Gold solder flow issue

[purplepepper8]

Hello,

I’ve been trying to solder these small gold pieces onto a much larger gold plate and i haven’t had any success. I made the exact same thing in sterling silver without any issues.

I made my silver piece by heating the plate from the bottom, but when I do the same thing with the gold, the solder doesn’t flow. I have heated to the point where the plate melts/ warps but the solder still doesn’t flow (you can see the solder ball didnt melt but the piece warped in the photo). When I tried heating from above, the little piece gets heated much faster and the solder jumps onto that. I tried with both a small sharp flame and a big bushy flame, heating from both the bottom and the top, and first heating the top and then moving the flame below and also first heating the bottom and moving the flame to the top but haven’t had any success. I also tried making sure the whole piece is hot before focusing on the solder joint.

I suspect the issue to possibly be that both the small and big pieces aren’t being heated evenly (but that doesn’t explain how the plate melts before the solder flows (the solder is placed so that it’s touching both the plate and the small piece)). I didn’t have any issues with the separate elements heating evenly in the silver piece.

I am using 18KY gold, I tried 18KY easy and medium solder, and I coat the piece with fire coat and use flux on the joint.

Please let me know if you have any suggestions/ possible solves. Thank you

 

[Stock682]

Silver has the highest thermal conductivity, followed by copper then gold.

Try heating from a different direction

 

[medaniel]

It's a little tough to tell what's going on here from the photos. As a retired goldsmith, I think there are a couple things that could be causing the problem. When the solder balls up like this and won't flow, it could mean that you have used up your flux....too slow to heat? And/or your metal wasn't clean enough to start with...brighten it with abrasive, bristle wheels work well for this. Heat control and clean metal with proper flux is the key. 18k gold should solder much more easily than sterling! Also don't forget to brighten your solder. Hope this helps. Cheers!

 

[Mike Cirelli]

Try using silver solder instead of 18k, clean very well and flux twice. If you have to use gold solder use one that has a low melting point. Using a bushy flame and patients brushing the flame all over the piece. Also, try soldering it on a charcoal block.

 

[Chujybear]

Maybe that you are trying to solder gold as tho it were silver.. with gold you don’t have to worry as much about heating up the whole piece... you can focus on your joint much earlier than you would with silver.. that said, you still have to sneak up on it a bit...
I barely solder anymore, I will mostly weld using the same material as the base.. in this case some 18k prepared in the same way you would solder.... either way, solder or straight gold, i would bring the filler material to the joint just as it reaches flow temperature (your flux runs clear will be pretty close)

 

[purplepepper8]

Hey guys, thanks for all your messages. I went through them all and tried out some of the things until I found the solution- I was balling up the solder chip and then putting them on the joint (which is the way we were taught at school and the way ive always been doing it), but the solution was to just put the chip on there and melt it there itself once and for all.

 

[Sinterklaas]

For next time. You can also put the solder on the big sheet and heat from the top. On the solder. Then when the solder has flown on the big sheet. Then you place the small part and heat again. Or keep heating and add the small part. But then you need steady hands.

 

[purplepepper8]

Thank you, will keep this is mind

For next time. You can also put the solder on the big sheet and heat from the top. On the solder. Then when the solder has flown on the big sheet. Then you place the small part and heat again. Or keep heating and add the small part. But then you need steady hands.