Topic: naval jelly and POR-15

[gmonkey]

I've got a rusty tank with lots of pinholes that I'm soldering up and coating with POR-15.  I want to dump some naval jelly in the tank to eat up the rust so that it makes the holes more apparent so I know where to solder and so I'm soldering cleaner metal.  Plan is to thin it with hot water a bit, dump in, swirl around let sit, drain into container (to use later, probably) then rinse out with water, toss in some dry ice to displace any fumes, solder, clean up, and do the POR-15 kit.  I realize the kit comes with rust dissolver and it's redundant but it seems warranted.

Naval jelly being phosphoric acid supposedly etches the metal and leaves a bit of a coating.  Is this going to interfere with the cleaner and etcher that come with the POR-15 kit?  I could try electrolysis but the naval jelly seems more straight forward since it's a jell and there's holes in the tank so I wouldn't have to stick the whole tank into a tub of the electrolysis solution.

I'd appreciate any input.

[Gordon]

I don't think the Naval jelly is necessary if you're already buying the Por-15 kit.  The "Metal-Ready" that comes with the kit is phosphoric acid, IIRC, and it works very well at removing the rust. 

[gmonkey]

I don't want put a soldering step in the middle of the POR-15 kit procedure.  Plus by the time I get to use POR-15's liquid etchant, the holes should be closed up and it won't all leak out.  I'll make sure metal-ready is phosphoric acid since if it is then naval jelly shouldn't be a problem.