Introduction: Make Your Own Eco-friendly Soldering Flux

Picture of 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!

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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

Step 2: Mix It Up

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Rinse the two containers with a little alcohol to remove any coffee grounds.

Cut the cone leaves from the pine cones and place them in one of the containers.

Pour the alcohol over the cone leaves making sure they are submerged. Save the empty can for storage of your finished product.

Cover and let soak overnight.

Step 3: Refine Your Product

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Stir the container of cone leaves and alcohol to insure that all the sap has dissolved.

Place the strainer over the top of the empty coffee can and pour the contents of the cone mixture through the strainer to remove large pieces of debris.

Throw away the debris in the strainer and the remaining pine cone debris in the can and rinse the can with clean alcohol.

Place a white coffee filter in the strainer. Place the strainer on the clean coffee can and slowly pour the contents of the strained liquid through the filter.

The liquid will be light amber in color and smell of pine.

Filter again if you like and /or bottle your product in the empty alcohol container. Use a small bottle with an attached dropper (like an empty Bactine spray bottle) for applying your flux to your project before soldering. Yeah!


rpotts2 (author)2016-11-14

Nice 'ible! I have a small container that I made from rosin gathered on a hike. I think it may be easier to harvest if you cut the tree a bit (nothing huge, just an inch or so) and just wait a while (days or weeks). if you plan far enough ahead you can harvest the brittle stuff.

afridave (author)2016-07-11

cool...I have two large pine tress in the front going to look for some blobs of sap and try disolving that in some form of alcohol and give it a bash..

afridave (author)2016-07-11

cool...I have two large pine tress in the front going to look for some blobs of sap and try disolving that in some form of alcohol and give it a bash..

afridave (author)2016-07-11

cool...I have two large pine tress in the front going to look for some blobs of sap and try disolving that in some form of alcohol and give it a bash..

afridave (author)2016-07-11

cool...I have two large pine tress in the front going to look for some blobs of sap and try disolving that in some form of alcohol and give it a bash..

afridave (author)2016-07-11

cool...I have two large pine tress in the front going to look for some blobs of sap and try disolving that in some form of alcohol and give it a bash..

iFix8 (author)2014-10-17

Heck with rosin flux. I've found what may be the single best, cheapest alternative that is already being sold for as low as $15 per gal in most hardware and department stores. When added to desoldering wick, it turns it into super wick with about 10x the effectiveness. I'm still experimenting with it, but after using it to successfully solder to any type of coin, battery, etc., I'm pretty sure it works better than flux and has less ill health effects. It also has many other beneficial uses around the house and shop. Can you guess what it is?

sjones124 (author)iFix82015-09-27

What gives? I didn't see anyone guessing, and you didn't give it up either. $15/gal for flux is cheap enough to keep me from hunting sap covered pine cones. Given the topic of this Instructible I'd guess a pine cleaner, like Pinesol?

iFix8 (author)sjones1242016-06-28

Sorry, I thought I'd answered you. Since flux basically turns to acid when heated, and the acid is what de-oxidizes the metal, I figured I'd just go with a cheap, weak acid that was readily available. There may be a lot of these around, but I chose the one acid that is safe, readily available and found in a lot of foods, probably one or two that you've had this week -- phosphoric acid. It is found in many foods because it slows the growth of molds and bacteria, so not only does it add the zing to soda pop (not citric acid, as you might have thought), but it keeps the sugary treat from becoming a bacterial soup. Got to maintain those profits!

You can get it online, but it is only $15 per gal at Home Depot under the label, KleanStrip Prep & Etch, for cleaning and etching cement floors, etc. It needs to be diluted with alcohol, of course, which means it is even cheaper than $15 per gallon. Try it on a circuit board to see if it is diluted enough. If it doesn't eat away at the coating on most circuit boards, it should be fine, but you can always clean away the acid after you're done soldering, just as some like to do with flux.

I've mixed my own flux with pine resin, and that stuff is super sticky and not fun to use. It really has to be diluted. But why bother if phosphoric acid does the job without the complications? I've also filled cheap markers to use as flux pens. Dip your wick in it and it becomes super wick! It's wick'ed stuff.

kedwa30 (author)iFix82016-04-21

I'm going to guess: Turpentine?

DaMonkey (author)iFix82015-11-07

Going to go out on a limb here. CLR?

JohnJ21 (author)2015-06-15

Parnian.Ahmadi (author)2015-01-19

Hello thank you very much great instruction , I want to know the exact ratio of HCL ,

ZnCl۲ , or maybe SnCl2 in tin -lead 63-37 soldering Flux the exact ratio the percentage ???

solar world (author)2014-12-20


solar world (author)2014-12-20


iFix8 (author)2014-10-16

Why wouldn't molasses work as well as rosin? and instead of plain alcohol, why not window cleaner since it has alcohol with an additional wetting agent?

jwms (author)2014-08-23

Never thought to make my own as I use solder with flux in it already. But it did give me an Idea how to "refine" it for other uses. You could add zinc chloride (small amounts) to improve the action on steel. Thanks.

z1rc0n (author)2012-09-17

I tried something very similar using pine gum rather than the cones. It worked fine. A few drops of glycerine are supposed to help stop it burning.

beehard44 (author)2010-12-03

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)

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.

Awesome 'ible !!!


Yaa Liquid Rosin Flux is stupidly expensive around my ways and being severely mobility impaired (house-bound!) means i cant go out on the hunt for pine cones so im stuck with mail order!

I really need to make my own Rosin Flux and this 'ible is the way for me !!!

I have a quick Question for: Original Woodchuck & burningsuntech:

ive managed to find 2 ounces of Damar Manila Copal Loba C Purified, is this suitable for the manufacture of Rosin Flux as described in this great 'ible ?!!!?

i would really be grateful for some insight into this as im running low on flux and really cant afford to buy any more for the next 2 months at-least (state benefits are crummy!) & i appreciate any/all help kindly given for this aim & many thanks in advance!


I'd say give it a try, using the methods of burningsuntech. Manila copal is soluble in alcohol. (Or it used to be). I believe it is a sort of fossilized rosin, something akin to amber. If that doesn't work, get a little block of bow rosin for a violin.

Good luck, and do report results!


oh yeah, i completely overlooked the violin rosin !!!

thanks a million Original Woodchuck !!!

i had found some Dark Violin Rosin, its very cheap!! not quite sure how big the block is but i have an inquiry...

as its a solid block, would i need to shave it into the alcohol or would i be able to just dunk it into a container and have the same effect of the alcohol doing its business overnight ??

oh and i wouldnt need the coffee filter-strainers either if i used the rosin block , would i ?!? 

sorry for the newbie questions, ive no idea with all this as im rather new to electronics too, only stared learning this year and albeit on a shoestring so liquid flux is really expensive for the likes of me!!!

thanks again for the great insight !

Such blocks are typically around 1cm x 2xm x 3cm or thereabouts. Large enough to draw a bow across it. To dissolve, usually you should
crush it. Put it in a thick plastic bag or rap in thick paper, give it a good
whack with a hammer, it should shatter. Paint makers would use a
cast iron mortal and pestle for this, for larger quantities, a bucking boad
as it is called in the US... a cast iron plate about 50cm square with a rim around it, and a special shaped large-headed convex hammer; these were used for crushing ore in old-time assayer's offices.

You may still want to filter it. After it dissolves, see if the solution
is clear and free of suspended matter.


Thank You so very VERY MUCH for the excellent advice !

i was extremely interested and amazed with your knowledge about the bucking board and bucking hammer and googled it straight away as im really one for collecting the tools of the old fashioned world because they always intrigue me!

alas i couldnt find one for sale here in the UK but now armed with this knowledge i will be keeping a keen eye open for one !

i should have the rosin by the end of next week fingers crossed, i have a pestle & mortar so will be crushing it with that but im always trying to crush things like this rosin with the pestle & mortar and just want a fine powder with very much less effort so will be building a device to crush it one day soon (as soon as i can get all the parts for it !) i dont know what its called but its a sort of drum/container that is half filled with heavy ball-bearings and this drum/container sits side-ways on a base that continously rotates it so whatever material you put inside it gets slowly (but noisily,lol) crushed into a find powder, eventually, might take a few days or a week being on continuously but will make in 'ible about it!

Sorry for straying from the point and this 'ible, i also wanted to ask if i could make this into a non-alcohol based flux as i have a no-clean flux that is alcohol based and it annoyingly evaporates FAR TOO QUICK for my liking, so what would be the best way to do this ?

Oh and one last thing (Colombo Moment, lol) its very difficult to get Denatured Alcohol where i am too but a quick Google-Search said that Methylated Spirits are the same thing but the problem im thinking is that metylated spirits are coloured purple here in the UK so people know what it is clearly from just looking at it and other safety things but im worried that it will spoil the flux i am trying to create with the rosin, is there a substitute for denatured alcohol that is more commonly found and i could buy a few litres/gallons of it without breaking the bank ?!!!!?

once again many thanks in advance and a HUGE thanks for the trip to the past for how ore was crushed in the beginning days, very very interesting info !


(bucking board...) I used to be a chemist out in Wyoming in a mineral laboratory. We still used stuff like this on occasion. Once I visted a "ghost town", a gold mining camp from the mid 1800's. I could identify every piece of equipment in the assayer's laboratory.

Just use a hammer and baggie on the rosin. All else is overkill.
The machine you're describing is called a "ball mill" and is useful,
but is overkill for this job -- you're going to dissolve the stuff, so
getting a precisely graded powder doesn't matter. Use a ball mill
for making a powder when the powder is a final product. (And I
suspect rosin will make a big mess of the inside of the mill, sticking
to everything. It's supposed to be sticky.)

Notice I say "whack it". Rosin is one of those things that might, if
you press it, flow like a liquid, but usually will shatter if given a sharp
blow. It should remind you of treacle.

(methylated spirits) the dye probably won't harm anything. If you still fear it, look for "Shellac Thinner" at a paint store. Buy it by the pint
or less, like 250ml. This is just spirits, denatured/methylated/whatever. There are ways of removing the purple color, but they're not particularly simple, safe or easy. If you can get a little bag of
activated charcoal, used to purify water, pouring the meth. spirits
through it might do the trick. "Denatured alcohol" is just American
terminology; although we often do not use methyl alcohol as the denaturant. Gasoline is often used instead to poison the ethanol
in a way that cannot be reversed easily.

(evaporation retarder) I don't know of an official ingredient. But spray painters use an evaporation retarder (called in the US, "lacquer retarder"!) to control the evaporation of spray lacquer. Ask at a place that caters to the automobile repair or furniture refinishing trades, or an industrial paint store. I don't think you'll need it.. I think I recall that most retarders are some sort of ester along the lines of butyl cellosolve. You won't need much if any. You might be able to bum some at a shop that uses it. (Any place that paints autos or motorbikes, probably.) It may be hazardous, read up on it on wikipedia. Bum some butanol from a school or uni lab. Safer, stinkier.

Keep it simple. Get the rosin, whack it, dissolve some, test it.
You can do all this in the kitchen or garden shed with ventilation.


Now thats what i call Legendary Help !

Once again i am in your debt Original Woodchuck !!!

yaa your darn-right about the ball mill being overkill for the rosin, totally understand its structural make-up alot better ! ive always wanted to make pyro aluminium (400 mesh) for making some fireworks with so will be making one someday when i have acquired all the necessary components!

hammer & a baggie to the rosin looks to be the best and quickest way to do this and thanks again for putting me back on the rails, lol !!

usually i love a great deal ove overkill (as its sooooo under-rated, lol x 2 !!) but just as you say, its going to be dissolved anyway so not really much point in making it a fine dust equivalent of fingerprint powder !!!

i really wish i could find a cheap outlet to buy chemistry laboratory equipment like they have in schools because that apparatus is really expensive around here, i do have some activated charcoal (somewhere, lol) and meths and remember there were some really neat glassware to aid in purifying/filtering stuff, but i suppose i should stop day-dreaming about stuff i dont have and just get on with what i do, so will try using the coffee filters with the meths and activated charcoal as that stuff i have to hand but will be looking into the auto sprayers places for any quantity of BUTYL CELLOSOLVE or something very similar and i did a quick google on it and its perfect for resins and its one of the fastest evaporating ethers so once again O.W i stand beside myself in sheer Awe at your most-excellent advice and truly great knowledge-base !! Absolutely amazing !!!

Also, to make this flux i want to create a non-alcohol based flux (so it doesnt evaporate whilst using it) do i just make the rosin flux with the ether type mentioned above in caps and then add the same amount of water into the mixture, then let it evaporate at room temperature in a well ventilated room ? would that leave me a virtually alcohol free liquid flux ?!? (sorry, totally forgot to say its a liquid flux i want to make, and maybe a slightly thick consistency so that IC legs on SMD/SMT components stay in place when placed on a fluxed surface ready to be solder-tacked into position etc!) not too runny, not too thick, but ive alot of experimentation ahead of me now and cant wait !!!

Once more i thank you immensely for such great advice worthy of remembrance throughout the ages !


no doubt i will be back here with my test results and findings and may even do a short 'ible too if i get some good results !!

(butyl cellosolve) Don't know how this would work as the sole solvent for rosin. There are two issues: will it dissolve rosin? and Will the resulting flux be good for soldering? (would it damage components? Attack PC boards? Or, annoyingly!, dissolve the silkscreen info on the boards? A danger with butyl.c. is that it might be *too good*, causing the flux to spread out.

(water) What water? Rosin is insoluble in water, which is why the tree secretes it to seal wounds. If you dissolve rosin in alcohol or some other solvent that itself is miscible with water, I *guess* that at some point the rosin will fall out of solution. (This is sort of standard lab technique.)

(duplicating commercial stuff) Your first hints about what's in a commercial product are the "contents" disclosure on the package. The next step is to look at a MSDS, which for products sold in the US, contains more information (but still, no working recipe or formula). These MSDS are posted online very often. The EU no doubt has similar disclosure forms; they are related to worker and environmental safety laws; I don't know what they're called. Then there's the google.

(alternate solvents) You might try what we call kerosene and you call paraffin. Or what we call "gum spirits of turpentine", don't know what the Brit. Eng. is for that. It is a solvent distilled from pine, smelling strongly of same. But it's volatile. "Pine tar", a thicker pine distillate, might work directly as a flux. It can be gotten from veterinarians. I have no experience with this, sorry. All this stuff is flammable -- be careful.

(cheap chem lab equipment) Hard to get. In the US, there is some sort of conspiracy to make the price of small quantities extremely high. This is to discourage illegal drug labs. You might try importing from Hong Kong or China. Chemicals are hard to get, too, same reason plus "terrorism".


Thank Again Original Woodchuck !!!

Once again im extremely grateful !

You know what, i'll just stick with the meths for starters and try filtering it through some activated charcoal to see the results in a nice small quantity! but at the same time research other spirits youve mentioned comprehensively and shall try to get my hands on some denatured alcohol too just to do the procedure as standard as described in this 'ible!

Yaa i totally understand (now!) why lab equipment is so darn expensive, it didnt even occur to me about the nefarious uses people would use this stuff for, guess i am a bit naive when it comes to buying equipment and tools not taking in for account what their illegal uses could be, definitely will be searching ebay China & Oriental Country Sellers for lab stuff as i really want to work with a few chemistry projects ive bookmarked over the years and am a member of the UK rocketry club for some fun!

Youve given me more than i could have ever dreamed of and ive got a great amount of details to chew on for now, will post my results as soon as ive made some flux and once again many mnay thanks for the extremely invaluable help these last few great days!


burningsuntech (author)beehard442010-12-06

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?

nadav (author)2011-06-06

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

eric m (author)2011-05-30

why not just lemon juice or vinegar?

handyman6042 (author)2011-02-21

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

craferr (author)handyman60422011-03-04

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.

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.

handyman6042 (author)2011-02-24

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 (author)2011-02-14

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.


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

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 (author)SharpyWarpy2011-02-19

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.

burningsuntech (author)2010-12-29


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.


hore (author)2010-07-17

hi, is this really work,

burningsuntech (author)hore2010-07-19

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

hore (author)burningsuntech2010-12-04

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

hore (author)burningsuntech2010-07-19

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

burningsuntech (author)hore2010-07-21

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

hore (author)burningsuntech2010-07-22

alrite thank you....

steveastrouk (author)2010-02-17

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

hore (author)steveastrouk2010-09-02

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

steveastrouk (author)hore2010-09-02

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.

About This Instructable




Bio: I am a distant relative of the Apache Warrior Geronimo. I enjoy working with electronics, wood, metal and gold. I love the flashes of inspiration ... More »
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