And to repair something with a damaged component, what do you do? Wave your magic wand? You REPLACE the part - which DOES require reflowing the parts. And mixing the two solders is NOT recommended practice. And if the RoHS compliant part you use for replacement is not tin coated (and very many parts today are ONLY stocked in RoHS, and a large percentage of them are NOT tin coated), you will not get proper component lead wetting at leaded solder temps, and higher temps will often cause flux problems (black scale from flux overheating).
Like I said - you can get lucky sometimes - but repair of RoHS equipment with leaded solder is NOT recommended, or best practice.
I think I have the next model up, "Weller EC 2001" adjustable and with digital temperature readout. Great tool! It's over 20 years old and there were many times it was on 8 hours a day. I think I replaced the whole heater and cord once, lots of tips.
My old Pace solder sucker went through a lot of heaters, the second one I bought is much better, (Pace ST115) I think it's been about 8 years with no problems. I love to desolder a 40 pin IC and have it litteraly fall out of the board.
You're obviously clueless. For pretty much anything other than BGAs you use a soldering iron. Even for them one can do a reflow of the one part, rather than the entire board. They have tools to do just that.
Complere nonsense. Almost *all* parts are tin plated.
I love those vacuum desoldering stations, I had one sold by ECG back in the late 70's and like you said, a DIP chip would often fall out in your hand after sucking the melted solder off the circuit board. The ECG unit was affordable by just about any electronic tech back then.
I don't know who this Claire is - might well be a moron. However, This from an expert: Traditional tin-lead materials are not compatible with lead-free device finishes. Because proper reflow for lead-free materials can only be achieved with higher temperatures, attempting to process lead-free terminated devices in 183?C tin-lead conditions leads to incomplete wetting and the related issues of voiding and opens.
Doug Dixon, Global Marketing Director Henkel Corp Mr. Dixon has been in the electronics field for over twenty years and is the Global Marketing Director with the electronics group of Henkel. Prior to joining Henkel, he worked for Raytheon, Camalot Systems, and Universal Instruments.
I'll take his word over someone ( a usenet engineer) who fudges his ID on usenet.
And another expert agrees: Many of the components manufactured in the last few years have been lead free, especially surface mount chip components as they are Tin plated.
Can you solder these with 60/40 tin/lead solders, the answer is yes and millions of solder joint have been soldered this way for years. The problem however is some of the Lead-Free component plated RoHS components have a SAC alloy for a lead coating and this is the issue.
The 60/40 alloy will not be hot enough to melt the SAC alloy to create a sound joint. Yes, many papers have been are being published stating that this will work, but keep in mind the thermal profile and the length of time the solder joint needs to be above the reflow temperature to all complete dissolution of the Tin/Lead into the SAC alloy coating or solder balls on the components. This is much different than what was used to the low temperature Tin/Lead alloys and dwell times above the reflow temperature is going to have to increase to create a sound solder joint.
Leo Lambert, Vice President, Technical Director EPTAC Corporation At EPTAC Corporation, Mr. Lambert oversees content of course offerings, IPC Certification programs and provides customers with expert consultation in electronics manufacturing, including RoHS/WEEE and lead free issues. Leo is also the IPC General Chairman for the Assembly/Joining Process Committee.
Again, I'll take the word of an acknowleged expert in the field over that of the unknown usenet engineer.
If you are 100% certain your RoHS compliant components have tin coating, you CAN use leaded solder. If you are just ASSuming all RoHS compliant components have tin coated leads, you are treading on extremely thin ice. I have stated that using leaded solder with RoHS compliant components is "not best practice" and can lead to product failures. I'm not saying you can't get away with it some or most of the time - I'm saying it is not correct, and it is wrong and dangerous to say it is "safe" or "proper" to solder RoHS compliant components with regular lead-based solders. Recommending it is not being responsible, without at least adding the possibilities of the "gotchas" which are well documented and recognized by the experts, and which I have provided cites for.
Other than BGAs, one doesn't reflow the part, dummy. The solder paste gets reflowed. ...and once again, we were talking about *repair*.
Wrong. As long as the solder paste is appropriate, it doesn't much matter whether the part is tin, tin-lead, or gold (or any other commonly used finish) tin-lead solder will wick just fine. ...better than lead-free solder will on the same parts, in fact.
You can't read.
Yes indeed, who would believe a Usenet liar, like Clare?
Indeed, almost all *are* tin plated.
Nonsense. It works fine.
They *all* are. Yes, I have checked all of our parts because that's part of what I do.
Back to the original point, *REPAIR*. Leaded solder is just fine to repair RoHS gizmos.
Clueless Clare.
Again, clueless. Repairing RoHS boards with leaded solder is, in fact, better than using lead free precisely because of the difference in temperatures and better wetting.
No backpdaling at all. I said in the beginning you will often get away with it, but it is not the "recommended" way, it is not "best practice" and in some cases it WILL bite you.
In your case you have double checked and all your components are tin coated leads, so for you it will work. Some components are NOT tin coated, and those can cause problems.
Everyone on the list is aware of it now , and knows your opinion. They also now know that there CAN be issues - so they can do as they like, and take their chances in situations where they are not sure of the coating if they want to.
A few weeks ago I installed a couple of 35 amp bridge rectifiers. The leads were, as they often are, blackish colored and do not tin very well. Seems they always come that way, even from different distributors. They always get hand cleaned with the same brass wool I use for the soldering iron before being installed.
It sounds like these are contaminated. Any abrasive cleaning can damage the plating and could *easily* cause problems down the road. We used to call these sorts of things "solder proof" leads. It was generally because the stock was old.
Black coloured component leads?? Sure sounds like silver plating. Sulphur in the air tarnishes silver, making a very black coating. Removing the tarnish by abrading should make a reliable solder joint.
Actually it does look like silver... oxide? I've been told that it is a great electrical conductor, but not great to solder to. Do you know if the black stuff does really make a better conductor for something like a switch?
The black tarnish is Silver Sulfide, which is almost as conductive as metallic silver. Silver oxide, while still a conductor isn't nearly as good. Scraping it isn't a good idea because it can reveal the metals below. I doubt that it's silver sulfide, though, because it still should solder well. It's likely a tin-lead coating that's oxidized. You probably didn't scrape through it, if that's what it is.
No, it does not - and if my hunch is right they were not black when they left the factory. It is NOT silver Oxide - it is more like siver sulphide - Ag2S, or silver chloride.
Both sulphur and chlorine will tarnish (blacken) silver very quickly.
Sulphur will often also blacken tin - so it is possible you just have "tarnished" tin coating. Blackened tin is neither a good conductor or a suitable substrate for soldering. Tin can also de-zinc brass, which can cause blackening as well if tin coating is used on brass terminals without a copper or nickel strike plating as a barrier.
I know Smitty is going to dissagree with me, but so be it.
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