Has anyone had any good or bad experiences using Fusor Metal Adhesives? I'm considering using it to bond my outer longs on and the long clamshells on. Then using structural rivets to prevent the unzippering effect of the bonded surfaces.

Pros I've read
1. Metal adhesives shear strength is greater than spot welds or the sheet metal being bonded.
2. Provides corrossion protection on surfaces being bonded (bonded surface)
3. No warping of metals, unlike welding.

Cons I've read
1. Bonded surfaces can unzip, which is why a spot weld or rivets ar needed along bonded seam.
2. Don't let it get into areas that you don't want bonded or filled.

Any thoughts are appreciated.

Sounds new fangled. I's sceered

It may be stronger then spot welds, but is it stronger then rosettes or seam welding?

Do you have a welder? The long is a structural part. The epoxy MAY be perfectly fine. But I would be skeptical and look for others that have used it to repair hi stress areas of cars before moving away from the tried and true welding.

Zach

Have to see results; test- proven- trued and repeated. Sounds like possible adjunct to a long that is welded, however. Seal old and new into one- but rely on the welds to fasten and carry the load. Like to hear more...pics? intel?

This looks very interesting. You can even weld and glue at the same time! You can glue in the long and then spot weld. Now there is a glue / sealant over the full contact surface. I do not know about rosette welds. But this looks like it would be better than weld through primer. You will also not need seam sealer.

Fusor Metal Bonding

As ever, a glue joint is no better than the surface it attaches to.

Rusty metal? Yer gluing to expanding rust cells that never sleep.. Rust comprises ELECTRO-chemical cells. Rememember, there's a battery in yer car and it conducts through the body.....

Rub yer finger along the glue joint area before gluing? Yer gonna be sticking the adhesive to the oil film from yer finger.....

Did you notice that none of the repairs listed on that site are structural?
Yes, there's a bumper but it doesn't absorb stresses, impacts, and flexes from normal driving like the rockers. With todays plastic bumper/metal underbumper designs, the metal only has to be loaded once- during a crash. Then it's trashed.....

The rivets are really to minimize glue thickness. Too thick, the shear performance is lousy. Thin is best for shear so the rivets are used to pull the surfaces together. Depending on the pattern and rivet design (solid or hollow core), they can also help transmit loads.

Any idea how much pressure a rust cell can exert as it bubbles up? It's enormous and can exceed the glue holding properties. In that case the rivets can help unzipping.

That being said, it's one case to glue together new clean metal and an altogether different case to glue together old rusty metal. Honestly, have you ever coated a rusty panel with paint, glue or whatever and stopped rust dead in it's tracks???

That stuff is designed to bond outer panels, not the backbone of your car. I have used that product many times to glue on bedsides or quarter panels but nobody would use it on a frame rail. 3M has it, Duramix used to before 3M bought them, and maybe others. It's not a new thing just from Fusor.

A friend who worked for 3M was on a flight and in conversation with another passenger regarding adhesive use in jet construction managed to panic another passenger. She yelled at my friend and accused her of lying and trying to scare other passengers. She used to get me some pretty awesome deals at the 3M employee store too.

Used correctly its great stuff. Knowing the correct method and application is the key. I don't, but I first saw that being used on a 356 at a friends house. There is also a writeup was referred to in the 356 registry about 6 years ago on how to bond a lower door section with glue. Sacriliggggg.

My only concern is that the metal around the rivet may tear or develop stress cracks. I've got a lincoln 185 tig welder and could seam weld the edge.

As for the factory spot welds on the 914 longs I'd recommend that everyone take a look at them. I dismantled a 1975 914 not too long ago and was able to easily pop the factory spot welds apart with screwdriver without much effort. If I can find the scrap piece of the long I'll post a pic of the spot welds. The welds weren't rusty either, a few of the welds were tacked good and the metal tore before the weld failed. I'd say about 80% of the spot welds I easily popped apart on that particular car. Thats just a bit of info I thought I'd put out there, not sure if anyone else has come across that or not.

Everything has its place. Adhesive joints are great, if they are used in applications that were designed to be adhesive joints. I have a 50' wingspan glider that I built that has quite a few of the structural joints in aluminum held together with epoxy. However, these joints were designed to be glued. As mentioned before, the key is also to have perfectly clean bare metal for the glue to adhere to. Anything less than perfectly clean, is perfectly worthless as far as strength goes.

I would use the adhesive you referenced to install outer panels that were not structural, with no worries. I would be careful using it to refab the longs, etc. If it were used correctly, it should be OK, but the key is how the parts are installed. The key to the strength of the glue is that it is extremely strong when loaded in shear (ie. pulling along the plane of the glue). The relatively large surface area of the glue provides the strength. When pulled perpendicular to the plane of the glue, it is nowhere as strong. In this case, the load is transferred to the edge of the glue, and can unzip it, as someone referenced. If the pieces you glue in are loaded incorrectly (for example at the edges) they could fail.

I removed quite a few of the factory spot welds on my car, and they were all very strong. It was very, very hard to split the overlapping panels with a chisel unless most of the spot weld was drilled out.

I bond all my 914 panels with Miller instant glue AKA MIG

Does anyone have any input on the riveting. Is or would riveting be as strong as the factory spot welds?
Thanks

Yes, I was referring to the Weld Bond Procedure adding to a reinforcement like Engman's Inner Longs Kit that is welded with Rosette welds and you are instructed -not- to seam weld it. Inside- metal to metal it is primed only or bare.
Even with the best recommended seam sealer- I am very uncomfortable leaving these two surfaces facing each outer like battery plates nearly bare and waiting to exchange and oxidize into an internal rust pocket. Limited perhaps or not, I like the sound of bonding them effectively but only if retaining the physical welding. Not the chemical welding. I would reserve this first for corrosion resistance but conceiveably; even when those longs were rosette welded and the frame torqued its force down the frame, it would only pull from these round welds. Now with full contact, this would be greatly reduced (even if it never was an issue before).
It would be worth its weight as even smaller-slimmer pieces could provide greater stiffness still. Time will certainly tell. -Jordan

Here are two rivets I've found that has good shear and tensile strength.

Q™ Rivet Stainless Steel
Q™ Rivet Diam. 1/4" (6.4mm)
Head Diam. 1/2" (12.7mm)
Shear strength 2450 Lbs equates to approx 49,936 psi shear strength
Tensile strength 2250 Lbs equates to approx 45,859 psi tensil strength


Q™ Rivet Stainless Steel
Q™ Rivet Diam. 3/16"(4.8mm)
Head Diam 3/8" (9.53mm)
Shear strength 1650 Lbs equates to approx 59,787 psi shear strength
Tensile strength 1300 Lbs equates to approx 47,105 psi tensil strength

Those clamshell stiffeners should be WELDED on! Anything less is a waste of time.

Do you want to be a DAPO???

Pretty piss poor metal properties for those rivets.

Prolly pop rivets so that the operator can easily exert enough force with a hand tool to pop them.

For contrast, I'm now working on a product made from 17-7PH stainless with a yield strength of 220,000 psi. It's about as tough as it gets.

A lot of the military structural fasteners are in the 130,000 shear range...

Have you ever looked at an airplane? those are solid shank rivets with one formed head and one peened over head. Note they are on a 2 inch or so spacing to get enough cross sectional area to hold on a skin panel. The number of rivets and the patterns change to an even closer spacing for structural work.

If yer rivets are hollow (pop rivet style), the hole really weakens them. For stress calculations, subtract the hole from the available shank to find out the area in shear.....

This reminds me of glued together ebay turbos.



I'd stay away.

Does anyone have any good ideas on a mechanical fasteners that would be cosmetically appealing. I just need ideas on a fastener that has better shear/tensile strength than the sheetmetal on the car. The metal adhesive shear strength is definitely stronger than the sheet metal. Need a fastener that has stronger tensile strength than the sheet metal.

Just looking for a fastener that can be concealed by the trim or one that is appealing if left exposed.

I think that the spot weld on a car is god for about 4900 Lbs of froce before the metal around the weld begins to tear. If anyone has good specs on the shear/tensile strength of factory sheetmetal and spot welds that would be very helpful.

Thanks

Air frames are riveted because the metal expands and contracts in altitude. The rivets and spacing are engineered to react and move.

The only time I would consider using adhesive for a chassis is if it was in a completely tempeture and humidity controlled environment with all setting clamps calibrated for proper compression and adhesive film retension. A chassis is nothing to mess with. I have bonded lots of non structural panels with great success.

I used fusor all over on my race car project.
(2 tubes actually)
I did NOT use it on anything structural.

about 30% of my fusor'd items have come loose in the last 6 years.
I cleaned the metal meticuously and still they came loose.
I believe it to be a lack of "brand new perfect" metal as the cause
I would never use it in a structural application.
it will never stick to a rusty longitudinal.
it won't stick to a painted application
and it won't stick 30% of the time to an application with the paint removed
(my case)

Thanks for the input. I knew someone on the board must have used it and had some success and failure.