Chips out of Acrylic blank

[LarryS]

I'm having trouble with chips out of my Acrylic pen blanks.

I'm fairly new to pen turning and really new to turning Acrylic blanks. I started out turning with a gouge and that was leaving chips in the blank that I had to sand. Then I went and bought some Easy Start Rougher, Finisher, and Detailer and still same results. I thought I wasn't taking out to much material when I was turning, but I just don't know what I'm doing wrong? I end up sanding and sanding alot. Dry sanding and wet sanding. The method I was using to sharpen the gouge was my belt sander. That is one reason I went out and bought the East Start Tools.

Any help or advice would be greatly appreciated !!

 

[ed4copies]

What is the temperature in the room you are turning?

Where are the blanks stored, what is the temperature?

What "acrylic" are you turning.

Tell me these things and I can give you tips, without them I can only guess.

 

[LarryS]

It's not very warm. I probably started out turning at 32 degrees.
I did leave this blank out in the cold shop.
Not sure about the acrylic? It is from Woodcraft and it just says Solid Pink Acrylic Pen Blank.
The other blank I turned I had it in the house before turning and it did the same thing. That one was Pink Quartz Acrylic Pen Blank from Woodcraft. This one did not chip nearly as bad as the Solid Pink.

 

[csr67]

I'm new to this as well, and I've turned several acrylic pens with my Easy Woodworker tools with no issues. Are your Rpm's high enough? Also, make sure you're holding the carbide tools level to the ground and taking light passes. I also found it critical to have the tool rest at the proper height. I found the easy carbide tools cut best when the cutting edge is just below the center line of the blank. Keep at it and you'll soon have nice ribbons of shavings flying off the tool.

I use my easy woodworker square roughing tool until the blank is round, and then I switch to the round bladed tool.

 

[ed4copies]

Woodcraft will sell acrylic acetate, usually. A nice material to turn, if the temp is "normal".

Turning ANY plastic at freezing is a challenge. I used to say you have to raise the temp, then other guys said, "I can turn it at zero degrees". So, now I will tell you, yes it can be done---BUT it is much more difficult than warmer.

Acrylic becomes much more brittle as it gets cold. Do yourself a favor and get a torpedo, or other effective heater. And store your plastics in the house. At least bring in the ones you plan to turn this week.

This WILL help.

Turning plastic is always a good idea to have highest RPM you can use and be comfortable. Yes, the tool should be sharp. IF you use Easy Wood Tools, I am just learning about them. They are designed to be held parallel to the floor, cut about dead center of the blank.

Hope this helps,
Ed

 

[Jim Smith]

I'm with csr67 on this one. Once I get the acrylic blanks fairly round, I crank up the speed on the lathe. It will smooth out the cuts and reduce the chipping until it's completely round, then you'll be producing long ribbons of material which will wrap around the blank and that tail stock.

Jim Smith

 

[flyitfast]

Actually, faster speed is your friend when going from square to round. You are cutting less air and the chisel has less time to go in and out in the empty areas.
Also, with acrylic, the more corners you can sand off the less likely you will have chipping unless you are being aggressive. I like EasyWood tools for acrylic, although the skew or the roughing gouge rolled over (like a skew) will also work on acrylic if you are not too aggressive.
gordon

 

[lwalper]

Some acrylics are just plain hard as a knot, and absolutely brittle and generate a lot of powdery dust. Others turn like hot butter. On those hard ones I usually turn close to size and leave enough material to be able to sand to size. A little 220 grit will do an amazing job of reducing the size and removing those divots left from the cutting tools. I usually turn the acrylics at about 3000 RPM -- they're all different -- you'll find a sweet spot for speed and depth of cut, but generally faster is better.

 

[switch62]

Firstly, there are different types of "acrylic" blanks and some turn easier than others. Some acrylics are a bit softer and will turn smoothly without chipping. Others are very hard and will chip easily.

Everyone will have their own method for the hard acrylics. I use a gouge to get the blank to round. Extremely light cuts initially and then light cuts once the corners have been have been knocked off. I will still have some shallow chips but they are well above the final diameter.

After that I use a skew to get to the final diameter and shape. The skew should produce continuous ribbons of plastic. So much so, that they wrap themselves around the work piece and you have to remove them regularly.

I also use the skew as a scraper (flat on the tool rest) for fine tuning the shape, very light cuts.

During all this you need to have very sharp chisels and I touch up the edge on each, several times with a diamond stone.

Hope this helps

TonyO

 

[thewishman]

Hey Larry, are you anywhere near Columbus? I'd be happy to have you come over and show you how I do it. Just click on my underlined name on the left panel of this message and choose the second option - send a private message to thewishman, I'll send you my phone number.

 

[LarryS]

Thank you everyone for the advise!!

I'm turning at a speed of 3200.
With the gouge most of the time I can get the continuous ribbons of plastic but I still get the chipping. With the Easy Start I don't get the continuous ribbons of plastic. It just looks like it is chipping off. Since I'm new to the Easy Start Tools, is that normal with them? I admit I do have a little bit of a learning curve with the Easy Tool. I'm starting to hold it flat on the tool rest.
I think I just need more practice time. And I need to get the shop warmer while turning Acrylic blanks. I do have a salamander but I don't have any insulation in the shop. So it just takes longer to heat up. Temps are to be rising next week. After all of this cold weather I'm just anxious to get back to the shop.
I'll make it work but I just have to figure it out. If not I'll keep coming back for advice from all of you.

Chris I really appreciate the offer but I'm about 165 miles northwest of Columbus.

 

[Chasper]

Practice, practice, practice.

Warmer blanks will help, faster speed is good, any sharp tool is fine. The blank you are turning is one of the easiest. Turn a few hundred of them and you will find yourself getting better.

I turn them with a scraper and touch them up with a skew, any carbide insert tool is just as good. I turn at 4000 RPM from start to finish because that is the fastest my lathe will spin.