Coating for Carbon steel or Aluminium tank?

[FisHaRNekEd]

I've been welding for a little while now and am planning a large tank build. maybe 36" tall 6-8ft wide and 18-24" front to back. Probably a 6-8ft by 36" sheet of 3/4in glass up front

I have not seen this done. It would be similar to the concept of a plywood tank. I've used various primers, paints and chemicals to coat steel and aluminum, but I'm overthinking what would be the safest and most permanent for the inside of the tank.
As far as i know right now, a coat of self etching primer followed by a layer of epoxy is the direction I'm looking. What do y'all think?
Again, i can't find any builds like this, on here or even google.
Would silicone effectively seal the glass to the epoxy layer? There would be several inches thick of metal frame on all edges of the glass. I really don't want to deal with drilling the glass and have to seal nuts/bolts.
Also, raw stainless steel is not really an option, due to price (unless the coatings for carbon steel are more than $300)

 

[FisHaRNekEd]

Somewhat similar to this, for example. This is plywood

 

[fishhead0103666]

I’m not sure if this will help but this thread is about a metal tank.

Norwegian 530 gallon stainless steel

Hello, I've got my 240 gallon up and running a couple of months ago. The guy I bought the asian Arowana from, had a 530 gallon stainless steel tank (And fish to go in that tank) The dimensions are 98x40x31.5 I havent seen many stainless steel tanks, and im open for suggestions on how to...

www.monsterfishkeepers.com

 

[Hendre]

Would caution with carbon steel for obvious rust reasons, most people use some sort of epoxy or fibreglass to seal the insides of their tanks. Regardless, looking forward to this.

 

[jjohnwm]

I would suggest contacting the manufacturer of any epoxy you may be considering to get their suggestions on its suitability for use on steel. They will have a recommended procedure for surface preparation, primers, etc. Follow it! A lot of plywood tanks fail...immediately or eventually...as a result of a simply inability or unwillingness to follow instructions. Don't carry this stubborn attitude over into the relatively new area of steel tanks.

PPPPPPP...which is short for Proper Prior Preparation Prevents Piss Poor Performance.

Using three different brands of epoxy over the years, I have had excellent silicone adhesion with all of them in plywood tanks. Glass up to 2 x 8 feet and 1/2-inch thick has been adhered and sealed strictly with silicone, no other supports necessary. A couple of these tanks are now owned by friends or friend of friends and are well into their second trouble- and leak-free decade of use.

I have read varying opinions on this method; some folks have no luck with it. I can't say why, but can only refer back to my first paragraph above.

Edited to add: I recall that back when silicone-sealed glass tanks first became common, there was a short period of time before all-glass construction was used, when tanks were made with the same type of steel frame as previously but with silicone used in place of the original black tar-like glazing compound. Those tanks seemed to work just fine, with the silicone adhered directly to the metal. I'd love to find one today, I'd buy it in a heartbeat.

 

[fishdance]

I went through the same exercise with a 2m deep tank. Aluminum was not structurally strong enough for my needs and I used steel with a Dulux 2 part protective coating suitable for commercial applications (oil, acids, aggressive liquids etc). Do need a 2 part epoxy, surface must be properly prepared. I was very impressed and have no issues with silicon adhesion (I used DOW 795 neutral cure).

Because this was an unknown to me at the time, I added magnesium sacrificial anode to protect the steel from rust if the coating failed.

There are several brands that produce protective coatings. What you seek is fairly common (just not used for aquarium) Shouldn't have any issues.

Also several hybrid silicon adhesives being produced now if you are concerned with adhesion.

Technology has enabled big tanks to become commonplace. Good news for everyone here.

 

[FisHaRNekEd]

Thanks everyone.
Can anyone name a brand of epoxy that they trust and recommend???

 

[fishdance]

I have a glass panel and used Dulux STE - https://www.dulux.com.au/specifier/products/775 but just look at the technical spec sheet to compare as there are more and more choices.

Don't use a protective coat that has zinc in the mix even though zinc (galvanized) reduces rust.

Similarly look at the silicon technical specification sheet.
I used DOW 795 (black) as I wanted flexibility (50% modulus) and to span 25mm gaps besides adhesion (tear strength). You would use less flexible (25% modulus) most likely.