Tacking? Smoothness!? Running bead to tack and other options

[stee1e]

We have spent weeks doing bead pads, writing names etc. and have now been welding scrap box section to plate, basically driving ourselves nuts repeatedly doing fillet welds over and over. After the intitial headache of making sure the torch is at an 45 degree angle and not just welding the wall of the box we seem to be getting good penetration and the welds are getting better. We think! A large hammer appears to prove this

We are tacking each corner of the box then running a bead from tack to tack. This seems to give a strong weld but not the prettiest. In the long run we want some of these welds to be on show.

What would be your advice on running beads on box sections, stop at the tack? Go around the tack? or not tack at all if that corner is to be visible?

Thanks

 

[Bill Edwards]

Well generally speaking you have to use tacks to hold everything in the right position and avoid distortion, unless you're working with things tightly clamped to some kind of jig.

You need to grind the tacks right down so they aren't really raised. You should only need a tiny amount of it left to hold the metal correctly, grind off the excess lump then you can weld through it without leaving a mess and it will be stronger as tack welds don't tend to have great penetration anyway.

 

[Richard.]

^^^^^ yep exactly this.
Sand your tacks back so there is enough holding the steel in place but without any excess reinforcement causing a bumpy appearance to the run. Either that or find a way to clamp it securely and dismiss the tacking all together . If your going to do this make sure it's clamped down well or your first run will pull it out .

 

[stee1e]

Great advice. thanks for the help

 

[norlander]

try turning your settings up for tacking,use a very short burst and maybe fit a spot welding nozzle, I have found these help when I pass the torch to a mate to put a tack on, but they are not so handy sometimes when tacking into a fillet set up. http://rapidwelding.com/dynamic/DisplayItem.aspx?c=145.0168&zl=3.
Remember to put your settings back for welding though.

I usually "burn through" my tacks but can't really explain how, but as has been said, for best results, dress the tacks up with a grinder-be careful-if you go too far the weld on one side can pull and break the tack if its too weak.
For nadgery grinding access to tacks, these are handy http://www.weldequip.com/cut-grind-discs.htm use a light touch, keep a good grip on the grinder and be careful.

 

[Jan]

I prefer a flap disc for grinding welds smoother. A decent one can last for a very long time while giving a mirror smooth finish.