Weld seams on quarter panels visible in hot sun, but not garage--how to remedy?

[442_Mustang]

Hello all, I was referred to this site from a link regarding a problem I am having right now so I figured I would join the club
I am doing up a 72 Cutlass S and I'm having problems with the welded seams on my quarters showing up in the hot sun but when I drag it back in the garage it smooths out again. I may have a solution to the problem. It involves some rewelding plug welds along side of the seam and blasting it and using some special marine grade body filler that sands like a rock but is very very ridgid and will not flex. A guy I know does custom and restoration work and he had the same problem on a GTX he did and he redid the car over 10 years ago and it still looks perfect. I will find out more and keep you posted if anyone is interested however I am going to wait till later this summer to redo it. I've got a lot of put together to do and I'm not ready to attack those quarters again. Here's a couple pix of it as of last week. I just sanded and buffed it this saturday and sunday I drug it out to see if I missed any spots buffing it. It looks awesome while it's in my garage...

[Ralph LoGrasso]

Welcome to the site.

I'm going to rename this thread for you and move it into the Paint and Body forum. Hopefully that will generate some more replies and help you to solve the issue with your quarters.

[LateNight72]

I'd recommend welding the seam solid, in addition to the plug welds. Also, if it were me, I'd use lead. If that's not feasible, All Metal or one of the metal impregnated fillers.


The problem is that the heat is causing the seem to heat up and expand. Then when you pull it back into the cool garage, it contracts into proper shape.

[442_Mustang]

Ok, I just made that first post in that section to introduce myself. I welded the seam solid on a lap weld. Some time I will do the plugwelds on the part that is overlapped. I am also wondering if I do a bunch of heat shrinking along the seam. It's not really warped but maybe there's some extra tension in that area from the welding. I also was told of a type of filler primarilarly for marine use that is so ridgid that it won't do that shadowing. A friend uses it in a custom and restoration shop and thinks it will be the cat's meow. I will let you know when I do it. I'm glad I was referred to this forum.
Tnx.....
Derrick

[PRRC]

The problem lies in the welded section itself. The metal expands and contracts at different rates allowing the weld seem to show. As you are welding.The seem becomes very ridged and the surrounding metal expands at a quicker rate than the weld seem.
The product you may be thinking of is dynaglass. Yes very hard to sand. Its like liquid fiberglass and filler mix.

[gearheads78]

aw hell .....another Olds guy. Who invited you here

[442_Mustang]

Heh heh. Hi there Gearhead. Thanks for the link to this group. PRRC, Is that Dynaglass rated to like 800 degrees? The stuff my buddy uses is rated to something like 800 degrees. And does anyone think after I grind it out and clean it up would running a torch over the weld area or doing some heat shrinking around the area would help?
Thanks.

[ProdigyCustoms]

Duraglass, Dynaglass, all have a tendency to develop wicked air pockets. Grind some and you will find air pockets (pin holes) everywhere. And because these products are so sag resistant we tend to glob it on to fill the void. The air pockets expand in the heat and contact in the cold. So that is actually a big part of your swelling.

All metal is a option, we use a ubber expensive product from SEM called Carbo fill. Carbon fiber reinforced filler.

Whatever ones uses needs to be spread in multiple thin layers with firm pressure to help reduce air pockets
.

Steve, I am surprised to hear th Rage Extreme is doing OK. While not prone to pin holes (air pockets). it is a lightweght filler. We use quite a bit of it for thin layer work. Glad your doing the R and D on seam work! LOL!

[442_Mustang]

I appreciate the input but the problem is most definitely something about the weld line. In the sun there is a line that is jagged and looks almost like one long curtain run. I am a body tech by trade and I know I worked the duraglass type product into the seam very thouroghly while spreading. I think that carbofill may be the product my buddy uses. Actually now he mig tacks the seam and tig/butt welds his seams. but he just got his tig a couple years ago. The cars he did before with that expensive(Around 100.00 a gallon with shipping) have held up well. I know it's hard to guess without seeing my actual car but do you think that spendy filler will do the trick? Thanx

[yellowrallys]

Frank, I have definately ground into some air pockets before. I always press the filler thin with a firm wipe, trying to avoid pockets.

I've never used (or heard of) Carbo Fill. Is it as coarse or thick as the fiberglass reinforced fillers? I will be looking for some to try. Where do you use it mainly?

[442_Mustang]

The stuff my buddy uses is called ADTECH #17. I will look into it. Ifanyone wants to check into it too... I need to find out what will save me from doing something scary...
http://www.adtechplastics.com/pc-15-...nt-filler.aspx

this must be the stuff

[442_Mustang]

apparently the stuff is only good to 446 degrees f

[442_Mustang]

Here it is... Shame I will have to dig it out and start from scratch...

[68fusion]

Is the weld close to the surface?........weld expands at different rate than the sheet metal so you tend to get some movement around those areas...especially if not hidden by a body line or seam...with heat and being black just makes it worse.

[442_Mustang]

Yes I took a lot of time to not warp the panel. The filler isn't very thick. I may have a buddy swing by with a TIG welder and will cut and reweld it

[68fusion]

Yes I took a lot of time to not warp the panel. The filler isn't very thick. I may have a buddy swing by with a TIG welder and will cut and reweld it

The thin filler may be causing it, not enough build to mask the expansion of the metal and non movement of the weld. If you spread filler on that area and had patches of bare metal showing in that "seam" area then it wasn't enough filler. You can put whatever kind on you like... kitty hair, duraglass, or carbo whatever but if the build is not enough then you'll have the same problem again. Metal and welds do some strage stuff in the sun.

[442_Mustang]

I' decided to have the top seam TIG welded and purchased a gallon of that Adtech filler. I'm gonna use a bit more filler thickness to try to mask any strange expansion characteristics. I'll let you know how that stuff works. That filler is definitely not a Lightweight filler... Like a gallon of lead.