Since we see more, and more, adhesives in cars; I'm wondering about the good and bad of gluing in floor pans. I know the welding isn't that bad; but if you are paying for it, there is cost versus benefit. Thoughts?
I am interested in what others who have done it , opinions and long term results . Structural and non structural.
Ive been using adhesives for twenty years and never had a problem. You would be surprised how many panels are adhered by the OEM on a new vehicle, the joints are stronger than welded plus the seam is waterproof.
For a lot of us working at home with minimal equipment and room using the right adhesives on non structural floor panels might be a real plus. I do all of my welding outside now because my ancient wood garage wouldn't last long if a stray spark got in the wrong place, For the guy in a tight corner of an attached garage being able to use adhesive rather than welding the whole panel in not only would save time it would save the chances of sparks starting a fire.
I have done my most recent rust repair jobs with structural adhesive. The prep is about the same but, if the repair panel fits properly, the installation is faster and easier. My experience is that it is tighter, quieter, and feels more like a new car. There have been no failures that I'm aware of. I concur with oldiron 440 above about current usage, strength, and waterproof. I tried them out after discussing the topic with two engineers from an import car company. They are also effective in joining dissimilar metals. Lou Mangl***
I’ve been to the cl***es, I’ve used the products, did the destructive tests. I don’t glue anything not glued by the factory. The OEs use glues but uses them with welds or mechanical fasteners in most cases. A roof skin may be glued above the doors but welded or riveted beneath the front and rear gl***. QTRs, rockers are also glued with welds or mechanical fasteners. Wheel wells that are glued are usually hemmed like a door skin creating a mechanical attachment. I’ve glued in many plastic trunk pans and vette panels. Cars like vettes have a ch***is designed for that. The 3m product is nice, it comes with a misleading instruction sheet demonstrating all the parts you can glue on. I have searched a ton of OE repair procedures. Very few are glue only. Most are rivet/SPR bonded. The others had OE designed sleeves bonded with the new part. I digress, sorry But we work on old cars and modify them. I guess it up to you on those but as long as I can weld I’m not gluing
I want to see it in action with lasting durability. Not some guy on you tube demonstrating a 15 minute video with zero proof. I know of the procedure but I don't know anyone who has done it.
The longevity of even the best floor pan graft regardless of process is going to be dependent on how well the seam is sealed on the underside and on a glued panel the overlap is going to be where the moisture collects starting the rust process all over again.
A lot of new car companies bond panels, in ‘04 the all aluminum XJ8 came out that used bonding etc. Even still most panels that where bonded had either rivets , a few spot welds or flange locked panels to add a bit more to the joint then just the glue/bonding agent. was this done to simply hold the panels together while the glue dried or it’s a critical feature of the joint , I don’t know. but I do know there are still a ton of these cars on the road and they are still in good shape and drive well. Right out of the box they where the quietest jags built up to that point.
I'm inclined to locate the Glue Age within the motor industry's quest for One Big Part, and hence the disposable car. As a general principle of design, I'd like to see stuff bolted together as far as is practical. It ought to be possible to dis***emble and re***emble things an infinite number of times with no deterioration to anything except the fasteners. Having said that, I am strangely unoffended by large glued timber ***emblies. By 'large' I mean sort of furniture scale, the size of a substantial sideboard or dresser. I suppose it is because the timber pieces are so permeable to skilled fabrication: they aren't pressings or injection-mouldings.
Rust can creep under the glue. Seen it happen. I have seen several OEs that recommend an epoxy primer in the joint but not all do. I’m looking into the Aston replacement procedures. That’s interesting. The Benz process used a special cleaner to make sure the joint was prepared to accept the adhesive. The 2 main reasons OEs use them is crush or energy transfer and bonding incompatible materials. A steel structure with aluminum outer panels or aluminum structure with a steel shell. And the use of composite structure used with metals. Plus all composite. The self piercing rivets, SPRs, are also structural The glue in a joint transfers energy better than spot welded. The SPRs add to the strength. But I also would think the SPRs speed up production over waiting for the glue to cure. The repair process using the glues and rivets is a much better repair procedure for advanced designed cars. Imagine shops that can barely mig weld steel trying to repair aluminum. As far as glueing in a floor patch in an old car, probably won’t hurt. But if something like a seat or seat belt anchors to it? I’m not.
As much as I am willing to use adhesives I only use welds on panel seams that are going to need bodywork over the top. I also use welds in addition to adhesives on certain panels.
Did a little research. Aston does state the mechanical fasteners for the Vanquish have little structure properties once the “heat activated adhesive has been cured in a 190•C oven” One thing to consider is that a high end super car is designed slightly different than the junk we drive. A roof, rocker, qtr....... designed to be welded doesn’t mean it’s designed to be glued. The flanges along the roof rial on the cars we build are not wide enough to to be glued only (my worthless opinion) A panel glued from the factory has bonding surfaces designed for adhesives. Newer cars have a considerable amount of additional structure thus lending itself better to new technologies in adhesives. I still go back to the 3M panel bond instructions. You see a pic of all the panels you can glue. The fine print says do not use on structural panels and states it can be used with both rivets and spot welding. The instructions have changed since a lawsuit over a completely bonded roof failed in an accident. So 3m panel bond is an excellent product when used where it is designed to be used according to 3m.
with a beach buggy body, maybe a transverse rear electric motor- real small one, nissan leaf - battery packs in the frame rails groovy, so the technical question is are modern motor vehicle bonded parts annodised is the glue merely sticking to the electroplated annodise i.e. IF you were to glue two allooominoominoom parts together, would you not first raw them, and scratch them 'key' them up real good to promote a bond - liek you do with paints
My uncle is a body man, and he swears by 3M panel bond. So I needed to replace one half of the floor pans on a 40 Ford. I went ahead and used the panel bond, then to make myself fell better I tacked it every inch or so along the seams. It held fine, but then again I had to wonder if in a head on collision or something like that if the seat would rip the floor out. I know guys have been gluing in VW bug floor pans for years. If it was just a small patch and not really structural, I would have no problem at all gluing it in.
There's a longtime expression about someone 'losing it'. They are said to have 'come unglued'. They never said 'come unwelded'...
I built my hood hinges. After painting the hood I used panel adhedive to glue the aluminum to the hood. 15 years ago, without a problem....
The question is will the anodize affect the bond. I would call the adhesive manufacturer. the generic answer is a form of abrading is recommended either sanding/scuffing amd even blasting the adhesive area. Ford says to “grind to clean metal with 80-120 grit, clean, apply adhesive covering any exposed aluminum” Isopropyl alcohol, acetone or a cleaner provided by the adhesive manufacturer is necessary. The parts must be glued quickly before any oxidation.
Gawd I have had my share of Testors headaches over the years. Some of them on purpose. Back in the '80s we used panel cement on a couple of restorations that required glued panels. They were not cars that got driven but they were glued from the factory and the glue held up better than the panel. I would not glue one of our type of cars just because. I have been known to skip weld a floor and use seam sealer to seal it up though. I am a cheap ******* so as long as I can do it I am probably not going to pay someone to weld one up for me.
Use a combination of both. I used panel adhesive for years and it's great stuff. That ****py primer that introduced to the Hobby 30 years ago uses the same resin as Gorilla Glue. Being frugal I have used it for gluing things together, considering you can never get the ******* lid off the can ,so on a floor pans use a few fasteners and the panel adhesives. A lot of the younger people , hopefully coming into the street rod community may not have welding equipment or the skills to use it yet so panel adhesive is a alternative
To my way of thinking I wonder if panels designed to be installed with modern adhesives are built the same as repair panels designed to be welded in? Will gluing in these panels be as good as what the factory glued panels are, or will this be a less than optimum installation? I understand there are those without all the equipment needed to be able to weld in panels. Or maybe not the work area needed to do so. But I'm not sure that's much more than an excuse to me. I've always been on a tight budget with my car builds, and never had a nice shop. Yet somehow I managed to save up and buy a decent Miller welder, and even when I had no shop at all I built two cars in a 10'x20' canopy in my backyard. Gluing on panels because you feel you have no option is an excuse I personally don't buy.
Cars and parts that are bonded are designed to be bonded. Just because car company A does it on a new car doesn’t mean it’s ok to use that same adhesive on a car company A built 40 years ago. A ford truck built is 1950 is not the same built today. Panel bonding as an excuse due to lack of skill or tools should be a reason to wait until you have the skills or tools. I’m not anti panel bond. Comes in handy for simple tabs, mounting interior pieces, used in conjunction with welds, maybe rivets. Kinda like an adhesive seam sealer
♥ ♥ "A roof, rocker, qtr....... designed to be welded doesn’t mean it’s designed to be glued." ♥ ♥ I picture a bonded/glued structural joint needs LARGE areas to be strong. Typically "****" glued joints have practically no strength compared to the parent material. **** welded steel can be mighty strong. Yeah, design trumps materials in nearly everything we touch. ***embly quality can sometimes make a marginal design perform "OK" and obviously mortally wound a decent design. If a frame, steering knuckle, or clothes line pole are bending or cracking, the design probably ain't anywhere near right. Duplicating the poor design in "chrome moly" might work, but there is an excellent chance that simply tweaking the design or even an existing part to eliminate stress concentrations and stress raisers could achieve excellent results.
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