3M Bonding Adhesive in lieu of welding?

[PocketThunder]

Has anyone used this 3M bonding adhesive?  A freind at work has a body guy that uses it and he was going to use it on his quarter panels on his Chevelle.  I think i will stick to welding but just thought i'd ask about it here.  Maybe since the chevelle is a full frame car then he can get by with it, but our unibody cars consider the quarter panel to be structural.

http://multimedia.3m.com/mws/mediawebserver?66666UuZjcFSLXTtmxTXMx&aEVuQEcuZgVs6EVs6E666666--

[FLG]

Im sorry but id run very fast and very far away from any body guy that would rather use adhesive over welding.

[moparguy01]

actually modern day panel bonding adhesives are quite good. I have seen studies where the panels would shear before the adhesive would let go.

That being said I still would not use it for a large panel like a quarter panel, but for smaller panels I have absolutely no problem using adhesives.

[FLG]

What about years down the line? How will they hold up then?

[moparguy01]

auto manufacturers have been using adhesives for years, and i have yet to see anything fall off that was properly attached.

[bull]

I think it depends on what you use it on but yes, these adhesives today are getting very good. I think one of these reality show restoration places tested it by using it exclusively on all sorts of replacement panels they would normally weld and it turned out fine. I don't remember which show it was now though...

One benefit I can think of off the top of my head is that welding burns e-coating or epoxy primer off in areas that are hard to treat once the part is in place. Another benefit might be a more plyable joint rather than the potential for cracking in areas that experience a lot of flex.

[chargergirl]

Hey something I do know about! It does bond well and you REALLY, REALLY got to decide where your putting it! Once there it will not come off.

[restoman]

Your body guy will have no problems bonding a full quarter to a Chevelle, if it's done properly, and if it's a full quarter, not just lower skins.
The big advantages to panel bonding are it is much faster, no danger of starting a fire, no welds to grind, and since the adhesive is spread evenly at every attachment point and not just at single points like a weld, it is potentially MUCH stronger.
But, it has to be done right. It is actually so easy, most guys end up short-cutting things and that's where the problems arise.
Test fitting and cleanliness is critical.

Adhesives were designed to be used on unitized construction vehicles, so it would work on some of our favorite muscle cars.

A big quarter like on most Mopars from the day, take so much time to hang and align, most of the adhesive would be squeezed out or compressed too much for a proper bond. A 60s or 70s Chevelle is much faster to hang and align, so adhesives would be fine.

[superbirdtom]

I bond stuff every day  and i love it . usually you use bonding and welding on the same panel it would take too long to explain. but when i do my 70 charger roof skin it will be bonded on sooo much faster. and in rollover tests it holds up very well. go to some of the bonding glue sites and do some work. go to a body shop where they do it everyday and look to get some pointers. if you bond a quarter panel on a charger you bond on most of it and plug weld by the taillight panel and use a pinchwelder around the wheelwell but put a piece of rubber between the inner wheelwell and skin .this way the pressure from the pinchwelder will lok authentic to get the pinchweld look but then bond it and you have a seal. or get the weldthrough sealer for pinchwelds.

Theres so many ways to do things  but don't be afraid of glue. especially when patching as theres never welding pinholes to worry about it is seald inside and out and doesn't have a bunch of wirefeed welding wire all over the inside of stuf.and if you ever have to take it off just heat up with a good torch and it can be pried off.

[FLG]

heh,

Guess im the only one just not comfortable with it. I know things have gone a long way, but again what about long term???

[restoman]

What about it?

[Mike DC]

 
In the 50-year sense?  I don't know.  I don't know who would know.




Some of you guys that are experienced with the stuff might be able to answer me this one:

What about the bond-line issue in years past?  The "ghost line" that used to appear if you put an adhesive bonded seam under an unbroken paint surface, like if you were patching a quarter panel or something?   Do the bonded seams still need to always be hidden behind existing visible seams/gaps, etc? 

   

[tan top]

bonded on panels  , are used all the time on modern stuff !! & thats where it should stay as thats where its OEM  !! , yes its strong !!! but !!!!  not something i would ever consider on old time muscle cars ..even Chebbys

[superbirdtom]

 
In the 50-year sense?  I don't know.  I don't know who would know.




Some of you guys that are experienced with the stuff might be able to answer me this one:

What about the bond-line issue in years past?  The "ghost line" that used to appear if you put an adhesive bonded seam under an unbroken paint surface, like if you were patching a quarter panel or something?   Do the bonded seams still need to always be hidden behind existing visible seams/gaps, etc? 

   

older true fiberglass vettes have been using panel adhesive for years . now ,tho it is created for vettes. if you ever see a old vette especially a black one out in the 105 degree scorching sun you can see lines appear then when it cools down they dissappear. this is true more of redone ones vs factory ones ,thus we have ghost lines

Theres another ghost line I call it (ring around the bondo) now put that ring around the rosie song in your head and from now on when you see some car with it you will say the tune in your head.   ring around the bondo appears usually when someone doesn't do bondo work right in some way and when the sun beats down on it it appears . now to steel ghost lines I believe that if you took a black car and did some quarter skins it would depend on how much finish putty you would put on top of your glue line. now the glue if I did it the line would be almost non existent on a quarter skin as The overlap edge would be very tiny  if you are using glue putty or some other goop to filla big hole or something you might get the dissimilar material stretching and ring arround the bondo or glue or putty.  Glue has its place and When I glue my stuff on my charger no one will be able to tell and it will last my lifetime.

[restoman]

 
In the 50-year sense?  I don't know.  I don't know who would know.




Some of you guys that are experienced with the stuff might be able to answer me this one:

What about the bond-line issue in years past?  The "ghost line" that used to appear if you put an adhesive bonded seam under an unbroken paint surface, like if you were patching a quarter panel or something?   Do the bonded seams still need to always be hidden behind existing visible seams/gaps, etc? 

I wouldn't recommend bonding anything where the overlap is not hidden somewhat or covered by a decent skim of filler, such as a quarter to roof seam. Bodywork and paint costs too much, in my opinion, to risk a ghost line coming back to haunt you someday. I have no doubt people have done it with success (and I've seen some that have failed miserably), but I'm not willing to put my name on something that might not stay the way I intended. Comebacks cost bigtime.

[superbirdtom]

The only place on a muscle car where you would have overlap is if you quarter skinned a car and not installed a full quarter.  I always lead in the sail panel like the factory did on a non vinyl top car My charger has a vinyl top so I will glue on the roof and full quarters. I have a process where the wheelwell pinchwelds look like factory.

Like I say glue has its place. I have seen more welded on jobs go to hell than glue jobs because of moisture behind the welded area pinholes bleed through any skim bondo you put on top. I have seen people bring their california restorations up here and start to explode in rust  to in 2 years bubbles start to appear where someone welded in a fender lower patch panel on a cuda. the bubbles never would have happened if it was glued on.

Now some people live in better weather places and some body work holds up better than other places. I will take some pictures of gluing to post so you all can see how to duplicate spotwelds . i will say that i was the biggest skeptic around but if i can do something better and faster I sure will.

[restoman]

Like I say glue has its place. I have seen more welded on jobs go to hell than glue jobs because of moisture behind the welded area pinholes bleed through any skim bondo you put on top. I have seen people bring their california restorations up here and start to explode in rust  to in 2 years bubbles start to appear where someone welded in a fender lower patch panel on a cuda. the bubbles never would have happened if it was glued on.

Now some people live in better weather places and some body work holds up better than other places. I will take some pictures of gluing to post so you all can see how to duplicate spotwelds . i will say that i was the biggest skeptic around but if i can do something better and faster I sure will.

I get a big kick out of how some guys in very fair weather climates handle rust repair. You can tell they don't do it very often.

I'd like to see your spot weld duplicates. I've got my own little method as well, but it's always nice to see what other guys come up with.

[superbirdtom]

I will take some pics this week and e-mail them too you as I am too much of a computer dummy to know how to downsize them etc to post them.  I too am interested in your spotweld duplication process.

[wayfast1500]

Maybe it's because I'm a welder I'd rather fire up the mig than use glue.  I'm sure it's a 2 stage and prep has to be perfect to get a good bond.  I have no idea tho, never looked into it.

[bull]

Based on some of what's being said here I don't think I'd use it where you would normally have a butted joint and do an overlap instead, like a partial quarter panel replacement. However there are some places where it makes sense to me such as fusing the outer and inner wheel housings together or doing a full quarter replacement, ie., places where there is a natural joint with a bracket or substructure base plate to glue it to should be fine. In other words, if you're butting two pieces of metal together with no factory joint I think I'd be welding instead of overlapping with glue.

[superbirdtom]

yes you have to take a scotchbrite black drill wheel and whizz all the primer off down to bare metal the mating surfaces then you punch holes the size of the factory spotwalds glue and clamp the quarter panel into place then vicegrip and clamp in areas .

The next days you whizzer wheel off the glue from the holes and they make little craters and after you seal and prime they look exactly like spotwelds. I just redid a bedside I glued on and just took a torch and heated it up to almost red hot and the bedside came right off with a little prying and it was ready for another one after a crash.

If I would have welded it it would have taken a lot longer to get it off and prepped if you have ever noticed all the welds on the top of a bedside. and When youve taken off a part that has been plug welded all around the weld in the inner side of the panel its all rusty.

The factory uses weld through seam sealer. I heard that Balow restoration does this now and they also do point spotwelding to duplicate all the spotwelds in trunk floors that one would lose by plugwelding a trunkfloor in.    

I am going to be taking pics for a week or so at the shop and try to get someone to post them so everyone can see how cool they turn out

[superbirdtom]

I see your point. I just hate when you do a quarter skin climbing into the trunk to seal the mess left inside . First place I look on a car is inside the trunk and look up at the top bend in a quarter panel and see a mess of welding burns . enless you get into the trunk and reach your arm way over the wheel well to get the seam sealed with a good 2 part seam sealer and smoosh it out with a rubber glove , and then climb into the car and reach up under the rear rolldown window area and seam seal all that after cleaning and grinding and such the inside to accept seam sealer.

With the glue way the mating surfaces are already sealed all the way and when the panel gets glued you reach in and smoosh all the excess smooth inside  and then undercoat it and all looks close to factory.

Of course the best way is to do a whole quarter.  but if your talking about a true butt joint for a quarter patch panel you can't use glue, you need about a half inch overlap.  with glue patches work very well as all the seams and edges are sealed and I mean sealed against any mousture trying to work its way from the back. remember one tiny pinhole in a weld and moisture can get through and ruin a whole quarter job . Ive seen it many times. 

[restoman]

I've got two pair of Vise-Grips that I modified to replicate spot welds. Really I just added a 5/16" pin to one side of the jaws so I can clamp it over an area and squeeze it tight. One pair is a large curved jaw VG, the other is a long C clamp. They work pretty well, considering they low-tech engineering.
I've also done something similar to your method - never tried it on glued panels tho. I've used my hole punch to create the holes for plug welding and simply punched more than were needed. After welding and grinding, I run a skim of fiberglass filler over the un-used holes and hit them with sandpaper so the edge of the holes are visible. A coat of primer and a little sanding and they look amazingly like the real thing.
I've also tried putting an air regulator on my hole punch so I could reduce the inlet pressure and not punch thru the steel. It worked ok, but some "spot welds" were deeper than others.

[superbirdtom]

gotcha.  I really like the vise grip idea. and like you said with the hole punch trying the different pressures.  I will experiment around with both. took some more pics today but will wait till I compile a bunch before sending.  thanks!

[dodgecharger-fan]

First place I look on a car is inside the trunk and look up at the top bend in a quarter panel and see a mess of welding burns . 

I have some pictures that'd make your stomach turn itself inside out.

It's all fixed properly now, but it was bad.