Make PCB Tinning Solution ("Liquid Tin") by Redox Flipping
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- เผยแพร่เมื่อ 20 ต.ค. 2017
- In this video we make a tinning solution for printed circuit boards.
Tinning solutions coat copper metal with a thin layer of tin. This is used to protect them from oxidation as well as make them somewhat easier to solder.
To make the solution we first get 1g of lead-free tin solder containing 95% or more of tin metal. Check the MSDS to be sure. Now to the solder we add 10mL of 30% hydrochloric acid. What we're making is tin chloride. The solution will bubble hydrogen as the tin dissolves. Leave it overnight and pour off the clear supernatant into 100mL of commercial metal polish that contains thiourea. I used "Tarn-X" brand for my experiments. You can also buy thiourea directly and use 5g per 100mL of water directly along with 1g of sulfuric acid. Anyway, however you obtain your thiourea solution, the added tin chloride will make it into a tinning solution.
Now just add in copper metal like that of a PCB and a thin layer of tin will coat it.
What's happening is that normally Tin chloride does not displace copper metal so you can't make tinning solution from just tin chloride. One perspective is that Tin has a lower redox potential than copper so it would actually consume energy to displace copper.
But thiourea forms very strong complexes with copper. This drives down the redox potential of copper to below that of tin. Now tin can displace copper.
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You don't need Tarn-X specifically, any thiourea based cleaner will work. Usually check under the categories of "Metal polish" "metal cleaner" or "Tarnish remover" when checking the hardware store. If you can buy thiourea directly then use 5g per 100mL of water and follow the rest of the video for making the tin chloride.
NurdRage Please send you a message
Sooo how do you make a PCP solution? :)
Nice vid :)
Sadly, at least in my area, thiourea-based silver cleaners are pretty hard to find.
Nice follow-up video would be making thiourea.
It can be done by making calcium cyanate,roasting it to get calcium cyanamide, and then reacting cyanamide with H2S, with or without CO2 in water slurry.
I might try that soon, but sadly I don't have much free time to do that :/
But if you wanted just Tin metal. How could you do that?
Dissolve lead-free solder in HCl, filter off all those other metals, and electrolyse solution. Tin crystals will grow
Excellent... sometimes NurdRage is one of the best ELECTRONICS channels on TH-cam.
edgeeffect check electoboom
Uh, have you figured out what the PCB is though?
Hey Nurdrage you told us in a previous video where you replaced the heating elements of your hot plates to remind you in 1 year on doing a follow up regarding the quality of the new heating elements and if the hot plates are still fine. Now it has been almost 1 year and here i am! Sorry if you already made a video regarding this, i might have missed it
Good memory!!! Doesn't seem like a year already. Time flies!
You know, I almost forgot about that. Can't believe it's been almost a year already.
This will SAVE A US A LOT OF MONEY!!! Thanks NR, for this great explanation! Companies have been harvesting ridiculous amounts of money on their proprietary tinning-solutions for too long now! Thank you so much!
This is very good to know that the ingredients for this solution are available. I don't normally tin my PCBs because I don't need that extra protection against oxidization but maybe one day I'll need this.
This made my day, my nomad grandpa (& best friend-RIP🌹) taught me how to build circuit boards, read (reed) circuitry components (eg. transistors are color coded) & how to solder when I was a young child😌. We use to make everything from fm listening devices that would fit inside pens to metal detectors, etc...what a gift he gave me.
A lot of ppl thought he worked for the ČÏÂ but no he was just a very intelligent man who naturally thought outside the 📦 (aka: a free thīnkêr ) sooo long story short you remind me of him🤔, all the best with your journey my friend✨
Absolutely fantastic, I am a long time user of your peroxide/muriatic acid etchant recipe and this video has been on my wish list for years. Thanks so much.
I've had everything I need all along, but have been buying fairly expensive liquid tin for some time. Awesome, I can't wait to try it out. Thanks
You know...I haven't actually taken chemistry. Watching you and a couple of other channels, I can follow along but sometimes I get REALLY lost! Now I have a few new terms to look up and expand my knowledge base. Just wanted to say thank you for being such an awesome springboard :)
This is great, cause I just started making PCBs yesterday. Thanks!
It is pretty neat bc I was wondering if there is an easy way to do tinning for Atari, NES cartridges. The contacts oxidize over time and it prevents the game from working. Sandpapering the contacts each not is not a good idea.
Thanks for this! I just made a batch and it works as good as the Liquid Tin that I've used in the past. I got a gallon jug of 31% muriatic acid at the hardware store for about $8 and a bottle of TarnX for $6. I didn't have a way to heat the final solution, but after straining it through a coffee filter, the solution was pretty clear. I think I'll purchase thiourea crystals and use the 5g/ 100ml distilled H2O to replace the metal polish. Looks like I'll be investing in a hot plate/ stirrer as well.
So many people will find this handy! Thanks!
Heeey, this is actually really useful knowledge for me. I knew subbing to this chemistry channel would pay off for an electrical engineer.
Great stuff! I could have used this back when I worked in the electronics industry. I may yet use it for one of my infrequent projects.
Thank you Nurdrage! I love your videos and I do not have a strong background in chemistry so I really appreciate the explanations. (I still have to look things up, but you give me a place to start!)
Thanks so much. Iv been wondering about this stuff for years.
That was awesome to see. Just some back grounds from a PCB-Designer:
For professional PCBs, bare chopper is a clear no-go, chopper is too sensitive too oxidation. In Europa, we have mainly settled for chem. NiAu or chem. Tin (as shown here). In asia, it is a bit more complicated, but you see a lot of OSP (organic surface protection) over bare chopper - but everything else is available "on demand". OSP and chem Tin are best for the soldering metallurgy, the solder can interact with the base chopper forming strong joints. Chem. NiAu mainly is a good for storing and handling, the soldering metallurgy is kind of a mess, as the gold is going into the solder alloy and the solder joint beeing formed on the thin Nickel Layer.
very interesting! I might do other coating processes in the future.
Checked back to write this down again. I pulled out my solution and it is either cleaning only or making a slight copper deposit now. The copper is that new bright kinda pink. It is very old. I made it a few days after you published 3 years ago. I read comments and 2 weeks to a month is all it lasts for but still had to try. The crystals only recently turned to dust in solution. It sparkled with needle crystals for years.
Okay I've got one for you. More electrochemistry. I've been thinking about Baghdad batteries. What is the ideal metals to use in the reaction? Is water the best liquid to use for a slow reaction (not wanting to clean the metal to often or have to replace it often)? What are the rations of fluid to metals for an optimal reaction? My mind has been going wild thinking about all this, alas I have to means of testing. Thanks for your awesome videos!! I always enjoy them. I thank chemical engineers for making most of our tech possible.
Thank you for making this... It will be very useful...
Excellent. That was good to know.
i don't even speak English and i don't understand what you talking about or what you are doing
but i like watching your videos because they make me relaxed :P
Your English is pretty good for not speaking it!
@@padathir LoL yeah, you're right
This was very interesting, thanks!
Thanks - a great tutorial!
Nice one; good explanation.
Thanks, will be doing this in Costa Rica :)
I dunno what tf is going on but I enjoy watching your vids.
you do some amazing things
Big thanks Sir!!
Thank you for this video. Can you tell me how thick the layer of tin will be before the deposition stops and if it was necessary to buffer up the solution once the tin was dissolved by the acid so t hat your PCB would not be damaged?
Excellent video. Could you please make a video on through hole activation and plating ? 🙏
Great video 👍
I can't find tiourea in stores, what else can we use instead?
I love your videos and I think they are great. But occasionally I can't figure out if you are speeding up the video. Could you add a clock or timer next to your experiments?
Would leaving the copper wire in the solution for a long time cause tin crystals to grow like in the classic iron nail in copper sulfate reaction or does the tin plate the copper to such an extent that it passivates?
Hi NurdRage, Ive been a fan since freshman year! I just graduated collage and i've started my first real engineering job. I was recently educated by the head of engineering that we can't produce ROHS compliant boards because of the threat of forming a "tin whisker". Is the formation of a tin whisker at room temperature just another means of forming the allotrope grey tin?
Your a gem, please post if you sell any videos that have a compendium of you processes. I would love to buy.
I would be interested to know more about how the mixed solution ages. Is there any way to inhibit the formation of stannic chloride.
I have used the ready mixed electroless tin plating powder, which I assume is a mix of stannous chloride and thiourea, but its shelf life is very poor when mixed. I plate my PCBs immediately after etching because it is difficult to obtain a good tin coating once the copper has oxidised, and this happens really quickly. Is it worth washing in dilute HCl and boiling the distilled water to drive out oxygen?
Your video shows a good tin coating on not very clean copper, any tips for obtaining the best results?
I have subscribed to a number of chemistry TH-cam sites, but practical chemistry is difficult with the restrictions on obtaining chemicals. In the UK the chemicals in over the counter household products appear to be very limited compared to those sold in other countries.
How do you do that cheap and amazing looking "golden brass plating" (AKA Gold plating) the Chinese recently started adding to alot of products and this process doesn't seem to be that expensive and find out that even in the cheap products it is somewhat of a long lasting finish
Yeeessssss !! Thank you !!!!
A long time ago I regularly used commercial tinning solution - the made-up solution didn't last very long - maybe a week or two
@@lewisavinash1 How'd it go
Great video. Very hard to find all the items in New Zealand.
Question? If you buy the Hyaluronic acid as a powder, that I have managed to source. How and what would I mix it into to make a liquid and how much would I use of the powder? Or did I just waste some money.
This recipe worked perfectly, down to the white room temperature precipitate from the Tarn-X. Can NurdRage explain what compound the precipitate is? The reaction looks a lot like saponification. I wonder if there is a buffer or solvent that will adjust the temperature of the precipitation point.
Nurdrage...I've been following your vids for years now...great stuff....at the end of the vid....you said you didnt knw the storage life of stannous chloride.....since its used by all of the really gold recoverers/ refiners as an indicator for the presence of gold in solution ...the consensus seems to be that a fresh batch of stannous chloride will last abt a month before losing its oomph
I've done this before, mostly just for the hell of it. Used the rosin core solder as that was all I had.
It took an extremely long time to dissolve, and in all likelihood the solution was probably still mostly hydrochloric acid. I dropped a penny into the solution and left it for a couple of days and the tin did end up depositing on to the penny.
Would the HCl change the reduction potential of the copper on the penny? (This was a Canadian penny circa late 1970s, so 95% copper)
What's the alternative for Thiourea ? Can we use other chemicals ?
Is this the same process that's used to tin coat electrical wires? If so, do you know what the ratio of tin:copper is for different common size of plated wires is?
AWESOME!
A good companion video, would be the precipitation of stannic tin from solution, to reclaim the stannous tin and acid.
Thank you Nurdrage.
I experimented with 23% HCl, tin and thiourea >> ( thiocarbamide) in glass container, but didn't work. I used 97% tin + 3% copper, it takes about 1 week to dissolve
It seems normal to me with hci > 23%.
Do these products look correct ?
Order operations matter ?
Thank you for your understanding.
Can I use a small amount of pure thiourea, some tap water and h2so4 instead? don't have distilled water...
Can i also use tin lead based alloys instead of pure sn ? If lead not react with hcl ?
Just curious, could you use this to plate onto other metals?
How does one dispose of the excess tinning solution? Is there another neat chemical reaction to make this inert?
thank you , chemistry is interesting
Great video. What is next? Maybe photo-resist chem?
Hello thanks for the great video.please can you say in gram how much of thiourea do i have to put with 10ml of hydrochloric acid above and 1gram of tin lead free .thanks for the reply
what is the molar concentration needed for this tinning process
i saw many different methods of making tin choloride using many different percentages of tin to hydrochloric acid
some uses 12g of tin with 50 ml of hydrochloric acid
other uses 10g of tin to 20 ml of hydrochloric acid
and you here used 1g of tin to 10 ml of hydrochloric acid
Does liquid tin work on anything other than copper? I have a need for a white conductive powder and haven't found anything I can buy, so I figured I would try to make my own by somehow tin-coating titanium dioxide.
Can I use flux core solder if I smash it up and dissolve the flux in acetone, then thoroughly wash?
+NurdRage can you filter the precipitated if the goal is just to see the reaction later?
Hello, do you know about brass materials? If I put a brass bar, for example, happen the same thing?
Thanks.
Thank you for this. If I have sncl2 and thiourea powder, in what ratio should I mix them and with what to make the tinning solution?
yes
will this process work on aluminum, or would I need a different solution/different steps?
Can this be dehydrated/boiled down to crystals? Then rehydrated later, to prevent it degrading in storage? And if so, rehydrate it with water or HCl ?? Thanks
Could you use this stuff to tin a soldering iron?
hi nurdrage,
can you make a video on pcb through hole plating for double sided pcb?
You need Palladium Dichloride + EDA solution to do it.
i cannot get this Eo math. is it just electrical current generation by Cu dissolution, and utilization of this electrical current with Sn recovering ? electrical current will stops when Cu-surface became covered with Sn, so Sn-layer thickness will be very very thin?
If it wouldn't be too much of a hassle, could you refine uranium ore into the metal or yellowcake?
Hi Nurdrage, could 20% Hydrochloric acid work, if I use more in the ratio?
I have copper plated things with acid and copper. If I make a solution of acid and tin and a solution of acid and zinc can I mix them together and brass plate steel?
Thank you
Really neat! Any chance you could take a shot at doing electroless copper deposition on fiberglass with easy to get chemicals for making PCB vias?
You can deposit copper on fiberglass?
What should be the process of disposing of the mixed solution after it no longer works? Is there a way to neutralise it to make it safe to flush?
+NurdRage, can you please make videos on organometallic compounds, really appreciated, I heard that they have interesting properties
I agree I would love to see some organometallic chemistry. Maybe make and use a catalyst?
bismuth trichloride and a soluble iodide in hcl can be used in the same manner to immersion plate copper with bismuth.
thankyou so much nurdrage
I wonder if this would work with bismuth, though the issue is the bismuth is hard to keep from oxidizing with oxygen, so you get BiOCl and not BiCl
i got 600ml of highly concentrated Sncl2,
btw how much thiourea needed for 1x use?
Will thiourea dioxide work or do I need a different thiourea?
Can I replace thiourea for only urea with similar properties or the same? What kind of solution can I replace for Thiourea? Does have one?
Could that be used to refine Tin, to get rid of Lead contaminated Tin?
Hi there! I have stannous chloride dihydrate, thiourea and sulfuric acid. Please can you tell me how to mix them properly in order to obtain this solution? I have a white precipitate after the solution settles for a few hours
A quick search of my local hardware store's website and they've got exactly the right silver cleaner. It's called "Tarn Off", so I might pop over tomorrow to pick some up and give this a go! And of course, grab a sausage sanga while I'm there!
Be sure to check the back that it contains thiourea. From what i read online "Tarn Off" brand doesn't have thiourea.
got "Tarn-off" to try..thiourea 65g per litre + sulfamic acid 35g per litre
Hi NurdRage. The solution crystallizes when it gets to room temperature. is this normal or should it stay in the clear liquid form?
Just did this - worked great! Only difference I used a local brand silver polish instead of Tarn-X. But I have to heat it up to make it liquid, when coolling down it turns into white paste. Any way to keep it liquid and clear without heating?
I had the same problem. I bought some Thiourea from a photographic supplier, and I think it was the extra things in the Tan-X that caused the white formation of what he called Salts. I did not want to have to heat it up to use it.
Can I use EDTA instead of thiourea or other chemicals ? Please answer me😢
Can I use another compound instead of thiourea?
Tarn-X ugh...that rotten egg scent every time my mother had one of her DAR tea-parties... My engineer dad explained how silver could pull sulfur atoms out of the atmosphere enough to tarnish in just a few months; even when in a velvet-lined box, and that still blows my mind.
NurdRage, I dissolved 10 oz of 96% pure tin into 2 quarts of acid, it did take a while. I bought 6 oz of Thiourea crystals, how much of the Thiourea (once I mix it with water, will I need to make the 2 quarts of Stannous Chloride into a tinning solution? If I don't get an answer, I will start adding it a little at a time, then test it with some bright copper, I would expect that once it starts working, ia can stop adding the Thiourea. I tried the first time using the Tarn X , but the salts were so thick, and I had to heat it to use it, that was not what I wanted. The Thiourea crystals were easy to find at a photographic supplier. I have 6oz of Thiourea crystals.
can you tin coat steel with such a selution? that will be great for the boating industry even as a priming coat under pain
prevent rust....
Important - your cleaning chemical contains not only Thiourea, but also sulfamic acid #1:40 Seems like it is also a key component. Some other recipes mention replacing it with tiny amounts of sulfuric acid. I am wondering whether it can be replaced with something safer...
Would this work on Steel or Nickel instead of copper?
thank you very much for your videos... i have a question please
how much of thiourea acid i have to use if i have it in it's basic chape ( powder ).. of course ( in grams )
5 grams
How to remove lead from tin.... Could you please tell me how to refine tin? Thx
Quick question: Is this kind of "liquid tin" the same type that is used for silvering mirrors? The commercially available tinning solutions for making mirrors is also a clear liquid with a short shelf life, but it doesn't show any kind of deposit or film on a piece of glass until the silver solution is added afterwards.
No that is silver nitrate aka. Tollens test. TH-cam it and check the video by a youtuber NileRed (he is also a chemist). He silver plated some light bulbs.
Fantastic Channel!.
Have one question; can the tin plating described here be used as an etch resist so a PCB is plated, resist cleaned off and then etched with common etchants (Sodium Peroxide, Ammonium Peroxide, Ferric Chloride, Cupric Chloride, etc) but leaving the tin still bright? The reason for asking is that a thicker deposit of tin (if required) could be electroplated onto the 'solid' board before the board is etched. Am' also going to try to make Cupric chloride after watching your channel, Great work.
Its called "Pattern plating" and i second that, it would be very interesting, they say that it has better performance then just the film on the copper clad, besides it would allow you to eliminate tenting because the tin would protect the vias...
Havin said that, thanks for your videos man...
Could you breefly through a short definition of chemical etching?
Hi thanks for this Video it helped me a lot. After an odyssey of finding a solution with thiourea in Germany, I was able to mix some solution and it works perfectly. But after a minutes when it cools down it becames solid. I have to heat it up to use it. Any ideas why it acts like this?
Nevertheless thank you again and keep the good work!
Would this work on small BRASS figurines?
How many grams thiourea did you use to make 100ml thiourea solution?
POGGERS! ty sir