Stand up rads

yoop

   I have a customer that had all their stand up radiators break. The two that didn't break had most of the sections open up. I found a bunch of old ones that the owner had removed but he removed the bolts and took them out in halves. In order for these to match up I had to remove some of the sections and am ready to pull them together and air test them. Hopefully most will not leak. The question is; should I pull all the nipples from the exposed sections and clean them up as good as possible or just coat them with a lithium grease, pull them together and see what happens with the air test. Someone suggested using liquid lead on the nipples. Anyone ever tried that? What do you suppose the odds of many not leaking are?  Any other tricks to try before pulling them together?