Replacing shields on phone boards?

[FireHazard]

I've managed to "repair" a water damaged mobile phone (corrosion removal mostly), but I had to remove a number of metal shields on the main board. These shields were soldered on, I removed them by heating a pulling them off with tweezers.

None of the resources I've found cover how to replace these shields...is it just a matter of putting them back in place, heating them and hoping for the best?.....

[coppercone2]

if they have a flange you can trim the flange very slightly to expose some pad so you can see the solder bead. Might be tricky with a phone or impossible, then you are left with intuition only.

[FireHazard]

Yeah....it's all so small...my biggest concern is shorting things under the shield ... since it's a fixed phone now...restored from failure, if it doesn't work correctly without the shields then still I'm in no worse state and have gained some new information.

[coppercone2]

you can stick up some flux to make it tacky, line the bottom of the shield, then get a very thin solder strand and line the bottom, then press and heat, like making a sandwich. You can meter it very carefully this way.

I think they have solder down to 0.2 mm or whatever, so you can pick which one you think has the correct coverage.

tinning it to make absolutely sure there is no squeeze out might actually be harder because its hard to tell how much solder there is, but if you clean the flange with braid so its solder free, then line it with solder, you can control it better, maybe. 

Or you MAYBE can get solder preform sheet, that is very thin, and cut a 'gasket' out of 4 pieces to line the bottom of the shield. Or run solder through a roller lol