How smooth do welds have to be before sending to body shop?

[viiking]

I'm doing a body off restoration of my Father's 1968 Beetle. It's a "keeper". I have done rust and damage repair work with MIG welding. I'm still learning the art of body work and welding. It's important to me that I do the work myself.

Despite my best efforts of weld and cool, weld and cool, some weld areas have the distorted "V" valley because I cannot get a dolly in behind to massage the area.

In the photo below, I have replaced a large section of damaged area around the fuel filler. It's a bit hard to see with the light etc. Where I can get the dolly behind, I've been able to push out the weld area and ground it almost smooth. My technique is to use a cut-off wheel and grind perpendicular to the weld, grinding down almost to a flat surface, then use a 40 grit 2" grinder to blend in. I haven't gone any further with finer grits at this stage. On the N, E, and South side of this patch, it looks reaonable, but on the W side I still have the "V". I cannot grind any further for fear of taking off too much of the metal at the top of the "V". The depth of the "V" is about 2mm in the centre.

The question is (and I know it's like how long is a piece of string), how far do I need to go to grind the welds down, particularly the W side before a body shop can proceed to paint? I know body filler is frowned upon, but I don't know how else I can pull out that V. I don't have a stud gun and am not sure if I did have that the "V" could be pulled out successfully being so close to the edge of the panel.

Or is this an area that the body shop can finesse? I'm just not sure what the capabilities are for most body shops on old VWs. Easy on a new car as they usually just replace the panel.

The reason I'm doing it myself is that I just don't want someone to do a half-ass job and throw a ton of bondo at it. But tell me if I'm doing a half-ass job myself please. I see photos of other peoples' unground spot welds just being covered with bondo.

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1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[modok]

The filler should be less than 1mm thick.
In order for you to find out, you should do the filler yourself, and then you will know. I don't think there is any way to learn besides doing it.

IMO polyester filler is too weak, I prefer to use marine epoxy.

In either case the metal should not be smooth, rather about 80 grit finish. About as smooth as a fine file.

[VW_Jimbo]

Its a feel thing. I cannot explain it. I will try and type some sense out but …..we will see.

Get a piece of card stock. Go over to the other quarter panel and cut that card stock to fit, EXACTLY, the contour of the panel. Now, walk back over to the side under renovation and see if it is good. Should be dead on the money. That is the starting point.

Now bolt the fender on and check to see how the body line runs parallel to the fender. You should see no deviations in the gap or the body line. If either of these two general items is off, you will need to cut and paste metal to fix it, or beat, pull or push as needed. For those spots you cannot access, a slide hammer with a segment of wood screwed to it, at the interior of the panel, works wonders.

Once close, pin holes are fine. I go through and clean it all really good. Big pin holes, I will braze or solder, file flush to the surface. If good, epoxy primer, guide coat and a few sanding strokes, followed by some body putty.

If you are still off the mark. Bead blast it and slap some bondo on there. But I would beat on it or slide hammer it for awhile first!

The picture is hard to make out, surface wise, due to the sander lines. Send me a better picture with a shot of primer and some lighting and I my have another option lurking somewhere around here!

Good luck man!
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Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[beetlenut]

If you're getting valleys, your most likely not going slow enough for the metal to cool and not distort. I was using the thinnest wire I could in my MIG, might have been .035, and tacking every inch, and waiting. It took a while to completely weld in a patch, but it was worth it. On areas that I still ended up with low areas that I couldn't grid out, I used kitty hair (cut up fiberglass mixed with resin) for structural rigidity to bring it level with the rest of the panel. You also have to be careful when grinding to not get too aggressive or go too fast, as that too can put too much heat into the piece.
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scrapyards are for quitters
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[Onceler]

You’re at the discretion of the body shop as to whether they trust your work or not. If the body shop sees butt welds ground smooth, how are they to know that there’s not only a couple thousandths between the steel cracking and the filler cracking and now you’re complaining? The shop would probably walnut it in, check for cracks, weld the cracks and fill it up with filler. Who knows?
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1972 Karmann Ghia

[bomberbob]

Does any one use lead when they do body work? I have not (yet), but have watched some interesting videos on youtube on the use of lead when doing body work. Not just yokels in their garage, I watched one with Chuck Barris and one of his body men working with lead. I know I know, lead will kill you, but the guy was there chewing on a cigar and leading on a car, and he was still alive.
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1968 Beetle (storage)
1990 Jetta GLI megasquirted, burning E85 (currently in heavy maintenance)
2004 Jetta turbo GLI
Marion, Iowa

[viiking]

I sprayed some rattle can primer and took some more photos. I think I will drill some holes in the weld and use a slide hammer to see if I can get the valley out. Then weld the holes back up and see where I’m up to.

Re the speed of the weld, I tack welded every few inches and let it cool knowing that there is going to be distortion. As I said, where I could get a dolly behind I had little trouble and no valleys of any note.

I’ve retired now and this exercise is to get me to learn new skills even at my old age. The alternative is to die in a rocking chair holding the remote control. No thanks!

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1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[Bama Dave]

Learning to do this good. But it takes a very long time to get proficient.

Is it too far along to straighten without making it worse? Depends on skill level. There is a lot of weld to deal with. Since you can’t get to the backside, it is more challenging. Easy to make it worse, if not careful.

At some point, you will decide if the juice is worth the squeeze for this area. If you decide it isn’t, get yourself a very good quality filler and make that gap level. Is doing that a hack job? If you were in a business of restoring cars for a living, yes. Would a good filler there last 30 years or more? Probably. Be sure to protect/encapsulate the back side of that area, too.

Best of luck.
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David Richerson

1970 Beetle
1971 Super
1972 Baja