Tining of PCB - Page 1
Forum section: electronics / general

author: geggi1
author_rank: Frequent Contributor
timestamp: November 22, 2016, 01:49:49 am
content: I'm just in the process of starting with pcb-milling. I have seen some postings writing about tinplating of the board.What is the simplest way to get a nice finish?The processes I see is.Plane old solder, paste or regular solder.Electroplating.Non electric plating by a chemical tin solution.

author: rob77
author_rank: Super Contributor
timestamp: November 22, 2016, 02:10:02 am
content: electroless tin plating doesn't require expensive chemicalsit's relatively cheap but usually you have to buy bigger amounts of the chemicals - so it might require some investment into checmicals but it's not expensive per plated area.what you need is Tin chloride, thiourea and sulfuric acid and distilled/demineralized water.. i'm making my own tinning solution and it works perfectly, but i would suggest to mix only small amounts because the shelf life of the mixed solution is really short (days to 1-2 weeks).i'm buying the chemicals from a local chemistry supplies store. SnCl2 is approx 35Eur for 500g, Thiourea is approx 10Eur/1000g and sulphuric acid approx 2Eur/1000g

author: rob77
author_rank: Super Contributor
timestamp: November 22, 2016, 02:22:25 am
content: this is what i'm using:SnCL2 . 2H2O : 4.6gram/liter (little less for anhydrous SnCl2, 3.8 grams IIRC)Thiourea : 49.5 gram/literH2SO4 : 12gram/liter

author: sleemanj
author_rank: Super Contributor
timestamp: November 22, 2016, 05:34:21 am
content: I know it's boring, but my advice: don't bother.Chemical tinning is messy and stinky and usually expensive (or hard to get the chemicals).Solder tinning (with solder soaked braid, or with spreading paste on hot PCB) is tiresome and frustrating (bridges!) and finger burning and too easy to overheat and pull off a pad, and ruin your day, and it always ends up looking like crap.Just tin the through hole pads using iron and solder as it makes it easier to get a good fillet, for the surface mount ones, just solder as you go.Spray lacquer after assembly (protect anything that it might affect) if you want better protection against the copper oxidising.

author: Jay_Diddy_B
author_rank: Super Contributor
timestamp: November 22, 2016, 05:56:18 am
content: Hi,I use M.G. Chemicals Liquid Tin 421.Link:http://www.mgchemicals.com/products/prototyping-and-circuit-repair/prototyping/liquid-tin-421A 500mL bottle costs about $40.00 CDN.I clean the copper with 600 grit paper. Then I wipe the board with Lacquer thinner. I place the board in a tray and pour the liquid tin over the board. After 1 minute I pour the Liquid tin back into the bottle.I 500mL bottle lasts a long time me a long time, several years. 500mL is supposed to 3600 square inches.Here is an example:Regards,Jay_Diddy_B

author: Kean
author_rank: Unknown
timestamp: November 22, 2016, 06:20:12 am
content: I also use the MG Chemicals Liquid Tin. A bit pricey, but I think it is worth it when I need to present a prototype PCB to a client.For prep, I shine up the copper with ultra-fine steel wool, and then wash the PCB with IPA & shake it dry before immersion in the tinning solution.Previously I mixed up my own solution, but it was too much mucking around and the shelf life was quite short compared to the Liquid Tin.

author: rob77
author_rank: Super Contributor
timestamp: November 22, 2016, 02:56:17 pm
content: i don't know what is messy on mixing small amount of 3 different chemicals in a jar with 1 liter of distilled water and then dipping the board for a minute or two. the formula i posted above works perfectly and it's pretty cheap , approx 1 Euro per liter.

author: richardlawson1489
author_rank: Regular Contributor
timestamp: January 09, 2017, 06:52:11 am
content: Here is the simplest way to get a nice finish, Tinned of PCB. Check it out.http://stompville.co.uk/?p=85

author: technotronix
author_rank: Regular Contributor
timestamp: January 09, 2017, 02:21:02 pm
content: There is nothing complicated in mixing 3 chemical elements. You can get tining very easily.