Airsoft Canada - View Single Post - Electrical connectors: where to use a mini, large, or Deans connector

Syn · July 27th, 2008, 14:13

I can't find a better thread to post this.

My deans connector 24k gold plated:
Electrical connection on 2 of the connectors I soldered months ago are coming apart. I am buying new solder tomorrow so I decided to google and find out if I needed a fancier solder for gold plated parts. Found this:

http://en.wikipedia.org/wiki/Gold_plating

Soldering issues

Soldering gold-plated parts can be tricky.
Gold is soluble in solder. Solder which contains more than 5% gold can become brittle. The joint surface is dull-looking.

Gold reacts with both tin and lead in their liquid state, forming brittle intermetallics. When eutectic 63% Sn - 37% Pb solder is used, no lead-gold compounds are formed, because gold preferentially reacts with tin, forming the AuSn4 compound. Particles of AuSn4 disperse in the solder matrix, forming preferential cleavage planes, significantly lowering the mechanical strength and therefore reliability of the resulting solder joints.

If the gold layer does not completely dissolve into the solder, then slow intermetallic reactions can proceed in the solid state as the tin and gold atoms cross-migrate. Intermetallics have poor electrical conductivity and low strength. The ongoing intermetallic reactions also cause Kirkendall voiding, leading to mechanical failure of the joint, similar to the degradation of gold-aluminum bonds known as purple plague.

A 2-3 µm layer of gold dissolves completely within one second during typical wave soldering conditions. [1] Layers of gold thinner than 0.5 µm (20 microinches) also dissolve completely into the solder, exposing the underlying metal (usually nickel) to the solder. Impurities in the nickel layer can prevent the solder from bonding to it. Electroless nickel plating contains phosphorus. Nickel with more than 8% phosphorus is not solderable. Electrodeposited nickel may contain nickel hydroxide. An acid bath is required to remove the passivation layer before applying the gold layer; improper cleaning leads to a nickel surface difficult to solder. A stronger flux can help, as it aids dissolving the oxide deposits. Carbon is another nickel contaminant that hinders solderability.

Also read that silver solder is better for soldering on plating:

http://www.bhavanimetals.com/Solder_...ore_Solder.htm

So far this is the quickest buying option for me
http://www.thesource.ca/estore/Produ...roduct=6400013

maybe second option???
http://cgi.ebay.ca/WBT-SILVER-SOLDER...QQcmdZViewItem
edit: ordered the WBT from ebay it is mostly tin >96% and some silver ~3.8%, no lead. Lets see how good it is.

Also found this link that kind of confirms the 60/40 I used before may not have been the best choice.
http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXKX34

"Silver or Gold plating requires a special solder. Ordinary solder
causes a chemical reaction which will degrade the joint. Deans
Racing Solder is 2% silver with high activity ProFlux."

good cheap 3rd hand http://www.misbehavin-rc.com/pit-lan...-procedure.asp

July 27th, 2008, 14:13	#30
Syn Trader rating Join Date: Aug 2005 Location: Toronto	I can't find a better thread to post this. My deans connector 24k gold plated: Electrical connection on 2 of the connectors I soldered months ago are coming apart. I am buying new solder tomorrow so I decided to google and find out if I needed a fancier solder for gold plated parts. Found this: http://en.wikipedia.org/wiki/Gold_plating Soldering issues Soldering gold-plated parts can be tricky. Gold is soluble in solder. Solder which contains more than 5% gold can become brittle. The joint surface is dull-looking. Gold reacts with both tin and lead in their liquid state, forming brittle intermetallics. When eutectic 63% Sn - 37% Pb solder is used, no lead-gold compounds are formed, because gold preferentially reacts with tin, forming the AuSn4 compound. Particles of AuSn4 disperse in the solder matrix, forming preferential cleavage planes, significantly lowering the mechanical strength and therefore reliability of the resulting solder joints. If the gold layer does not completely dissolve into the solder, then slow intermetallic reactions can proceed in the solid state as the tin and gold atoms cross-migrate. Intermetallics have poor electrical conductivity and low strength. The ongoing intermetallic reactions also cause Kirkendall voiding, leading to mechanical failure of the joint, similar to the degradation of gold-aluminum bonds known as purple plague. A 2-3 µm layer of gold dissolves completely within one second during typical wave soldering conditions. [1] Layers of gold thinner than 0.5 µm (20 microinches) also dissolve completely into the solder, exposing the underlying metal (usually nickel) to the solder. Impurities in the nickel layer can prevent the solder from bonding to it. Electroless nickel plating contains phosphorus. Nickel with more than 8% phosphorus is not solderable. Electrodeposited nickel may contain nickel hydroxide. An acid bath is required to remove the passivation layer before applying the gold layer; improper cleaning leads to a nickel surface difficult to solder. A stronger flux can help, as it aids dissolving the oxide deposits. Carbon is another nickel contaminant that hinders solderability. Also read that silver solder is better for soldering on plating: http://www.bhavanimetals.com/Solder_...ore_Solder.htm So far this is the quickest buying option for me http://www.thesource.ca/estore/Produ...roduct=6400013 maybe second option??? http://cgi.ebay.ca/WBT-SILVER-SOLDER...QQcmdZViewItem edit: ordered the WBT from ebay it is mostly tin >96% and some silver ~3.8%, no lead. Lets see how good it is. Also found this link that kind of confirms the 60/40 I used before may not have been the best choice. http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXKX34 "Silver or Gold plating requires a special solder. Ordinary solder causes a chemical reaction which will degrade the joint. Deans Racing Solder is 2% silver with high activity ProFlux." good cheap 3rd hand http://www.misbehavin-rc.com/pit-lan...-procedure.asp __________________ Last edited by Syn; July 27th, 2008 at 17:23..