Pinholes in HLT. Epoxy?

[INC 82]

I have an American made 20bbl HLT. It had a weld malfunction (they say it’s due to hard water) and recently just had a guy come out and weld a new plate in it to fix the leaking areas. Now I see that it is leaking again. Instead of re-welding all the tank seams is there any sort of epoxy that I can use for the weld seams to keep it from leaking? Something high temp that can also withstand an acid wash. Or am I screwed and just need to suck up ordering a new HLT? Thanks

[dick murton]

It won't be hard water as such that is causing the corrosion, but, I suggest, a combination of poor welding/passivation and chlorine left in the water or from chlorine ions from salts additions, typically calcium chloride.

I have seen epoxy resin coatings on FVs and CCTs, where there is little temperature variation, but not hot liquor tanks where there can be considerable localised changes as the tank empties and is refilled. I seem to remember that chlorine and epoxy resins especially in hot conditions are not good friends, the chlorine degrading the epoxy, and producing some unpleasant odours. If you can find a suitable resin that can cope with variable high temperatures, the whole tank interior would need to be treated to prevent water getting under the epoxy, which would then allow chlorine to concentrate causing even more rapid corrosion.

So, my suggestions, assuming my comments about chlorine are true.

Firstly you need to identify where the chlorine is coming from and eliminate it in the hot liquor - e.g. add suitable amounts of potassium metabisulphite whenever topping up to remove the chlorine added as a sterilant, don't add CaCl2 (or any other chlorides) to the hot liquor tank, but to the grist instead, along with any other salts additions.

Secondly, get the tank repaired, or replace with a fresh one.

For what it is worth, I have seen the top of a tank be virtually separated from the main body at the "fill to" level due to chlorine corrosion, and have seen FVs sanitised with hypochlorite (and not rinsed off or refilled immediately after sanitisation) with so many holes in the base that you could have had a decent shower from the pinhole leaks - so chlorine corrosion is serious.

[Rosie]

Sounds like you need to get it fixed properly, but will share that we've used JB Weld products before to fix my bad soldering on our glycol loop, the stuff is amazing. They do a high heat version, it is like an epoxy putty...every brewery should probably have some in their toolbox. Our brewery installer recommded it, said he fixed a crack in the crankcase of his moto x bike with it...

[Bigredwelder]

An epoxy type fix will be temporary at best. My recommendation is to have the tank repaired properly or invest in a new tank. Dick's suggestions are right on the mark if it is indeed chloride induced stress cracking/corrosion. There are, however a couple other options such as MIC ( Microbial Induced Corrosion) like we have here in the Phoenix valley. My suggestion would be to first get a water analysis done specifically lookin chloride levels and microbe content to determine the true cause. Both will have a different approach as far as repair.

[liammckenna]

Certain epoxies can solve your issue depending on the size/severity of it. Ensure to distinguish between food grade and food safe epoxies. Different things. You will need food safe. Ask Dr. Google. There are a few available.

Best of luck,

Pax.

Liam