Is all your info available collated together on a website somewhere. ?
Any comments on the following If replacing new (ROHS) components to old boards (leaded solder) then scrape off most of the hard mirror-like finnish on the leads before tining with and then soldering with Pb-Sn solder
21Century RoHS boards , repair of but not production (heavy solder usage), use silver solder, or is that likely to lead to as much a problem as mixing RoHs and PbSn solder.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
Having worked in electronics assembly and manufacturing for many years, I can confirm your assumption that all new production work gets wave soldered and it has its own set of issues as evidenced by many cold solder joints found in the field! That said, hand irons are still used for repairs...
None at all. I'm love to see a comparative study, though; must be one out there somewhere in the vast Intertoobz. I've been pleased with it. No more hiss'n'sizzle.
Wave soldering is going away, and being replaced by reflow ovens, due to increased SMD construction. The electronics manufacturing I worked with had three reflow ovens, and no wave solder machine, and that was 10 years ago.
I have only ever seen one wave solder machine in actual use, and all components were through hole, and it was over 15 years ago.
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I can assure you they don't unless you take half a minute to make each joint. I an of course talking about fibreglass (FR$) or CEM material not paper crap.
Well let me explain something to you.
The process in question involved soldering a number of TO-220 devices onto a largish PCB. The TO-220 devices were already mounted on a substantial heatsink.
You could get what 'looked' like a good joint using a 700F tip because of capillary action up the component lead but maybe 2% of those joints were 'dry' or cold' because the component leg was itself being heatsunk by the big heatink. 800F tips fixed it. Then the manufacturing smart alecs went back to 700F tips and as I said the returns rate went up again.
I recall one example where I was asked to look at the return since it was design of mine. Took the retaining clip off the TO-200 device and could pull it by hand out of the PCB leaving perfect 3 rectangular holes where the leads had been in what looked like perfect solder joints. Of course it worked to begin with because of mechanical contact which then loosened up with thime.Case proven I think.
In short, you're plain wrong. I have VERY considerable experience in electronics manufacturing, design and production I will add. Indeed I act as a consultant in the field.
Well I simply don't let it idle all day. It's guarenteed to give those nasty 'inter-metallic oxides' in the long term anyway that make re-tinning near impossible. A guy I used to work with would switch on the bench (including iron) and maybe not use the iron all day. Whenever I noticed, I'd switch it off again. Why waste electricity anyway ?
I hate to think what's lurking in the woodwork. At least aerospace is exempt !
I don't know about car ECUs though. That could be fun. Lead-free hates vibration with a vengeance.
As I may have said elsewhere I know that at least one loudspeaker manufacturer got an exemption because the sound was causing lead-free lead-out wire terminations to fail. There's implications there for a lot of sound equipment.
Stop screwing around with Weller if you're serious about soldering and production certainly qualifies. Get a Metcal. It's ready to use in 10 seconds and with the vastly superior heating element, you don't need to push it to 800 and live with the temperature 'coasting' down every time it touches a cold connection. The heating element in the Metcal _is_ the temp sensor and it's as close to the tip as you can get. Try one of those and your Wellers will be like both of mine - in a box in the garage.
So far I've bought 8 Metcal systems, initially one for me personally and then 6 soldering stations and 1 de-soldering station at work. eBay is great for this. The cheapest power unit I got was $10 and since it was local (Los Angeles), I picked it up on the way home and paid no shipping.
I recall our Bombay sub-contract had a decent wave solder machine with proper pre-heat etc, good meterials used like Kester solders and fluxes etc. Only trouble is, every board has a different thermal profile so you should make a batch of X number of a certain board using one level of pre-heat followed by another with its level and so on.
However they were not sufficiently organised to be able to do this so they use some 'average pre-heat' value.
However that pales into insignificance when I discovered what they were up to at an earlier stage in the process.
We had a LOT of dry/cold joints from them. Prosound / Ahuja. Avoid.
I read somewhere a while back that the military, aerospace and telecoms guys were sending components out to de 'de-tinned' of lead free and re-tinned with the proper stuff.
When you see brand new components with that hard shiny neat? tin finnish its hardly surprising there is tin pest problems before anything to do with microcracking in the solder. Not surprising that such components, after a few months, can be pulled out by hand leaving neat square holes . It would take a blow torch almost, to meld with that tin finnish, when on thick say TOP3 leads.
-- Diverse Devices, Southampton, England electronic hints and repair briefs , schematics/manuals list on
I don't have info particularly collated anywhere, but if you want to contact me off group with an address that's monitored for input, I'll send you a copy of the article, which contains references to where I got info, and who from. I don't think that there is any particular need to remove the surface of RoHS compliant components' leads. I seem to recall reading somewhere that most component leads are now tin plated, as in coated in neat tin, rather than being 'tinned' with any kind of solder, as they were in the past. A coating of pure tin should not cause any problems when used with a conventional SnPb solder. As far as using silver solder is concerned, I don't believe that there is any need to go to those lengths. Given the limited life and price of modern equipment, I think that any repair that keeps a piece of kit going for another year is a result, and if the joint that you made as part of the repair gives up after that time, then san fairy ann ... Some commentators suggest using a lead-free alloy which contains a small quantity of silver for hand work. These alloys have a melting point closer to that of SnPb solder, and similar 'workability', but do of course, cost significantly more, so I don't bother with them, for the same basic reasons of equipment life / value.
On that score, just out of interest, I bought a little DVD player from the local Tesco store last week. It's about the size of a portable player, but without the LCD screen. It plays every format imaginable, gives a cracking picture on my (CRT !) TV, and came with all leads and a very comprehensive user guide in good english. It even has a full function 'credit card' remote control. How much ? Fifteen quid !! ($27).
If it goes wrong, it's just toss-away. Don't care what solder it's made with ...
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Aha ! When I first started in the business way back when dinosaurs roamed the countryside, we used Adcola irons with a bakelite 'tortoiseshell' handle, and a neat spiral of what looked like tinned copper wire wound right up the length of the business end. Those irons used a solid copper tip, and we always used 'Savbit' cored solder with them. This solder had added copper, as you say. The best thing about those solid copper tips, was that you could file them to any shape that suited your work, without compromising their performance. A quick touch up with a file fully restored the soldering tip, which would then tin immediately, and stay tinned until you flicked the solder blob off, ready to start using it. The solid copper tips were, as I recall, remarkably long lived, and could be filed into almost non-existence, before they needed to be replaced. Using irons like that really taught you the skills of good soldering, skills which stay with you your whole life. The Antex CN15s and 25s from the same era also had solid copper tips, and the same things applied. They were the first ones that I can remember changing over to (first nickel ??) and then iron plating of the bits. Once that plating wore through though, there was no rescuing the tip, even though it was copper inside. Touching it up with a file was a one day only fix, and a new bit was rapidly required. Odd that. perhaps the copper used was a softer grade or something, once they had it 'protected' by the plating ...
A few years back, it probaly wouldn't have bothered me, but the older I get, the shorter the fuse I seem to have. If I were to pick up my iron to do some soldering, and it wasn't instantly ready to use, I would just get mad at having to wait for it. I actually don't keep my vacuum desoldering station powered all the time now since I changed from the Weller to the Pace. The Weller tips were about seven quid apiece, but lasted for ages, even with the station left idling. The Pace tips are about the same price, but you have to buy them five at a time, which hurts a bit more. Add to this that they don't last above a few weeks when idling, and this has led me to only switch it on when needed. However, it has to be said that whilst I am waiting for it to hot up, I fume worse than lead-free solder flux, and tend to pick it up to start using it as soon as the heat light has started flashing, which then often results in a clog, as the tip hasn't reached full temperature right up the (long on the Pace) pick up tube that is part of it ...
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