Make your own solderpaste!

Have you ever wanted to reflow surface mount circuits but not wanted to pay for expensive solder paste?

Have you ever had a good de-soldering sesion and found lots of old solder particles all over your desk and wondered what to do with it?

Well, I have an answer to both of these questions in one hit. You can make your own solderpaste!

In this instructable we are recycling old solder, and parts of old PCBs and components.
The only non-recycled part is the solder paste.

This is useful for repairs on the go, if you need to solder wires together, you put some of this paste on the joint and use a lighter to reflow.

A little warning first. The used solder you might use could contain lead, especially if its salvaged from old boards. but since you solder you probably has already accepted the risks of such exposure.

Ok, now the formalities are out of the way, here's what you need:
> Safety glasses
> An old board to desolder
> A solder sucker
> Flux paste (or soldering paste as it is sometimes called)
> A pair of abrasive sponges (or some kind of abrasives that won't leave its own dust or flake off)
> A piece of paper to catch the solder dust
> A piece of plastic or something to mix the paste on
> Something to mix the paste with (I used a blanking plate from the back of a PC and a paperclip)

> A cup of tea (I'm English so this is a must for me)
> A good soundtrack (For this instructable I listened to Billy Talent III)

The quality of the paste varies depending on how fine you can grind the solder, the quality of the paste used and the ratio between the two when mixing. This is something you will need to experiment with.

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nedry6 months ago

I would like to advise people to not do this. Lead is a potent neurotoxin and accumulates in the body. It only takes 1 mg of lead (assuming 5 liters of blood) to get you to the threshold for lead poisoning. At a density of 11.34 g/cm^3, that is very little dust and you could easily be exposed to that amount through cross contamination of tools and surfaces or poor technique. The risk of exposure when you are grinding lead into dust is much higher than the risk when soldering. In solder the lead is bound in a metal and is not available for ingestion. The lead oxide on a soldering sponge and solder paste require more caution but are still not as dangerous as the powdered lead in these procedures.

The money you save by making your own solder paste is just not worth the risk of brain damage. Don't do it.

Or, to minimize the risk of aerosolizing and subsequently breathing in the solder:

place the file under water and, while wearing gloves, run the solder across the file. Drain the water, collect the filings, and in a draft-free space, let the particles dry. Once dry, mix the filings INTO the flux (to minimize agitating the filings into the air).

Yes, this method is more time consuming, but it virtually (IMHO) eliminates any health exposure, Until you forget to look before crossing the street and get run down by the motorist engaged in a text exchange.

nedry nedry6 months ago

Actually the threshold is 10 ug/dL, so with 5L of blood you would only need to consume 500 ug. That quantity is probably barely visible.

aalain1 year ago
Congratulation! Nice work! I will try out.I need soldering paste for smd devices
waldosan2 years ago
this is really good don't you know. i'm not into surface mount stuff yet but it seems like this will be a simple yet useful idea that i'll find myself using often. where is a good place to get the flux paste, i think i have some but i'm pretty sure it's meant for plumbing.
Try a mortar and pestle for grinding the solder particles.
Apolo83 years ago
Try to freeze the solder first in the fridge...once it´s frozen try the coffee grinder...

Un Saludo...
phevtron3 years ago
we have the same paste :O
mjawed3 years ago
Good Idea to get easy solder paste...I really like this!
I believe that the recovered solder should be more grind to use with SMT components for better joints.

BTW...its great to try with..;)

Thanks for sharing!

ratgod (author)  mjawed3 years ago
I couldn't grind it much more with the abrasive blocks I had unfortunatly, but I do agree if it was ground more it would be perfect. I'm trying to find a better way of doing it. I should try an old coffee grinder and see if that works as good.

Many thanks for your comment.