Stainless Steel Tanks
- Thread starter dimfer
- Start date
I have just finished looking at all of the picks you posted in the gallery of your tank building process. That is the tank that I would like to make ! and I have about a year to get er done before my fish will be big enough to go into it. There are some things that I did not see in the pics though. How was the stainless 316 sheet fastened to the stainless frame ? I only saw 1 small weld on the outside or was it welded on the inside? Also it looks like you used acrylic instead of glass or am I wrong ? How thick was it ? Any other usefull info that you could give woulld be great !
By the way that is a SWEET tank and the aero's look awsome !!!
By the way that is a SWEET tank and the aero's look awsome !!!
I built a steel and glass tank, it wasn't stainless though, but I wish it was. I used 12G cold rolled steel and painted it with Palgard Epoxy on the inside and Krylon spray paint on the outside. The dimensions are appr. 108"x 30"x 28".
I kept it in a greenhouse were outside temps in the summer hit about 90 & down to about -15 in the winter. Had lots of water besides this tank in the greenhouse, and an electric heater on a thermostat that kept it from freezing in there. The tank was in direct sun, and I'm sure it got over 100 in the greenhouse at times, but I opened the doors and windows on each end in the summer.
The top front frame was 2"x2"x1/8" angle, the front sides and bottom frame was 2"x 1/8" flat strap, as was the top sides and back. I put 3 evenly spaced 2" x 1/8" flat strap braces bolted front and back across the top. 12G sheet metal top sides and back. The sheet metal does not bow much in the back at all when full. The bottom is well supported on the stand.
I stick welded it with 3/32 7018 and it came out great. Tig would be better, but I didn't have the option at the time. I have a tig welder now, and would probably use it if I had it to do over again with stainless, but it wouldn't be necessary at all. If you just have a stick welder, buy some stainless rod, practice some and go for it. I staggered the welding to keep from concentrating the heat in one area at a time, and had no trouble with the metal warping from the heat.
Welds never leaked a drop. I cleaned the metal with first wire wheel then a liquid metal cleaner that was recommended by the paint store, then painted 3 or 4 coats of epoxy paint. Paint store recommended not to use a primer.
Laid the tank on it's front, used Dowl Corning 832 silicone to glue in the 1/2" Float glass. I used a support under the glass (in what would be the viewing area of the glass, not the bearing surface) all the way around so it wouldn't smash the silicone all out when i laid the glass in. When the silicone cured it was about 1/4" thick between the glass and the frame.
I never had any problem with the seal even with the difference in coefficient of expansion between the two materials, even with the wild temperature swings.
Now the bad news. After only a few months i started noticing blistering in the epoxy paint all over the place under water. The blisters were about 3/4" apart and across. I am still puzzled as to why it did this. The paint store was clueless too, and tried to put the blame on my prep of the metal. They did however give me some new cans of palgard epoxy.
I went through the process of removing the glass, stripping all the paint off, sand blasting the metal, then reapplying the paint. Lot of work that was, but I wound up with the same results a few months later.
The tank has sat for a long time (a few years) and the paint has fallen off the inside of the tank and it is pure rust. The Krylon paint still looks fine on the outside though.
I don't know what to think, except that I sure wish I had used stainless. I say go for it. You can always cover the outside with a nice wood so it looks like cabinetry if you are worried about the metal conducting electricity. I never worried about it, didn't have anything electrical in contact with the tank, although I guess the water could conduct electricity through the piping if there was a short. I would be sure to use a GFI breaker with anything connected too or close to the tank.
I want to re-do the tank, but have another project more important right now (gotta finish my house). I think I might look into stainless, or go with plywood/fiberglass/epoxy. Whichever is cheapest. I'm going to go 48" front to back this time though.
I kept it in a greenhouse were outside temps in the summer hit about 90 & down to about -15 in the winter. Had lots of water besides this tank in the greenhouse, and an electric heater on a thermostat that kept it from freezing in there. The tank was in direct sun, and I'm sure it got over 100 in the greenhouse at times, but I opened the doors and windows on each end in the summer.
The top front frame was 2"x2"x1/8" angle, the front sides and bottom frame was 2"x 1/8" flat strap, as was the top sides and back. I put 3 evenly spaced 2" x 1/8" flat strap braces bolted front and back across the top. 12G sheet metal top sides and back. The sheet metal does not bow much in the back at all when full. The bottom is well supported on the stand.
I stick welded it with 3/32 7018 and it came out great. Tig would be better, but I didn't have the option at the time. I have a tig welder now, and would probably use it if I had it to do over again with stainless, but it wouldn't be necessary at all. If you just have a stick welder, buy some stainless rod, practice some and go for it. I staggered the welding to keep from concentrating the heat in one area at a time, and had no trouble with the metal warping from the heat.
Welds never leaked a drop. I cleaned the metal with first wire wheel then a liquid metal cleaner that was recommended by the paint store, then painted 3 or 4 coats of epoxy paint. Paint store recommended not to use a primer.
Laid the tank on it's front, used Dowl Corning 832 silicone to glue in the 1/2" Float glass. I used a support under the glass (in what would be the viewing area of the glass, not the bearing surface) all the way around so it wouldn't smash the silicone all out when i laid the glass in. When the silicone cured it was about 1/4" thick between the glass and the frame.
I never had any problem with the seal even with the difference in coefficient of expansion between the two materials, even with the wild temperature swings.
Now the bad news. After only a few months i started noticing blistering in the epoxy paint all over the place under water. The blisters were about 3/4" apart and across. I am still puzzled as to why it did this. The paint store was clueless too, and tried to put the blame on my prep of the metal. They did however give me some new cans of palgard epoxy.
I went through the process of removing the glass, stripping all the paint off, sand blasting the metal, then reapplying the paint. Lot of work that was, but I wound up with the same results a few months later.
The tank has sat for a long time (a few years) and the paint has fallen off the inside of the tank and it is pure rust. The Krylon paint still looks fine on the outside though.
I don't know what to think, except that I sure wish I had used stainless. I say go for it. You can always cover the outside with a nice wood so it looks like cabinetry if you are worried about the metal conducting electricity. I never worried about it, didn't have anything electrical in contact with the tank, although I guess the water could conduct electricity through the piping if there was a short. I would be sure to use a GFI breaker with anything connected too or close to the tank.
I want to re-do the tank, but have another project more important right now (gotta finish my house). I think I might look into stainless, or go with plywood/fiberglass/epoxy. Whichever is cheapest. I'm going to go 48" front to back this time though.
I would like to make a comment about using a gasket to seal the glass in also. I have thought about that method quite a bit myself, because I too was concerned about the possibility of the silicone tearing loose because of difference in expansion/contraction rates of dissimilar materials. Especially when using Acrylic. (maybe I'm just being paranoid ?) I found it really expands/contracts with temperature change more than any other material I have worked with.
Well.... I haven't tried it yet, unless you might consider that the silicone actually may be working as a gasket in some cases. I have heard of more than one problem with sealing an acrylic window in with silicone though. Why the silicone wouldn't just work as a gasket even if it didn't stick to the Acrylic has got me puzzled. I have read of using a primer on the acrylic before applying the silicone so the silicone would adhere, but I'm still a bit nervous about a leak.
I remember reading in the 1st edition of Dynamic Aquaria (Adey/Loveland 1991) about using a gasket (a rubber hose if I remember right) with just the water pressure holding the glass in place.
They claimed it was water tight for a time, but eventually the pressure pushed the gasket out. They claimed they remedied it by siliconing the gasket in place. ( I have a copy of the 3rd edition and I noticed they left that part out)
I wouldn't think silicone would stick to the rubber hose, but I have thought of making a groove for the gasket to set in in the frame. Not deep enough for the gasket to completely smash flat into the groove, but enough to keep the gasket in place. A groove wouldn't be hard to build into a concrete tank, or a wood or metal face frame.
A wide flat rubber gasket might work better than a hose on a large tank because it would allow more surface area for sealing.
Using a gasket, especially with acrylic should allow movement from temperature change while keeping a seal from the pressure of the water. Why wouldn't a thick bead of silicone do the same thing?
Why don't one of you MFKers try it and let me know how it works, because I'm dreaming about building a decent sized concrete tank with an Acrylic window one of these days, and I have heard too many stories about problems with sealing acrylic with silicone.
I wish one of the builders of the huge commercial tanks would clue us in on how they fasten the acrylic windows in.
I heard recently that the aquarium At the Bass Pro in Tempe AZ was leaking. I hope they got it fixed.
Well.... I haven't tried it yet, unless you might consider that the silicone actually may be working as a gasket in some cases. I have heard of more than one problem with sealing an acrylic window in with silicone though. Why the silicone wouldn't just work as a gasket even if it didn't stick to the Acrylic has got me puzzled. I have read of using a primer on the acrylic before applying the silicone so the silicone would adhere, but I'm still a bit nervous about a leak.
I remember reading in the 1st edition of Dynamic Aquaria (Adey/Loveland 1991) about using a gasket (a rubber hose if I remember right) with just the water pressure holding the glass in place.
They claimed it was water tight for a time, but eventually the pressure pushed the gasket out. They claimed they remedied it by siliconing the gasket in place. ( I have a copy of the 3rd edition and I noticed they left that part out)
I wouldn't think silicone would stick to the rubber hose, but I have thought of making a groove for the gasket to set in in the frame. Not deep enough for the gasket to completely smash flat into the groove, but enough to keep the gasket in place. A groove wouldn't be hard to build into a concrete tank, or a wood or metal face frame.
A wide flat rubber gasket might work better than a hose on a large tank because it would allow more surface area for sealing.
Using a gasket, especially with acrylic should allow movement from temperature change while keeping a seal from the pressure of the water. Why wouldn't a thick bead of silicone do the same thing?
Why don't one of you MFKers try it and let me know how it works, because I'm dreaming about building a decent sized concrete tank with an Acrylic window one of these days, and I have heard too many stories about problems with sealing acrylic with silicone.
I wish one of the builders of the huge commercial tanks would clue us in on how they fasten the acrylic windows in.
I heard recently that the aquarium At the Bass Pro in Tempe AZ was leaking. I hope they got it fixed.
Silicone sealant will work fine with glass!!! Just rough up the steel at the point of adhesion and make sure it's clean! Silicone is EXTREMELY elastic! It will stretch WAY over 2 times it's size! I used black silicone when I rebuilt a 500 gallon, 100 year old, bronze tank for a friend of mine and no leaks!!!
If it were me i would think about using very thick acrylic for the veiwng windows front and back. That way you could drill thru the stainless and plastic and bolt them together with a gasket in between and then the veiwing windows would be part of the tanks structure and would make it stronger. i beleive it will work with alot of framing on the tank and many top braces. The main thing i can think of would be the sides bowing and that would cause the seal to fail rapidly. If you stop it from bowing any then the seals should be fine for ever. -----------------------------------------------------------------------------What thickness stainless are you contemplating. i personally would do 3/16-1/4. i think with the smaller gauges if your frames beams were more then about 18'' apart anywhere that the metal would bow there.
I am really leaaning in the stainless tank direction. I think if I used 1/4" 316 stainless the govt. would have to bail me out too. LOL I would like more info on sealing the acrylc to the stainless though. I would think after the the first filling of the tank expansion problems would be nil, the heaters should keep the tank at a fairly constant temp.
