- Thread starter clarkey
- Start date
Sheet metal aside, overlapping tacks/spot welds is not really a good technique. Often results in lots of lack of fusion issues (voids in the weld where the tubes meet) and you also get a bunch of stress risers from the craters in the middle of each tack and where the tacks overlap
Have you done any destructive tests on sample joints- cut/break 'em open to check that fusion was adequate?
Have you done any destructive tests on sample joints- cut/break 'em open to check that fusion was adequate?
Hi Hotrodder, first off thanks for the advice 
I used to just weld a constant weld all the way around and i was told that i was doing it wrong, so i started doing it this way instead.
Before i start i got some scrap metal and i set the welder up to basicly come out the other side of the tube, it was on the MAX setting of the 160amp welder and i was basicly spotting it for a few seconds in each location. thats why the welds appear flush because they are sinking into the metal.
I cut the weld in half and it was defo coming out the otherside, that ment more to me then the looks.
Hey Luke,
I hope to thing the power i used and the fact it came out the otherside of the tube would be ints strong enough, but the metal is 2.5mm think tube so there is alot of metal to grab ?
My car
http://doristars.com/v-web/gallery/bdc32009/DSC_1218_copy?full=1
quick video
http://www.youtube.com/watch?v=Drp77STEfOE
I used to just weld a constant weld all the way around and i was told that i was doing it wrong, so i started doing it this way instead.
Before i start i got some scrap metal and i set the welder up to basicly come out the other side of the tube, it was on the MAX setting of the 160amp welder and i was basicly spotting it for a few seconds in each location. thats why the welds appear flush because they are sinking into the metal.
I cut the weld in half and it was defo coming out the otherside, that ment more to me then the looks.
Hey Luke,
I hope to thing the power i used and the fact it came out the otherside of the tube would be ints strong enough, but the metal is 2.5mm think tube so there is alot of metal to grab ?
My car
http://doristars.com/v-web/gallery/bdc32009/DSC_1218_copy?full=1
quick video
http://www.youtube.com/watch?v=Drp77STEfOE
I would ignore the guy that told you to switch to spot welds. From what you've said about the test welds sounds like it's worked better than many similar examples. You can still end up with lack of fusion where the spots overlap though, despite weld reinforcment on the back side of the joint- harder to spot without macro etching the weld though. In the absence of the proper etching reagents you can get a view of the fusion zone using battery acid, section a weld, polish and apply a little acid. After a cup of tea/beer there will be a feint outline of the welds fusion zone
and yes kinda goes hand in hand 