Replacating factory spot welds

Dan, that is going to be tough! Recently I was looking online at spot welders & there seem to be units that are not too expensive & look like they'd do the job. I remember using one back in my metal shop class in junior high - it was easy to use & worked great. If I was going to do a major sheetmetal job like this, I would invest in one. Whenever I go to car shows, I look at all the restored cars & I look closely for cars that have had sheetmetal work done so well that you can't tell they are not factory - and that means perfectly duplicated spot-welds! You almost NEVER see that! Good luck & all I can say is I don't know how you did it to have your daughter interested - but my hat is off to you. Neither of my daughters could care less about my Cudas.

Posted By: mopar346

Re: Replacating factory spot welds - 12/29/14 03:28 AM

So the lenco doesn't require jaws that limit access such as deep inboard on the floor. You just have to line the 2 leads up and pull the trigger? Very interesting.

Thank you.

Posted By: DusterJeff

Re: Replacating factory spot welds - 12/29/14 03:32 AM

May I suggest practicing on some scrap pieces of metal the same thickness as your patch panels. When I do my "SpotWelds" with the MIG on my Duster, I run .023 wire in the gun.Takes a bit of "Practice" to get a good "Rosette" looking weld....

Good luck on your Father-Daughter Project....

Posted By: fourgearsavoy

Re: Replacating factory spot welds - 12/29/14 03:34 AM

I have seen one collecting dust at Mike Ross's shop over at B/E&A Restorations.It's a big professional collision repair unit and he might be interested in selling it.
Gus

Attached picture 8376734-moriaburnout.JPG

Posted By: draginmopars

Re: Replacating factory spot welds - 12/29/14 03:41 AM

Quote:

So the lenco doesn't require jaws that limit access such as deep inboard on the floor. You just have to line the 2 leads up and pull the trigger? Very interesting.

Thank you.

you can place the leads side by side to spot weld

if you weld with one lead on the front and one on the back

Both sides of both metals must be cleaned

there is a lot of "resistence Spot Welding" videos on U-tube.

My snap on mig has a spot weld timer that does,okay.
I still use it, it's just the lenco is faster and easier to weld with

here's a interesting Mig spot weld procedure

https://www.youtube.com/watch?v=0Pa7zIq3VkE

Posted By: flypaper

Re: Replacating factory spot welds - 12/29/14 03:56 AM

Quote:

I would not be against a Lenco spot welder, but from what I have heard you can't get a strong enough weld. I think the problem is on areas like the pans to the rails where the rail is much thicker metal and you can't get enough penetration to make it structurally strong. Is there any truth to this?

yes its true
i have seen stuff welded together with one
that could be pulled apart by hand!
i would not trust one myself
i was thinking of getting a used one
not to take the place of plug welding
but just for cosmetics instead of using a pencil eraser.
i have also seen cylindrical die cutters used
for replicating spot welds that have looked pretty authentic.

Posted By: Evil Spirit

Re: Replacating factory spot welds - 12/29/14 05:08 AM

I would really suggest evaluating how important having correct looking spotwelds are before I would spend the money and time to try to duplicate them. From someone that has literally performed millions of spotwelds and performed destructive testing on them in a manufacturing environment, I can tell you it isn't as simple as holding a couple tips together on a couple pieces of sheet metal. I've probably cut apart 20 full bodies to test spotweld integrity, so I kind of know a little about them. You can't tell a good spotweld by it's looks, so you are left to using a proper, repeatable process to make strong welds, which is almost impossible in a shop setting.

A good spotweld takes the correct current for the proper length of time, proper tip diameter (to heat the metal without burning it) and alignment, proper clamping pressure, and clean materials CONSISTANTLY to perform. While you can have decent results from the stationary machines with the footpedal - it takes a lot of trial and error to get REPEATABLE results, and they are limited to panels that you can fit between the arms.

Many times in the You Tube videos I see people performing spotwelds with the two handheld contacts, and I see that a lot of the time they have spatter coming from between the panels, which indicates they don't have enough clamping pressure between the tips. Those welds typically WILL FAIL TESTING, due to the panels didn't melt together fully. I don't see how anyone can CONSISTANTLY apply the correct pressure required, which can be 100+ lbs in certain circumstances, with handheld contacts in a shop environment.

I also see people "test" their welds by putting several welds into the ends of two pieces of sheetmetal, and try to pull them apart - LOL. The CORRECT test is 1 weld, and trying to twist the 2 apart - if the weld is good, you will tear a hole out of one of the sheets of metal - a bad one the weld fails. Or a chisel between the sheets to see if the weld pops before the metal tears. Point is, you have to make it fail to test the weld - many good looking spotwelds will fail testing. While they can produce acceptable results under controlled conditions, I don't see how someone could produce consistant spotwelds in a shop environment, especially with the handheld contacts.

Posted By: Stanton

Re: Replacating factory spot welds - 12/29/14 05:29 AM

If its "looks" you're after then go ahead and spotweld it. If you want it solid and safe, mig plug welds are the ticket.

Posted By: screamindriver

Re: Replacating factory spot welds - 12/29/14 07:22 AM

You stated your using a mig so...Plug weld the panels then use a flat,round metal punch BETWEEN the plug weld areas to dimple the metal for the spot weld look...Vary the striking angle to mix it up and use a backer where needed...

Posted By: John_Kunkel

Re: Replacating factory spot welds - 12/29/14 08:54 PM

I've heard of people grinding the plug welds flat then using a fresh pencil eraser in the wet paint to replicate the spot welds.

Posted By: mopar4ya

Re: Replacating factory spot welds - 12/30/14 02:17 AM

Quote:

If its "looks" you're after then go ahead and spotweld it. If you want it solid and safe, mig plug welds are the ticket.

Believe me, solid and SAFE is the only way I will build this car. My daughter is a graduate of Shriners hospital, she's been through enough in her young life, looking to build something she will enjoy in the years ahead.

Thanks
Dan

Posted By: DeMopuar

Re: Replacating factory spot welds - 12/30/14 04:07 AM

I would plug weld for strength, and then grind smooth so you cannot tell anything was plug welded -- then I would do the "artwork" to replicate the look of the spot welds with whatever method works best for you. It's a lot of work to do this I know, I know of a guy that does this on a regular basis for his OEM type of restorations, and that is the best way he has found to do this. He only does this on his own cars because no one wants to pay him by the hour to do this work. It is very time consuming, but probably the best solution to your issue. I totally agree, I would not trust spot welds either, just not good enough; plug welds I would trust all day long.

Best of luck for your project.

Posted By: hemicar1971

Re: Replacating factory spot welds - 12/30/14 04:28 AM

Have your Daughter do as much work as you will let her on HER car. Factory uses 550 and usually all others like mine use 220. So a factory spot weld will be a lot deeper. If you lived anywhere near me you could have the welder to use till all the body work is over. I know some restorers use another method of airbrushing the spot welds into the body work. Using this method would require a skill also.

Posted By: 6pkaar

Re: Replacating factory spot welds - 12/30/14 06:07 AM

I've heard of doing a plug weld, then heating the plug with a torch and striking it with a punch the diameter of the spot weld. Anybody tried this?

Posted By: scatpacktom

Re: Replacating factory spot welds - 12/30/14 03:32 PM

I plug weld with the MIG then grind it flat. Then I sink a carbide bur into it to make it look like a spot

Posted By: GeorgeH

Re: Replacating factory spot welds - 12/31/14 06:13 AM

Quote:

I would really suggest evaluating how important having correct looking spotwelds are before I would spend the money and time to try to duplicate them. From someone that has literally performed millions of spotwelds and performed destructive testing on them in a manufacturing environment, I can tell you it isn't as simple as holding a couple tips together on a couple pieces of sheet metal. I've probably cut apart 20 full bodies to test spotweld integrity, so I kind of know a little about them. You can't tell a good spotweld by it's looks, so you are left to using a proper, repeatable process to make strong welds, which is almost impossible in a shop setting.

A good spotweld takes the correct current for the proper length of time, proper tip diameter (to heat the metal without burning it) and alignment, proper clamping pressure, and clean materials CONSISTANTLY to perform. While you can have decent results from the stationary machines with the footpedal - it takes a lot of trial and error to get REPEATABLE results, and they are limited to panels that you can fit between the arms.

Many times in the You Tube videos I see people performing spotwelds with the two handheld contacts, and I see that a lot of the time they have spatter coming from between the panels, which indicates they don't have enough clamping pressure between the tips. Those welds typically WILL FAIL TESTING, due to the panels didn't melt together fully. I don't see how anyone can CONSISTANTLY apply the correct pressure required, which can be 100+ lbs in certain circumstances, with handheld contacts in a shop environment.

I also see people "test" their welds by putting several welds into the ends of two pieces of sheetmetal, and try to pull them apart - LOL. The CORRECT test is 1 weld, and trying to twist the 2 apart - if the weld is good, you will tear a hole out of one of the sheets of metal - a bad one the weld fails. Or a chisel between the sheets to see if the weld pops before the metal tears. Point is, you have to make it fail to test the weld - many good looking spotwelds will fail testing. While they can produce acceptable results under controlled conditions, I don't see how someone could produce consistant spotwelds in a shop environment, especially with the handheld contacts.

X2 Lenco's not recommended for body repair these days as per ASE, I-car, and OEM repair procedures for what's that's worth. There are resistance welders out there that are used, but they produce somewhere close to 300 psi clamping pressure, example Pro-Spot, but due to required clamping presures the available arms aren't but so long, 18" I believe and not everybody is going to shell the 10k, so your back to the eraser trick anyway. As per I-Car, supposed to put 30% more welds on a replacement panel than what was there. Realistically, not every weld is a home run on the thinner metals. Another thing that hasn't been mentioned, and always a source for argument is when you grind a plug weld totally flat you get into the base metal surrounding the weld and you be surprised how thin you've left the metal and how little is holding it together. Technically every piece on a unibody is considered structure. better to err on the safety side. I had to have welds pass for I-car Cert, and most are really surprised the first go around with what looks good and doesn't pass. I'd never use a Lenco, they're just not consistent enough. Sometimes strength needs to win over easy and/or pretty.

Posted By: Stanton

Re: Replacating factory spot welds - 12/31/14 06:52 AM

you're building this car for your young daughter ... is she going to drive it or show it ?!?

Posted By: cudaman1969

Re: Replacating factory spot welds - 12/31/14 06:54 AM

I have an much older Lenco spot and i made arms to align the tips up so no guessing, right now i can span 24 inches. Mine also has a lot of amp adjustments(two switches) and i can melt holes through 0.060 steel. I keep the tips about 1/4 diameter, slightly round.I clamp or clecko? entire panel. I would like to see someone pull these apart(i tried), did a lot of testing first. Metal has to be clean, no paint where the spot goes. Next i'm going to make a tool the size of the spot, clamp, then prime every where except the spot.

Posted By: Stanton

Re: Replacating factory spot welds - 12/31/14 03:57 PM

Quote:

Next i'm going to make a tool the size of the spot, clamp, then prime every where except the spot.

The problem is that the heat will burn and char the primer in the heat affected zone and you're back to square one.

Have you heard of "weld through primer" ? There are some crap brands out there but the Upol copper works great (not cheap !).

Posted By: mopar4ya

Re: Replacating factory spot welds - 12/31/14 08:29 PM

Quote:

I would plug weld for strength, and then grind smooth so you cannot tell anything was plug welded -- then I would do the "artwork" to replicate the look of the spot welds with whatever method works best for you. It's a lot of work to do this I know, I know of a guy that does this on a regular basis for his OEM type of restorations, and that is the best way he has found to do this. He only does this on his own cars because no one wants to pay him by the hour to do this work. It is very time consuming, but probably the best solution to your issue. I totally agree, I would not trust spot welds either, just not good enough; plug welds I would trust all day long.

Best of luck for your project.

I definitely will be plug welding, I just don't trust the spot welds of a small shop spot welder. I really am only concerned with appearance of the welds on the areas you can see, not so much where it will be covered up. I have lots of patients so don't mind taking the time to do some art work.

Dan

Posted By: mopar4ya

Re: Replacating factory spot welds - 12/31/14 08:35 PM

Quote:

Have your Daughter do as much work as you will let her on HER car. Factory uses 550 and usually all others like mine use 220. So a factory spot weld will be a lot deeper. If you lived anywhere near me you could have the welder to use till all the body work is over. I know some restorers use another method of airbrushing the spot welds into the body work. Using this method would require a skill also.

I plan on having her do as much as I think is safe to let her work at, but she is involved in a lot at school so time is limited. Thanks for the offer on the welder! I have a friend that has a body shop that would lend me his if I wanted.

Dan

Posted By: mopar4ya

Re: Replacating factory spot welds - 12/31/14 08:41 PM

Quote:

you're building this car for your young daughter ... is she going to drive it or show it ?!?

I hope a little of both. But even if she doesn't want to show it I want it to look right. I'm kind of a perfectionist when it comes to things being done right. I hate to see shody body work, you need a good foundation to build on!

Dan

Replacating factory spot welds