solder dials and bezels

[willofiam]

need some help on the best way to solder a bezel or dial to the bezel, the issue is that there is usually a 100 year old paper dial on a metal plate, DO NOT want to burn that!!! also some have glass holding pieces and when soldering those into place I have accidentally heated the glass too much and it cracked. What type of solder????? maybe I am not soldering right, I try to heat up both pieces, using flux until it smokes away and the either have a small piece of solder and it flows in or apply when everything is hot enough. I have tried everything, mostly using silver bearing solder lead free acid core, 40 watt iron to a 140 watt iron to a micro torch, on this particular project I have not used the micro torch as I am afraid I will heat it too much and burn the paper face, besides I feel like I am not doing this right and need to find out a better way, thanks, William

[arutha]

Hi Will, does it have to be soldered? sometimes glue in this situation could be a safer bet. Have you tried general solder that has a very low melting point and you can use it with a 25w iron?

[Bob Tascione]

Hi guys,
I just had this problem with one of my own clocks a couple of months ago. There are a few tricks you can try which seem to work well for me. There’s a good chance that the dial pan is zinc. Problem with zinc is that it forms a zinc oxide when heated which puts some kind of barrier between the solder and the plate itself…I don’t know much about how this stuff works so I’m sure there are many who can elaborate on this. Anyway, one thing that I do know makes a big difference is the prep work. Surfaces have to be EXTREMELY clean. I remove all old solder completely and then wire brush down to shiny metal leaving the surfaces rough and clean. I also use a liquid brush on flux. Paul’s exactly right about using low melting point solder! Silver solder requires more heat than regular Tix or 60/40. I had absolutely no luck at all using silver solder! It just rolls around and laughs at me. I think TIX and 60/40 are made up of both lead and zinc so maybe the zinc content makes a difference when sticking to the zinc pan…just a guess though. Also only use a soldering iron and NOT a flame. I use a Weller with a chisel type tip. If the surfaces are super clean and you use the correct flux and low melting solder the solder will spread and follow the flux and the temp won’t be high enough to cause any damage to the paper dial. At least that’s been my experience. I don’t put much solder at all and only flux a small area for the solder to follow as I want the solder to sort of melt and sit there as a small dab with a little height rather than spread out into a flat surface. I find that the height is needed because the normal gap is sometimes pretty large between the two surfaces
being soldered.

Hope this helps William!
Good luck and let us know how it works out.
Bob

[willofiam]

Hey guys, thank you, this is very frustrating, I wonder how they originally soldered this stuff, as always you guys were both on the nose with ideas. I just read that for 2 or more metals the solders loosely classified are “hard” and “soft”. solder made mostly from lead and tin, generally the higher percentage of tin the less temp needed to melt.. in what I was reading a 96%tin and a 4% silver has a melting point of 440 F and will form a strong joint and a solder iron should work well, using a rosin flux so it doesnt corrode the metal, and like you said Bob cleaning very well beforehand. well thats me diving in before looking 🙄 thanks again and if there are any more ideas on this they will be greatly appreciated, William

[willofiam]

O.K. :geek: I bought 60% tin / 40%lead rosin core solder,melting point of 361 – 375, cleaned the surfaces, used a little dab soldering paste anyway and a solder iron, was able to accomplish the task, had smaller areas of solder but seemed to hold good, I also tested this on 2 flat pieces of brass to see if I could get a good lap joint, It takes awhile to get the heat thru but it did work. But Bob you said you had 60/40 zinc???? maybe I should look for that…. I think this would work good for the hinges ect…???.can you guys tell me why my head hurts 😯 William (Pauls friend)

[Bob Tascione]

Hi William,
Sorry, disregard that portion of my post. You’re right..I was confusing zinc with tin! The pan may be zinc but the solder is lead and TIN…senior moment I guess.
Glad that worked for you.
Thanks for the correction William,
Bob

[willofiam]

Thats fine Bob I do the same thing but only once in awhile 🙄 , I guess that one was for this year, right? anyway now I know why my head hurts, 😆 William

[arutha]

Glad you got the job done, I forgot to mention about the surfaces being spotless too, good catch Bob

[Author]

Posts