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Originally Posted by spynic
how much does d whole kit cost (approx)?
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I live in a remote place where things are not easy to come by, so when I visit a metro, I usually buy enough copper-clad board and Ferric Chloride to last me several years. IOW, I buy them once every 5-10 years.
It's been quite some time since I last bought them, so I'm not sure how much I paid. As an indicative figure, I'd say something like Rs.50-60 for a one-foot-square phenolic board. Glass-epoxy will be around 100-150/-.
I'm even less sure about Ferric Chloride because my current stock was brought by a friend for whom I'd solved some technical problems, and he wouldn't tell me the price. As a rough guess, I'd say around a hundred bucks for a 500-gram pack.
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n how long does it take to make it (excluding the time for designin circuit)??
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Generally 5-15 minutes. It depends on certain factors -
1. Temperature. Cold weather slows it down.
2. Strength of the solution. A weak or partly used solution works more slowly
3. Agitation. If you simply immerse the board in the solution, it may take more than 30 minutes. Rocking it side to side will dramatically reduce the etching time.
I prepare the solution as 350gm of FeCl3 to one litre of water. It's also available as a solution. I think the standard strength of a ready-made solution is 22%, though I'm not sure.
Caution :
1. FeCl3 can stain skin and clothes.
2. It dissolves metal, so use only glass or plastic containers.
3. When solid FeCl3 is first dissolved in water, it can get very hot - enough to melt and/or deform some plastics. So using a thin plastic container such as an empty Coke bottle is not a good idea. I use a large-neck glass bottle (e.g. an empty Horlicks or Viva bottle). I first place the bottle in a plastic bowl, just in case the glass breaks. After the solution has cooled down, it can be stored in any non-metallic container.
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Originally Posted by aditya.shevade
Hi there, can you tell me which make do you use?
I have tried Faber Castle's OHP+ marker, but it partially dissolves.
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I'm not very particular about the brand of pen. I use anything I find in the market, including Faber-Castle. At the moment, I'm using Luxor. I use one with a fine tip (those that look like ordinary pens) for drawing narrow tracks, and a thicker one for filling in larger areas.
The important thing is to select a pen that has a good flow of ink and apply it as thickly as possible. The solvent of marker pens evaporate easily and even a newly bought pen may have partially dried out while in stock.
Cap the pen immediately any time you stop drawing for more than a couple of seconds. This is inconvenient, but it's the only way to ensure a good flow when you draw the design.
When you buy a marker pen, test it in the shop by writing on glass or polythene, not paper.
The solvent can be replenished if it has partially dried up (instead of the ink being used up). Methylated spirit can be used, but automotive paint thinner is better. I use Duco or Garlac thinner. Open the marker, take out the fibre rod holding the ink, and apply several drops of thinner to it. I soak a small ball of cotton-wool with thinner and squeeze it on to one end of the fibre tube. It can get messy if you're not careful.
A small bottle of marker refill ink is also easily available.
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The best so far has been oil-paint.
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Oil paint is OK. In fact, almost any non-metallic, non-water-based medium will protect the copper against FeCl3, provided it sticks firmly. The trick is to find a way to draw the intricate patterns on the copper.
PCB Etching
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