How to build a stainless water tank and baffles

Hi G N

Make it so you fit the lid (top ) last that way you can passivate 90% of the inside.

What thickness material did you have in mind.
I would use 1.6 or 2mm.
Baffles every 250mm or so. Grade 316 would be the best.

When mounting the tank if you can mount it with straps with rubber under the straps.Don't weld brackets of the side S/S really dos'nt like vibration.

Scoof. :-)

Have folded ends, as it gives a lot better welding surface than butt welding.

Hi G N
The angled end on the baffles is more to stop the baffles from cracking the tank it allows them to move slightly and also the tank to flex.
We always bend the baffles with a 30mm return on both ends then weld the cut edge to the side of the tank this allows the tank to move without undue stress on the weld which is where the cracks start
Kev

Hi GN, I can send you a couple of pics of the one I made for my hilux to give you an idea. Send me your email adress and I will send some pics to you. Have also sent you a member email if you dont want to put your email adress on here for all to see you can reply via that. Regards Steve M

Hi Vic.
I built St/St tanks for my camper. I am a Tafe Boilermaker/Welding teacher. The 1st tank was welded by TIG, and was not passivated, had baffles, and had a bilge pump inside. Turned out to be too small, and the design would not let me flush it out when required. But otherwise was solid and strong and made from .8mm sheet. The second tank was made from the same thickness but was folded, riveted and with food grade silicon to seal it. Going great and is 5 yr old and has travelled over 4000kms on desert roads, and about 25000kms allup. St/St is much tougher than Mild steel so it does not have to be thick at all. Any more questions, send one.
Graeme.

Hi Vic.
My tank dimensions are approx 900 wide x 300 high x 400 front to back. 2 Baffles across width equally spread and 10mm gap top and bottom. Inlet at top part of front edge into a welded boss, and then a hose to the fixed pump inside. The pump is bolted to a welded base plate inside the bottom. I get about 5mm of water left in tank when empty, but with the outlet (for flushing) fitted as close to the bottom edge at rear on a boss. All welding done with TIG, and all baffles and tank parts riveted and siliconed. The tank is supported by straps ( 50mm wide with folded .8mm) and with rubber between tank and straps. Have placed folded 1.6mm Mild steel sheeting in front and underneath. The tank is supported rather than welded to.
Hope this helps, keep sending questions if needed.
Graeme

Hi Vic.
That is the 1.6mm sheet is for protection from rocks etc. It has never had problems, but whatever your design, as the other guys say, a little thicker is better. Depending on your skills, and innovation, you will design a bit and build on the run a bit. I finally chose to rivet mine as it did not distort from welding and I could dissassemble it for cleaning or repairs to the pump when that might arise.
Cheers Graeme.