Floor Pans, To bond or not to bond

[Steve P]

I am new to this forum and returning to MG after my wife rolled my '68 MGBGT 27 years ago. The '73 roadster I am restoring needs new floor pans and I was considering using a 3M product called Automix Panel Bonding Adhesive which they claim is as strong as welding. Has anyone any experience with this or similar product for this application. If it is as claimed as strong as a weld, it should provide a superior seal at the seam. Thanks in advance for any thoughts on the subject.

 

[Guest]

That would be great if that were true. It sure would bypass the drawback that welding can cause and that is rust. I wonder if it is simular to JB weld. They claim that it can repair an engine block. I did a temporary repair on the stripped threads of an idler puley bolt once and it held so good I left it that way and it is still holding after a year.
Bob

 

[Mark Beiser]

Frome thier website:

"3M announces an unprecedented automotive adhesive, 3M™ Automix™ Panel Bonding Adhesive (PN 08115), so strong that it's guaranteed to perform to specifications for the life of the vehicle. The guarantee is just as strong. The lifetime guarantee covers all parts, materials, labor, and loss of use of the vehicle"

https://www.3m.com/US/auto_marine_aero/au0222b.html

3M seems serious about their claim on the product.
Definatly something to think about for my TR7 project that is starting next week.

Something to keep in mind about your MGB though. Almost everything in the MGB body besides the front fenders is stressed in some way.

[ 12-06-2003: Message edited by: Mark Beiser ]</p>

 

[Guest]

check out fusor it claims that the bond is stronger than the surrounding sheetmetal. I know a guy who used it on his floorboards and is happy with it. I'm using it on mine, probably next week

 

[thegoodbeamer]

Hey Chuck.
The stuff sure sounds good.I sure hope you will fill us in on the results and how you liked using it and such things as set time.
Chuck

 

[Mark Beiser]

The more I look at this stuff, the more exited I get. I didn't know this kind of stuff existed, its been about 10 years since I did any kind of body repairs.

I can think of about $600 I'm gona save on my TR7 right off the bat. I was going to buy new front fenders rather than just using wheel arch repair panels. I didn't want to deal with heat warping the metal, now that won't be an issue.

TR7 front fenders ~$300 each + truck freight shipping for at least $150.
Compare to ~$25 each for wheel arch repair sections + $15 max for UPS shipping. =)

 

[Guest]

Fusor may be good, but I am just not sure I want it holding what is keeping my flesh from dragging the aspalt. I welded my floors in. Now, body panels may be a different thing altogether......

 

[Mark Beiser]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by gmasterman:
Fusor may be good, but I am just not sure I want it holding what is keeping my flesh from dragging the aspalt.<hr></blockquote>

Haha, now THAT is definatly an important consideration!

Maybe for a patch in the footwell area, but I would weld in the part the seets are bolted to.

 

[Guest]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by gmasterman:
Fusor may be good, but I am just not sure I want it holding what is keeping my flesh from dragging the aspalt. I welded my floors in. Now, body panels may be a different thing altogether......<hr></blockquote>

Blake used it on his and is still happy with it. the factories are using it to bond roofs and quarters on new cars and have been for years

 

[piman]

Hello all,
my only thought on the matter is how are the joints prepared?.
Taking a standard floor pan, (or any other panel for that matter) the usual flange for spot welding is approximately 1\2" wide. Is this wide enough to give a sufficient surface area for the adhesive to provide an adequate bond. Also what is the maximum gap that will provide an adequate bond. Replacement body panels tend to not fit too well and it may be difficult to get a close fit for all the perimeter of the panel. Not a problem when welding as the panel can be manipulated to fit.
Bonded pannels are nothing new but I would seriously question if panels designed for welding will work with adhesive.

Alec

 

[Steve P]

Thanks for the feedback.
Chuck, how long ago did your friend do this repair, how many miles etc.??
I asked 3M about this application and they replied that on unibody cars it should not be used in a structural application.
My thoughts are that although this is a unibody car and this is a somewhat structural application, the bonded area will be significantly greater than that covered by original spot welds and therefore at least as rigid. Not to mention the other advantages.
The gap filling properties of epoxies are generally excellent so proper preparation of the bonded surfaces would be the most critical operation.
The way the floor panel sits on the frame flanges would preclude a downward exit of the vehicle,so that should not be a concern.
I would be very interested in hearing from anyone who tries this and their results. It may be a while before I get to mine with several other projects ahead of it.

 

[Guest]

Blake used Fusor just a few months ago and I don't think his car is been on the road much, yet. Good, solid flanges would be a must in my eyes, as well as some other form of fastening to make a good mechanical joints. Sure, the manufacturers have been using the stuff for years for fenders and roofs, but to me that's not the same as floors. I look at it this way, if your roof or fender comes off, the worst thing that can happen is that the piece could hit another car. On the other hand, if the floor comes loose at 70MPH, a bad wreck could follow. Would you care to glue your wheels on and drive accross country? I may be overreacting, but safety should be of prime concern