How to stop solder sticking to brass thread

solder.

Tippex correction fluid works quite well - can even use it to stop silver solder spreading where you don't want it. The chalky deposit takes the heat quite well.

AWEM

Nasty one that.

You probably want to screw something in like a piece of dowel maybe wrapped in tissue, that will at least stop masses of solder getting in. Solder is soft, so the male fitting will cut its way through any small bits anyway, and the threads are not that tight on those things and need filling with PTFE tape as well...

Generous dollops of grease may help too.

Ah. Thats a tip to remember.

Is it possible to wrap a wet rag around thread? just enough time to do the joint.

cheers, Pete.

Clean and flux up properly and get everything hot. Apply the solder to the outside of the end feed joint as one would normally do but stop the moment the silver ring appears inside or better when the external silver ring completes. You need surprisingly little solder to make a sound joint, around 1/4" of the 1/8" gauge plumbers stuff. Any more just runs out where you don't want it or forms an ugly drop that you have to wipe off.

Carr's solder mask

Try

I would make up a ring of solder and put that on the pipe before the fitting. That, together with careful fluxing, would ensure that the solder went where you wanted it to and nowhere else.

Colin Bignell

and from experience it's probably the only solution so far suggested that actually works! Careful fluxing as suggested by some is in my experience a waste of time, flux runs/tracks everywhere when heated, soft solder paste fluxes especially.