Making a alcove tub removable before setting it in plaster of Paris. Plastic?

[ARC]

Hi. What's your best practice for making the tub removable before you lay it in mounds of plastic of Paris? I read plastic somewhere but not sure if there is a best technique/thickness, etc. Is there a way? I'm worried if you put some down it would squish out the plaster of Paris too much.

Also how many 25# bags of plaster of Paris do you tend to use?

Thanks

 

[Reach4]

Lumps of mortar in sandwich bags would be better than plaster of Paris.

Plaster of Paris hardens with drying, and water later will dissolve plaster of Paris.

Mortar hardens through a chemical. Try searching the forums here for

 

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[ARC]

@Reach4 I like the sandwich bag idea. Thanks.

I read an older post here where there seems to be some back and forth about mortar or PoP. My Jacuzzi brand alcove tub instructions say to use casting plaster or plaster of Paris. I guess since it doesn't shrink, but I think it tends to crack over time. Mortar is stronger but if it shrinks then what. Other people's instructions say specifically not to use PoP. I'm kind of surprised there isn't a specialty mix just for this to resolve the issues with both products.

 

[Chucky_ott]

Plaster of Paris may set faster than you like. I'd go with mortar as well. In a plastic bag or just a sheet of poly vapor barrier on top.

 

[Chucky_ott]

Plaster of Paris hardens with drying

Plaster of Paris, unlike pre-mixed drywall compound, sets via a chemical reaction. The more you have, the hotter it will get, and the faster it will set.