We were using rosin/ethanol solution as a flux during my work as electronics engineer in the 1970s-1980s. It worked pretty well. For me the best way to use it with the solder wick was to dip it into solution and let it dry. The wick became much more usable. Thank you for this very interesting video.

Hey now, making what you need with what you have is the heart of engineering. Enjoyed this one a lot, thanks Mr. O'Stuff.

Rosin (pronounced raw zin) is a component of natural pine resin (pronounced the way you think it is) that is distilled out of the resin kind of like the way gasoline is distilled out of raw petroleum. Ethyl alcohol works best as a solvent for rosin. Denatured alcohol (ethanol with added methanol) works good too. You can use less alcohol to make rosin paste but it takes forever to dissolve. The commercial stuff has additives to lower the melting point and make it dissolve faster but I don’t know what they are. You can use a salt vinegar solution to remove oxides and clean soldering pads too but get it all off before soldering. Borax in water does the same thing. I learned all this in High School Metal Shop in 1968.

@gorak9000

5 ай бұрын

Salt + vinegar makes HCl acid - probably not the best thing to clean circuit boards with before you solder - if you don't remove ALL of it, it will keep eating away at the copper for a long time. It works wonders on copper bottomed pots and pans though - scrub normally with soap, then vinegar + salt - takes ALL of the oxides off and leaves the copper bare and pink, and then some soap again. You'll have the nicest looking pots and pans ever (until you put them on the heat again, and immediately oxides will form again and make it look dark)

@markfergerson2145

5 ай бұрын

@@gorak9000 Yep, that’s why I said to get it all off. I used it many years ago to make cavities and waveguides out of sheet copper, and had some issues until I learned to have way more deionized water on hand than I thought I needed to rinse it clean.

@gorak9000

5 ай бұрын

@@markfergerson2145 For making wave guides and cavities out of copper sheet, wouldn't plumbing flux work? It doesn't seem to eat away at the copper forever like HCl does, and presumably some of it goes inside the pipes too and you end up drinking it... so maybe it's not _too_ toxic??

When I made my rosin flux, I filled my small bottle like yours to about 75% with Isopropyl alcohol , then kept adding crushed rosin until no more would dissolve. The saturated solution works fine, and lasts ages.

@jj74qformerlyjailbreak3

5 ай бұрын

Love making flux from the many different pine trees in my local. I think the blue spruce makes a great smell when being burned.

I just use my can of rosin flux since I'm no engineer and only solder once in a while for my model railroad electronics, i.e., LED's, LED strip lighting, crossbucks, etc. I think all my solder is Kestor. I apply my rosin flux with an A-proxo knife or small screwdriver. I never use X-acto knives because I'm not exact, just approximate. Cheers from eastern TN

Resin and Rosin are two different forms of the same product. Pine sap unrefined, is Resin Rosin is after it has been refined by heat, filtering etc.. That is why you Rosin your Violin Bow, because putting Resin on it would lead to a very sticky situation.

Small tip : just look in the MSDS of various fluxes and you'll find proportions - for example a decent liquid flux Topnik TK-83 from AG Thermopasty contains up to 85 % isopropanol , < 20-25% rosin , < 5% benzoic acid and

@orange11squares

5 ай бұрын

i have Topnik TK-83 and i don't like it at all....and the smell is really bad , full of chemicals.

@mariushmedias

5 ай бұрын

@@orange11squares That's funny considering it's actually made out of just those 4 ingredients. You're smelling burnt rosin, other fluxes add extra fragrances to make the fluxes smell better.

@orange11squares

5 ай бұрын

@@mariushmedias i looked at the bottle, they don't say the ingredients other than rosin.

In my childhood and youth there was no liquid flux around in the GDR. So i used to prepare a more or less sticky mixture of crushed Kolophonium, which is used by Violinists to resin their bows, and normal alcohol (95.6% ethanol some 4% water and a lillte bit of Cyclohexane to avoid drinking of technical alcohol). It lasts a while to dissolve but it the honey like substance worked very well for soldering.

@pileofstuff

2 ай бұрын

That "Kolophonium" is the same stuff I used here. (when I searched that word, I was directed to this Wikipedia article: en.wikipedia.org/wiki/Rosin ) I suspect people in other countries at the same time were doing things similar to you. Elec tronics supplies are very much easier to buy in modern times than they were 50 years ago.

I tried the DIY rosin flux years ago - mine was way more concentrated - and it didn't work any better than the Chinese fluxes, so I went to a pro shop and bought Caig(now DeoxIT) Rosin Soldering Flux and it's night and day better. With the smallest amount it can make any bad solder super shiny, the problem is that it's so sticky/gluey it's hard to clean, ie, with IPA/brake cleaner it still feels sticky so you have to use a strong surface spray cleaner(Nifti) to totally get it clean. It also makes and cheap wick super good.

I got some flux from a friend, it was a clear gel. It was freaking amazing! I wasn't using it for electronics though. It allowed me to solder a brass ferrule onto stainless steel cable though. I gotta get a hold of him to get more, simply amazing stuff! Just imagine soldering copper wire onto steel sheet.

For slightly oxidized surfaces is good to add a bit of citric acid to the mix (beware it becomes conductive), if need more texture leave it open so alcohol evaporates, in my youth I learned soldering from an very old technician (the guy was from the vacuum tube age) of course i am a fossil from the transistor age, making custom PCBs, using chemicals to thin the cooper mask and all chemical used were made from scratch, during that time we had not the luxury of the modern soldering irons. (sorry if my english not so good).

17:10 top tip, put the flux on the braid...

Non-activated soldering flux (expired patent) May 1, 1973 The patented recipe for flux is: 1) Isopropyl alcohol (60-70% by weight) 2) Water white rosin (30-40% by weight) 3) Glycerin (2-3% by weight) 4) Cationic flurocarbon surfectant (0.01-1% by weight)

3:38 😂😂😂 Yes I have these too. Whenever they need a pee sample I take a couple of these jars extra with me. They can come in very handy.

20% you have 4 times the amount of fluid as you have solid, so a mix of 4 to 1, so you have a total of 5 parts and one part is rosin, or 1 fifth, therefore 20%

@restorer19

5 ай бұрын

That would be a "rosin by volume" measurement, but that's typically only used for ABV (alcohol by volume), and definitely not for bulk solid powder volume into liquid. If you dissolve 5 cc of rosin (especially if measured in powder form) into 20 ml of alcohol, you likely won't get 25 ml of final solution volume.

@generaldisarray

5 ай бұрын

@@restorer19 however due to the Law of Conservation of Mass the amount of final product will be bigger than the initial amount of liquid

That was a neat video for sure, experimentation is always fun. Thanks for sharing, I never thought of doing that but now I'll have to give it a try.

You can add stearin to this solution, to make much better flux (you can make stearin from soap).

@rogierius

3 ай бұрын

Why does it make flux better? And in what way?

I made some liquid flux by dissolving paste flux in 90% rubbing alcohol and had to strain out the solids with a fine mesh tea strainer. The solids were the petrolatum they put in to make it a paste. Otherwise it's the same dissolved resen liquid flux that I put in a empty flux pen dispenser sold online. And yes it works. The pen get's it on without so much extra being applied to run off from the intended work area.

When I've done this I've just dropped the block of rosin whole into a jar of ethanol and left it for a couple of days giving it a shake every now and then. Worked well with minimal effort.

Great job! Very informative and interesting. Thanks.

I've been trying to do the same myself. I'd say the best way to try to benchmark the test is to use solid wire solder which doesn't have a flux core in it.(to test out the flux this will be the real definitive proof whether we got the sauce mix right or not since this is kind of like cooking if you will lol) I've done the rosin & ipa mix and it works but it does tend to evap fast I couldn't work much with a hot air station but with my iron it was decent. What we have to relalize is that most companies add extra ingredients to strengthen and maintain the activators which is something we might be missing. I was reading some data sheets and most companies tend to use acids whether malic acid or citric acid. I've also seen some use mixed Carboxylic acids as well but it is considered proprietary so I've been trying to get some people to talk to say what it is but I haven't been able to get them to budge. The next would be a stabilizer some fluxes are parafin or petroleum based which is why some folks commonly referred to vaseline due to the petrolatum. I hear paraffin oil for candle burning might work and also help absorb some of the smoke properties since it burns clean. Its okay but by smell I was able to tell some fluxes use PEG (polyethylene glycol) which is found in laxatives or shampoo making. Also glycerine at no more than 2% but your milage may vary some use it others don't. This is just a collection of information I've been able to gather. I hope others can chip in to help us refine or create a friendly formula for all. The big thing which I was stuck on was the Rheological properties and thixotropic properties which is how they get it to turn into a full paste or gel. This is what I would like to learn if anyone has insights.

Interesting experiment. As you did mention, this Channel is on electronics , not on chemistry or basic physics. But there are ways to dissolve more rosin/resin (in German it’s „Kolophonium“) and these Solution would work a bit better, I think. And, if you dare… There should be some easy way to make your own flux paste by mixing the rosin ,or better a highly concentrated rosin/ipa solution, with vaseline. So, whenever your struck by couriosity again, share your further experiments. I will watch and like 👍

I tried this a couple of years back using 99 percent IPA with the Rosin crushed up, mine did not blend very well, but i think I was aiming for a paste flux, all I ended up with was a pale white paste, I did try it for soldering and it didn't do much. That chinesium solder is shit, I bought a 250 gram roll , I ended up throwing it in the bin.

I use raw pine or cedar sap works great

@duanecjohnson

5 ай бұрын

Thats what I do also. redrok AD0TJ

@jackkondreck

5 ай бұрын

You don't dissolve it in anything? Just straight off the tree onto a solder?

It's a neat idea that I've seen around. Curious as to if the cost/effort is worth it compared to just commercial stuff. For me it'd kinda have to be a considerable benefit to do more than just the experiment or in a pinch type stuff.

good video and great comments

That rosin is cleaner than the stuff I can get locally from the music store! I made mine by dissolving it in hot isopropanol, heating it in a small polypropylene container in a microwave oven. I had to filter it through a cotton plug several times under pressure to clean it up- it was a pain to filter but it worked. Rosin is light sensitive; it will break down if left under light for too long, leaving a dark residue.

@hullinstruments

5 ай бұрын

High quality instrument grade rosins usually don't look that clean. They are complex blends, and the type of stuff shown in this video is what's giving away for free by the bag if you're in the violin business. Nothing wrong with it..... It technically works fine. But The darker pithier stuff you're purchasing from "the music store" is actually more refined and has very carefully developed characteristics over decades.....or even recipes that may be hundreds of years old. There's a huge difference and if you want to read more there are a lot of great articles on maestronet, and even entire books dedicated to rosin and varnish development.

@douro20

5 ай бұрын

@@hullinstruments Well the stuff I used was dark because that was all they had, and it wasn't particularly expensive. It contained a lot of carbon and it was a pain to filter.

I feel like breathing in methyl fumes would be worse than ipa fumes but I'm not a doctor. I just play one in video games.

Personally, when I use the solder wick I prefer to dirty it in the rosin powder: it becomes very effective

(-: my first try was cherry tree sap, fail. Found some pine trees, too much work, Bought some china resin and used Iso, worked great, strength adjustable.

I’ve spent 50+ years using nothing but commercial multi core 60:40 solder and nothing else works better for hand soldering. Life is too short for this sort of experimenting!

@pileofstuff

5 ай бұрын

You may have noticed I do have a few rolls of good 'ol 60/40 here. Experiences like this are more about learning than in hopes of finding a practical or cost effective solution.

Congrats, this video was mentioned on the Hackaday Podcast!

Ha ha. I use dirty pee jars too.

14:48 - You try to solder there on this brown patch what is at the copper, this will never work. Use citrus acid to remove the brown oxide before. I use all types of flux, but I started with Kolophonium and I still use it. But a good ventilation is always necessary. (I did not see a fan on your desk or a ventilation pipe to bring this fog directly outside)

Hey that reminds me, I have a half pint of that lying on my shelf for the last two years I haven't finished, lol. I used isopropyl the higher percentage you can get off the shelf everywhere. I used 8 of the resin blocks you have there and crushed them all into a bottle I only added enough to get everything to dissolve. after two years on the shelf, there is only an eighth teaspoon of white granules left in the bottom without any agitation. It is very thick compared to yours. I had read in one recipe to use Glycerin in a small amount was supposed to help with something and I picked up the Glycerin when I could remember to. and that was a year ago so I need to finish this it looks promising. that sounds better than buying another $20 bottle of liquid flux. but heck I have another year to go before I need a new one now. lol

Every liquid flux I've ever used seems to flash off too fast. I do have a tube of Amtec which is great...especially for cleaning pads with solder wick/braid. I have a couple paste flux tins that I purchased from Jeff Bezos...I've had mixed experiences (some are good, some are not). I've considered trying to make a paste flux but haven't had the motivation to figure it out. I have seen some people just stick their hot iron into a chunk of rosin and bring it over to their work, but I have not tried that method myself.

@Sydney268

5 ай бұрын

It's still effective after it has dried, it's used for wave soldering and you have to let it dry first.

I made my own a few years back, its suppose to be a paste not liquid. Let them evap a little the ml scale would need much more product as there are air gaps between particles, you mixed them a little to strong on the alc. it should be the same as he paste in the larger container when done

The last desolder on old board connectors, was on MUCH LARGER copper area. Lack of desoldering most likely soldef melting, NOT the flux performance.

I sometimes use this with around 35% rosin but beware not to spill because it leaves a sticky mess.

@pileofstuff

5 ай бұрын

Yes it does get sticky. Cleaning the hammer and syringe after the video was a bit of an ordeal.

isn't the solvent isapropol or methyl alcohol just a vehicle or media to carry the rosin which is used to block oxidation of the metals? then which ever solvent works the best is preferred. I have some really crap solder braid which I can get to work better by applying flux to it the solvent evaporates leaving the rosin behind to melt with the heat of soldering and allow the solder to flow by capillary action into the wick. nice experiment!

High tech alchemy 😆--- I pronounce it as "rosin" and not "rosin" -- the difference between agitation and aggravation is you agitate the solution and it aggravates you -- a final consideration for flux is ... how well does it clean up?

@pileofstuff

5 ай бұрын

It cleaned up very easily - at least while it was fresh. But I suspect cleaning with alcohol at any point in the future should work well. (a lot of problems are solved by adding enough alcohol...)

@johncoops6897

5 ай бұрын

You realise that "Rosin" and "Rosin" are the same word?

@tiagoferreira086

5 ай бұрын

@@pileofstuff Once upon a time a wise man said: "a lot of problems are solved by adding enough alcohol...". You are absolutely right 😂🍺🍷🥂

I've used isopropanol (100%, not 70%!) and ethanol. Both make a very runny flux and it can take a bit of time to dissolve. Not sure how much rosin I used (a random amount). It works for example refilling pens or if you need something to apply with eg. brush or spraying. When you want a paste, you want something else. I've used liquid also to make some partially dried solder paste more or less usable.

@pileofstuff

5 ай бұрын

I was using 99% for this experiment. I wasn't confident that whatever the other 30% is in the lower concentration alcohol would be helpful.

@hoggif

5 ай бұрын

@@pileofstuffI think you told (or indicated) that on video. If you had 70% (common in some countries) the 30% water more than probably.

@pileofstuff

5 ай бұрын

@@hoggif Sometimes that 30% can also include some oils, especially if it's labelled as "rubbing alcohol".

@hoggif

5 ай бұрын

@@pileofstuff I think in US that is also a possibility.

Very interesting. I wonder how just the alcohols would fare soldering. Is the rosin actually doing any work?

@pileofstuff

5 ай бұрын

As I understand it, the rosin is doing most of the work, and the alcohol is largely just a solvent and carrier medium.

You can also mix vaseline into it and make paste, from my limited testing it worked great

@pileofstuff

5 ай бұрын

Interesting idea.

@alexstone691

5 ай бұрын

@@pileofstuff I melted it in a glass jar in pot of boiling water, work great mixed really well but had to add little ethanol so it dissolved properly, it did dry out after months but its easy to add little bit of alcohol into it

@blablaenfrak8481

5 ай бұрын

​@@pileofstuff you can use benzoin with alcohol and vaseline it gives a better result as well as salicylic acid (aspro) the disadvantage is the nauseating odor when welding on peut utiliser du benjoin avec de l'alcool et de la vaseline ca donne un meilleur resultat de mem l'acide salicylique( aspro) l’inconvénient l'odeur nauséabond lors du soudage

Yes you can! I've done it for years 😅

@Onkel.Moetrik

5 ай бұрын

Hello Mr. PileofStuff (I don't know your name🥸) It's no longer in the middle of the night, the notification woke me up, so I wrote the comment half asleep😝 I have been experimenting with rosin for a couple of years. I have tried IPA 99.9%, Acetone, turpentine (white spirit), and ordinary household alcohol 97% - you name it🤭. My conclusion is that it is not that important which alcohol or solvent you use. There is not much difference, because the alcohol/solvent vaporizes so quickly, but you *really* have to pay attention to, what the fumes might contain. Also, I use a lot more rosin than the 25% you use. So my potion is extremely sticky (no wonder rosin is the main ingredient in epoxy😜) For making a gel, I haven't found the perfect solution yet. Right now, I use Vaseline. Vaseline is based on kerosene, so ventilation is needed. I can see, that some people mention things like starch, but be careful with additives that burn. Burning means ashes and that usually makes a big mess. I guess some kind of natural wax would be great. I have several types of flux like a gel or crème, but I bought it in China, so I don't know what it's made of. Furthermore, I have one like the can you have, and that smells almost like plastic when it melts.. BTW, rosin is a superb isolator. A really heavy mixture is good if you need an isolation "paint" or a makeshift solder mask. Also, I suggest that you buy rosin in 500-gram bags, it is much, much cheaper. The last time I ordered I bought 2000 grams, (I have an electronics store where I sell it) and I paid almost nothing. As usual, the shipping was way more expensive.. Finally, heavy grinding isn't necessary, after a couple of hours in the solvent the rosin will dissolve. That was my two cents.. Claus

Nice. For thickening agents Xanthan Gum or Corn Starch might work? RS Components here in the UK refused to sell me lead solder (restricted item). The flux pens & wick that did turn up came with *33* A4 pages of safety info. CPC Farnell seem better. I have an order on the way.

@douro20

5 ай бұрын

They will only sell RoHS restricted items to businesses in industries which have a valid end use waiver under the RoHS Directive.

@michaeltempsch5282

5 ай бұрын

Xanthan didn't work for me with methanol/ethanol (during the hand sanitizer shortage during the early pandemic) - dont know how it does with other alcohols though. Xanthan did work with BAC which for skin use is diluted to like 99ish % water. For flux I'd be concerned with residue for both xanthan and cornstarch, even if it'd work.

@noggin73

5 ай бұрын

@@douro20 CPC Farnell sent me some. I used the name of the company I work for just in case 🙂

Engineering Marvels says "rah-zin" not "reh-zin". :)

I made my own liquid flux a long time ago, because on our Ali friends it is very difficult (at least I could find it) to get a bottle of liquid flux. All come in the form of pen unfortunately. I used a 2:5 ratio and used it a couple of times and it worked pretty good. But after letting it sit for a year.The rosin and the IPA (not the beer) seem to lose their bond and I ended up with a bottle with a ball of wet rosin floating in a jar of alcohol. I didn't try to revive it and I am still looking for a seller that sells the pen flux, but than in a bottle 😀 That also made me think that it is not just rosin and alcohol. There must me something else in there to keep it nice and liquid. But anyway, if your batch holds up... I'd like to buy some from you 💰😅

@thiagokeizo

5 ай бұрын

You can use glycerin or something similar to keep the stuff dissolved

@DustinWatts

5 ай бұрын

@@thiagokeizo Never heated glycerin. Your sure that's ok to do?

What's the reason for using highly toxic methanol over relatively safe isopropanol or ethanol?

@pileofstuff

5 ай бұрын

high concentration ethanol is not easy to get here, and if you can find it, it's very expensive. Methyl isn't *that* much more dangerous than isopropyl as long as you don't get it all over your skin. (and, obviously, don't drink it)

@notsurt

5 ай бұрын

​@@pileofstuff Here in Australia we can get methylated spirits (denatured ethanol, doesn't actually contain methanol these days) for cheap in any supermarket or hardware store.

@edgeeffect

5 ай бұрын

It's not like you're gonna drink your flux. ;)

@notsurt

5 ай бұрын

@@edgeeffectYou absorb it through your skin.

21:12 -- F yeah it helps!!! 😀

I tried with AliExpress small box of hard rosin but suspect it's crap quality as the end result for me is crap.

Good video, but not something I would not try myself, also since using tip tinner my my use of flux is seldom to rare.

I prefer IPA, India Pale Ale

@pileofstuff

5 ай бұрын

I'm more of a stout guy, myself...

@graftedin3

2 ай бұрын

@@pileofstuff I like both

Awesome, being lazy ish as .my body starts not to do what i ant anymore even unexpwected thing only old people need to know about so we can try not scare our belved children and grandchildren~ doesnt help havig many many passanger car accidnts,oh sry i went off course~i subbed the bench reminded me of muy days builing motors for some reason~ ok now after 25 rs of computing~im 2nd year now building drones.!now ima going to hopefully learn from u about Flux,bit like argon imo..thank you for sharing in advance,much love from south aussie outback!

@MichaelRogersJesusrules

5 ай бұрын

Good stuf! im sure we all try to save money just to be cheated with uter rubbish solder~Goo d to know the homemade resin / paste works.Yay!. Thank you again for sharing.xo

These tests are ridiculous! Your using flux core solder? You are guaranteeing tainted results! You apply paste to the wick approx 2 inches up test on the end and cut off the inch tested, but then use the next inch also fluxed for the next test which you dribble on the board not on the wick. No surprise that after that test the last one is worse, it s also dribbled on the board not on the quick and that part of the wick is the untreated section probably. Just ridiculous! I actually wanted to see this. Do it again! Use solid core solder only. Cut your wick test pieces first and saturate them individually and try to remove it again. If your going to test something you have to isolate it!

This is not homemade. You need to go out and pick resin from pines or other plants.

@pileofstuff

5 ай бұрын

It's too cold for that kind of foraging at the moment.

Dave, watching you struggle with soldering using those terrible "hoof" bits makes me sad 😢 Fit a CHISEL bit, so that you can add heat to both the PCB and the Component lead at the same time. The hoof bits only have one flat face, so you tend to put that against the component lead, which then draws up all the solder. Then after absolute ages, the PCB eventually heats up enough and you get a blob-ulated joint every time 😂 . If you use a chisel bit you can easily heat BOTH parts equally. Generally you'd put the wide face down so the pad gets a bit more heat, with the side of the chisel on the lead. Your joints will be far quicker, you will reduce the thermal stress on the component, and it'll will look heaps better too.

@pileofstuff

5 ай бұрын

Everyone has their preferences.

you need good quality flux not that Chinese one in little boxes its trash... also you need to leave it at least 24h to stay and than use it.

Need to zoom in --on your soldering --camera is way too far from your work --hard to see !