Adhesive vs Welding

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xlexl

xlexl

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So while on the hunt for information on Fusor 800 seam sealer I ran across this little nugget.

http://www.nastyz28.com/forum/archive/index.php/t-4293.html

My initial reaction was to curse GM guys for their idiocy, than point and laugh the way American auto guys do to rice. I mean seriously doors? FLOOR PANS? Quarters? My roommate and career body guy heard my cursing and quickly informed me of my ignorance. Apparently many manufacturers including high end cars like Maserati are bonding body panels now, he told me of tests they'd come in and do where the adhesive would hold beyond what the surrounding metal could endure.

I'm still not sold, there has to be a downside that I can seem to find, otherwise body shops would all sell their welders. The one downside I did find was heat seems to be the devil to this stuff. Now i'm not sure whether i'm looking at the data sheet for the correct stuff, however this one seems to indicate that as low as 180deg(Needles CA will see 130) the bonding shear strength dropped dramatically.

http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTt4xMcNxT2EVuQEcuZgVs6EVs6E666666--

No I'm not planning on welding the floor pans in the Fish, just extremely interested in unbiased strengths and weaknesses of both methods.
 
Yes, bonded body panels are on the road, including in some very high-endy cars, and they work well. But keep in mind that original body construction and in-the-field body repairs are almost entirely, completely different processes. Techniques that work well for original construction are in many cases not suitable or not possible to duplicate successfully in the field.
 
I rep a small mfg. co in Michigan that makes an adhesive that glued my console brackets to the floor in my Demon...I also used a couple of sheetmetal screws for good company.
 
Was looking for more of the technical side. i.e "strong shear strength, weak torsional" (as an example). Everything has its strengths and weaknesses, things it does extremely well and things it doesn't, trying to understand "under the hood" so to speak.
 
I have a friend that is a rep for 3M Marine and he
let me use his demo panel glue gun (must have item)
when I replaced the quarter on my Scamp
To say the least very impresed and easy to do just
had to lip one edge - glue - cleco or screw it together
let set up then light fiber bondo then light bondo done
 
xlexl said:
Was looking for more of the technical side. i.e "strong shear strength, weak torsional" (as an example). Everything has its strengths and weaknesses, things it does extremely well and things it doesn't, trying to understand "under the hood" so to speak.
Click to expand...

3m suggest to weld at stress points
you could probably find this on their web page
 
Years ago I had a 69 GTO that I replaced the 1/4 panels with full fiberglass 1/4,s.I used Vette adhesive,the stuff was amazingly strong....sold the car.:walk:
 
I have parts that a company I used to work for flying on the space shuttle.
No mechanical fasteners, everything is bonded.
Prep work is everything, no second chance to re-do anything if you make a mistake.
When I put the new quarters on my duster they will be bonded.
 
A continuous bead of the right adhesive would be as strong if not stronger than a series of spot welds.
 
And that is???? what kind? I could have used some, instead of full welds on the rear 1/4.
 
green1 said:
And that is???? what kind? I could have used some, instead of full welds on the rear 1/4.
Click to expand...

The Fusor products I guess. I haven't seen another brand available retail that meets or exceeds Mfgrs standards.
 
I used the 3M bonding adhesive when I installed my airbox to the bottom of fiberglass hood.
It was a great way to install it & turned out great.
We are on our second season of racing, no signs of cracking or separation.
 
I have bonded multiple panels in the bodyshop also. The process works great for most situations. Much faster, less mess. It also works much better in the corrosion resistance area, when you spot or plug weld something back together you need to find a good way to cover the bare metal after welding, with bonding you cover it all before and it stays that way. You still need to weld the seams, and any location you need to do filler work. The body filler tends to not want to stick to any exposed glue and will lift. There is some debate as far as structural integrity, the glue tends to be much stronger as you are fully attaching a panel where it was spot welded from the factory. The spot welds are actually engineered in collapse zones, the glue does not collapse or allow the panel to collapse in a collision the same way the spot welds do.
 
To my public educated mind, I would think the welded metal would only be as strong as the metal is thick. Welding also has affects on the surrounding metal. The bonding of two pieces could be stronger because you can increase the surface area of the bonded metal and no heat stressing,

Look at the aircraft industry. Bonding is common in that industry and the failure of a joint can mean a person life.
 
green1 said:
Hit potholes yet? Stressed it with a hard launch, with traction? Interested.
Click to expand...
Try not to hit potholes - daily driver no hard launch BUT WAIT I did have a quarter replaced on my 71 Demon and the person glued it and it's seen a ton of abuse NO PROBLEMS PERIOD
 
Im down with the glue, but Im not going to back half a car with Bondini...It has its place. Rear quarters and door skins are perfect candidates, along with many other places.
 
67Dart440GT said:
I have bonded multiple panels in the bodyshop also. The process works great for most situations. Much faster, less mess. It also works much better in the corrosion resistance area, when you spot or plug weld something back together you need to find a good way to cover the bare metal after welding, with bonding you cover it all before and it stays that way. You still need to weld the seams, and any location you need to do filler work. The body filler tends to not want to stick to any exposed glue and will lift. There is some debate as far as structural integrity, the glue tends to be much stronger as you are fully attaching a panel where it was spot welded from the factory. The spot welds are actually engineered in collapse zones, the glue does not collapse or allow the panel to collapse in a collision the same way the spot welds do.
Click to expand...

Thats closer to what I was looking for :) thanks!
 
No problem, if you decided to use any of these processes I can let you know a good system to use.
 
We learned out here at WyoTech the most automakers are using it now. They say is stronger than welding. The door skins on my comp car were adhesive bonded.
 
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