Swimming pool????

Is galvanic corrosion an issue between mild steel and stainless? I any case a cushion is good between the two structures (If they are to be independant) I had imagined the initial strength in the panels would be achieved by folded 90 deg returns similar to a watertower build (smaller panels, more 'ribs')

 

Word of caution on the welding, MIG on stainless seems to produce a huge amount of UV, welding in a polished tank is going to cook you like a turkey! Even through heavy clothes I was getting sunburn working small areas of 316. I'm sorry for the loss of your father, my father built stainless tanks for petrochem and he still has scars from the sunburn 30 years on.

 

Hey Peedee, what are you doing for 6 months next year? How about all the bbq you can eat and beer you can drink? Ya got me thinking about folded 90degree returns, but not in your application. I wonder if the wall to bottom transition would be better served if it had a 90 degree bend at the bottom? Then the weld could be on the floor rather than the corner. hmm.. something to think about. This stuff is pretty heavy to haul around and the less I have to screw with someone bending pieces so I can assemble, the better. Andy has a good idea above for rounded cove like pieces in the bottom corners. That's another great idea too. Rounded bottom would be less likely to trap crap and allow the cleaner to do it's job better.

Peedee, do you mind explaining this water tower method a little more? I think you are suggesting a hollow 3 sided box section say 3ft long made of stainless and welded directly to the walls for support?? Here is a few photos that might be keep me from waving my arms like an idiot. This method could eliminate the need for a mild steel ladder cage under it. I'm liking that sir! If it's something simple as in the first picture, that's a breeze. Dump the metal off at a shop and I'll pick it up next week. BONUS! I have ZERO desire to bend even one single piece of this shit. I don't even like drilling SS, but I can get over that one.

Now, I literally have a 8 calls out to various pool and SS pool manufactures at the moment. Getting these clowns to return phone calls is friggen nutz! I want a live human on the phone to pick some brains. One company I did find spec'd floors out of 7ga and walls from 10ga!!!! Now you guys see where I come up with 11ga all around. 1/8" is going to be a breeze to weld for an amateur welding such as myself.... (By it not being deep, also cuts down on beefing this thing up too) Ya see, I have these awful visions of blowing through thin stuff. I know I'm going to spend my winter this year learning how to weld SS. The wife told me to order the new mig machine, but I believe HTP runs sales right around thanksgiving and fathers day every year. Waiting a few months wont bother me to save 4-500.

 

Thanks for the heads up. So it's sunscreen city for me or I wear my chrome zuit suit I pour metal in! Got it! Yeah it sucks losing your dad when he becomes your best friend in life. Just glad we had the times and relationship we did. Not all are that fortunate as many fathers don't reach the "dad" level.

 

http://lepsod-shop.com/en/home/80-s...basins_with_skimmer-shell_with_skimmer_3x9x13

DAMN, why cant these guys ship to the states! That's a DEAL. Must be using slave labor.
Look at the thickness in the specs. 2.5mm for walls and 2mm for the reinforcements.
Floor is 1.5mm. WOW! Seems thin to me. Okay.. Maybe 12ga.

 

I think Peedee just saved me THOUSANDS.

 

I think 1/8" or thicker will be less prone to welding distortions and buckling than thinner sheet, even though it would have the strength. Not to mention someone kicking the sides while drunk at a party: I remember a party some girls I knew from high school threw, while their dad was out of town. They had an above ground pool of plastic lined thin gauge sheet: a drunk pick up a girl and tried to throw her into the pool but he missed and she hit the rim and folded the sheetmetal side over and collapsed the pool, emptying it.

 

Just bring some Polish ship workers over and keep them in beer......hmm that would work out more expensive in the long run.

 

True, they are some professional drinkers there. I'm cool with 1/8" for walls and floors. Last thing I want this thing to do is "oil can" on me. That's annoying! For the supports, I probably could go a little thinner on them. I'm interested in seeing what a shop is going to charge me for pounding out 50 of these U shaped channels.? Might be worth adding a plasma cutter and a break to the shop?? I'm not opposed to spending the money and sending stuff out, but if I can net some needed equipment in the process, I'm all in. You guys see that Dewalt tile saw in that last video? Yup, I skipped out on labor laying 18" travertine in a kitchen and net that saw. Large format tiles are a pain in the ass to set, this was my solution. These worked great!

 

Well forget the brake idea. Bending 1/8" in my garage is not going to happen. Not worth dumping that kind of money to bend these at home.

 

I was wondering whether you had ever priced an 8 ft brake.

Read their site, those guys do ship to the States (part of "all over the world).

Note they have 16 ga walls and 13 ga floor, and they say their pools are reinforced for one piece shipment. You don't have to ship assembled.

I also noticed they TIG all their welds. You can build a tent and weld all winter.

Have you ever kicked the middle of a 16 ga sheet? Oil canning won't be an issue once water is in it.

I like the idea of the hat sections for external reinforcement. If you plan right the flange on the hat can be the backing for long seam welds.

 

A scale model in the form of a spa bath would let you learn and make mistakes on a much cheaper scale too

 

You think those guys would ship a kit completely unassembled in a container to the states? I can hear them laughing at me now..

I'm guessing those reinforcements on the sides are probably the same that is under the floor on it. None of them I saw had a solid bead the full length either. Looks like they insulate the floor and sheet over it with super thin SS. Pretty straight forward so far.

Let's see what happens in a few months when I try my hand at mig on this. If I can keep from warping the hell out of it, I'll look at going thinner. That propulse machine is pretty much the best on the market right now. Check out some stuff on you tube. Search HTP propulse200. I think you'll be amazed. It's not like any mig I've seen before. Ya gotta hear what it sounds like. Some real voodoo going on here.

 

Fell down the YT rat hole tonight and learned a little about the passivation tool market. Do you know there is probably 100 different companies all pitching their own over priced battery charger is better than the next guys? Typical prices start at 800bucks and the sky is the limit. Price depends on how many bs lights are attached to the space age looking plastic containing the evidence of chinesium parts. Average is a couple grand and don't forget to grab your ankles for their "special secret sauce" in a jug. AKA, nitric or citric acid. One clown was pitching what was obviously a water/soda media blaster. Sure that cleaned the weld, but is that truly passified?

Is the end goal really to just put a polish on the weld to bring the chromium back up to the surface to prevent poopy looking welds? My visible welds will be ground smooth up to a couple hundred grit so am I missing something?

 

Pulse arc has been around a long time for exactly this kind of stuff, it reduces the overall amount of heat you put into the weld. I've never used it but listened to a few stories about spending days inside a tank knowing it was going to be very heavily pressure tested at the end.

You seem to be finding some really good reference stuff there, why re-invent the wheel.

If I have actually saved you a few bucks put it to one side and buy me a couple of beers if I ever make it to Tx again, I drink a lot less than the eastern europeans!!!

 

Your welcome any time at my place Peedee! I like that almost no splatter is left behind with that machine.

Decent no bs article on passivating.
https://www.cartech.com/en/alloy-te...guides/how-to-passivate-stainless-steel-parts

 

You're only grinding back the bead not the surrounding metal, the problems we had extended about an inch either side of the welds. (So much so the customer questioned if we just sold him a bunch of mild!!) It never got fully resolved because the project got boxed and hidden when the city council realised they hadn't thought through fire access. It was a whole web of frames that clamped together through the entire cavern quarter area in Liverpool to create a 'Lucy in the sky with diamonds theme'

If I can get my dad to hear me well enough I'll tap his knowledge on this stuff, it's exactly what he was doing with the tanks and he understands the metalurgy and science a great deal more than I do.

Edit: Thanks, It may well happen one day (after the pool is full!)

 

If you use 316 SS I really don't think you need to consider passivation.

 

I don't know enough about stainless steel yet, but if it does need it... It's a no brainer, cheap, fast and does one hell of a good job cleaning up welds that aren't ground smooth and pretty.

 

Any time 316 gets welded there will be surface iron that needs removing as well as the protective oxide layer to repair, in other words passivation. It's especially important to resist chlorine induced corrosion, such as salt exposure or pool chlorine. Stainless steel fabricators will either have a tank they can immerse the fabricated item in, or use a variety of sprays, pastes and swabbing the item down to remove any surface iron. As recently as yesterday I was looking at a park bench built by an artist and noting that they didn't passivate the stainless properly and it went a uniform dark tea brown colour after a few years by the sea.

If you use commercial strength 68% nitric acid and mix a 20% solution in water, you'll end up with something that will pickle the stainless and also passivate it without any high current low voltage DC power supplies. After a few applications the iron will be removed and the remaining nickel and chrome will have surface passivation. Most stainless sheet should already be supplied in this condition which is why they only treat the welds, but if it gets bent, then it won't hurt to treat the bends too.

https://www.edelstahl-rostfrei.de/downloads/iser/PostFabricationSurfaceFinishing_EN.pdf