switch to lead free solder- how difficult?

[BrianE22]

An OSHA inspector visited our place the other day and she really didn't like that we were using leaded solder. She referred me to a Federal OSHA website that lists what you need to do in order to use leaded solder and keep OSHA happy. I spent about 10 minutes navigating through it and then gave up. Is lead free solder still a pain to use? We do about 30 fairly small boards in the solder pot per month spend about 5 minutes hand soldering on each.

 

[ScottyUK]

Considerably higher tip temperature, which can upset some components if the hand soldring operation is fast and accurate, and you need a decent flux to get a good joint which may affect your cleaning process. The water-washable fluxes are generally quite active and are easy to clean, but at the expense of prolonged drying time. Inspection will need to adapt because tin solders have a less bright appearance than 60/40 and 60/37.5/2.5 alloys.

 

[itsmoked]

The hotter tips Scotty mentions are the biggest PITA as the tips all oxidize in a big fat hurry. Whereas a lead iron might oxide-up after 10 or 15 minutes of neglect in the holder, a tin operation tip will oxide out in 15 minutes of even continual use!!

It's much harder to get a "good looking" joint. The products can be subject to tin whisker problems though I have never seen any and I'm using some pretty fine components and traces.

Since I'm shipping to Europe I started using lead-free and now do most everything that way because it just nice to not have to wash one's hands every time you get up from soldering.

Rework with tin is about 2x harder.

Keep tip cleaner around - that milky zombie-white paste that you dig the oxided tips into to de-oxide them and keep a box of new replacement tips on hand.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[ScottyUK]

"...if the hand soldering operation is NOT fast and accurate..."

Oh for an edit function!

 

[mcgyvr]

Is your solder pot compatible with lead free (this usually involves a titanium pot or other suitable material)?
Do you have customers that require or standards that require lead free?
We are actually required to NOT use lead-free due to reliability/ROHS exemption.

For such a small volume and assuming you have nothing forcing you leadfree then I don't see the point in spending the money to switch. Now if your customers are going elsewhere then there is a valid financial reason to switch.

OSHA cannot force you to lead free. They have zero say in the matter. She is just looking at it from an "industrial hygienist" point of view and probably had very little else to say about your facility so just brought that up.

That being said the switch to lead free isn't that bad at all. Its been made out to be a huge deal but its really not.. Just a few simple steps and slightly higher costs due to increased maintenance/slightly shorter tip life,etc...

 

[BrianE22]

Sounds like it's do-able. The other question then would be, how reliable are the joints? I read years ago that lead free solder was not allowed on military or medical devices due to reliability concerns.

Some of my dealers are sending my product to Europe. I don't know how they get past the regulations. Also, my hazardous waste inspector doesn't like the leaded solder. If the technical headaches balance the regulatory headaches then maybe it's time to change over.

 

[MacGyverS2000]

Whiskers are the biggest concern, not joint reliability, per se... comms equipment (satellites) are exempt, military, etc. I don't like working with Pb-free and will take leaded whenever I can, but it is what it is.

Dan - Owner

http://www.Hi-TecDesigns.com

 

[BrianE22]

I'm going to do some hand soldering with lead free. If it works o.k., I'll try using lead free in the solder pot. Thanks for the help everyone -

 

[itsmoked]

Raise your temps about 50F minimum.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[mcgyvr]

Again make damn sure your pot can be used with lead free solder before you attempt it..
Nothing like having the pot dissolve and it pouring molten solder out onto the operator..
OSHA REALLY won't like that.

http://www.leadfreedod.com/images/fig4.jpg

http://www.kester.com/kester-content/uploads/2013/03/How_to_Ready_a_Solder_Pot_for_Lead-free.pdf

Also I'd expect the circuit boards you are using now are not "lead free" either and are probably just hot air solder leveled with tin-lead solder so that will require a different PCB/substrate/finish on those too.
Not to mention increased dross levels in the pot..increased frequency of solder analysis due to more rapid contamination,blah blah blah..

 

[MacGyverS2000]

And you will contaminate the entire pot the moment you put even a single (missed) leaded component in there. It's a royal PITA...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[Comcokid]

Watch your circuit boards also. Lead free solders require more heat. Not all PCB materials will withstand the higher soldering temperatures. Most FR4 type materials in use now are rated for the higher temperatures, but if you're using bare PCBs you've had in your inventory for a long time, or a less common material, then they may be an older type material.