jamespetts Posted February 10, 2019 Share Posted February 10, 2019 I understand that it is necessary to use separate soldering iron tips for leaded and lead free solder, because contaminating lead free solder with lead can cause lead embrittlement. However, I have also read that it is necessary to use separate tips for whitemetal/low melt solder than for other solder. What was not clear from what I have read is whether "other solder" here means other leaded solder or lead free solder. Given that white metal/low melt solder contains lead, it should, of course, have separate tips than lead free solder. However, I am not at all clear as to why it should have separate tips from other leaded solder. Can anyone explain? Also, does this apply to 100C low melt solder, or only the 70C type? Link to post Share on other sites More sharing options...
RMweb Premium Andy Hayter Posted February 10, 2019 RMweb Premium Share Posted February 10, 2019 I am not an expert in these things but I would avoid mixing any low melt solder with 145 or higher solders. Without getting bogged down in the specifics of the chemistry and physics, the problem is that traces of one metal can affect the melting of other metal alloys and can also affect he strength of the subsequent joint. Think of it a bit like ice. Throw a bit of salt on it and it affects the melting point and the ice has no strength - having turned to water in this case. 1 Link to post Share on other sites More sharing options...
RMweb Premium 30368 Posted February 10, 2019 RMweb Premium Share Posted February 10, 2019 Hi James. I sometimes have to solder brass or nickel silver to white metal when building my loco's. The last loco I built required a scratchbuilt cab spectacle plate which I fashioned from brass. This was soldered to a whitemetal boiler. To make a joint I tinned the brass with high (185) melting point solder and then made a very good joint between brass and whitemetal using low melt solder. The joint is good with sufficient strength and I have noticed no detrimental effect on the soldering iron bit. I don't know if that helps? Kind regards, Richard B 1 Link to post Share on other sites More sharing options...
RMweb Premium Andy Hayter Posted February 10, 2019 RMweb Premium Share Posted February 10, 2019 Inevitably you will get the "I did it and got away with it" post - and perhaps 9 times out of 10 you might be right. A bit like driving down the motorway at 90mph. It all depends on how risk averse you are. Personally I would avoid. If you do contaminate a casting with the wrong mix of solder, you have two choices: hope to melt it and wick it away - but if the new solder mix has a melting point close to or even above your white metal then good luck with that and let's hope the manufacturer still has some castings. grind/sand away the material and hope you don't damage the original casting. Either way it is a lot of work compared with a couple of pounds for a tip to the iron that can be reserved for low melt. 1 Link to post Share on other sites More sharing options...
Steamport Southport Posted February 10, 2019 Share Posted February 10, 2019 Nah. Just use the same iron. I use an Antex 25 watt for nearly everything and a cheap and nasty 40 watt iron for anything hefty (£10 job from a hardware store). Just clean it after use. Loads of information on here. http://www.jimmcgeown.com/Questions.html Jason 4 Link to post Share on other sites More sharing options...
jamespetts Posted February 10, 2019 Author Share Posted February 10, 2019 Thank you all for your responses. That FAQ was quite interesting. I will in the circumstances be keeping three sets of solder tips: leaded (general/electrical), lead free and whitemetal/low melt. Link to post Share on other sites More sharing options...
garethashenden Posted February 11, 2019 Share Posted February 11, 2019 Why bother with lead free solder at all? It’s fine if you’re a robot building circuit boards, but for the type of soldering that most modellers do leaded solder will be far easier. Just don’t eat it and wash your hands afterwards. There’s probably lead in any white metal castings anyway. 5 Link to post Share on other sites More sharing options...
RMweb Premium 30368 Posted February 11, 2019 RMweb Premium Share Posted February 11, 2019 Interesting ideas Mr Hayter. I must check which soldering iron I have with me when I next drive on a motorway! Kind regards, Richard B 2 Link to post Share on other sites More sharing options...
david.hill64 Posted February 11, 2019 Share Posted February 11, 2019 I would avoid going down the 'lead-free' solder route. I use standard electricians' 60-40 (non-corrosive) fluxed solder for heavy duty work and for the initial joints on complex structures where additional pieces will be added later. I also use this for tinning brass or nickel silver parts that will have whitemetal components added later. I use 145 degree solder for most structural work. It tends to flow better than the 188 degree solder. I use 70 degree solder for whitemetal components and for filling small gaps or for forming corners of tender flares etc. It is also possible to use 100 degree solder on whitemetal components and the 100 degree solder will tin the brass. If you just try to use 70 degree solder with brass components it is unlikely to work. I generally use the same soldering irons for all jobs and from time to time will wet the tip of the iron with the fluxed 188 degree solder to keep the tip in good condition. It will deteriorate if you just use the lower melting point solders. I have a big boy 80W iron, a 40W iron and a temperature controlled 'whitemetal' iron but to my mind this runs at too low a temperature. Santa was nice to be and bought me an ERSA temperature controlled workstation though I have yet to use it. You will have no problems whatsoever in tinning brass with 188 degree solder and then forming the joint to a whitemetal part with with low melt solder. There is going to be an issue with the availability of lead containing solders, but given that whitemetal also contains lead, I would not worry too much about it if you take normal hygiene precautions. 2 6 1 Link to post Share on other sites More sharing options...
jamespetts Posted February 11, 2019 Author Share Posted February 11, 2019 I was not intending to use lead free solder for electronics work, but I understand that Carr's Speedy Solder is highly recommended for general applications (e.g. soldering droppers to track) and is lead free. Also, some of the other Carr's and similar higher temperature solders are lead free. The higher temperature solders, I understand, are good for sub-assemblies (and the very high temperature solders for sub-sub assemblies). It is thus useful to be able to have tips available for lead free even if I will not be using this for electronics work. Link to post Share on other sites More sharing options...
hayfield Posted February 11, 2019 Share Posted February 11, 2019 16 hours ago, Steamport Southport said: Nah. Just use the same iron. I use an Antex 25 watt for nearly everything and a cheap and nasty 40 watt iron for anything hefty (£10 job from a hardware store). Just clean it after use. Loads of information on here. http://www.jimmcgeown.com/Questions.html Jason I agree with this, the only issue is to clean off the solder from the tip on some scrap brass/ metal with plenty of flux, otherwise the next joint you do will take ages to go solid 1 2 Link to post Share on other sites More sharing options...
RMweb Gold 57xx Posted February 11, 2019 RMweb Gold Share Posted February 11, 2019 10 hours ago, david.hill64 said: There is going to be an issue with the availability of lead containing solder They've been saying that for as long as the music industry has been claiming "Home taping is killing music" and they are still raking in the coin. 1 1 Link to post Share on other sites More sharing options...
N15class Posted February 13, 2019 Share Posted February 13, 2019 You only need to use lead free solder in commercial electronics due to pollution on scraping and potable water pipes. This was my understanding anyway. I always used more lead solder plumbing, as I did lots of lead work. 1 2 Link to post Share on other sites More sharing options...
dibateg Posted February 13, 2019 Share Posted February 13, 2019 I use 7 different solders 70/100/145/188/210/ thick 6040/thin 604 all with the same bit. Never had a problem. I use the Building O gauge online safety flux mostly, with phosphoric for the low melt jobs. The last bit - and I'm building pretty well full time lasted a year... I do solder white metal with 145 sometimes, but there is no margin for error! I tried lead free solder, it was hopeless... Regards Tony 2 Link to post Share on other sites More sharing options...
jamespetts Posted February 13, 2019 Author Share Posted February 13, 2019 As stated above, my interest in lead free solder largely comes from the many recommendations of Carr's Speedy Solder, which is lead free. Link to post Share on other sites More sharing options...
hobbyhorse Posted February 15, 2019 Share Posted February 15, 2019 (edited) Over the years I've had many people ask the best method to solder my castings (ex Hobbyhorse) it's really straightforward, firstly tin the brass or N/silver with 145 solder, next clean the white metal casting and using a product called Woods Metal solder the two parts together. Woods Metal is available from various suppliers (Tirante is my supplier) and is cheaper than model shop type solders. The soldering iron I use is an ERSA type with a 1mm tip and temperature around 250, yes it's a high temperature but the key is the solder will flow very easily, and you won't melt the casting. The photo shows two white metal castings soldered, notice how clean the joint is without blobs. Some care is required with Woods Metal as the fumes are dangerous, so and extractor is required. Hope this helps. Simon Edited February 15, 2019 by hobbyhorse 3 4 1 Link to post Share on other sites More sharing options...
michl080 Posted February 15, 2019 Share Posted February 15, 2019 Simon, I have used "Roses metal" instead of "Woods metal" with success. The melting point is slightly higher (94C vs 77C), but it doesn't contain Cadmium. The same procedure applies, brass / N/silver parts need to be tinned with 145C solder. Michael 1 Link to post Share on other sites More sharing options...
hobbyhorse Posted February 16, 2019 Share Posted February 16, 2019 16 hours ago, michl080 said: Simon, I have used "Roses metal" instead of "Woods metal" with success. The melting point is slightly higher (94C vs 77C), but it doesn't contain Cadmium. The same procedure applies, brass / N/silver parts need to be tinned with 145C solder. Michael Thanks Michael, I'll have a look out for some. I do have some concerns with the Cadmiun in woods metal. Simon Link to post Share on other sites More sharing options...
Jol Wilkinson Posted February 16, 2019 Share Posted February 16, 2019 Carrs 100 deg solder is Lead/Tin (no cadmium) and can also be used to attach w/m parts to brass or n/s without pre-tinning. Link to post Share on other sites More sharing options...
Grovenor Posted February 16, 2019 Share Posted February 16, 2019 On 13/02/2019 at 13:46, jamespetts said: As stated above, my interest in lead free solder largely comes from the many recommendations of Carr's Speedy Solder, which is lead free. Are you sure this is lead free? It does not currently appear on the C&L product list although google does show it on sale elsewhere without any detail info. Regards Link to post Share on other sites More sharing options...
jamespetts Posted February 16, 2019 Author Share Posted February 16, 2019 1 hour ago, Grovenor said: Are you sure this is lead free? It does not currently appear on the C&L product list although google does show it on sale elsewhere without any detail info. Regards See here. Link to post Share on other sites More sharing options...
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