Will these weld pass

dfink · 12-17-2008, 05:41 AM

No response on my install thread so thought I would try itself before I weld the other side. I know they are not perfect but should they pass inspection. They look much better in the car. Damn camera finally takes a good picture just when I want a little blur. Sorry for the repost but the other thread is kind of on a downhill spin.

sezme · 12-17-2008, 05:53 AM

Don't "stutter". Keep moving in a consistant pattern. Weld might be a little cold as well.

Mo_Gearhead · 12-17-2008, 06:02 AM

Quote: "Weld might be a little cold as well."
__________________

Hard to tell from the photo but I agree.

Make sure you are getting good 'flow' into the thinner sheet metal body ...otherwise the weld will be weak as it just 'sits' on top, with little penetration.

It's tricky when mating thicker plate to thinner base metal (burn through possible).

Practice!

dfink · 12-17-2008, 06:49 AM

Thanks for the input. I am positive it would break the metal out of the car before the weld broke.
It is melted to the thinner metal good. I watch the puddle and can see it going togeather you are correct that it needs a bit more power on the tube part. I don't think I could use more on the plate it already is extreamly close to burn through. I did the weld in short bursts to avoid getting the metal too hot and starting the car on fire.
You are correct very hard to weld the thicker plate to the thin body metal.

DW SD · 12-17-2008, 06:59 AM

I'd be concerned about penetration. I find it relatively easy to weld thick to thin. Keep the gun tip pointed at the thick metal and heat range setup for thick. Then quickly (but deliberately) drag the puddle into the thin and back again. Spend 75% to 80% (maybe more) of your time pointing the gun at the thicker metal. Use a cursive v pattern as you drag the puddle around.

Any way you can have someone go over it with a TIG?

Caveat: if someone like Ben McFarland gives different advice, go with it, in lieu of mine. He's a welding teacher and I'm but an amateur, albeit one who's welded for more than fifteen years.

The way I see it, there is no point having a roll bar that isn't 100% attached properly.

crustychief · crustychief's Garage

+1 about "stitching" the thicker to the thinner metal.

Porsche_monkey · 12-17-2008, 07:39 AM

As a weld engineer let me say this: No one knows how good that weld is. If a visual inspection was worth anything then destructive testing would be non-existent.

Just like a home-built aircraft inspection, you should weld a similar sample at the same time and destroy it to verify the weld integrity.

To answer your question, I would guess the welds are fine, they could be prettier, but who cares?

Here's hoping you never test those welds.

GaryR · GaryR's Garage

Quote:

Originally Posted by DW SD

I'd be concerned about penetration.

Looks that way to me also, but i'm no weld engineer..

DW SD · 12-17-2008, 08:35 AM

I humbly defer to Porsche Monkey. I can confidently state that visual inspection does reveal things about certain welds. Is it definitive, clearly not!

Doug

dfink · 12-17-2008, 08:56 AM

Thanks for all the input.
I do agree that at least the tube to base plate could use more heat. What you see in the photo is actually a second pass the first pass offered better penetration but had some spots to tie togeather. What you see was a second pass that was woven over the first pass in attempt to tie everything togeather. It is really not as bad as it looks in the picture. It is still possible to take someplace when I am done and have someone with a much better welder than mine just run a nice bead. I have definately seen worse.

There is a definition on the SCCA web site of what is considered a good weld, a continuous weld, no cracks, craters filled entire width of weld, no wiskers, and cut back less than .01"

If I wasn't so scared of catching the car on fire I would run much longer continuous beads on the base plate.

One problem I have is I am using a 110 welder. 5 positions running on 4. I can go to 5 it just won't weld very long before the overload goes. No subsitute for having a good welder. I used to tig quite a bit, did stick on the heavy stuff, and used to be very good with a torch, this is my first mig and I have not been welding for quite a few years.

Porsche_monkey · 12-17-2008, 09:01 AM

Quote:

Originally Posted by DW SD

I humbly defer to Porsche Monkey. I can confidently state that visual inspection does reveal things about certain welds. Is it definitive, clearly not!

Doug

Valid point: You can sometimes tell a weld is poor from visual inspection, you can never tell a weld is good from a visual.

Quote:

Originally Posted by dfink

No subsitute for having a good welder.

True. But with a good machine you have no excuses.

dfink · 12-17-2008, 09:04 AM

Quote:

Originally Posted by Porsche_monkey

Just like a home-built aircraft inspection, you should weld a similar sample at the same time and destroy it to verify the weld integrity.

I do plan to make a similar weld on a test piece and use it for my own verification. I know the base to car penetrated. In a few spots it penetrated to much and I had to fill. There is also some places where it very touchy. You are welding and all of a sudden "POP" just like with a torch. I assume that is where there is some form of contamination. Once those spots are filled then you can go back over and tie it all in.

Porsche_monkey · 12-17-2008, 10:30 AM

A cut and etch test will tell you if you penetrated the big piece.

Guess at the strength you need, then figure out the area that requires based on the tensile strength of steel and you will be surprised how little welded area you really need.

You likely have more chance of ripping the parent material away than breaking your weld.

Zeke · 12-17-2008, 12:07 PM

I, too, am an amateur at welding, however I sometimes get paid to do it.

Really, it's more of the total concept of the project I'm doing as the welding is only one process.

Anyway, I'll certainly have to agree with the comments about visual. Yet, you seem to have nailed it right at the front base of your main tube and at the front of the plate. If you are concerned about the roll cage tearing from the chassis, make L shaped plates and wrap them down on the vertical surfaces a bit. You'll be gaining some shear value.

dfink · 12-17-2008, 04:10 PM

A couple of updates first picture is what the other weld looked like before I did second pass trying to smooth it. Second picture is with welder turned on high. First one I think is good. Second one is better.

calling911 · 12-17-2008, 04:49 PM

Quote:

Originally Posted by dfink

No response on my install thread so thought I would try itself before I weld the other side. I know they are not perfect but should they pass inspection. They look much better in the car. Damn camera finally takes a good picture just when I want a little blur. Sorry for the repost but the other thread is kind of on a downhill spin.

You can weld pretty hot on Porsche un-rusted body work. If you are concerned about getting to hot stitch it together by doing 1/4" welds and keep moving from side to side letting the metal cool as long as you can between welds. There is nothing wrong with the stitching pattern you have there.. MIG will never look like TIG.. although, if you do a quick burst and then move and burst it will look damn close.