Sealing water tanks

I'm trying to build a water tender tank and I'm having problems getting it water tight by just using soft solder. Is there a sealant I could use to do the job I understand that some people have used petrol tank sealant can any one point me in the direction of a supplier.

Cheers

Stew

"POR 15" gets mentioned quite a bit on the traction engine forum but not tried it myself, it's meant for fuel tanks. Link

Edited By JasonB on 23/01/2019 08:10:37

Greetings,

I have used marine grade epoxy with great success, but the tank needs to be clean, I use a rotary wire brush.

I have used it on 71/4 gauge ride on tenders, with no problems.

Marine epoxy is a bit more runny than araldite, but needs 20 to 25 degrees to set properly.

It can be stiffened with various additives, if you need a paste, and from your local yacht chandlers you should be able to get the "West system", which is the most well known supplier.

It will seal over the solder, and during its working life remains a little flexible.

Regards

Brian

I had the same problem and research pointed to fuel tank sealant kit. I bought it but have not yet done the job.

I have used Por 15 on all my engines as Jason posted it works well it’s been used from 2 in scale to 4 1/2 highly recommend

Bitumen based, paint-on sealant is available from hardware stores. It remains slightly flexible and is a traditional way of sealing water tanks and shower floors. (not for drinking water).

A lot will depend on what access Stew has to his tender, if just a small hole it will be hard to brush anything on, with the POR and epoxy you just pour some in swill it about and then drain the waste.

Thanks for you help full replies chaps, I've left the top of the tank off so that I can get at the inside getting the top sealed is less important than the bottom

Stew

The tanks on most original engines have a removable cover on the side of the tender which allows access for inspection. The cover should be removed to allow the tank to be completely dried when storing the engine to prevent rust.

I am building a tender for my model engine at the moment and have also added a removable cover on the top panel (under the coal bunker) for just this reason, so I can coat the inside with sealant.

Paul.