Stitch Welding

[78nismoZ]

Hey guys I am at the point that I am ready to start stitch welding my car and I am not exactly sure of what would be the best weld to go with. Would a series of spot welds every inch or two be better that one to two inch weld beads every one to two inches? Any help would be great so I can start tomorrow. Also particular places I should spend more time on would help as well

[jkgts1]

When I did mine I did 1 inch long welds every 2 inches, of course alternating areas to keep heat down.

[JMortensen]

When I did mine I did 1 inch long welds every 2 inches, of course alternating areas to keep heat down.

I did one inch and skipped an inch until I was told to do the above about 1/2 way through.

[frank280zx]

Also dont stitch wel behind the rear strut towers or in front of your sway bar mounts. In case of a mishap you can repair it easier and you give the impact force a place to go (ie curl up some frame rails) if you stich it all the way through it will tend to tweak the frame more if the impact is strong enough.

[palosfv3]

There is a proper weld type for the area and metal needing to be welded. If the panel was spot welded from the factory replace the spot weld with a plug weld. Try to replicate the spacing and size of the original spot weld. Replacing a spot weld with an edge weld can result in fatigue cracking around the weld as this moves the load point of the weld away from where it was engineered to be . Just like in painting preparation is key to a good weld. Clean unrusted metal and tight fitting pieces go along way to ensuring a good weld. Learn to read your welds to ensure you are getting proper weld pentration. Practice welds on similar pieces of scrap metal are sometimes necessary to make sure you have the correct set up on your welder. While Z cars dont use any HSS or UHS steel , its important to understand how loads move through the structure and how weld type and placement affect the movement of these loads.

 

Since the availability of low cost MIG welders there are many new people trying their hand at welding. There is more to welding than just purchasing a machine.

 

The old addage is " If you dont weld well , weld often. "

 

 

[78nismoZ]

So now I have an opposing argument about the stitch welding. Every stitch weld I have seen have been an edge weld on a lap joint, regardless of a spot weld made in the relative same location. This car is not going to be a track car, it will rarely see a track as of right now, I am only doing this in case I decide to go to an auto x day or something like that, so do I need to worry about stress cracks on the stitch welds on a daily driven car?

Also if anyone had any pics of the stitch welding on their z I would love to see them just to see what I'm getting myself into.

[78nismoZ]

Anybody got some pics to show me what I'm getting into? Any pics would help.....

[JMortensen]

Do a search. Should find pics of my car and bjhines' car, and I think johnc has posted pics of one of his betamotorsports.com customer's cars.

[78nismoZ]

Thanks J!

[Nismo280zEd]

There is a proper weld type for the area and metal needing to be welded. If the panel was spot welded from the factory replace the spot weld with a plug weld. Try to replicate the spacing and size of the original spot weld. Replacing a spot weld with an edge weld can result in fatigue cracking around the weld as this moves the load point of the weld away from where it was engineered to be . Just like in painting preparation is key to a good weld. Clean unrusted metal and tight fitting pieces go along way to ensuring a good weld. Learn to read your welds to ensure you are getting proper weld pentration. Practice welds on similar pieces of scrap metal are sometimes necessary to make sure you have the correct set up on your welder. While Z cars dont use any HSS or UHS steel , its important to understand how loads move through the structure and how weld type and placement affect the movement of these loads.

 

Since the availability of low cost MIG welders there are many new people trying their hand at welding. There is more to welding than just purchasing a machine.

 

The old addage is " If you dont weld well , weld often. "

 

 

I guess I don't understand your reasoning here.

 

Lets say you have a panel with 10 spot welds every 4 or 5 inches. You want to stitch weld it to increase rigidity. So you put in 20 1" welds on the panel.

Now your panels has 10 spot welds and 20 1" long beads. This increases load transfer area through the panel, while I see you point of it tranfering loads more towards the edge of the panel where the spots weld where recessed back from the edge. Still you have more area to transfer the stresses so wouldn't this equate into less stress per weld than originally?

 

Just curious.

-Ed

[Boy from Oz]

Here are a few photos of my car. The chap who did it has been involved in race car preparation for 40 years so I just let him go at it. It was my plan to weld the whole car but, as pointed out in an earlier post, he advised against this as any accident could significantly distort the alignment of the shell rather than just keeping the damage local. I don't intend to race it at all and did it mainly for an LS1 installation.

[tube80z]

I guess I don't understand your reasoning here.

 

Still you have more area to transfer the stresses so wouldn't this equate into less stress per weld than originally?

 

 

Some showroom stock racers I knew years ago told me they stitched because you can pull the damage back out. With just spot welds the parts often split making it impossible to do. So I also don't understand why you wouldn't want to have things welded up front and in back.

 

cary