Casting Chipping

[Rippa]

OK you casting Guru's I need some help, I am pouring resin into a groove around the edge of a platter but when I machine it it wont cut clean it takes chips out:C it seem too brittle. The mix is 60 mls resin 19 drops of catalyst.(as per the info sheet) Do I need to reduce the amount of catalyst so it dosn't cure so brittle.
Thanks for any help :U
Rippa

[Les in Red Deer]

That sound like a lot of accelerator for 2 Ounces (60mls) of PR.
With the brand of PR I use they recommend 5 drops per 1 Oz. (15mls).
I use only 3 drops/Oz. to avoid the Pr from becoming too brittle.

Les

[dai sensei]

Resin is naturally brittle and I have found the amount of catalyst makes little difference in bowl filling circumstances. The most important thing is to sand down the sharp edges before returning to turning with chisels, or you will catch and tear it out. I use a dremmel with a little drum sander attachment. Also ensure your chisels are razer sharp, due to the difference in hardness between timber and resin, even slightly blunt chisels will also tend to chip the resin.

[gawdelpus]

That sound like a lot of accelerator for 2 Ounces (60mls) of PR.
With the brand of PR I use they recommend 5 drops per 1 Oz. (15mls).
I use only 3 drops/Oz. to avoid the Pr from becoming too brittle.

Les
Hmmm! is 5 drops per 15 mill different to 20 drops per 60 mills lol. Some of these things have other dependancies though, temp, thickness etc. my first clear casts took 2 days to harden as I put too little activator in the mix .:~ cheers ~ John

[Rippa]

Thanks for the comments gents the insert is only 4mm thick and 25mm wide around the edge of the bowl. So might use less catalyst next time as I am not in a hurry for it to cure.:U

Cheers Rippa