WPP Acrylic blank explosion.

[dbriski]

I was going to make a pen out of one of the Wood pen pro round acrylic blanks from the group buy a while back. A few weeks ago I cut one to size on my table saw (can't recall the blade but I think WWII) no problem (never did drill or turn it). I wanted to cut another one and get it preped, this time on my SCMS with Freud LU91M 60 ATB TK as as soon as I touched it with the blade KABLAM! it exploded in 2 and lost of little fragments. I picked up one of the 1/2 to see if i could trim the mangled end off, KABLAM! same thing happend. Has anyone had any experiences like this with these blanks? I may just have to cut them on the band saw, or was it possibly just this blank(it was one of the red ones I think maybe lava flow)? or the blade choice?

 

[TellicoTurning]

Hi David,
I always cut acrylic blanks on a band saw.. I have a little Ryobi 9" that I use specifically for acrylics and antler.. fairly fine teeth on the the blade.

What kind of blade do you have in the Tbl saw.. if it isn't a 60 or 80 tpi, you may have put too much pressure on the blank, too quickly.

 

[mick]

David I've cut the blanks from WPP on both my miter saw and table saw. Both have thin kerf 80 tooth blades. I've never had any trouble cutting them. As a matter of fact they are one of the most forgiving blanks I've ever used or turned. Sounds like maybe it was a fluke or a bad blank.

 

[gketell]

Rock You HardPlace

Too few teeth and too much pressure=Kblam. Too few teeth and too slow=Kblam (because the plastic melts and sticks). I use my 80 tooth to cut acrylic sheets without issue as long as I keep the sheet moving at a steady pace. And I've used it to cut PVC pipe (but not reliably). In both cases, the bandsaw works much, MUCH better. ((I've never tried to cut an acrylic blank on the tablesaw. I don't think I Would try to cut a round acrylic blank on the tablesaw based on the occasional KBLAM from trying to cut PVC pipe)).

Now, I've READ where some people turn their blades around backwards on the saw so that it can't grab and that (supposedly) works better. *SHRUG*

GK

 

[cozee]

My table saw has a 40T blade and haven't had any problems cutting acrylics. Of course I go slow and allow the blade to determine the speed and pressure.

 

[Malainse]

I also did that with the first acrylic that I cut. I now use a HAND SAW.... Yes, the thing that you do not plug in......hahahahah

 

[Pipes]

BANDSAW [8D]

 

[Tea Clipper]

Reading the headline, I had a gecko swirl explode on me when starting to turn it round. The blank separated along the lamination seam. I thought maybe that is what this post was about...

I'm with the other guys here -- I use a bandsaw to cut the blanks, wood or acrylic. I think the secret is the higher tpi as others have pointed out.

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[leehljp]

I think the real problem is that the round blank was not held down sufficiently. Short pieces on a SCMS are VERY suseptable to being lifted. The reason for the negative rake blades on MS, CMS and SCMSs (and radial arms) is to take out some of the lift from the blade and make it cause an initial cut with the blade force being towards the back fence. A typical TS blade has positive (forward) rake and it "pulls" the board being cut downward into the table at the front edge. But CMs & SCSMs lift up on the back side of the blade, necessitating a negative rake to prevent excessive lifting.

However in your case, the round blank pretty well made sure that the blades initial contact was on the upswing even with the negative rake, which translates into "lift" from the base that it was resting on. A very secure hold down near the blade on short pieces is an absolute necessity.

I have exprienced this a couple of times, but in moments when I was not paying enough attention. I thought I could hold a short piece, 4 in long by 1 in square - by hand. Don't do it. Sharp clean blades are a necessity also. Dull blades or ones loaded with pitch will lift those suckers even QUICKER! I would say that blade lift with insuffecient hold down was culprit.

 

[dbriski]

Ok thanks for the tips guys. The first one on the Table saw I think was using a Forrest WWII TK and my blank cutting miter guage with hold down. Cut was flawless. Seccond one was SCMS with the Freud LU91M 60 ATB TK with negitave rake, only held by hand, kablamo. I'll figure out a hold down system for the blanks for my SCMS or use my bandsaw for the acrylics.

 

[Mikey]

I use my table saw and a 40 tooth blade and never have any problems. I don't force the blank though and let the saw do the work. If I was using a CMS, I would let the blade get to speed, back up the cut, and then go slow. Wood is forgiving if you hit it too fast, Acrylic is not.

 

[Blind_Squirrel]

Originally posted by Malainse
<br />I also did that with the first acrylic that I cut. I now use a HAND SAW.... Yes, the thing that you do not plug in......hahahahah

One of these things?

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