> chemistry > divers > make-pcb-tinning-solution-liquid-tin-by-redox-flipping-nurdrage

Make PCB Tinning Solution ("Liquid Tin") by Redox Flipping

NurdRage - 2017-10-21

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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NurdRage - 2017-10-21

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.

Thomas Rufer - 2018-04-24

Thanks for this info-bit! As somehow in switzerland thiourea is really hard to find in tarnish removers or metal polish, but is easy to be sourced from ebay as technical purity, thats the route i would like to go. Thanks!

Joseph Massimino - 2018-11-13

My tin is in ingots, can I still use them, or does it need to be cut up in smaller parts? Getting the measure quantities is difficult when shopping the internet for the best quality, I think these are 96% tin. One ingot is 5.7 oz. Should I be bale to calculate the difference and make proportional adjustments to get the desired results?

Joseph Massimino - 2018-12-07

You can buy it in crystal form at Adorama camera via the Internet. it is used in photo work is my best guess. 3oz for $6.95. It will have the same effect as the metal polish, in that it will produce the solids that have to be heated to dissipate. I was sure that it was some other ingredient in the polish that did that, but not being a chemist, I had no idea.

Bruce T - 2019-05-11

Thank You!

I was so pleased that I posted comment with Photo's at http://forum.fritzing.org/t/pcb-tinning-solution-homemade-that-works/7226

 I used three different metals: BernzOmatic, Oatey and some Tin sinkers (for fishing).

I cut 1gr of each metal into 1/8 inch pieces.

All worked!
Dissolving them (in hydrochloric acid) showed differences between them (all left overnight):

BernzOmatic completely dissolved, leaving some dark debris-like dust.
Oatey left big chunks of bright/whitish metal.
The sinkers (almost) completely dissolved - similar to the BernzOmatic.
After adding Tarnx: both the BernzOmatic and the Sinkers; the solution turned foamy, thick, chunky white.
The Oatey solution remained clear (looked like "Liquid Tin" product).

After soaking a PCB sample, each plated well (though the Oatey solution appeared a little thinner on the PCB, but that's only a visual observation and I didn't fuss much with cleaning it first).
Soldering to each is good - all solder well bonded.
This saved me a fortune of money as Liquid Tin price is astronomical!

Thanks again

ngoc diep nguyen - 2019-08-13

can i use sn63/pb37

edgeeffect - 2017-10-21

Excellent... sometimes NurdRage is one of the best ELECTRONICS channels on YouTube.

Nishit - 2017-10-21

edgeeffect check electoboom

Siana Gearz - 2017-10-29

Uh, have you figured out what the PCB is though?

Mr. Hibipster - 2017-10-21

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

Brian Streufert - 2017-10-21

Good memory!!! Doesn't seem like a year already. Time flies!

Rakin Kazi - 2017-10-21

You know, I almost forgot about that. Can't believe it's been almost a year already.

mikeselectricstuff - 2017-10-23

A long time ago I regularly used commercial tinning solution - the made-up solution didn't last very long - maybe a week or two

Akshay Vyas - 2017-10-22

hi nurdrage,
can you make a video on pcb through hole plating for double sided pcb?

Inner Paths 2 Outer Space - 2018-05-10

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✨

aud_io - 2020-01-07

I hope to be like that when I grow old

rt tr - 2017-10-21

+NurdRage, can you please make videos on organometallic compounds, really appreciated, I heard that they have interesting properties

Samuel Mun - 2017-10-22

I agree I would love to see some organometallic chemistry. Maybe make and use a catalyst?

SkaterK3 - 2017-10-21

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.

ShinyMajor - 2017-10-21

This is great, cause I just started making PCBs yesterday. Thanks!

Jonas Hii - 2018-03-02

>"What's happening is.."

VejyMonsta - 2017-10-21

Heeey, this is actually really useful knowledge for me. I knew subbing to this chemistry channel would pay off for an electrical engineer.

JamesG - 2017-10-21

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.

slacksijie - 2017-10-21

this just showed in my recommended

Tobias Mädel - 2017-10-21

This was very interesting, thanks!

Dewald Klaassen - 2017-10-21

Thanks so much. Iv been wondering about this stuff for years.

Charbel Aoun - 2019-11-22

Hello thanks for this great channel ,i would like to ask ,can you make a solution that remove tarnish ,from enamel wire copper ,quickly ,for making coils .Thanks

mendebil - 2019-12-14

2:45 HAHA so funny

TheOtherWhiteBread0 - 2018-05-04

Well hot damn. Thanks man appreciate it.

Felipe Siqueira - 2018-02-18

Just a question: what to do with the remaining "liquid tin" after usage? How to discard it correctly?

aud_io - 2020-01-07

That's a really good question actually... Most things don't cause any real issues when they get poured down the drain but I imagine this could be a plumbing nightmare lmao

Kermit Frog - 2020-02-16

If it's like the commercially available tinning solution, it can be used over and over.

Thad ward - 2017-10-23

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

NoSpace4Bass - 2017-10-22

Hi, Will this work for other metals as well?

Such as Iron for example

NoSpace4Bass - 2017-10-22

I'd like to tin iron I mean

(and maybe coat it other metals if possible)

milyan360 - 2017-10-22

Electroplating is what is done industrially so i'd probably look into that

nilamotk - 2017-10-21

Yeeessssss !! Thank you !!!!

Ahmed Nabil - 2018-07-01

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 )

Charbel Aoun - 2018-11-17

5 grams

tahwnikcufos - 2017-11-19

A good companion video, would be the precipitation of stannic tin from solution, to reclaim the stannous tin and acid.

Quantum Lab - 2019-02-08

Just curious, could you use this to plate onto other metals?

rabbeseking - 2017-10-22

Never knew diarrhea was so reactive with copper

Kees Hessels - 2018-01-10

Thanks, will be doing this in Costa Rica :)

ryebis - 2019-04-30

Excellent video. Could you please make a video on through hole activation and plating ? 🙏

The Eminent Joshua E. Hrouda - 2019-08-10

NurdRage: can you do a video on how to iron vanadium plate a copper soldering iron tip please??

Gaby Eid - 2018-09-22

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

Alexandra van Asperen - 2017-10-21

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!)

MrSmartguy0 - 2017-10-24

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?

_____ - 2017-10-29

10/10 made me rock hard.

noilex - 2017-11-03

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!

Kevin Miedema - 2017-10-23


x3ms - 2020-01-24

How to remove lead from tin.... Could you please tell me how to refine tin? Thx

thebestofall007 - 2019-02-01

Could you use this stuff to tin a soldering iron?

Quantum Harvest, LLC - 2019-02-22

I just make my own with dry ingredients from Amazon: Sulfamic acid, thiourea and stannous chloride added to hot distilled water. It's fast, cheap, and works like a charm.

Quantum Harvest, LLC - 2019-03-11

Sure. The recipe is 6 grams sulfamic acid, 4 grams of thiourea, and 1 gram of stanols chloride dissolved in 200 ml of distilled water .

Quantum Harvest, LLC - 2019-03-11

stannous chloride

Ali Mehmet - 2019-03-12

@Quantum Harvest, LLC thank you very much for your reply

Caleb Hill - 2020-01-16

just checked the prices of ingredients as of 2020 and the upfront cost is 66+$ but with that you can make 2L (2000ml) of liquid tin

Shrinath Rajadnya - 2020-02-16

Hey, quantum harvest, would you please share links to the ingredients? Thanks!!

sam tukua - 2017-10-22

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?

Greg Allison - 2019-01-19

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

zozozoli - 2017-10-21

Can I do a "nickeling" solution the same way? I'd like to nikkel plate my soldering iron tips

Žan Pekošak - 2017-10-21

Probably better than electrolysis. I failed at every single electrolisis I tried.

stamasd - 2017-10-22

Plating of nickel is a complex process unfortunately, not as straight-forward as tin or other metals. I've had some success using electroplating with the following solution:

nickel sulfate heptahydrate 240g/L
sodium chloride (table salt) 15g/L
boric acid 15g/L
glycerin 2.5g/L
saccharin 1 pinch per liter (found in artificial sweeteners)
thiourea 2g/L
(1 pinch would be about 0.25g I guess)
cobalt sulfate 6g/L (cobalt acts to facilitate the deposition of nickel)
few drops per liter of a surfactant (I used Tween20, but probably other detergents would work too)

Use a current density of 0.2A/cm2 using a pure nickel anode and your object as cathode. Voltage shouldn't be above 5V. The plated layer of nickel was thin and didn't adhere too well to steel, but it did adhere well to copper and couldn't be rubbed off. Don't expect it to be of the same quality as commercially plated nickel. Make sure the object you're plating is very very clean or else the deposited layer won't stick.

Michael - 2019-11-27

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

Agrha tea - 2019-11-06

Hi.., please make solution for desoldering pcb for reuse component parts? Thanks

Sadik Ayad - 2020-02-11

Can I use another compound instead of thiourea?

gsurfer04 - 2017-10-21

Eleventy first viewer!

Kristian B Lerche - 2017-10-21

Thank you for making this... It will be very useful...

Maxx B - 2017-10-21

Excellent. That was good to know.

Matija S - 2019-07-09

will it work with Urea? CO(NH2)2

Eric Foster - 2018-11-24

Hi Nurdrage, could 20% Hydrochloric acid work, if I use more in the ratio?

verdatum - 2017-10-24

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.