choosing solder for original work and repair

Used leaded.

Depends on whether you are located within a geographical area subject to the RoHS regulations, whether you are exporting to, or taking repairs from any such area, and whether anything you build or repair is for your own use, or for commercial gain. There are also some (unresolved) possible metalurgical issues with regard to whether older equipment, manufactured in leaded solder, should be repaired using lead-free solder. There are several recent threads on here regarding lead-free solder, which may serve to further enlighten you if you hunt them down. In general, lead-free, which has been forced on the manufacturing sector as a result of dubious eco issues, is not much liked by the repair fraternity, as it has led us to experience many more bad joints - which are often very much harder to locate than if they had occured in a leaded solder environment - than we had been seeing in recent years. Perhaps if you can let us know a bit more about what exactly your operation is likely to involve in terms of technology - surface mount or thru' hole - whether we are talking primarily new build, or repair or a mix of both, and whether equipment for repair is likely to be up to date (post June 2006) or older stuff, we might be able to offer you better advice on solders, fluxes and tools that will be suitable for you.

Arfa

Thanks for the detail on lead-free solder. Can you elaborate on the different types of fluxes. No clean, water soluble and standard rosin. Thanks

should be repaired using lead-freesolder. There are several recent

Again, it depends on what you are intending doing. My main line of work involves repairs to existing equipment. For this I use both leaded and lead-free solders of the multicore varieties - that is bog standard off-the-shelf wire solder, with multiple built in cores of flux, that are predominantly rosin. These tend to leave the customary brown residue behind them, which is claimed by the manufacturers to not require cleaning off. However, I always do just to make the job look tidier. Many many years ago, my apprentice mentor told me that the only way you should be able to tell if a component has been replaced, is if the soldering is *better* than the manufacturer's original. For this reason, and this reason only, I always clean the board after doing any soldering work on it. For this, I use a a product called De-Flux 160 from Servisol.

I do build the occasional one off piece of equipment, sometimes for a customer, sometimes for myself, and I just use the same solder for the job. I have been doing this for 40 odd years now since I was a kid, and have never had a problem. So if you are just going to be repairing, with the occasional new build job, don't worry too much about fluxes. Any pre-fluxed solder wire that is sold as being suitable for electronic work will be just fine. If you are going into production, however, then flux types become more important, and there are production solder people on here who can better answer you on this. Basically, as I said before, you need to tell us the area that you are going into so that we may better advise you. As an aside, if the work is going to involve surface mount repairs that will be done by hand soldering, then you will need to have some liquid flux to hand. This is essential if you want to do a reliable job. I use a product from Electrolube for this, and have done for some years.

Arfa

Yours is the second recommendation I have seen for De-Flux 160 from Servisol. Do you know where to find it in the U.S.? The only distributors that seems to carry it are from the UK. Repair work, I always used rosin core. But for personal PCB projects, I prefer something thats easier to clean where the results look neater. I have heard about long-term reliability problems with no-clean and water soluable flux solders. So I wanted to hear from more experienced people and their opinions of these two types in regards to problems that were experienced.

detail on lead-free solder.

I really don't know where you would find it over there. I had never really thought about where they came from - I have just been using their products here for years. I had a quick look on Google, and found several other countries where it seemed to be available, so maybe someone in the U.S. carries it. Try asking Servisol if they have a U.S. agent. Other than that, there must be an equivalent product.

I have never really had anything to do with any water based or soluble flux, but I have used no-clean formulations. These still leave a residue, it's just that the manufacturers claim that the resisdue is stable and 'dead'. However, I still clean it off, as I don't like the look of it on the board. De-Flux 160 removes the flux completely with a tiny spray of product, and a quick scrub with an old toothbrush. It does not touch any solder resist on the board, which some solvents that I've come across, do. If you are doing a large area, a slightly 'tacky' residue can be left behind, but this is quickly and easily removed with IPA.

Arfa

Does the company have a website, and do they list MSDS (Material Safety Data Sheet) for their products? These tell what chemicals are used, in case of an accidentally spill and so that people using it know if they have to worry about health risks. They are also required before a chemical can be sold in the US.

Servisol is part of the CRC group.

I've given the URL of the UK site as the link to their US one appears to be down ATM

For rosin, we've tried various products, and ultimately concluded that none of them worked any better than the gallon of 99% isopropanol that we could get for $25 and put in a $1 spray bottle.

Water-clean generally removes well with hot water as advertised. We consider no-clean essentially unremovable - it always leaves that white residue unless you scrub it with a brush.

Somebody mentioned long-term problems with water clean, but we haven't found any so far.

I've used both no-clean and water soluable. The no-clean still leaves crap behind. Just that it supposedly doesn't need to be cleaned...but I clean it anyways. For cleaning - I use Techspray Ecoline Flux Remover and a boars hair brush. Don't buy the tiny can with the attached brush on the nozzle -- guaranteed to plug up within the first

I use water soluable on new boards. For the big stuff - we pop the boards into a board washer. Hot water sprayed on and the stuff comes right off. For small jobs -- hand soldered with the water soluable flux. Has the consistancy of ear wax...yeucky stuff. Run under hot water, couple swipes with a soft brush, rinse and dry - looks perfect. Just make sre everything on your board is washable.

If you are using boards with washable parts - I recommend the water soluable stuff. Much better results when things are cleaned up.

-- Ed

Agreed, but if you're building here in Britain, get your supplies NOW, before the nanny state takes them away from you. Leaded solder is about to become a thing of the past. Bastids.

Cheers, Pete.

But are they really concerned with the disposal of all the leaded stuff out there right now? Here, just about everything gets dumped into the garbage. I tried to find a place to get some hazardous liquid disposed of, and there was noplace near my home. They said there may be a place to take it once a year, but I quickly forgot about that idea. I just threw away a half gallon sized capicitor, which I hope did not contain PCB. I would like to get rid of the Chloradane I have, but maybe I should use it around the house, or send it to Canada. I understand they still have it for sale.

greg

Avionics, military, (and possibly medical), all have exemptions afaik. Reliability reasons.

was noplace

capicitor,

have, but

Waste recycling sites are becoming more common here, (Or "Civic amenity centres" to give them their proper designated title) but they've got a ways to go yet. Leaded circuit boards, old PC's, hi-fi's and whatnot are just dumped in with the "metal" junk. Plastics, paper/cardboard, wood, "green" waste and earth/rock/ceramic waste are seperated out and dealt with individually, and the workers, Gawd bless 'em, are diligent in ensuring that "customers" put the right stuff in the right skip. But IMHO, it's too little, too late, and it doesn't do anything to stop Johnny Householder from chucking out anything he likes with his regular trash collection. Ye Gods, I haven't had a good rant for ages. I feel much better now.

Cheers, Pete.

Where did you get this information? As far as I know there is no intention to stop the sales of leaded solder for repair etc work. It will of course be more difficult to obtain - but all the major electronics suppliers still have it in all types. I'm not including Maplin as an electronics supplier...;-)

RS, In-One catalogues, etc, are listing most non-ROHS-compliant components/materials as "Available until stocks are exhausted." Pretty sure leaded solder was in there with them last time I looked. Oh, yeah, here ya go - Latest Farnell catalog, book 2, pp1032 - 1034. Awful lot of red triangles in there! Then again, I've been wrong before. I'd be delighted if this was the case in this instance!

Cheers, Pete.