I just duplicated your situation.......
If you didn’t use 710/787F. (1310/1450C) white gold solder sweated
to 18K palladium white gold and then soldered to a base of palladium
white gold, you didn’t duplicate the situation…:-)…Any other
materials are not problematic!
it is possible that your tiny discs (2-3mm x.35mm is not weighty
at all) are 'floating' on top of the liquid borax..... and not
actually touching the main piece. Try pressing lightly with a
clean poker.
Pressed hard with a clean poker during heating. Didn’t help because
the sweated solder did not even melt at all, let alone liquify.
hope this doesn't come as a disillusionment but its not advisable
to rely on heating the solder directly. Heat should pass from
piece to solder. If the parent metal isn't at the flow point of the
solder, the solder just won't flow no matter how hot you make the
solder.......
I ALWAYS melt the solder by heating the pieces to be joined to the
melting point of the solder. I NEVER heat the solder
directly—that’s why I don’t pick solder…:-)…
If its glowing red its TOO HOT. You prolly boiled the solder.
Unlike silver and yellow gold, highly polished palladium white gold
looks red VERY quickly, so the usual ‘rules’ about glowing red don’t
apply…If the solder had ‘boiled’, the disk would have been
sucked flat into contact with the base by capilarity as usual and
would not have remained the smooth, small blob it was before
heating…
I never liked easy solder for this reason (which is why I don't
keep it onhand), it boils too quick.
With silver and yellow gold solder, I have ALWAYS used ONLY hard,
even with over fifty solderings on the same piece with not problems.
Special considerations are necessary when doing a piece which is
composed of 18K yellow gold, AND 18K and 14K palladium white gold,
AND sterling silver. Must use yellow gold solder, white gold solder,
and silver solder with the similar melting points. The only white
gold solders I have found with a melting point similar to hard
silver solder is always listed as Easy. White gold hard and medium
solders are WAY higher than hard silver solder!
My Easy Rio white gold solder is 710/787F. and 1310/1450C.
I dunno what you have there but it doesn't sound right. Get thee
some medium or hard solder and can the borax.
What were you using?? If anyone knows of a white gold solder with a
lower melting point than Rio’s Easy white gold solder (=Hard silver
solder), please do let me know where it is available!
Doing the same exact piece with hard silver solder instead
presents no problem whatsoever
Afraid not…:-)…! The whole point of the post was regarding this
particular type of solder on these particular materials…:-)…!! No
problem with silver—I would rather use gold solder on gold…