I did read somewhere that men used to pee on parts before pressing them together seems to encourage rusting !

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Perhaps a rather broad generalisation, given the range of Loctite products

MichaelG.

Lots of different takes on line, but soft solder seems to have the edge. Also, I found one reference to soft soldered copper-to copper joints having a strength of 200MPa.

Loctite 3422 at various cure temperatures:

Lead-tin solder

Most of the old methods – drive fits, rivets and upsetting, cross pins etc. – are still in use. I can remember first coming across superglues in the mid 70s for bonding the ends of O-rings in injection mould cooling circuits. Their general usefulness has expanded a good deal since then, but where you need to be sure to be sure, and you don't have comprehensive and detailed knowledge of the value and direction of stresses, it's best to add something you can be more certain of.

Although the nominal joint strengths are very similar one important difference between adhesive bonding and soldering is peel strength. Adhesives are generally much weaker than solders in peel because very high stress concentrations can be developed at the separation point between the bonded surfaces. Sufficient to tear the bonding material apart or pull it off the surface if initial preparation was inadequate. A little bit of additional mechanical locking at the ends of adhesive joints is often appropriate.

Oversimplifying adhesives rely on surface wetting to generate the bond strength whilst properly applied solders have a degree of inter metallic penetration which is inherently far more resistant to localised joint line stresses. Its not actually that much stronger. You just can't build up the localised stress. Peel is good test for improperly tinned and improperly heated soft solder joints. The joint may look fine but if it hasn't taken properly it will peel quite easily. One of my mentors showed me that many years ago. Much to my surprise as I thought I'd made a nice neat joint. Big electric soldering irons aren't quite as easy to use as I'd thought.

Adhesive joints can be amazingly strong as its relatively easy to cover quite large areas. The achilles heel in the home shop is surface preparation and environmental factors. Usually temperature. Its hard to achieve and maintain optimum conditions in the home shop.

Clive