Extruding Polyresin?

Signed-In Members Don't See This Ad
C

crokett

Member
Joined
Dec 4, 2012
Messages
610
Location
Mebane, North Carolina
Looking at some blanks at Woodturningz.com and the only way I can see they are done is extrusion. Since I am a bit crazy, was thinking of a way to do the same extrusion in my shop. there would have to be a way to keep the colors separate during the extrusion. Anybody ever done this, or attempted to?
 
Signed-In Members Don't See This Ad
no more something like this. doesn't have to be that complicated.

PBPOLY03_5.jpg
 
pretty sure its not traditional plastic extrusion.
you would need a separate extruder for every color and a die that has some 20 layers.
I guess you can just pour layers of resin as they dry into a mold, that's not how these round blanks where made but should give the same effect.
 
crokett said:
Looking at some blanks at Woodturningz.com and the only way I can see they are done is extrusion. Since I am a bit crazy, was thinking of a way to do the same extrusion in my shop. there would have to be a way to keep the colors separate during the extrusion. Anybody ever done this, or attempted to?
Click to expand...

I had a lot of fun trying PR extrusion with two colors and layering with multiple colors. I got some interesting casts, but nothing like what I intended. Here's what I remember.

1) You have a very short time window to get the resin extruded. Too soon and the colors mix (or the heavier color settles faster than the light color (based on colorant)). Too late (after it gels) and you need a honkin powerful extruder. More powerful than my little hand powered mish mash (based on a pastry gun).

2) It makes a mess out of whatever you use for the extruder. The first time I tried cleaning up with alcohol (what I normally use) and that was only moderately successful in getting the resin out of everythingl. The second time I upped the ante and used acetone which resulted in a melted extruder (it was plastic). The second attempt was my last attempt at extrusion.

3) I tried many color layering and discovered that PR shrinkage will cause a many layered cast (1" thick, maybe 30 layers) to bow significantly during the casting process. It was an interesting effect, but not what I was going for. A thinner cast (~ 0.25" with maybe 10 layers) can be folded a couple of times if you catch it at the right point in the cure which gives a really neat effect similar to the layered picture above. It's a sticky mess when it can still be folded and folding without entrapping air was beyond my abilities.

So that's my story. Give it a try. Maybe you'll figure out a better way than me.

Ed
 
Typically something like that requires a separate extruder for each color and they come together in a die. Though not easy, might be easier to glue up ribbons or compression weld them.
 
You must log in or register to reply here.
Back
Top Bottom