Make your own Eco-friendly soldering flux

Flux is used in soldering to remove oxides from the contacts of the parts to be soldered together. Fluxes can be made from hydrochloric acid, zinc chloride or rosin. Here is a simple and easy homemade rosin flux made from pine cones.

Step 1 Go Shopping!

Only two ingredients are required:

10 to 15 pine cones with pine tar (sap) on the ends of the cone leaves (found around pine trees)
1 Quart Denatured Ethyl Alcohol (found in the wild at a hardware store or you could distill your own)

Tools required:

2) Metal or plastic containers with a lid (coffee cans work great - consume coffee first)
1) Pair of rubber gloves (removed from kitchen without Mom's knowledge - disavow later)
1) Tea strainer (likewise but wash after using and return to kitchen under cover of darkness)
White coffee filters
Scissors or shears
Empty Bactine bottle for application
24 hours

Comments

[beehard44]

is it possible to use lemons as soldering flux? I live in the Philippines and my local electronics supplier doesn't carry flux and we don't have pine trees (duh!) although we have calamansi (known as Philippine lemons or calamondin)

[Original Woodchuck]

Try a music store. Rosin is used to treat the bows of violins etc. Or a sporting goods store. Rosin is sold in a powdered form to increase the friction on the hands of various athletes (baseball players, pole vaulters, etc). Or an art supply store; there are various uses for rosin in that field. A pharmacist might also have some. Interestingly, the Philippines exports large quantities of rosin to the rest of the world! Just not the pine rosin mentioned here. "Manila Copal" is one type; it is used in the manufacture of old-style oil paints and varnish. These might even be superior, they are superior for varnish making.

[burningsuntech]

beehard44
Some soldering fluxes are made from acids, like hydrochloric acid based flux used in joining dissimilar metals with solder.

Acid based fluxes will work, but are not recommended for electronics work as they can corrode the circuitry and cause major problems, even if you clean your boards very well.

Now... will lemons work? Dont know, but you could try it on scrape circuit board and see what the results are... It would be interesting.

Let me know how you do... If it works well and cleans well, how about an instructable about it? huh?
RA

[nadav]

I cant fine any denatured alcohol, can I use methyl hydrate? Or regular rubbing alcohol.

[eric m]

why not just lemon juice or vinegar?

[handyman6042]

I am wondering if a person can use rosin that they make for fiberglass. Instead of pin cone sap?

[craferr]

Soldering rosin or resin should be dirt cheap, but the prices it sells for now are incredible. So naturally you would want to find a reasonably priced substitute. Hope you havent used epoxy or polyester resins that are used with fibreglass yet. Epoxy, polyester resins are thick gooey chemical products that will be difficult to clean off- thats why they're used. They adhere to materials, and then a hardener makes them solid. They will probably prevent the solder from adhering to the material being soldered. Rosin/resin soldering flux is greasy, becomes a vapor at soldering iron/torch temperature, cleans and prevents the material being soldered from oxidizing so the solder adheres, and is easy to clean off. I would'nt dream of using epoxy or polyester resins.
If you did in fact use epoxy or polyester, we would be very interested in what happened. Thanks.

[burningsuntech]

handyman,
I'm not familiar with the rosin you speak of or the process by how it is produced.
I can say that if it is a derivative of pine rosin, then it will work.
Beyond that, I do not know.
RA

[handyman6042]

Sorry guys. It is not rosin. It is called fiberglass resin. And it would not break down in the alcohol.
But I did find some cedar oil. That I can get for free. And mixed it half and half. With the alcohol. And it works great. I never had solder flow/look that good ever. thanks for all that you guys do.

[SharpyWarpy]

I made some flux with your method and it turned out beautifully. I want to thank you very, very much for this Instructable and for the time and work involved. I thought I'd have some fun with it and did a couple of things differently.
Instead of denatured alcohol I used 91% rubbing alcohol from Walmart. And instead of pine cones I used rosin built up from an injury on the side of a pine tree. I just pried it off easily with a screwdriver. I was wearing leather gloves for this because the pine tar is very sticky. Then I proceeded just as you describe, cover the stuff well with alcohol in a can (I used one quart orange juice cans), left overnight then strained that into the other can. Then when I strained back into the first can, which I had cleaned well with alcohol, using the coffee filter like you said but I found putting a large rubber band around the top -- securing the coffee filter well -- helped avoid the filter's tendency to fall into the can. Doing it this way also allowed me to pour the mixture in there and leaving it to finish draining through the filter and into the can. This took quite some time as my solution of flux is apparently thicker than normal, very dark. But it works quite well. Thanks again and I hope you post some more stuff like this. I really enjoyed doing it.

[burningsuntech]

Excellent!

Thank you for your comment and praise.
The fun of instructables is in how they can be adapted to your own needs and ways of doing things, not to mention whats available in the garage at the time you decide to do one. I'm glad you worked it for your purposes. Flexibility in design helps in improvement of the final product. Glad you enjoyed it. - RA

[SharpyWarpy]

The flux solution was so strong I ended up diluting it with the alcohol. I added the same amount of alcohol as that of the flux, doubling the total amount of flux. This cut down on burning problems with the flux, especially at higher temps like when de soldering a multiple pin component. Much better results now. I really like doing things this way, it makes me feel like I've really accomplished something good.
I have subscribed to your instructables and I hope you'll do another one soon!

[SharpyWarpy]

I found a pretty good way to get the flux in there where it's needed and in the perfect quantity. I use a hypodermic syringe like those used to vaccinate a dog. I used diagonal side cutters to cut off the tip so it's blunt. The tip never clogs like I thought it might. I can leave it for days and it still works like I just filled it.

[hore]

(removed by author or community request)

[burningsuntech]

hore,

No. thinner creates a film that keeps the solder from flowing properly and it does not dry fast enough.

Rather than asking me about various possible solutions, do what I did and experiment for yourself.

That is half the fun of doing these kinds of projects.

RA

[hore]

hi, is this really work,

[burningsuntech]

hore Yes it does. Rosin is a natural cleaning material which removes oxides so the solder can flow more easily. RA

[hore]

i need to ask more questions, can i use any type of alcohol. or this the only stuff to make this flux.

[hore]

thank you, do you have any alternative to replace quart denatured ethyl alcohol

[burningsuntech]

The highest proof Vodka you can get above 100 proof will do. Just do not drink the stuff. RA

[hore]

alrite thank you....

[steveastrouk]

Colophony fumes (from burning rosin) are a major source of chronic chest disease in electronic workers.

[hore]

hei steve do you think i can use this to motherboard. ?

[steveastrouk]

Yes, its a very good, very traditional flux. In VERY high doses, it can cause chest problems - but unless you are working 5 days a week in a fume filled room, its not going to be a problem.

[xaviero]

is there any material equals for pine ??? it looks like difficult to find pine :(

[burningsuntech]

xaviero Sorry for not replying sooner. I did not get notification of this post. You could mix powdered rosin used for giving grip to gymnasts and other athletes with the denatured alcohol. Start with a very high ratio of alcohol to rosin, say 50 to 1 ? and work your way down. You will know you have it right when the mixture is as thin as possible and you still get good wetting action from the solder without a lot of residue left over. Good Hunting RA

[agis68]

Finally i found the flux really cheaper that producing all these stuff.....i don't know the price of it in states but here in Greece 100ml of flux costs around 5euro (8 USD)

[agis68]

Really grate idea. One question: flux and colophonium are the same???

[burningsuntech]

Agis A qualifier here. Not all flux is derived from pine tar. Some fluxes include zinc chloride or hydrochloric acid just to name a couple. raving apache

[burningsuntech]

Agis Yes they are. Rosin can produce a contact allergic reaction just like the pollen and sap from a pine tree can. Colophonium (or rosin) are derived from any of the genus pinus and can be found in lots of products. If you have an allergy to pine tar, this instructable is not for you. Be careful. raving apache

[GorillazMiko]

cool, thanks! flux is so expensive. well at least for me.

[burningsuntech]

Same here. Necessity, it seems, is truly the mother of invention.

[guyfrom7up]

pretty cool, but isn't it a bit runny? Does it make a much nicer smell when in use?

[burningsuntech]

It is supposed to be. The alcohol acts as a carrier for the rosin and as a cleanser to remove grease and other contaminants (fingerprints) from your work piece. Thick gooey rosin would only burn and the by product would itself become a block to your soldering masterpiece.

[burningsuntech]

As far as a smell. If it burns, it smells just like burning wood. Not that great.

[Kiteman]

Apart from giving the alcohol a pleasant scent, what do the pine cones do?

[burningsuntech]

The pine cones supply the pine tar which is rich in rosin, the flux ingredient. Once soaked in alcohol, they could be disposed of in a fire as a fire starter or just trashed. They are inert