Flux core Solders?

[Kansas Ed]

Ok.....I work for an avionics company, and being in the aircraft field, all solder is dated for a relatively short shelf life. We have a lot of out of date solders which are thrown away...well not anymore...cause I'm keeping them...with permission of course. So I've started a fair stash of different solders with more on the way. My question arises because I'm not sure what issues I will run into with the flux cored solders. All the different alloy solders I'm getting are flux cored. So are there any problems when combining with pure lead related to the flux in solders? Will it just skim off, or will it cause problems in the mix? Health issues other than the obvious?

I've been in contact with several contractors for sources of Lead Pipe, and roof sheeting...so hopefully will be addressing that supply chain very soon. But I do need to know what I'm going to run into with the flux in the solder. And yes, I am sorting the rolls of solder by 66/44, 63/37, 68/32 etc....

Ed

[Sergeant Earthworm]

I think you will run into two things to deal with using rosin core solder. First is that the rosin has to burn off and will generate a lot of smoke in the process and if rosin gets hot enough it can catch fire. Definitely something that would have to be done outdoors or with very good ventilation. The second is that as you note, solder for electrical/electronic applications contains a whole bunch of tin so if you are trying to use a lot of solder, to get the right alloy you will have to add a quite a lot of pure lead. Other than that, it seems to me you shouldn't have any issues. It might be worth reviewing the material safety data sheet (MSDS) for the solders you have to make sure there are no problematic ingredients, pretty unlikely but possible.

[cbrick]

The rosin is flux and it's purpose is to "flux" the surfaces (clean of oxidation) to be joined so the parts will join together. As flux it won't hurt the lead or the tin because if it did it would also ruin the solder, it will burn off of the surface. As mentioned, best outdoors and stay out of the smoke, I don't imagine lungs full of it would be a good thing.

Rick

[Spawn-Inc]

i would say it's a benefit as it will help with fluxing, at least i would think so.

melt a batch of lead and then toss in a few rolls and it should help with mixing.

[John in WI]

as already stated--it smokes like crazy when you add it to the pot! The couple of times I've done it (using about a foot of solder at a time) the flux just melted and floated around the surface. It looked a lot like fluxing with wax (and smoked about the same).

The nice thing is, you'll know exactly what the composition is (it's an excellent tin source). And if you have a lot of it, it might be a good bargaining chip for trying to find other alloys like wheel weight. Tin is the most expensive component in the alloy so it's a good thing to have!

[soli]

What about acid core,is it ok?

[SlippShodd]

What about acid core,is it ok?

It is, but avoid the fumes. Same as the rosin core, there's not much harm when you're soldering in small quantities, but in bulky amounts it can be nauseating. I'd smelt it outside to burn of the flux then cast it into useful sized ingots. 3 decades in the electronics industry and I still love the smell of burning rosin flux. :)

mike

[leadman]

I got a deal on flux core solder a couple years ago so use alot of it. The flux will rise to the surface so light the smoke and work the flux thru the alloy. Really cleans the lead! I would add the solder after the rest of the lead is melted so you get full benefit of the fluxing.
Acid core can cause problems if your pot is not stainless as it can corrode it. Think of a leaky car battery and what it does to the cables. After you use acid core wipe the exposed surfaces of the pot with a wet rag and check it the next day for corrosion.

[rexherring]

I used a lot of old solder my dad had stashed and was turning white. A mix of rosin and acid solders. Works good with sawdust for fluxing but lots of ventillation needed. Burning it helps the smoke when fluxing.

[randyrat]

I've melted a couple hundred pounds of each solder, very easy to deal with. Just use sawdust to collect the acid core or rosin whichever you have and place it in a safe container, then in the trash. It won't hurt a thing if you use sawdust to collect it off the top of the melt before it smokes like H E double toothpicks. The greatest thing about solder is LOW melt temp, be aware, it also holds heat very well. Great source for a life time of Tin/ Sn

[clodhopper]

I have put baking soda in acid core solder, stirred well and fluxed with sawdust. Did not see any ill effects on the pot.

[GaryN]

I've melted a couple hundred pounds of each solder, very easy to deal with. Just use sawdust to collect the acid core or rosin whichever you have and place it in a safe container, then in the trash. It won't hurt a thing if you use sawdust to collect it off the top of the melt before it smokes like H E double toothpicks. The greatest thing about solder is LOW melt temp, be aware, it also holds heat very well. Great source for a life time of Tin/ Sn e pot.

Good idea Randyrat. I melted down about fifteen pounds of the acid core. I did it outside and waited for the stench to abate. I would not want to be downwind of that. It was bad. It smelled very toxic.

[Kansas Ed]

Thanks for all the responses. I will "forge" ahead noting cautions as outlined above.

Ed

[OuchHot!]

I will throw this out just in case you are talking about serious quantities of electronic solder. Lots of experimenters in electronics are getting buggered by the high price of lead tin solders and would not care a fig about the date....you might try to fence some of this on electronics forums or evilb@y. I play with electronics as a hobby and "real" solder has gone through the roof.

[lwknight]

If you don't want to deal with acrid smoke, melt the solder separately. It will melt at low enough temperatures to float the core stuff without burning it. Then cast into small ingots to add to the lead.

[azchisum]

I have melted a few pounds of solder with the rosin core.. I just leave it in the pan and let it cool The flux is all on the top and will harden. Then just chip it off and throw away.