Not a great first time DIY project for someone who have never worked with fiberglass before. I'd be giving this one to my local fiberglass fabracation company that do that type stuff every day and have the equipment and materials to do it right.
They would built a mold shaped like that picture and spray it with mold reliece do a lay over with fiberglass cloth, then spray it with chopped fiber glass.
Might want to do some research on fiberglass boat building, and check out the West System web site.

 

Buy a hot tub....:thumbsup:

 

I got the beer and the honeys !! :drink:

 

I have done some unusual things like this with PVC roofing material. It works very well for this. You could build the form out of block or properly framed plywood, and fully adhere membrane to it, then heat weld it. You would need to heat weld skid resistant walk-pads on the steps, and I would add a handrail, otherwise someone could slip and hit their head, and you might end up having to perform two sacraments closer together than you anticipated.

 

We must have some boat builders here----

I could build that out of plywood using Hydroban to waterproof it

However tile would be needed to protect the Hydroban---

 

Well while the hot tube, beer and honeys does sound great, it might not be a suitable combination.

I will look into finding someone who does this type of work in SoFl, and there is alot of good information on the west system page. I wonder what sort of structural system would be needed to support a tub filled with water, or would the fibreglass be strong enough to be filled with water?

 

Al kidding aside this would be made very easily may cost a few bucks it can be done in a one pour concrete and re barb, then sealed and then marble-lite skim or tiled would need a pump and maybe a filter systems or drain water every time it gets used. maybe a heater?

 

Any boat builder or fiberglass pool maker could build one of those---ply wood will be needed for the substructure---

depending on where this is placed---a concrete one would also work---

Price and style are the big question----and load capacity of the floor it will sit on.

 

Concrete would be nice if it was a permanent structure, but this one is more mobile. A geat inground one would be something like this

but this one has to be mobile since it is not a permanent feature, I think a concrete one would be a bit of a pain to move around.

 

At our church it is all fiberglass with reinforced members embedded in the fiberglass, and a wooden frame. That one in your sketch could be made out of plywood then covered with fiberglass. The plywood would have to have webbing running vertical and horizontal to hold up well. If you need it to be portable you could put it on locking castors but they would have to be some heavy duty castors to hold that much weight.

Hopefully you don't plan to move it with water in it or you will really have some reinforcing to do. You do know you can buy them already made don't you? You might get the folks who do that kind of work to build it for you.

 

We actually use a portable unit, that has a fiberglass tub inside the Oak outer skin. One of our larger churches, actually built an in ground pool, that they use for baptisms, when they did a recent remodel a couple of years ago. Have you tried contacting Suburban Church Supply? Here is their website http://www.suburbanchurchsupply.com/html/baptistries.html

This is what our church's looks like https://sphotos-b.xx.fbcdn.net/hphotos-ash3/537859_10151732039741040_235189359_n.jpg When we need to move it, we empty with a hose, then slide furniture dollies under the ends, and roll it away. The heater is a 240vac tank heater.

 

What about one of those galvanized metal tubs, they come in all sizes and would be very practical.