How to remove old lead free solder?

[Citizen_Insane]

My bassist had me check out his amp because it's been acting up. What I've found are a ton of cold solder joints left by the person that last repaired the amp. Whoever it was used lead free solder. Not the new stuff either, it's probably been on the board for 20 years. (Vintage Ampeg).

Does anyone have any tips for removing lead free solder, because heck if it won't stick to any of the braid I've got here at home.

(I'm pretty darn sure I'm getting it hot enough, I've got a Hakko 936 w/ a max temp of 480*C and it gets moving pretty easily, I just can't get it to stick to anything)

 

[celeste]

Have you tried liquid flux? even a gel/paste could help.

How do you know it is lead free?

 

[Billm]

Heat the joint and feed it a bit flux core 60/40 solder. Use a solder sucker instead of braid.

I just got a Blues Junior in for service/mods where the previous "genius" had resoldered the entire board with lead-free solder, probably thinking he was striking a blow for the environment or something. Now it's all crizzled, looking like cheap pot metal that's been left in salt water.

He had to use higher temps to make it flow, so he lifted a lot of solder pads, too.

Ugh.

 

[Citizen_Insane]

Have you tried liquid flux? even a gel/paste could help.

How do you know it is lead free?

You know lead free solder when you see it

Thanks for the tips Bill, I'll grab a desoldering bulb at Rat Shack when I go to the mall later tonight.

 

[BiggerJohn]

Solder sucker. Get the spring loaded type.

I refuse to use anything but old school tin-lead solder, it works best.

 

[Billm]

The desoldering bulbs suck, but not in a good way.

Get the spring-loaded type. The one with the aluminum barrel, sold by Radio Shack and others. There's a larger, all-plastic type with ridges on the barrel and an exposed spring that's not nearly as good.

 

[joeyvelour]

it's probably been on the board for 20 years

Probably not a lead-free solder then. My guess is that it's simply a no-flux solder (as in plumbers solder) which would have required a separate rosin flux paste to strip the bare metal of dirt and oxidation and allow the solder to flow and form a proper intermetallic layer. Without flux the solder would have a dull gray appearance like that of lead free, but it's essentially a cold joint.
I could get into the physics of a solder joint if anyone cares that much but the bottom line is that the advice above is correct... A spring-loaded solder sucker would work best to remove it, add liquid flux if needed to aid in "wetting" between the solder and the iron's tip. You definitely want that solder removed as completely as possible before reflowing the joints with the correct solder.
I hope this helps...

Joe G

 

[jrfrond]

Why bother? Just heat the joint and add some 60/40 solder to alloy with the RoHs stuff, and you will be just fine. Remove solder from every joint??? You'd have to be mad!

A bit of RMA rework paste flux helps with the job too.

As long as you alloy it with lead solder, you will no longer have the look OR the fragility of the lead-free stuff. We do it all the time in our shop, and we will sometimes resolder entire circuit boards. Takes less time to do that than to try and find cold solder joints, because they ALL look cold with lead-free solder!

 

[Raybob]

You know lead free solder when you see it ..

I'd take issue with that statement. I build hand wired amplifiers and have sold many to European countries. For me to sell to a store in Europe, I must use lead free solder (RoHC compliant) as of RoHC rules that began in July 2006. I use silver solder (4% silver) and love the way it flows (180 deg. C melting). My solder joints look just like a lead solder joint, just a little shinier. It melts right into copper braid very easily.

Raybob

 

[jhundt]

I use the cave-man method: heat the joint and blow off the solder with an air compressor.

 

[Citizen_Insane]

Probably not a lead-free solder then. My guess is that it's simply a no-flux solder (as in plumbers solder) which would have required a separate rosin flux paste to strip the bare metal of dirt and oxidation and allow the solder to flow and form a proper intermetallic layer. Without flux the solder would have a dull gray appearance like that of lead free, but it's essentially a cold joint.
I could get into the physics of a solder joint if anyone cares that much but the bottom line is that the advice above is correct... A spring-loaded solder sucker would work best to remove it, add liquid flux if needed to aid in "wetting" between the solder and the iron's tip. You definitely want that solder removed as completely as possible before reflowing the joints with the correct solder.
I hope this helps...

Joe G

I really have no clue when the amp was last worked on. The current owner is 24, so I don't think that he's owned the amp longer than 8 years. The joints could be much newer than 20 years, I have no real reference for that. The solder on these specific joints acts like the stuff I've had to work with before.

Why bother? Just heat the joint and add some 60/40 solder to alloy with the RoHs stuff, and you will be just fine. Remove solder from every joint??? You'd have to be mad!

A bit of RMA rework paste flux helps with the job too.

As long as you alloy it with lead solder, you will no longer have the look OR the fragility of the lead-free stuff. We do it all the time in our shop, and we will sometimes resolder entire circuit boards. Takes less time to do that than to try and find cold solder joints, because they ALL look cold with lead-free solder!

I would just reflow the connections, but there is just way to much solder globbed on the board. If I remove the solder I will also be able to clean the board and make sure that I get good contact with the traces.

I'd take issue with that statement. I build hand wired amplifiers and have sold many to European countries. For me to sell to a store in Europe, I must use lead free solder (RoHC compliant) as of RoHC rules that began in July 2006. I use silver solder (4% silver) and love the way it flows (180 deg. C melting). My solder joints look just like a lead solder joint, just a little shinier. It melts right into copper braid very easily.

Raybob

Yes, but you're using new lead-free solder. The new stuff is much more manageable than the original alloys. The way this stuff behaves, it reminds me of the all the previous older electronics I've worked on that have used lead-free solder.

Regardless, it doesn't matter much, I just need to clean up the current stuff so that I can clean up this board and get the amp working as intended again.