Is this good enough tack welding?

[Simon W]

After spending the last few weeks blasting holes in scrap I have started to tack weld my "Locost" car chassis up. Have I got the right idea for a tack weld? It seems strong enough for light handling. Once I have completed the chassis do I grind the tack welds down and then do the proper weld?

Thanks in advance.

 

[Haze]

a tack is actually very very strong, in one direction it can take a suprising amount of weight, under twisting and other directional stresses though it will break, grind out the tacks but you dont need to remove all the metal and lay your weld on top.

 

[Simon W]

Ok, good to know. But my tacks look ok right? Not too small in length etc.

 

[Bigjoe]

Tacks look fine Simon.

 

[Justme]

would go for slightly more penetration but not extra length then you can weld over them with no grinding out. Also tend not to tack right on the ends as thats the worse bit to weld over too.

Justme

 

[Haze]

Ok, good to know. But my tacks look ok right? Not too small in length etc.

tacks dont need to be very big at all, but like the man said, more penetration, a good small tack is better than a big crappy one.

 

[Simon W]

Ok, I think the tallness is probably due to my action (not enough side to side) rather than too little power? Wire speed is not a factor in this? The next notch up for power would probably be too much so how will I increase the penetration?

 

[malcolm]

Torch action shouldn't come into it. Normally you'd set the power up a notch or two, and wire feed up slightly less than that, and hold the torch directly over the join and press the trigger for a very short time.

A tiny little tack will be weldoverable, and should be quite strong. Yours are maybe a little big. I was going to suggest people were being fussy - but you did ask.

Experiment with off-cuts - you'd be amazed how much power you can stick in over a very short time, and how strong the tacks are.

 

[weldequip]

weldoverable

I think you may have discovered a new word there Malcolm!
weldequip

 

[malcolm]

Sorry - had a bit of a welderoverablism there. Germans do it all the time (string words together when they can't think of a neat phrase that is).

 

[lexi]

If you tack up a Seven frame like that you will be able to bounce on it without breaking it.
Alex

 

[lorenzo]

What is the wall thickness of your tubing?

I don't know what size machine you are using but you may want to think about a single v groove as a joint prep. This will help with the penetration.

 

[HughF]

Don't ever put a tack in the middle of a piece of box (if you know what I mean), do them at and end so you can push into them. And always always, grind your tacks back and push into them. Don't start on your tacks or you'll have a cold lap.

Hugh

 

[lexi]

That tube is 16 g . Yes Hugh my frame was tacked at corners ........

Alex