Gold wedding rings - solder won't flow!

[Emsa]

Hello everyone - I have just joined, and I am already really grateful for the amount of advice that is on here, it's amazing! I am hoping to get some specific help with my wedding rings please, that I am trying to make. I am struggling to solder an 18ct yellow gold ring - 5mm x 1mm D shaped (but inside out if that makes sense - I think it's called flat court?) I have tried twice, and both times the solder just won't flow. It either just sits there and doesn't melt (even though the rest of the ring is looking dangerously hot), or it kind of melts but only sticks to the part of the ring that I placed it on. I tested the flux and solder (brand new) by melting it by itself, and it melted straight away. I cleaned the ring using pickle (should I be using something else as well?) and I'm using a butane propane torch and an asbestos substitute block (could it be that it's not getting hot enough?)
I have made an identical silver ring before, and didn't have any of this trouble! It is my first time working with gold though, so I am almost certain I am making a rookie error. Any help much appreciated!

[Dennis]

That's a puzzle, because normally gold is slightly easier to solder than silver.

Some things to look out for:

Are the solder and gold thoroughly clean? (most likely cause)

Are you getting enough heat? Perhaps build a cave with bricks to act like a little kiln. Gold does look redder than silver when soldering (second most likely)

Does the join open when you heat it? In that case make sure the ring is annealed, heat from a point remote from the join first and if that fails consider keeping it closed with binding wire. Dennis.

[LydiaNiz]

As long as the join is flush and tight, you might need a tad more heat across the join itself. I found when first trying gold it needed more heat locally than universally compared to silver, do it in a dark room and go gently! Good luck!

[Emsa]

Thank you both so much for the advice! I have ordered some bricks to make the little kiln, and will keep checking the join after annealing. It is interesting you say you find it needed more heat locally compared to silver, I was concentrating on trying not to heat the solder rather than the ring, so maybe didn't focus on the join as much as I could have.
Have you got any tips for cleaning the ring please, after my unsuccessful solder attempts? It went completely black after torching it, and I am just wondering if the pickle isn't getting it clean enough (particularly in the join)...Thanks!

[Dennis]

It should quickly come bright in hottish safety pickle or alum solution. Then lots of rinsing before starting again.

If the pickle does not work, then
1. The pickle is exhausted and you need new, or
2. The metal is not gold. Dennis.