Welding Tips and Tricks

Hey guys...
I got in a little tit-for-tat debate over on another forum. Here is the link to the thread, which is pretty exciting and interesting if you have a few minutes to kill : http://elmoto.net/tell-us-about-your-pr ... ratch.html

So my question was to the builders why pop rivets were used instead of tig, and one guy writes in with a link to some aluminium boat builder stating rivets are stronger then welding yadyadayada

Thats funny, because I know retired Alaska commercial fisherman that will only own a welded boat, period!
So I posted my rebuttal and took it on the chin, whatever!!

But I am the first to admit that I know minimal about metallurgy. Does TIG really weaken the aluminium??
Personally... I would rather have a dry, welded boat than a leaky, riveted one any day!!

Probably why ottonobedder and Alexi whip out the pop rivet gun when working with alum.

Welcome, upwinger,

Every weld affects the parent metal (and the filler rod affects the weld it fills).

It's the nature of the beast.

Rivets versus welded? I'll take welded any day, BUT you'd be surprised to see the strength comparison experiments....

Steve S

weldin mike 27 wrote:Probably why ottonobedder and Alexi whip out the pop rivet gun when working with alum.

What extremity of your arse did you pull that one from?

Steve S

Somewhere up there near the library of junk that I spout on a daily basis

Read these threads.

Welded is the way to go.

http://weldingweb.com/showthread.php?12 ... highlight=

http://weldingweb.com/showthread.php?41 ... highlight=

Great links John, thanks

Trev

It all depends what you weld and what filler you use. As already said here.

On aluminium, weld is always weaker than base metal. That is why aluminium welding can be very difficult when demands are high. You have to follow very closely your heat input and purity aspects.

Aluminium is not strengthened in the same way as normal metals. This is due to lack of phases in structure of aluminium etc.
So when heated, aluminium tends to lose strength quite a much. It all depends of the grade, heat input and time... However usually you don't need to think strength that much when doing basic welds and structures, but with some grades you will lose even 50 % of the strength right near the HAZ.

Also corrosion resistance is almost always weakened when metal is welded. How much then, that is a different story and resistance is usually easy to bring back to normal level with pickling, passivation or electropolishing.

Rivets or welds?
I would prefer welding. There are some issues with rivets too. They can act as localized corrosion cells and also there is always high tension point in some edge or so. Plus welds won't leak, when done right