The Stovebolt Site Forums The Shop Area Paint and Body Shop Welding or Bolting vs gluing panels on, a science project....

Well, we have talked about this a number of times, can "gluing" panels on a car possibly be as strong as welding it on. Well, my 10 year olds science project may have the answer!

He cut 12 pieces of 20 gauge steel. We then welded them together in pairs. We butt welded with the MIG, "plug welded" with the MIG, spot welded with a $20,000 ProSpot STRSW and drilled 1/4" holes and bolted two as well. HE (grinding and gluing them by himself) then bonded with Winzer Universal Panel bonding adhesive another piece of metal to each of the pairs of welded and bolted sets.

We put clamps on them and pulled them apart using the Chief frame rack at work (10 year old boys love destroying things, don't they?).

Here are the results, the glue won every single time! Pretty impressive I would say.

Brian

[img]http://i200.photobucket.com/albums/aa167/BasicsofBasics/Weldvsglue.jpg[/img]

Brian,

A+ for the experiment. It looks like the glues keep getting stronger and stronger...I wouldn't have believed it had you not posted this!

Stuart

My buddy swears by the glue, he has been using it on bedsides & quarters for years. I'm thinking it will be useful on my burb, some places I have removed spot welded panels to treat rust, & really don't want to weld them back in, looks like I will definately use the glue now. Thanks again, Brian

That's amazing. I guess you really better be sure that panel is where you want it to be before the adhesive sets up. Any idea by the way what kind of force was being applied?

Just AMAZING ! great test ! ...hope the youngen got a Blizzard or Milkshake after his hard work !

I don't know of the force being applied being the gauge is mounted right below where I was working and it was too dangerous to watch it. It is a 35 ton ram that was doing the pulling. I do know that the bolted one took the most abuse. It pulled and pulled, I didn't think it would ever break.

We are going to do it again, this time with more welds and less bond area. He made the bond area a little bigger than it would be on your average pinch weld. And I want to put completely weld the butt weld this time.

Brian

Congrats to ya Brian, and this is an excellent introduction to understanding stress analyses for our son. Ya never know, you may have a budding engineer in the family.
At my last job before I retired, we used lots of glue joints. Usually carbon fiber panels but ocasionally combinations of steel and carbon. We used Instron Universal Materials Testing Machines to pull the samples which gave us a graph of the tension, yield points and point of failure.
In sheer the glues are great but their peel strength usually leaves a lot to be desired. This is something to consider in its aplication or when your designing a joint. As you know, a tee joint welded from one side can be broken with relatively little force with the palm of your hand, but when filleted from both sides is nearly impossible to break. Joint design is very dependant on the way the load is being applied.
Testing a joint the way you are, does test the tensile strength somewhat but there is also the peel strength component to it because of the side loading of the joint. Normally a joint test specimen for sheer strength would be made using two single layers at each end sandwiched between two layers of material in the middle. That way there is more of an even pull on the joint with very little side loading. The bearing area as you mentioned also is a key factor on the strength of the joint.
I’m sure properly prepared glue joints would be more than adequate to hold body panels together, after all 30% to 40% of the 737 that takes you on vacation is glued together.
By the way, what glue are you using??
Denny Graham
Sandwich, IL

That's a great project for a ten year old.

Another thing to check would be strength versus temperature- try the same experiment again after soaking the test piece in an ice bath, and again after heating it to 100 degrees, and see how well the glue performs then.

Denny,its distributed through Winzer but who knows who actually makes it.


4onthefloor, I can't imagine that there would be a difference being this stuff is used by major manufactures on a regular basis. BMW has a recommendation to bond the spliced in frame rail on a 5 series without a single weld or bolt! I just don't think that is an issue.

Brian

HOLD on there cowboy! Nice to see a science project that is interesting to us bolters. Now about the results (there is always a guy like me). The surface area of the glued pieces is much greater than the welds. The bolted breakthru is predictable because of the thin metal and holes too close to edge. From the pictures, you have overlapped the bonded section to create about a 30-50 times greater surface area. The "beads" of weld and glue must be the same or the surface area must be the same. The Butt welded piece seems to have broken loose at the weld, as in cold weld or no penetration. Bonding may still prove to be stronger, but not by this test. Manufacturing uses bonding because it is strong enough for their application and has many manufacturing advantages over welding. One of the biggest advantages is that the surface treatment is not damaged by bonding and corrosion will not be a factor between the pieces. This opinion is intended for discussion here and is not for your 10 year old to see. I am not intending to say anything but good about his experiment, knowledge and the fun he must have had with his Dad.

I'm with you Bart, what this test proves is limited to the test.

But as far as the "overlap" being more with the glue, well, that is how it is used. The point being on a "pinch weld" on your average car, there are spot welds about every inch and a quarter or so. When you bond it, you apply the adhesive to the entire pinch weld area, much like my boy did here.

To make them "equal" in every way you would need to leave the welder unpluged being the adhesive didn't use any electricity.

The butt weld failed, not because of poor penatration but because the metal right next to the weld is the weakest point. This will be seen at any weld failure, IF the weld is well done.

Brian

I like the idea of glue- no warpage, a sealed joint so no moisture can enter, no grinding welds etc. but my first attempt yielded what I feel were so-so results. I am NOT a professional, just a backyarder who asks lots of questions and wants do be able to say I did it myself.

The only issues I have with the using glue is how do you clamp the joint properly on some panels were its impossible to get a clamp on it? I used sheet metal screws on one panel ( being careful not to overtighten) but then I have holes to fill. If I spot weld the holes will the heat not cause the glue bond to break? Someone suggested filling the screw holes with glue or body filler but I felt there would be a possibility the repair might "pop" down the road and ruin the paint job. Is there a better way or am I just being paranoid?

Great science project!

Congratulations to your son and his "foreman" for a great real-world, practical project. I love this kind of stuff. (Did a similar one years ago on ultrasonic welding of plastics.)

I'm the first to admit my eyes aren't so great, but it looks to me that the fasteners sheared on the specimen shown on the far right. I don't see where the sheet metal pulled through. What was the fastener diameter?

I think the equivalency issue is a non-issue. You used each process as it would be applied in real life, not "per square inch."

The adhesive is called "Winzer Universal Panel Bonding Adhesive"?

Thanks for sharing with us!

Bill

I'm sure its not a perfect test, but it still shows me that the glue will hold fine on non-structural stuff that I don't want the hassle of welding/grinding/finishing. Brian

Bill, the far right is the spot welded panel. Those "nuggets" left from the weld are a perfect example of what you see in a weld destruction test. The weld performed perfectly. The bolts are the one next to it, they actually held up the best. They are 1/4" low grade bolts.

Yeah, the adhesive was Winzer "Universial Panel bonding", I'll try to post the part number.

Brian

Well, the projects were judged today by some out of town science guy and out of 60 kids he came in second! This was a BIG deal for him. He doesn't usually get very good grades and struggles a lot with school so this was a shot in the arm.

Brian

[img]http://i200.photobucket.com/albums/aa167/BasicsofBasics/Weldvsglueribbon.jpg[/img]

The grin on his face says it all and is probably only surpassed by the bigger grin on your face.

Awesome!!!!!!!!

Great science project, Brian. My wife did all the science fair judging at our local school dist. She really liked yours. It was very different than most she has seen. Congrts on your award. I used the glue to put in a Nova trunk pan. Worked really well for me. Would definitely use it again.

i just talked to my local painter an he suggested the glue for certain things on my Ol Gal ..an he swears bye it for its durabilty

The Lotus Elise has a largely bonded FRAME. In a little search to find more info, I found some interesting stuff. A lot of these cars use a small amount of rivets or welds in conjuction with the bonding. But many structual parts are totally bonded in.


The Lotus Elise is a roadster conceived in early 1994 and released in September 1996 by the English manufacturer Lotus Cars. The car has a hand-finished fiberglass body shell atop its aluminium extrusion and bonded frame that provides a rigid platform for the suspension, while keeping weight and production costs to a minimum. The Elise was named after then Lotus' chairman Romano Artioli's granddaughter, "Elisa".


[img]http://upload.wikimedia.org/wikipedia/en/thumb/a/a0/P5120070.JPG/250px-P5120070.JPG[/img]

http://en.wikipedia.org/wiki/Lotus_Elise


"Unlike McLaren F1, Ferrari F50's rear suspensions are directly bonded to the engine / gearbox assembly. This means the engine becomes the stressed member which supports the load from rear axle. Then, the whole engine / gearbox / rear suspensions structure is bonded into the carbon fiber chassis through light alloy. This is a first for a road car. "


Lotus's technology was originated by its supplier, Hydro Aluminium of Denmark. Hydro discovered that aluminium extrusion can be bonded by epoxy resin (glue) if it is adequately prepared by a special chemical in the bonding surface. Surprisingly, glue can bond the sections together strongly and reliably. Most important, the aluminium extruded sections can be made much thinner than traditional welding technique. Why ? because welded joints are weak, so the thickness of material should be increased throughout a member just to make a joint strong enough. Therefore Elise's chassis could be lighter yet stiffer.

[img]http://www.autozine.org/technical_school/chassis/tech_pic_chassis_elise2.jpg[/img]

http://www.autozine.org/technical_school/chassis/tech_chassis2.htm

Hey. Where are the kids legs? Oh. He has camoflaged pants on. He looks like a good kid. Best of luck to him.

Is the glue expensive? Do you think it would work on stainless steel? Maybe, I could glue some bolts to the back of the front emblem for my 53.

where are his legs, Yeah, the glue would work like a charm for that emblem. But it isn't cheap, about $30.00 and $50 for the applicator. But if you check with the paint store many will loan the applicator gun out.

Brian

good project very good test a for the Day!!!

thats a neat project, congrats

This is amazing, I never would have believed it. Thanks for posting.