Which tool for turning large acrylic blanks

[midmaik]

I have large acrylic blanks, it's a mix of burl and alumilite poly resin, i infused the root burl with resin in a mold.

the blank is about 6 inches in diameter and about 10 inches tall. at the outside of the cylindrical blank is only resin, so i would like to turn a vase and for that I have to remove a huge amount of resin only.

I tried nearly everything from bowl gouge, to roughing gouge to scrapers and so on.

The worst tool is the bowl gouge, when the pressure against the blank is too much, the tool shatters and I getvery aggressive tear outs in the resin.

I don't have much experience with turning acrylics.

Does someone have some tips how I can remove the material fast and accurate ?


thanks

Maik

 

[1080Wayne]

Would think the roughing gouge would be best , but it needs to be very sharp .

 

[kovalcik]

For the outside:
roughing gouge to rough out the shape.
spindle gouge if needed for detail work.
skew to finish the surface.

Key point is all have to be sharp.

"Does someone have some tips how I can remove the material fast and accurate ?"

Pick one, fast or accurate. :biggrin:

With the gouges, start by rubbing the bevel and introduce the cutting edge slowly. You should be able to get long ribbons flying off once the piece is round. They will actually wrap around the piece and you wil have to clear them manually.

For the hollowing:
I would drill out what you can.
Then move to a sharp bowl gouge and scraper. Maybe an R2 square carbide or round to clean up.

 

[juteck]

I'm not sure what your experience level is, so please don't be offended if my comments seem basic. I use a bowl gouge on everything from faceplate to spindle work, and even pens. I've had no problems with wood or acryllic. I use a moderate fingernail grind on mine, probably most comparable to the length on the Ellsworth gouge, not near as long as an Irish grind. I keep my nose fairly round too. My "go to" bowl gouge is the Sorby 3/8" bowl gouge (which is actually 1/2 round stock). Small enough to take light cuts, but heavy enough to remove material if I want to.

that being said, you might be too aggressive with the bowl gouge, especially if you're using a larger size. Sharpen your tool, and go slow. Slow your lathe down a bit and try it then. Speed it up a little and try again. Find the sweet speed that works for you, but remember it is not a pen, so full speed all out might not be the best choice for something that large - stay within your own comfort zone. Practice with your presentation angle and riding the bevel. Adjust your tool rest so it's not too far away from the material, and move your tool rest as you move around the curve of your vase.

The roughing gouge can be dangerous on a vase. Remember that it is a SPINDLE roughing gouge. It will be Ok when you still have the vase mounted between centers, but you might want to consider an alternative tool when it comes to forming the mouth of the vase.

 

[ironman123]

I would think high speed and do not feed the tool aggresively or fast.
And as said, keep it sharp.

Ray

 

[its_virgil]

Fast and accurate don't play well together...especially on acrylics.
Do a good turn daily!
Don

 

[Dan Hintz]

I use a 1.5" roughing gouge (almost exclusively) to make my pens... if it's good enough for that, I imagine it will be just fine for roughing out a 6" diameter vase while still giving you some fine control.

 

[Dan Masshardt]

Surprised nobody's mentioned carbide. I'd expect easy wood tools type (square and round cutters) to be excellent on this.

 

[midmaik]

At first, many many thanks for your fast and very helpful answers, appreciate it a lot !!!!

Just wanted to know, if it's normal that turning acrylics takes much longer time than turning normal wood.

So my experience with turning wood is really well, but I was really confused when I tried to turn the wood/acrylic combo.

I thought every time, what's wrong here and why is it not possible to remove much material as when I turn just wood, then the shatter problem and so on.


So now I know that's normal that it takes much more time and I have to more patient

Can it be that I have to sharpen my tools more often comparing to turning only wood, does the tools become faster dull ??


I used yesterday also a negative rake scraper, and that works not bad and I could also be very aggressive without the shatter problem.

Oh man, such a big blank takes so long time, when it's finishes i will put some pics here.

But I don't want to think about the hollowing know


I tried the carbide stuff, but one time I was a little bit too aggressive and the a big piece of acrylic comes (brakes) out of the blank and from then I don't like it anymore, because I don't want to be very stressed during the turning process.

 

[crokett]

turning acrylics takes longer than turning wood. You need sharp tools and can't be as aggressive with the tools. for a mixed blank, I would pretend it is an acrylic. I use a sharp 1/2" spindle gouge on my acrylics, then for final shaping a carbide tool rolled at an angle for a shear cut. I am a little aggressive with the gouge - I am willing to trade time for some pitting on the acrylic but I leave enough to be able to smooth it out with the carbide tool.

 

[dartman]

I have good luck with the Easy wood tools.Square for roughing and round for shaping.I turn fast with light cuts or you will experience that chip out.