ed4copies said:


> TurningPoint said:
> 
> 
> > *I have found round blanks more difficult to drill with my centering setup on the drill press.* Square blanks are easily rounded with a belt sander (I'm lucky to have a 30 year-old industrial quality one, but any will do with patience). Mount them on the mandrel first to keep your fingers safe while sanding. I have not "blown-up" a single acrylic blank since I started doing that. After that, the only tool I need is a skew, and there are many more square blanks available than round ones!
> ...



I often have to do a 'first pass' on round blanks to get them down closer to 3/4" as they often are to big to stuff into the 3/4" collet.  I use the good ol' 4-jaw for that, trim down the one end to 3/4, then flip it over and do the rest with the collet chuck.

Ken


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