Cutting brittle resin.

[GARD9]

Hello All,
I am starting a rework project on a bust (actually a 3/4 figure) that is made from a very
brittle resin. I have heard it called "Cold cast porcelain" and/or "Polystone".
It is a Bonapartes kit (Shawnee) I got some years back. I am trying to cut it into a more standard proportion bust.
It breaks into shards like glass when I try to work it.

1st question..... Can anyone suggest a method for cutting/working this resin?

2nd question..... What is a standard (classical) proportion for a bust?

Any help would be appreciated.
Thanks,
G9

 

[Blind Pew]

The only thing I can think of is to heat up the resin before cutting it. Hope this helps...........

 

[jasonballamy]

DON'T heat it, the cold cast resin will not act in the same way that the usual PU resins do, it may well just shear.

If you have access to a bandsaw that will make easy work of it. If you have to do it by hand then a junior hacksaw will be better than a razor or piecing saw. Once chopped to size refine the shape with burrs and samding discs in a dremel.

The Cold cast resin uses marble dust as a filler that is why it is much harder.

A clasic bust is usually cut just below the chest mussel approx just under the nipple and the arms cut at about 45 degrees from the armpit.

It seems a shame to chop this one up as it paints up into a nice figure, here's mine.

http://photobucket.com/albums/v156/jasonba...nt=PICT0001.jpg

Jason

 

[Mongo Mel]

Hi John,
I've worked on a couple of Bonapartes busts now and I also found it to be very brittle. If you're set on cutting this one down, have you thought of grinding it with a Dremel tool? It would take a long time and would creat a ton of dust but i think it would work for your idea. When I use mine to remove a resin casting plug, I have a few tricks that help me. First, I use the sanding drum rather than a steel cutting burr. The second is I do it right over the end of my shop vac hose. If you position it so that the sanding drum grinds it in the direction of the hose, most of the dust will get sucked into the shop vac.
I hope this helps.
Good luck,
Craig

 

[Guy]

I myself would'nt cut it.......then it becomes like any onther bust. Being the way it is makes it unique to anyones collection

 

[GARD9]

Thanks All,
I am still pondering this idea. I haven't done any chopping yet.
You all have given me some good advice.
I think I have heard "No, Not This One!" enough to think some more before I cut.
It is obvious that most of you like this kit a lot more than I do. When I first saw a picture of it, I was really taken in by it. When I got it and opened the box to see it, I was less excited. When I started to work on it, I was discouraged. It has been in the
"To Do" box ever since.
I may not chop it down at all. If I do, I think high speed rotary tool is the answer.
If I don't chop it, I'll take it to a swap meet.
I think this proves a point made in another topic here this morning. It helps to see the kit and hear from others who have built it before you buy.
I'm thankful for your help and sage advice.
BTW, nice job on yours Jason.
G9

 

[Blind Pew]

Oops!

Always said I wsa a painter as opposed to an engineer!

 

[jasonballamy]

I found out the hard way, trying to adjust the legs on a cold cast horse, snapped into 3 bits

Jason

 

[Blind Pew]

Jason, don't talk me mate! I know all about this one.
I've only just in the last couple of weeks had to ditch a project involving a resin horse for the exact same reason! I was gutted as I was really looking forwards to that project as well.
I had both the physical properties of the resin to cope with, along with ALL the legs being VERY thin. I will have another go when I feel up to sculpting horses legs in milliput around steel rods. Wish me luck, I'll need it.........

For therapy purposes I'm doing a couple of Metal Models figures. Can't go too far wrong with them!