Lead corrosion and lead free soldering

[modeller_masa]

Hello.

I have a picky question about lead free soldering.

 

Today, I purchased a Revell 1:450 HMS Victory. Unfortunately, the masts in the kit are broken due to under 1.00mm thickness. I want to replace them to brass rod with soldering. The only thing I worry about soldering is a lead corrosion.

 

https://www.navsea.navy.mil/Home/Warfare-Centers/NSWC-Carderock/Resources/Curator-of-Navy-Ship-Models/Lead-Corrosion-in-Exhibition-Ship-Models/

According to the NAVSEA, the lead corrosion is caused by lead parts.  I have soldeing station and have experiences on lead free solderding. However, when I checked the compositions of the "lead free wire', I found that the wire has a very tiny lead.

 

http://www.almit.com/dloads/Specs/leadfree/spec_kr19sh lfm48.pdf

There is 0.09% of lead in the 'lead free' wire. This is a SAC (Sn, Ag, Cu) solder wire. Do you think the 0.09% of lead component will cause a lead corrosion in the future? Do you think it is considerably or strictly ok for 'Museum grade model'? I want to use the solder wire in the future if it is ok. It is scary to handle torch for silver soldering. If it is not a 'proven' issue, I'll wait for a conclusion.

 

Thank you for reading.

 

 

[kurtvd19]

I don't think there will be a problem with that small amount BUT there are lead free solders that are not silver solder requiring high heat. 

stay-brite by J W Harris Co is lead free, it blackens like silver solder and has a high silver content.  I have used it and it has replaced true silver solder in all but rare cases in my shop.  Nothing we do with scale models requires the strength of a true silver solder.

Look at Jeweler supply outlets - there are lead free solders that are easy to work with.

Kurt

 

[vaddoc]

1 hour ago, kurtvd19 said:

stay-brite by J W Harris Co

Kurt, you ve mentioned stay-brite before. I looked into it at the time but did not really understand how it works. Could you explain a bit more?

More specifically: I presume it just needs a soldering station and not a torch? Does it need flux? Does it have gap filling capabilities or does it need to be tight fit like silver solder? Finally, what are the advantages over silver solder paste/torch?

 

Many thanks

[kurtvd19]

As the needed temperatures are much less a soldering iron can work if it delivers enough heat.  I have used it with both a torch (that I am very comfortable with) and resistance soldering but because I have the small torch and the resistance soldering unit I haven't tried it with a soldering iron myself.  It comes with a liquid flux but I usually use a common past flux - Nokorode is on the work are now.  Parts must fit well it doesn't fill gaps.

The advantage is that it is easier to use than a true silver solder.  I have used stay-brite on parts that just wouldn't hold up to the temperature needed for silver solder.  Stay-brite really works more like a common soft solder than silver solder but doesn't fill gaps. 

I used to silver solder everything - and I got real good at it.  I had some parts I thought would possibly melt if I used a true silver solder and somebody told me about stay-brite.  I tried it and it worked great.  I have used paste silver solder and found it worked fine for some work but it still needs higher heat than stay-brite.  Use what is easiest to use and works for the job.  I wouldn't use anything but true silver solder if I was still doing radio control boats where rudder and other moving parts need a lot of strength.  I defy anybody to break a good joint made with stay-brite on a static model - I sure can't put enough tension on a rigging line to break a stay-brite solder joint.

Kurt

[vaddoc]

Much appreciated Kurt. 

[Charles Green]

Workers in the refrigeration trade use "silver bearing solder"; ordinary lead solder with enough silver added to prevent lead corrosion.  It comes coiled in a roll like ordinary solder and melts with a soldering iron.  It has good gap-filling properties and it stays bright.

 

It just occurred to me that "Stay Bright", the solder Kurt referred to (above) is the silver bearing solder I'm referring to.

[kurtvd19]

Stay-brite is lead free.  And it is as easy to use as common solder.

[allanyed]

Many thanks for sharing this again Kurt!!  I missed the earlier posts so very happy to see it come up now.  Until now I would never use anything other than silver solder, but am anxious to give Star Brite a try.  When you use your torch, do you just go with a softer flame than you would for silver solder?  If not, I assume the danger still remains of melting the part to be soldered,  which I think most of us have done on occasion.  

Allan

[kurtvd19]

It works the same as silver soldering - just less heat.  I have a Smith Little Torch so smaller flame is easy.

Kurt

[modeller_masa]

Oops. I turned off a notification setting. Thank you for many replies! 

 

After I read replies, I gained enough confidence and got much clearer plan to replace broken masts. Thanks again to your advices!