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Tinning product for sell

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icetea

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A friend told me about a product so i can tin my boards...

here's some photos of the product a board after i tried to tin it and a guide on how to do it.

http://diypcb.googlepages.com/index.html

they were very cheap and i bought some so if anyone is interested i got few of them for selling.
 

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The problem with chemical tinning is diffusion. The tin layer is about 1-2µm which will disappear after a while having merged into the copper.

For long lasting chemical tinning a diffusion blocker must be applied. Despite that the tin layer must be 5-7µm for a durable coating.

Those chemical tinning sets have been on the market for quite a while and it's not advisable to use them before soldering. It requires moore heat for good soldering on a pad treated with chemical tin.

Boncuk
 
Hans,

I agree about the chemical conversion coatings. But the link uses Rosol 3 (tin-copper alloy), which is a solder paste. I think it is spread on, then put in an oven or heated with air to melt.

I stopped using the conversion coatings a few years ago and just use lead-tin solder with a good flux. Then, I conformal coat. Since I use the photo method, I leave the photoresist on the boards to prevent oxidation until I am ready to assemble them.

John
 
Hans,

I agree about the chemical conversion coatings. But the link uses Rosol 3 (tin-copper alloy), which is a solder paste. I think it is spread on, then put in an oven or heated with air to melt.

I stopped using the conversion coatings a few years ago and just use lead-tin solder with a good flux. Then, I conformal coat. Since I use the photo method, I leave the photoresist on the boards to prevent oxidation until I am ready to assemble them.

John

Thanks for the explanation, John

this seems to be a method building a diffusion blocker while processing.

BTW, using photo resist base material there are big differences in the photolayer. Some are not the same thickness and require individual exposure and some are even different within one board. I had a pile of junk in a small series production leaving spots of underexposure resulting in copper areas causing shorts.

BUNGARD base material is the best according to the experience I've made.

Hans
 
I am not sure we can get Bungard easily in the USA. I use Injectorall and have had good luck. A product from MG Chemicals is also popular. While the basic photochemistry is similar between products, there are clear differences in the appearance (MG is green, Injectorall is orange) and details of the process. DuPont Riston is another option. It is a photosensitive film that can be laminated to bare boards and is mostly used by commercial board shops. Unfortunately, it is sold only in fairly large quantities and is out of reach for most hobbyists.

Fortunately, leaded solder and solder paste are still readily available in the US, so I have not had to worry too much about the problems of using pure tin.

John
 
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Guys the pcbs can work fine for years even if they aren't tinned!
provided of course that you don't touch the copper all the time.

Now imagine how much better things can be if you tin it with the above product or something simular,
if you ask me i'm very satisfied with the outcome, look at the photo of the board i posted, the common ground is huge! and i'm using a 12V/8W soldering iron to solder on these rails. If someone is interested they are still available and i can get more because they are extremely cheap!
 
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So what's you percentage?
 
Can you please tell use where you bought them from?
 
they cost $4.50 each but for you it's going to be free because you look
somehow offended, pay the shipping cost and i'll send you one so you can calm down.

I'm VERY offended. Can you send me one free AND pay the shipping? :D
 
Do you deliver to the UK?;)
 
Solderable conformal coatings are the way to go. I used to use Solder-Lac from LPKF but I'm sure the same thing is available elsewhere cheaper.

https://www.lpkfusa.com/Store/ProductDetail.asp?ProductID=107


I think that spray forms a plastic layer on your board. Is this the way to go? what if you want to unsolder? and what about the cost? your prefer to pay $19 for that thing? i knew as a product but i never thought of buying with $4.50 for the tinning product i postedi think you can do alot better.
 
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