|
Re: Replacating factory spot welds
[Re: DeMopuar]
#1716993
12/30/14 12:28 AM
12/30/14 12:28 AM
|
Joined: Jan 2003
Posts: 5,114
Chicago Blackhawks
hemicar1971
master
|
master
Joined: Jan 2003
Posts: 5,114
Chicago Blackhawks
|
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.
1971 HEMI E BODY REGISTRY
|
|
|
Re: Replacating factory spot welds
[Re: Evil Spirit]
#1716996
12/31/14 02:13 AM
12/31/14 02:13 AM
|
Joined: Aug 2014
Posts: 45
Delaware
GeorgeH
member
|
member
Joined: Aug 2014
Posts: 45
Delaware
|
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.
|
|
|
Re: Replacating factory spot welds
[Re: GeorgeH]
#1716998
12/31/14 02:54 AM
12/31/14 02:54 AM
|
Joined: Jan 2004
Posts: 8,290
fredericksburg,va
cudaman1969
master
|
master
Joined: Jan 2004
Posts: 8,290
fredericksburg,va
|
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. 
|
|
|
Re: Replacating factory spot welds
[Re: cudaman1969]
#1716999
12/31/14 11:57 AM
12/31/14 11:57 AM
|
Joined: Oct 2005
Posts: 8,880
Ontario, Canada
Stanton
Don't question me!
|
Don't question me!
Joined: Oct 2005
Posts: 8,880
Ontario, Canada
|
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 !).
|
|
|
Re: Replacating factory spot welds
[Re: DeMopuar]
#1717000
12/31/14 04:29 PM
12/31/14 04:29 PM
|
Joined: Jan 2003
Posts: 2,655
western PA
mopar4ya
OP
master
|
OP
master
Joined: Jan 2003
Posts: 2,655
western PA
|
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 
|
|
|
Re: Replacating factory spot welds
[Re: hemicar1971]
#1717001
12/31/14 04:35 PM
12/31/14 04:35 PM
|
Joined: Jan 2003
Posts: 2,655
western PA
mopar4ya
OP
master
|
OP
master
Joined: Jan 2003
Posts: 2,655
western PA
|
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
|
|
|
Re: Replacating factory spot welds
[Re: Stanton]
#1717002
12/31/14 04:41 PM
12/31/14 04:41 PM
|
Joined: Jan 2003
Posts: 2,655
western PA
mopar4ya
OP
master
|
OP
master
Joined: Jan 2003
Posts: 2,655
western PA
|
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
|
|
|
Re: Replacating factory spot welds
[Re: Stanton]
#1717003
12/31/14 05:31 PM
12/31/14 05:31 PM
|
Joined: Jan 2004
Posts: 8,290
fredericksburg,va
cudaman1969
master
|
master
Joined: Jan 2004
Posts: 8,290
fredericksburg,va
|
Quote:
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 !).
Thats what i use but hard to get a good bond if all primed, the reason for bare spot with tool. Still experimenting.
|
|
|
Re: Replacating factory spot welds
[Re: 5wndwcpe]
#1717006
01/03/15 10:59 AM
01/03/15 10:59 AM
|
Joined: Jan 2003
Posts: 2,655
western PA
mopar4ya
OP
master
|
OP
master
Joined: Jan 2003
Posts: 2,655
western PA
|
Quote:
Quote:
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
This is what I do as well.
By doing it this way, wouldn't you have a cup shape instead of a flat looking spot? I'm assuming you are using a bur with a rounded end? I don't think you could hold a carbide bur that was flat on the end in one spot to make a flat spot into the weld.
Dan.
|
|
|
|
|
