Hi there. I'm new to all this forum stuff but I suppose it's the best place to get advice. Having modelled in plastic for years, I thought I would give brass a go as its something I've always wanted to try but I've never soldered anything more than electrical wire. I have a OO tank engine kit. I soldered the valances and buffer beams to the running board/footplate no problem. Confidence up, I built the coal bunker. No problem. Then I couldn't fix the bunker to the footplate. I read every article I could, watched tuition videos, nothing helped. I took the bunker apart to try and fix the parts on individually thinking it could be a heat sync problem. It didn't really help. I've managed to cold solder it on, but it looks awful and nothing like the seams on the valances. I'm now having the same problem with the water tanks and I'm going insane. Here are the things I've tried:
Using a different solder (i used electrical solder with a flux core and low lead plumbing solder),
Cleaning the parts until I can see my reflection in them,
Using flux, not using flux (its plumbing flux and worked really well before)
Heating all parts in question with a blow torch
Filing the point of my iron in an effort to get it right into the joint
Tinning all parts that are due to contact each other, holding them in place and heating the general area both with and without flux (I think somebody referred to it as "contact soldering")
The annoying thing is is that when I tin the parts, it works fine. I get a beautiful flowing solder and a lovely clean silvery area. I just can't get the two parts to bind. Any advice is gratefully received.