Despite having made build bodies from scratch these VW rear arched have bowled me a googler .. I spent an absolute disproportionate time fitting trimming and making sure the job was ready for welding.. My first thoughts were to gas weld the panels a but welded seam being strong and water tight. However the construction of the inner panel work would not allow the gas weld to be plannished flat. I decided then to use the mig.. Its a big machine and I am using argoshield .. I had the welder set on 1st setting and a suitable wire speed using 0.6 mm wire.. ( less build up) .. I spent the next 2 hours taking it easy spotting the panel together then over and over until the weld was complete, There wasnt a lot of distortion but more than I would have liked, no waves and deep recesses just a uniform dip along the length of the weld bead, but more that I would have liked, say around 6mm... I wasnt to happy with it so stupidly ground out the weld and plannished the join where I could ... I should have known better, the area I couldnt get to held the panel tight on the weld and the area I planished was now loose, the result was a big wave on the panel with some oil canning further up the panel itself.. Managed to sort out most of it but got so *******ed off I decided to cut the repair off and start again Do you guys find you get distortion when you mig weld on these parts? If not, whats your secret ?
yes ....I've heard good things about the heat barrier putty from Frost tools ....not used it my self as it is expensive and I'm tight .....but might be worth a punt?
ive had the same problem with mine. my rear arch that ive fitted bulges out infront and behind the arch lip. it also dips in alot where the weld is. i was thinking about trying to find a pin dent puller like this http://www.ebay.co.uk/itm/Sealey-st...509?pt=LH_DefaultDomain_3&hash=item2a296801dd to pull the panel back out at the weld
DONT go for the dent puller option... the issue is shrinkage in the weld bead .. what you really need to do is stretch the weld bead area to de stress the weld and aloow the panel to lay flat. un fortunatly unless you can plannish the full length of the weld your stuffed .... If you pull the weld with a slide hamer you will manage to pull out the bead BUT the panel above it will distort ... something has to give if you dont relieve the weld by plannishing.. It looks like a wee bit of distortion will have to be the order of the day .... THOUGHT.. wonder if pre strteching the van panel and the repair section a little would work? the idea being that when the two parts are joined the shrink associated with the welding will bring everything into line ???? Im not a fan of joggled edges,,, the side panel has a slight double curve joggling the edge will shrink the edge, welding will shrink it further, could be more trouble? Have you got away with joggling the edge? how has the panel held up over the years, has the filler blown on the join, the joggle can be a moisture trap.....???? !!!!!! Looking for the best way to do this with minimum filler.... Ive resigned myself that it will need some
Spot welded a flat bar on repair panetthen tacked at both ends seemed to sort out the buckling for me.
I always over lap slightly, maybe 1cm or so, keeps the whole thing more rigid. Also, i never seam any body panels, just a quick blast, like filling a plug weld and move on. do one at one end, one in the middle, then one at the far end then repeat and gradually add more and more. I usually do a couple of passes, so maybe 6 spots, then cool it or do something else for a bit. Plus I grind it all down slowly. you can do almost as much damage with a grinder I reckon. It also helps to cool with compressed air to stop the heat spreading to far into the panel.
I never run a seam as such, just built up a solid weld from a series of spots... Ive seen a lot of busses with blown filler right on the weld join on these wheel arch panels,,, I dont want that to happen.. so was looking to go for a but weld and full width ( built up of spots) Im kinda up to speed on the welding theory and I know that distortion further up a panel is nothing to do with heat transfer.. all distortion eminates from the weld, the weld area expands initially then as it cools it shrinks, the shrink is what pulls in the surrounding metal and causes dips and bulges in other areas,, these dips and bulges disapear is you relieve the weld area , but if you cant get behind the panel to stretch the weld area ( plannish) your kinda stuffed Unfortunately MIG weld doesnt like to be plannished, its to hard compared with gas or tig... I though about tacking a bar behind the join to act as a heat sink but didnt know how well that would work.... how sucsessfull was that approach ? when I gas weld I dont use any filler rod, just tack one after the other than run a bead in one action the trouble with this job is access to the rear to plannish the weld... Ive had problems with repair sections before but this one on the camper arch has been the biggest headache.... Im a fussy btard attached a few pics of my Karmann GHia wing repair, gas welded butt edge no filler rod. Thats what Im after on the van......
The panels are so large and flat and the steel so thin its almost impossible to not get distortion The least distorted ive seen is when a joggled edge is used along with a series of plug welds A butt weld but built up from a series of tacks and cooling the panel with an air line or wet rag as you go along may help to minimize the distortion A hell of a lot of busses ive seen have the repair panel welded over the top of the original and the join hammerd in and filled right over so anything better than that and your allready winning
nice work there! personally, I've never had any problems with rear arches blowing out, but I always seam seal the weld and try to do the same to the back of the panel, but obviously you can't get to all of it. it's always going to be difficult to get it really flat because it's such a massive flat panel and it's got that internal brace in the middle of it.
i joggled the edge fixed every thing with rivets then tack welded drilled out the rivate more welding until i`d gone all the way a cross
Para, you will appreciate the fraustration this is causing me ... im kinda OCD with panel repairs. some things dont bother me but if I have to make a repair Im kinda over fussy on the finnish... I do a lot of aluminium stuff and got in the habbit of neat welds and metal finishing ( no filler) Since this is a personal project Im probably a wee bit less intense, but some things still bother me and I just have to try my best to got the result I expect.. Im probably going to have to settle for some sort of compromise... I dont think Ive overlaid a panel for 30 years, that was how we used to tart up Mk 2 Escorts ... I didnt know that method still went on, we didnt know any better, but the internet has opened up a whole wealth of knowledge... P.S I wasnt trying to be a smart ass with the tech on the weld bead shrinkage,, ive been butt welding panels with gas for years and am pretty up to speed on the theory.. sounded like I was asking for advice then throwing it back... its a bit of a two way street....
There are adhesives now available for bonding car panels on instead of welding them but i dont think they are for structual work A joggled edge filled with adhesive and the new panel pressed into position whilst the adhesive drys would give the minimum amount of filler work afterwards Its not somthing ive used myself and the idea of glueing panels on would scare most customers id imagine
The joggled edge is a moisture trap, if you joggle the van rather than the new arch then the lip will be open downwards so condensation won't run into the joint. You can edge to edge it, you can also use a burning torch to relieve some of the stresses, the other option is to do a proper job and fit a full height 1/4 panel
I fully understand ocd and trying to do the job to the best of your ability but as you say at some point you have to comprimise Id do it the best you can then over the join id clean up with 80 grade paper including the surrounding area and first use chopped strand fiberglass befre polyester filler This way the filler wont blow out at the join and i know of some people who mix chopped strand fiberglass and polyester filler together for the initial fill as it speeds up the shaping process Just be thankfull your not lead loading it all
yep quite right, it's also better joggling that way because you don't get the old paint/waxoyl etc running down and contaminating the weld. The only problem with the full 1/4 is that it's brazilian unless you get a body cut. I like to keep as much german metal as possible
Nobby, how much distortion did you get after that prep? Brother, its that bloody stifner in the middle then the boxed in rear area that makes the plannishing out impossible . I actually thought about cutting the whole panel off, welding on the arch planishing out then welding the panel back on the van, but I would probably still get distorting on the verticle seams... catch 22...... pity you cant buy whole panels for the rhd versions...fitting them looks like a right pain in the butt and one would lead to another.. Maybee I just need to get a grip and be realistic... and buy a dust mask
