formula for hydrocal to cover plaster cloth

The hydrocal will setup up too quickly.  Plaster or Gypsolite will provide more sculpting time. The hydrocal is best for rock molds.

Finish the details with Sculptamold.

Scroll through Trainman's saga for some ideas.

But, if you must, I would start with a small batch at peanut butter consistency. A really small batch. Work fast.

Good luck!

In reality I think I asked the wrong question.   I am not going to sculpt the Hydrocal.  I just want to get a stable base to attach the rock castings without more plaster cloth.  I will do the actual finish work with Sculptamold.  I have two layers of plaster cloth but too many areas have a "give" to them that I want to make more rigid.  I think I think a slurry of the Hydrocal to brush over the cloth should give me the result I am looking for.  You are right my first attempt was too thick and set so quickly I was shocked.  That is the reason I asked about the mix.  Is there anything you can use a a retarder?

Thank you

Howie

You might find that a little more plaster cloth in wads and rolls may do what you want.  I applied a base to this model and then added more for detail.

orkybrown posted:

In reality I think I asked the wrong question.   I am not going to sculpt the Hydrocal.  I just want to get a stable base to attach the rock castings without more plaster cloth.  I will do the actual finish work with Sculptamold.  I have two layers of plaster cloth but too many areas have a "give" to them that I want to make more rigid.  I think I think a slurry of the Hydrocal to brush over the cloth should give me the result I am looking for.  You are right my first attempt was too thick and set so quickly I was shocked.  That is the reason I asked about the mix.  Is there anything you can use a a retarder?

Thank you

Howie

No retarder to my knowledge. What do you mean by "give"?  If it's firm enough to push against it should be ok as it is. it can flex in some.

Rocks by Dave Frary

If you wish to skim coat over the plaster cloth, you may want to try a, 90 minute set, drywall joint compound.  Pre-mixed joint compound tends to be a lot longer set time applied thicker than 1/8" 

according to c c crow(builders in scale) who manufactures plaster buildings add a little vinegar to the mix, to retard the plaster. too much will cause it not to harden. 

I just watched one of your videos and saw how much give you had when adding the rock castings.  That is about the same as I have so it looks like I don't have a problem

orkybrown posted:

I just watched one of your videos and saw how much give you had when adding the rock castings.  That is about the same as I have so it looks like I don't have a problem

There is some flex even when using cardboard strips or screen behind the plaster work. Just watch some more videos and and then decide if it flexes too much to work on or if you'll be ok. It's all trial and error, just learn as you go.

watch some of these tutorial's that Eric produced on building mouintains.  There's more on YouTube by many author's.

Thanks that is what I did.  I appreciate your responses.

Howard