My observations on low melt solder.

Discussion in 'Hints & Tips' started by Keith M, Aug 31, 2017.

  1. Keith M

    Keith M Staff Member Moderator

    Messages:
    4,446
    Likes Received:
    2,902
    Joined:
    Dec 16, 2015
    Having just completed 3 white metal wagon kits built using solder rather than Araldite, the kits went together quite easily using 100 degree solder, rather than the 70 degree variety. I looked into the differences between 70 and 100 degree solders apart from the obvious temperature differences, and it seems that with 70 degree solder, the metal combines with the solder and flux and tends to form a joint with a lot of crud in it, thus leaving it weak, whereas this apparently doesn't happen with the 100 degree variety. I used DCC Concepts 100 degree solder, and this information is contained in their 'blurb', so I can't personally vouch for it, but it certainly melts easily and bonds white metal perfectly in my experience.
    One other important point is that after completion of a model, it's essential to clean off the flux (I use phosphoric acid flux) before application of paint or primer, and on a model such as these "Sealion" wagons with a lot of close fitting components, it's not possible to get a brush in between the parts, so you have to rely on a vigorous swishing in water as hot as the human hand can bear, but if you use 70 degree solder, there's a risk of the solder melting in the hot water, and your ending up with a bowlful of bits! Unless you were to use boiling water, this wouldn't be a risk if you use 100 degree solder.
    I've been using soldering irons (and blowtorches!) for getting on for 60 years now, but these models were my first use of low melt solders, and I have to say that there's no mystery to it, the only real essential is a temperature controlled soldering iron, and remembering to always apply flux before tinning, something that isn't necessary if you've only ever done electronics soldering before, using solder wire with flux cores.
    Hopefully these points will be of help to anyone considering building white metal models, although it could also apply to brass fret ones too. It's rather whet my appetite for white metal models and I'm seriously looking at the DJH models range of Southern models for future projects!
    Keith
     
  2. paul_l

    paul_l Staff Member Administrator

    Messages:
    9,848
    Likes Received:
    5,902
    Joined:
    Dec 5, 2015
    Thanks Keith - low melt solder will be on my Telford Shopping list

    Paul
     
  3. Ben Alder

    Ben Alder Full Member

    Messages:
    169
    Likes Received:
    240
    Joined:
    Apr 17, 2017
    100 degree has lead in it, I understand, which allows it to flow when heated, wheras the traditional 70o tends to gather in blobs unless flooded with flux and needs a good deal of encouragement with the iron to fill a joint. As it is mainly used on white metal, thebody of the kit can absorb heat from the iron, making this type of assembly a bit of a turn off for the beginner. Certainly changed things for me when I came across it, and made loco building a bit of a doddle compared to before. I use C&L's offering, with Powerflow flux, although I have now switched to LaCo, which seems to work well, but there seem to be almost as many preferred combinations of iron,solder and flux as there are modellers!However, I would encourage anyone contemplating white metal work to use the higher melt option.
     
  4. Toto

    Toto I'm best ignored Staff Member Founder Administrator

    Messages:
    15,419
    Likes Received:
    3,842
    Joined:
    Dec 5, 2017
    Good to know. I have the 70 degree stuff but will try out the 100 degree as well.anything that makes things easier is worth a go.

    Cheers

    Toto
     
  5. Rob Pulham

    Rob Pulham Happily making models Staff Member Administrator Feature Contributor

    Messages:
    3,881
    Likes Received:
    4,191
    Joined:
    Sep 15, 2017
    I use both, and I must admit that I tend to use 70 degree for white metal to white metal soldering and degree for brass to white metal soldering - you don't need to tin the brass when using 100 degree solder (it must be the lead in it).

    A couple of other tips for whitemetal soldering is don't use the same iron/tip for both high and low melt solder. By that I mean if you must use the same iron then reserve a tip specifically for low melt.
    Or do like I did and wait for Maplins to have their cheap solder stations on sale and pick one up for £9.99 and use it just for low melt - it doesn't need to be powerful for low melt and mine never gets turned up beyond the second mark on the dial. I bought mine 4 or 5 years ago and they were so cheap that I bought a second as a spare having had their more expensive 40 watt solder stations die on me. Needless to say I am still quite happily using the first one.

    My second recommendation is to get yourself a brass wire brush (like a suede brush) and give your castings a good rub before attempting to solder you will find it so much easier.

    Another thing about using low melt solder over glue (and I do use glue sometimes but mainly when gluing castings to styrene kits/scratch builds) is that it has great gap filling properties and you can easily repair white metal if you say drill a hole in the wrong place - add some flux and a small blob of solder, scrape/file away the excess and drill again. Simples:thumbs:
     

Share This Page