Thread: Welding VW fenders to body questions

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My VW Notchback project will have a fiberglass front end. The rear fenders will remain but I don't want to bolt them on requiring the use of the plastic spacer that's supposed to go in between the fender and the body. I want to permanantly mount the rear fenders to the body but I have a problem.

What do I do about the gap between the fender and the body?

I think I can bend the flange in along the fender and make it fit tighter against the body, but then what? There will still be a "crack" along where the fender meets the body along the side of the car and down the back where it meets the rear valance. Should I use a body filler of some sort? Should I at least tack weld it along the outside?

Has anyone succesfully done this before? Do you know of someone who has done this who will not mind a few questions?

Someone like Jay (Hotrodpaint) and others will have a more accurate answer, but to get you started, the old fashioned way was to weld the fenders in place and then lead the seam in to fill that gap. Lead is sort of old school now, and modern fillers like Rage and others are far superior for most repairs. However, none of them like to be very thick, or they will crack out. If it were me, I would weld them on and then use as thin of a coat of quality plastic filler as possible to smooth it out.

We'll see what the experts say though.

Don

Hi and welcome to CHR. I have done a wee bit of panelwork on the beloved VW's in my life before so here is how I would tackle this. First as Don said, dress up the edge/flange where the bolts go through so that the guard fits up against the body nicely. I would then using some made fender type of washers bolt the guards to the car. Once aligned and tight carefully tack weld every few inches along the seam with a tig or mig, oh I almost forgot to mention,grind back the too areas to be filled and prime before bolting the guards on. Once finished welding,sand back the tacks,prime and then fill the seam using a little filler.

Ralph, I would weld em up and smooth em out. Most people will never know they were welded up.

On my 40 Nash, we bolted the fenders on and then welded them. We ground the welds down so that the seams were smooth.

My initial thought was to bolt them into place and then weld them on the outside. The problem is that the weld will be in a crease in the body design. Here's a pic (Sorry I forgot to take a detailed pic). My experience is that it's very difficult to grind a weld where the metal makes a contour line. If I welded it, I would have to grind it down past where it needs to be and then add filler to make the contour lines match.



Here's my thinking. I will bend the flanges in some so that when I bolt on the fenders they will pull up close. I will then spot weld along the seam to help hold it steady, every few inches or so. I don't believe that merely bolting the fenders on will be steady enough to support any type of filler. I will grind the spot welds down past where it needs to be. I will then use some sort of filler to fill in the rest of the gap and shape the contour lines to match the doors. Does this sound like a reasonable tact?

If I take this route, what is the best filler to use? The gap will be tight, but the radius on the top of the fender may make a 1/8" to 3/16" deep fill.

I like Evercoat Rage Gold. Easy to work with and sticks well. Others may have different preferences, but that is just mine.

Don

Is that a 1-part filler? Is Eastwood the best place to get this kind of stuff?

if from rust if the flange were the fender bolts up is gone you use 3/4 tape to make a clean cut line trim only as much needed the clean it up . then drill some 1/8 self tap screws to adjust fenders for the best fit up were you use the 1/8 screws i punch a 5/16 hole in fender with fender washers or just bigger washer on the 1/8 screws so you can move fender abit if needed get them fitted good leave screws in for now all stuff needs to be very clean how you go about this is up to you . use a good weld thru primer you will have a over lap in a bad spot so it need to be sealed up very good . now on the out side of fender to body fit up needs to be very good less weld less grining better luck with no warping the outside weld you want small and clean neat so your not grinding the weld off and making metal thinner were you want it to hold as in time it can crack out .when all done you do want some weld on the fender and in time crack so EZ on the grinder so a ligth hand and blend... when the outer is all welded up go back take screws out and plug weld holes up this will help hold fender up as to how many plug holes i would go about 5 inchs a plug hole around the fender. tack the under side edge were you would cut fange off fender. yep alot of welding then you will have to seal this up when welding is done you will want to use a sealer . i brush west system in joints can use a thickener in the west system like ground glass. so first thing is every thing needs to be clean metal were your welding the hammer and doly fit up may be needed if you can bolt them up and no rust you could try to metal bond them on ? clean every thing bolt fender were it fits the best drill some 1/8 line up hole leave all bolts in that you can to get fender to drop for a air gap lay bead of metal bonder on then draw up with bolts not to much you would not want all the bonder to squeeze out. you would want to work fast. or bolt fender up and weld the fender on if you have rust free body parts .welding any body metal you want to move around alot to keep heat down i never weld more then 3/4 at a time if you use a mig you may have a hump up on the welds when starting to fill in your 3/4 welds i grind the ends of the welds down to cut down on weld build up and cold welds and less heat .i used a stone on a angle grind clean welds as i go and not after all welded up .on sanding disc as i feel you have less heat with a good stone wheel keeping warping down. for fillers first coat on welded or weak metal i all ways marglass or a good grade of ground glass filler

Have you considered using a Bonding Adhesive like they use today in Auto Body Shops like Lord Fusor, 3M or Duramix? You wouldn't have distortion, and it is as strong (or stronger) than Welding, and is designed for Sheet Metal-in fact, Audi will now disallow structural Body Warranties if the Body is Welded-just a thought-

http://www.lord.com/Products-and-Sol...roduct.xml/133

Pat, I looked up the West System and they have an extra slow hardener that would give me plenty of time. Would you use this to "bond" the fenders to the body? Is this to give it extra strength? Or would you use the West system to fill in the bigger portion of the gaps before applying filler?

The body parts are in really good shape. I am already working on cleaning these areas up. I do not have any areas of rust that need repair.

Originally Posted by 35WINDOW

Have you considered using a Bonding Adhesive like they use today in Auto Body Shops like Lord Fusor, 3M or Duramix? You wouldn't have distortion, and it is as strong (or stronger) than Welding, and is designed for Sheet Metal-in fact, Audi will now disallow structural Body Warranties if the Body is Welded-just a thought-

http://www.lord.com/Products-and-Sol...roduct.xml/133

No not yet. I would have to modify the mating surfaces to make them flat against each other. This would not be a big deal considering the amount of work any route will take. If I flattened out the mating surfaces and bonded them into place, would I then fill in the crack where the fender meets the body with a glass type filler like Don mentioned above? If I did it right, the crack would be very close and hardly noticable. It seems that I would have to cover the crack with some kind of filler to keep the paint from cracking.

Wow, the last time I did any body work, we had a two part Bondo, a credit card spreader and stack of sand paper. (That was 25 years ago )I really need to dive more into this subject.

The good news is if you mess up, you just have to start over

Originally Posted by v8notchman

Pat, I looked up the West System and they have an extra slow hardener that would give me plenty of time. Would you use this to "bond" the fenders to the body? Is this to give it extra strength? Or would you use the West system to fill in the bigger portion of the gaps before applying filler?

The body parts are in really good shape. I am already working on cleaning these areas up. I do not have any areas of rust that need repair.

no thats what i use to seal the back side up for after the out side was all welded to keep moister and water out of the back side of weld joint. to glue fender on like i said you would use a metal bonder like lord fusor or 3m