Personal/Portable Hottub Class Project

Kelly Christine

That is why it's called a "Class project" you need to do the work yourself. But let me see if I can get you started.

Use 8 lbs for every gallon of water, your hot tub should hold about 200 to 300 gallons of water. One gallon is 231 cu.in.

Now go and work out how much weight your going to need and then come back and tell us what you got, also bring back the yield strengh of the fiberglass..

Good luck

What you want is a boat - just fill it with water and put the motor on the inside. (Watch your toes.) It comes with a trailer, so there's your portability.

I'm only being partly facetious. A friend actually did this, except he used a standard hot tub pump instead of the prop job. But he's a wimp.

I can't get my head round a portable hot-tub . Why would you want one ?

Anyway , the mould is going to have to be rigid . You'd better figure out how you'll break the tub free of the mold.

Thickness ; copying is a possible shortcut , look around for an existing fiberglass product that contains a similar load and measure the thickness used.

Do you know about handling the materials safely .

No idea what a 'bom' is.

Good luck

I don't know anything about fiberglass. I have been looking on the net on how fiberglass is manufactured and formed. We didn't know if tubs are made by injection molding like they do plastics. We were considering a weight of 800 lbs. that the tub needs to be able to hold. We just want to know the process of the producing of a fiberglass tub.

To make a mould I would sugggest that the mould be made to be the inside. that way you will lift the finished product off the mould. This is how we made the body for our v.w. dune buggy in the 70's. Make a big plug and finish the surface smooth, wax it and then spray or paint the fiberglass gell coat on with the color in the mix. cover this with fiberglass mesh or cloth soaked in resin and build out to the thickness you need. Put some two by fours on the top, to make feet and leveling and when it is cured turn the mould and product over and pull the plug out. You now have a tub.... A hole saw makes a nice way to install the plumbing and you are done. This process has been used for years to make many products including the nice little hutches that the airlines use to crush your luggage on a trip. Good luck on your future project. Oh yeah, bom is bill of materials.

Ric willrw1@fuse.net

Kris,

bom = Bill Of Material

Thanks Labguy .

bom is aka Bill of Quantities in Brit-speak

Most Hot Tubs are really an Acrylic sheet that is sucked down on a mold then sprayed with fiberglass on the bottom using wood or metal as reinforcement. The plumbing is really just a pump leading to the nozzles. A pleated spun bound polyester filter is used prior to the pump to strain out any particles. Usually new filter are the in the 20-30 micron range but improve as the trap particles making the holes smaller and smaller. Chemicals are important to keep the water clean of algae, bacteria and other microorganisms. There are some commercial portable hot tubs out there you may want to get some information on.

Thank you for the information. Do you put the wood or metal reinforcement in the mold?

You actually form the acrylic around the mold. Once that is formed you remove that from the mold and use the acrylic shell to spray the back side with fiberglass and to save on fiberglass you reinforce it with wood and/or metal. That usually will suport the curtain you build around the outside for looks.

You may want to check if fiberglass and rigid is a requirement. I would see cost saving and increased mobility if it could be supported with air like the blow up pools.

BOM for hot tub should include material for the Tub, the filtration system and the pump and nozzles. And of course if you are making for marketability the sterio, LED lights, TV, uderwater speakers, towel warmer etc. Best of luck on the project.