Converted coal to gas steam boiler leek.

Dr Sam

I have an old conveyed steam boiler with a leek in the jacket.
I want to use Hercules liquid sealer.
I added one quart but the leak is low and did not seal.

Can I run the boiler with extremely low water to try and seal the crack?

Should I clean the rust and slag scale off the boiler jacket prior to trying sealer again?

Should I clean epoxy and try sealer again?

Please help
Thanks Sam

ben's plumbing

don't want to bring down the party...but if this is and old conversion...Its really time for a new furnace.... repairing it may not hold for long..ben sr