Seawater => Drinking Water

[meyermm]

you certainly like talking to yourself

[TOPGALLANT32]

nothing short of a comercial built reverse osmosis (water maker) is going to satisfy your needs or palate either for that matter. the cheapest thing going is the pur 40 and will provide most of your needs unless you ahve a large and wasteful crew.
I have tried every thing out there even attempted to build my own once.
fyi there is no such thing as an inexpensive WM. ps dont buy a used one either

[Tellie]

Originally Posted by TOPGALLANT32

nothing short of a comercial built reverse osmosis (water maker) is going to satisfy your needs or palate either for that matter. the cheapest thing going is the pur 40 and will provide most of your needs unless you ahve a large and wasteful crew.
I have tried every thing out there even attempted to build my own once.
fyi there is no such thing as an inexpensive WM. ps dont buy a used one either

I agree and disagree. I agree that for the vast majority of cruisers a commercial unit is what they should be getting into. But there are those and many on this board that have shown the mechanical abilities to properly design, build, and maintain their own water maker. The major problem with watermakers is a simple one, lack of owner care and the willingness to learn the basic care of their watermaker. I've built two of my own and they more than satisfied my needs and palate. The first one gave me more than I could ever use 38gph. I learned quick that bigger is not always better. WMs need to be run often and I couldn't give away the extra water I made. I built a 12V unit on a SW2521 membrane. I didn't care for the amps used to make the water though it worked fine and the 5-6gph was more than meeting my personal needs, but I wanted a little more to make life aboard a little more comfortable because I am not always by myself while sailing. Add two women on board and my needs go up. I did a lot of research on WM, visited several WM companies and tried to learn as much as I could. I learned, like many things in life, if you shop price chances are you'll be disapointed in the long run. This is true about water makers for the vast majority of boaters. While bigger isn't always better a PUR 40 will leave most wanting more and questioning their purchase. Some sailors are the ancestors of the Spartans to be sure. My experiances in repairing water makers is that most are not. Go into any second hand shops like Sailorman and you'll always find a few used Purs for sale. Not because they didn't work but mostly because the PO upgraded to a unit that better met their water demands. While speaking of second hand water makers I agree, if you don't have a lot of experiance with water makers or a have a very good friend you trust selling you theirs, stay away from them. Most will cost you near the price of a new one to get them operational again and they will still be an old used one. Most are usually not worth more than the few spare parts one could slavage from them. My advice for the majority of boaters is a Water maker with a 40' membrane not two 21" membranes. One 21" membrane will cost you just as much as a 40" when it comes time to replace them So it doesn't make sense unless space is extremly critical. I've always found room for a 40" on even the smallest of boats. Watermakers are like vehicals, sure you can buy a moped, it'll get back and forth if that's all you want. You could buy an old Vega or Pinto and rebuild it but you'd still have an old Vega or Pinto, not too many would take them off your hands and you'd never get back the money you sunk into them. You could buy a nice new Corolla that will last. But if you want to travel from the east coast to the west coast and back a few times a new Caddy is what you'd be happier with and will do the job far more comfortably than the Johnny Cash "I built it one piece at a time" Station wagon.

[Captn_Black]

Originally Posted by meyermm

you certainly like talking to yourself

Well its just as well that thats who I'll be sailing with!!

Morning all btw!

[Captn_Black]

Tellie, I gotta agree with you on the second hand issue, I've seen the price of the membranes, and unless their selling them whole machine, in fairly good order for half price it wouldn't be worth it. Also, who knows when other parts may fail... At such high pressures and salinity things are bound to go wrong sooner rather than later.

[Badsanta]

Originally Posted by Tellie

, I've built two of my own and they more than satisfied my needs and palate. wagon.

So are you selling plans, kits or putting on a seminar?
Just going to tease me? Inquiring minds want to know! I have a pur 80 but am hesitant to buy new membranes. I would think a generic pressure vessel and membrane would be an easy fix. every one seems to think they are made by the same company. Any idea for sources? Thanks

[Martinini]

These Guys sell Membranes Seawater RO Membranes Elements for Seawater Desalination WaterAnywhere RO Seawater Membranes

[04 Marine]

Perhaps you addressed the wrong thread. Sounds like an oceangoing still may be more suitable than a watermaker.

[osirissail]

I was looking at R.O. machines for a new cruiser a week or so ago and almost had a heart attack. In the past 8 to 9 years the prices have increased by a factor of 4, on average. The R.O. machine I purchased in 2001 for US$2500 now sells for US$10K - exact same machine! Maybe it is the "demand vs supply" thing as here in the Caribbean all the newbies with Cats all have R.O. installed and many of the monohull folks are frantically installing them also. So building you own sounds like a very good idea. Just be warned, there are two very different systems - those for processing fresh (non-salt) water to remove contaminants and those for processing sea-water into fresh water. Pumps and membranes are totally different.

[lorenzo b]

dude if all you need is one or two gallons a day just carry it in containers if you go out for more than fifteen days your new $3000 toy is going to break down anyway

[seandepagnier]

Does anyone know where to get a pump?

Would it be possible to use the same pump for filling scuba tanks as well as RO?

[Pblais]

Would it be possible to use the same pump for filling scuba tanks as well as RO?

No. RO pumps require very high pressures to force the brine through the filter material. For air tanks you want a pump certified for the purpose plus all the other attachments to make it all work.

[osirissail]

Originally Posted by geckosenator

Does anyone know where to get a pump?

Would it be possible to use the same pump for filling scuba tanks as well as RO?

- - Pumps and equipment are available on-line. Some are even advertised at the top of this forum. You can get "modular" R.O. machines from established R.O. makers. These are "sort of" do-it-yourself models where they send you the pieces and you put the unit together yourself locating the components where they fit best in your boat.
- - Seawater to fresh R.O. high pressure pumps put out 800 psi of seawater and are made quite differently and of different materials than SCUBA compressors which only compress air. These are "oil-less" compressors capable of putting out 4000 psi. However, for a Hookah unit there are reasonable priced commercial oil-less compressors available since the psi requirement is a lot lower.

[Canibul]

maybe forget about reinventing the RO system and work on a good design for a rainmaker instead?

[seandepagnier]

What do you think about getting a RO membrane for $150, then getting a pressure washer off ebay for $50, and hooking it straight up? After you make 5-10 gallons of water, run the fresh water through the system for a few gallons to clear salt out of the pressure washer and reduce corrosion. I would only need to run the watermaker once a week or maybe less. Any problems with this system?