Mabel, You need to give more info. Is that straight POP ? Did you use any reinforcement like cheessecloth to help hold the POP in palce? Whay kind of ball is that? If I were covering a sphere with POP I would wrap the sphere in a netting of some kind to allow the POP to stick to. It may help to do only half of the ball at a time. I hope others can give more advice. MSW

Thanks for the reply. I was trying to cover the ball with gauze bandage, and when that didn't work well, strips of old cotton sheets.

My plan was then to coat the POP with tufa, thinking the POP would set-up quickly and that the tufa would slump too much without the POP to cling to. It seems I read somewhere on this list of someone who used this method in the past...

I will try again with large pieces of cheesecloth. Thanks!

Mabel

Mabel, I think you can also soak your gauze in a slurry of portland instead of POP if I remember correctly. You can make some cool stuff that way. Looks like you got something going on there....just keep it going and I bet it will be fine.
Jo

Well, now I feel silly! I thought you were making a reuseable mold. Should have asked before I launched into that explanation on the other page. Sorry. Are you having any more luck now that it has dried some?
Regards,
spiderwoman

just found this forum. it REALLY looks interesting. i looked here and did a search but can't find POP. can you please tell me what it is? thanks sandy

Sandy, Plaster of Paris.