Resistance Soldering question - Model Train Forum - the complete model train resource
Model Train Forum - the complete model train resource

Go Back   Model Train Forum - the complete model train resource > Model Train Workshop > Beginner Q & A
Forgotten your password?

Beginner Q & A If you're new to model trains, stop in here!


Reply
 
Thread Tools Display Modes
Old 10-05-2019, 08:50 PM   #1
PatriceL
Hobo
 
Join Date: Oct 2019
Posts: 13
Resistance Soldering question

Hi. My name is Patrice Lemée and I am a metal sculptor.

I need help with resistance soldering and this seemed like a good place to ask. It’s hard to find people using this and I think you guys do. It’s not about trains so I hope it is still ok to ask. Let me know if it’s not.

I have purchased a soldering unit from American Beauty. Very happy with it so far but I am having a small problem. Well I hope it’s small. I am trying to solder a small piece to a much larger piece as you can see in this picture.



The thing is I need to put a lot of heat into the larger piece for the solder to properly flow to it. The result is a perfect solder joint but the carbon electrodes leave marks. Since I am doing this on a near finished sculpture and in hard to reach places I need to minimize this scarring of the surface. Not sure how to do that or if it’s even possible. These are carbon electrodes and they glow red hot from heat, more damage from the electrode e that glows more and also a little powdery residue on it afterwards.

Not sure if I explain myself well or if anyone here has an idea of how to do this better but I am taking a chance and would be very grateful for any help. Or of course if anyone knows of a better place to find info on this that would be great.

Here is my latest sculpture and the small feet are what I am working toward soldering.



Thanks for you help.
PatriceL is offline   Reply With Quote
Sponsored Links
Advertisement
 
Old 10-06-2019, 10:35 AM   #2
gunrunnerjohn
Admin
 
gunrunnerjohn's Avatar
 
Join Date: Nov 2010
Location: SE-PA, USA
Posts: 41,965
Scales Modeled: O-gauge 3-rail
Images: 3
Can't you put the electrodes on the piece under it to minimize the visibility of the marks?
gunrunnerjohn is offline   Reply With Quote
Old 10-06-2019, 10:56 AM   #3
wvgca
Station Master
 
wvgca's Avatar
 
Join Date: Jan 2013
Location: yorkton, sask
Posts: 3,029
Scales Modeled: HO 1890's
Images: 42
it may be necessary to use a 'sacrificial' piece under the electrode, to reduce the scorch marks , or a larger electrode that will increase the area of contact, and reduce the number of amps per square inch
__________________

wvgca is online now   Reply With Quote
 
Old 10-06-2019, 01:13 PM   #4
flyboy2610
Dispatcher
 
flyboy2610's Avatar
 
Join Date: Jan 2010
Location: Lincoln, Nebraska
Posts: 1,806
Scales Modeled: HO, too blind and fumble fingered for N
I can't help with the resistance soldering question, but I want to say that's a nice piece of work!
__________________
"If the women don't find ya handsome, they should at least find ya handy!"
Red Green
http://theworldasiseeit-flyboy2610.b...-i-see-it.html
flyboy2610 is online now   Reply With Quote
Old 10-06-2019, 09:43 PM   #5
PatriceL
Hobo
 
Join Date: Oct 2019
Posts: 13
John, I can't do that but I may have to live with the marks and incorporate them in the design if I can't get rid of them completely.

WCGCA, that is an interesting idea but I have no idea how I would implement it since it usually is on a curved surface and a bit cramped. But I'll look into it some more for sure.

Flyboy, you are very kind, thanks.

And a big thanks for the help guys, I'll post more if I get better results.
PatriceL is offline   Reply With Quote
Old 10-07-2019, 11:58 AM   #6
gunrunnerjohn
Admin
 
gunrunnerjohn's Avatar
 
Join Date: Nov 2010
Location: SE-PA, USA
Posts: 41,965
Scales Modeled: O-gauge 3-rail
Images: 3
Remember, the one electrode can be connected anywhere on the piece, it's the current that does the heating.
gunrunnerjohn is offline   Reply With Quote
Old 10-07-2019, 09:50 PM   #7
PatriceL
Hobo
 
Join Date: Oct 2019
Posts: 13
John I use a pliers stile handpiece, not a probe with a lead connected to the piece.

PatriceL is offline   Reply With Quote
Old 10-08-2019, 09:12 AM   #8
gunrunnerjohn
Admin
 
gunrunnerjohn's Avatar
 
Join Date: Nov 2010
Location: SE-PA, USA
Posts: 41,965
Scales Modeled: O-gauge 3-rail
Images: 3
It's quite possible that soldering on a finished piece simply isn't in the cards. I do wonder about the glowing electrodes, perhaps the excessive heat at the spot is the problem. Resistance soldering is supposed to heat the workpiece, not the tool. I've only used one resistance soldering rig, it was hand made. However, we had no red hot electrodes.

Have you considered low temperature solder for the critical pieces? Another option might be brazing or soldering with a torch, you don't get contact scoring with that method.
gunrunnerjohn is offline   Reply With Quote
Old 10-08-2019, 09:49 AM   #9
PatriceL
Hobo
 
Join Date: Oct 2019
Posts: 13
I'll make it work John, even if like I said it means a little scoring that in the end I might be the only one that notices it. The drawback of being a tad perfectionist (ok maybe more than a tad )

The red glowing is really just because I am dumping a lot of heat it doesn't happen until late in the process. Pulsing it might help too, got to try that some more.

I did not mention it but brazing would mean OA or Oxy-Propane and I can't have that because of insurance since my shop is attached to the house. That's why I am pursuing electricity based solutions. The solder I use is a low temp one for silver solder that is. About 435F if I remember right, not sure they make lower than that in silver which I like because it stays bright. (This one is named Stay-Brite after all )

Thanks again for your help.
PatriceL is offline   Reply With Quote
Old 10-08-2019, 10:38 AM   #10
gunrunnerjohn
Admin
 
gunrunnerjohn's Avatar
 
Join Date: Nov 2010
Location: SE-PA, USA
Posts: 41,965
Scales Modeled: O-gauge 3-rail
Images: 3
That's pretty good for silver solder. Dumb question. Why not use a large soldering gun like the Weller D650, it's a 300W model and will do significant soldering on large pieces. Resistance soldering may not be ideal for the work you're doing. You won't have any discoloration due to excessive temperatures at the contact point.
gunrunnerjohn is offline   Reply With Quote
Reply



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


» Visit These Sites:
LGB World

Or Our European Train Website ModelRailForum




All times are GMT -5. The time now is 07:55 PM.


Powered by vBulletin®
Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.