Mulja tv repair portal
General => General Forum => Topic started by: Technomaniac on December 12, 2009,18:03:01
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A couple of years back, I bought my first roll of lead free solder. Tried it out, didn't like it, and it sat in a corner of my toolbox until I ran out of the tin-lead stuff. Recently I had to make up a special little audio device from scratch for a customer, and decided to use lead free. Well, I suppose you all know its problems, but here's what I found... Weller soldering-iron tips don't like it, instead of getting a month out of a tip, it was eaten out in a week, I had to scrape any tarnish from the component pigtails, and I had trouble getting it to flow to the extremities of the little dots of copper foil around the pigtails. And it usually cools looking cloudy like a dry joint. When the travelling sales rep sold me the roll, he said that it used antimony instead of lead. Well, the other day I heard something nasty about antimony on telly and so I decided to do some research. I Googled lead-free solder and found that there are in reality several different recipes used, but no mention of antimony. But other info I gleaned was that you require the iron to be 20 degrees hotter, and that the jury's still out on whether its really any safer than the old stuff. It sets more brittly and the little tubes between layers of multi-layer pc boards lose contact at their joins, and here is what might be quite a serious problem, they said that there is tin in the mixture, and it migrates across the pc board to cause a short circuit beteen tracks. (Has anyone had experience with cadmium plated whiskers shorting out wafer switches? )This action has apparently already put a nuclear power station off the air ! The EU, I think it was, has set down either guidelines or rules for the use of lead, among other things, and limits for the amount of nasty substances which can be used in anything. And apparently there is lead in glass, so tellies with a picture tube contain more lead than the LCDs and Plasmas. The dumping of these after their owners tire of them must be quite a concern. But the percentage of lead used in all of the world's electronics, represents only something like 5% of the production. Car batteries are up there with most of the remaining 95%. Nothing was mentioned about bullets. So, given that there are different types of lead-free, does anyone have any experience with different types being better than others, info about which might be beneficial to the rest of us ? the stuff I have doesn't appear to use resin for flux ( I suppose they're not allowed to take it from trees anymore!) Manufacturers don't seem to like lead free either. Haven't seen a plastic picture tube yet.
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Hi,
Thought most LCD screens were mostly plastic, well they smash well with Wii handset input, and if we can grab them before China turns them into the next fashionable thing for the decadent West -
Well, you as an Aussie, might well see things differently - Chris.,