Too much hardener?

[jimskio]

I have cast just a few snake skins at this point and seem to have this problem. The pr I am using calls for 5 drops of hardener per ounce. I am doing 3 drops. When the blank starts to set up the outer edges cure faster and the center part drops as if someone took some of the resin out. Any help will be greatly appreciated.

jimskio

 

[KenV]

PR shrinks as it cures -- need to allow enough extra to allow for shrinkage. Alumilite avoids that problem.

If there is too little PR on top -- you can recast over the top.

 

[sbell111]

Another option is to simply use a mold that is large enough to account for any 'shrinkage'.