Solder Link Help [Archive]

gregg f

Feb 09, 2003, 12:14 PM

Originally posted by Dan Ahearn
Is there an easy way to do solder links that will ensure a reliable bond?

I'm trying to replace z bends on a Zagi, and I worry about vibrations.

Dan ...

here's one link Dan.
http://www.epemag.wimborne.co.uk/solderfaq.htm

moving this to modeling science for more exposure........g

BMatthews

Feb 09, 2003, 10:32 PM

You mean the solder on Quicklinks like Dubro means?

Basically clean everything well. Steel wire needs some fine sandpapering and the link should be OK as the plating is meant for accepting solder.

For structural joints like this the resin core electronics flux is not always strong enough. A small square tin of plumbers flux will last a lifetime. Lightly wipe on paste type solder flux on both the cleaned wire and the inside of the link. Put the wire in place. Heat the outside of the link in the center and when the flux sizzles apply the solder to the end of the joint. After a second or two the solder should melt and suck itself up into the joint. Some excess should form a nice fillet on the end and you should see solder flow up to the other end of the joint. Let cool to hardness before moving.

If it doens't flow on it's own don't force it. Obviously something is not clean enough. Also you don't apply solder to the iron itself other than to wet the end for better heat transfer. The metals of the wire and link need to be hot enough to melt the solder on contact or you will not get a good joint.

Practice on some bits of wire and brass tubing. A 1/16 wire pushed into an inch length of 3/32 brass tube for 1/4 inch and soldered should be able to stand a good 20 lbs pull with no failure. In fact it should probably stand up to about a 40 lb pull before something lets go. At that point it may be the brass rather than the joint. If you grab the brass with pliers and twist the brass should certainly twist apart before the solder lets go.