blowing up acrylics - HELP

[sgimbel]

I have 2 new acrylics I'm trying to round off and have blown 2 up in a row. One is from Woodturningz "Inlace Acrylester and 1 from woodcraft that just says "acrylic". I'm using a woodchuck with as light a touch I have. But when both got to just about round they exploded in the middle. Any suggestions what I'm doing wrong? They are getting very hot. At least the woodchuck is getting hot so I assume the blanks are too. I've been turning PR all day with no problems at all.

 

[G1Pens]

From my experience (which is very limited), the inlace stuff is very 'brittle'. I have a lot of trouble with it.

I also am having a great deal of trouble with the woodchuck and acrylics in general. When I bought my woodchuck, I also purchased a Round One. I use it to get my blanks round. That works great and never had a blank blow when turning round. However after it is round I switch to the woodchuck and more often than not the blank will blow before I am finished. I think I am going back to the skew for my acrylics.

I know that doesn't really answer your question. Just thought I would let you know that the woodchuck and acrylics just doesnt seem to work for me at all.

 

[kenspens]

hi i also found the inlace acrylics to be extremely brittle as well and had some explode with different tools i think certain tools are more suited for acrylics
i dont know if this would help but i have seen where some turners use a filing technique to finish because of the brittleness and the danger of it chipping or exploding!! that might help
ken
kenspens

 

[JimMc7]

I use R4 inserts in the Woodchuck and use what I think is a scraping cut (cutting edge ~ 90* to the blank surface). Same technique with a sharp curved edge skew and (knock wood) no problems with blowing up blanks. I've only done a couple of inlace acrylester and agree they are very brittle. No problems with the skew as a scraper to smooth but do experience chipping when initial rounding with a roughing gouge.

 

[Finatic]

I use an ultra sharp gouge to get them round and by all means, keep them cool. After round I use a scary sharp skew. I keep blowing them up when I use the carbides. I think I'm still too agressive with them.

 

[thewishman]

If your Woodchuck is getting hot, you may need to change the cutter, or at least rotate it to a new, sharp face.

Usually when I blow a blank up, it is my fault for improper glue coverage on the tube.

 

[Ted iin Michigan]

sgimbel - I'm new to the forums but have turned a few inlace blanks, albeit not with the carbide tool you're using. The bad thing about inlace is that it's brittle and soft. The good thing about inlace is that it's brittle and soft. I've found that when I get "close" it's time to switch to sandpaper - no matter how sharp my tool is - and, yes, yes, yes, the tool HAS to be sharp, even when roughing it out. Since the inlace is soft, I can remove quite a bit of material fairly quickly with an aggressive grit (say P80). Then on to finishing - or whatever.

Best,

 

[Lenny]

Always work from the ends to the middle ....especially when first rounding the blank .... working from the middle to the ends can leave it cut unsupported and result in Blow outs!
Not sure if that has any relevance in this case but something to consider.

I agree with Chris .... any blow outs I have had can pretty much be traced back to improper bond of glue or me being to aggressive with my cut! :redface:

 

[PenMan1]

IMHO, you should never use a Woodchuck, EZ tool or ANY carbide insert cutter to round over inlace.... Or any acrylic for that matter.

On really brittle materials such as IA, Bakelite, Tru-stone, alabaster, etc, I ALWAYS bring the blank round with "an 80 grit gouge (rough sand paper) before ever touching it with carbide.

Additionally, before cutting valuable blanks, I ALWAYS use a scrap of wood or acrylic to "ease" the edge of a new carbide insert tool.

One problem with turners coming over from HSS tools is that they are used to "pushing" the tool into the material. This is NOT RQUIRED with carbide, and in fact, causes many issues.

Respectfully submitted.

 

[tim self]

I hat to tell you this but it happens to the best of us. After a few hundred pens and telling someone last week I rarely blow up an acrylic, I blew up 2 tonight. Besides being brittle, be careful of the heat.

 

[JAZNCARR]

Every single thing i've bought from wood turningz has shattered or broken and I'll never turn acrylester Inlace ever again. I though it was because I was a new turner so 4 years later the blanks still shatter... switch tools and techniques. Nothing works for me.... There are other materials to turn and make nice stuff out of to stress over that garbage.. my hats off to the patient or lucky ones that actually get something turned out of the stuff ....

Not down playing the woodturningz Website one bit. Every time I order stuff shows up prompt and exact, inlace just doesn't like fat people or so I keep telling myself

 

[nava1uni]

I sat in on a workshop a few years ago at the Utah Woodturning Symposium and I learned that acrylic and inlace don't like many things. But that a verySharp scraper will do both with less difficulty. I now only use a scraper and I get long ribbons and very little blow ups or breakage. It is also how CSUSA instructs you to do acrylics.

 

[okiebugg]

Woodchuck

First I use a very sharp skew for roughing then go to the woodchuck and back to the skew when cutting the blank down to the surface of the bushings.

One thing I have learned about the Woodchuck is if you ever let the carbide get below the centerline of the blank, it doesn't take but one miscue to have a minor almost imperceptable catch and the blank will blow up. Keep the Woodchuck in a level position and never tilt it downward or it will create problems. I also use the rounded cutter bits so the corners of the carbide cannot catch as you are going acress the blank. FWIW