Moss Motors, Ltd

Just bought my first MGB.  A 1971 that's in great shape except for the floor pan on the drivers stde. M y intention is to buy 2 new pans from Moss and replace. I want to use an adhesive vs. welding. Please could someone adviise a product and advice.

Thanks

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The trouble with doing something right the first time, is nobody appreciates how difficult it was.

I'm sorry, but I can't advise the use of adhesives rather than welding on that job. I'm certainly not an engineer and not up to speed with modern adhesives, but from what I've read and learned when using adhesives the panel overlaps and joining surfaces need to be engineered with enough surface area for adhesive use. The MGB was designed to be welded as a manner of joining the panels and since the floor pans are an integral part of the structure of the chassis I woudn't consider using anything but welding to replace them. Adhesives might work great, but that word "might" is what scares me when we're talking about a structural part of the car. A joint failure on the floor pans wouldn't leave you sitting on the ground because of the basic design of the car, but it could allow flexing in the rest of the chassis that could lead to fatigue cracking and that could mean a catastrophic failure at some time. I'm not a purist and think that the only way to maintain classic cars is to stick with nothing but original components, but in this area I think the original attachment methods are the best.

 

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'73 Midget (V6)
'59 MGA (I6) under construction
'73 Lotus Europa

"There is a fine line between a hobby and mental illness"

I have always used welding myself , but Tony Barnhill's Autoist site has detailed procedures for using an adhesive for replacing MGB floor pans. The link is:  http://www.theautoist.com/fusor.htm

 

Don't make a mistake here which you'll regret later. Follow Bill Young's advice for the reasons he's stated. And just imagine what it will be like trying to get all that adhesive off everything when you realize it's time to do it right.

Further, just to make this even more painful, I advise AGAINST lap welding these parts in. They should be carefully matched up and butt welded, leaving no rust pocket producing overlapped joint. If you don't think you can do this yourself, hire someone who understands the difference and has the ability to do it right. You'll thank yourself later, for sure.

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Motorbill
From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon

I support what  has been said  by the two Bills, Im in the middle of doing drivers-side floor having done passengers-side last year. No serious rot anywhere, [Id really like to find out where this car ,73 MGB, spent its life] I chase out rust spots with a Dremel and a diamond point, tedious but satisfying. Anything deep, or thru hole, then gets blipped with the MIG. On passenger side I decided that a 2 inch strip was indeed required when too many deep  pits were present. But- welded as motorbill says, if you leave a couple of tabs on the insert you can tack then remove tabs afterwards  and/or use magnets to position the insert. Make sure that all the underseal in the vicinity of where you are welding is removed before starting and have a fire extinguisher handy!! Acid etch primer, top coat and plenty of goop underneath afterwards. On the drivers side it really is tedious, cars not driveable  of course and you   get lumps from the steering wheel!. Whilst no serious pitting was found I  did find a major lateral STRESS CRACK 3 inches long, about 2 inches back from the  rear inner rear seat location point. This was completely hidden of course. When I went to weld it, tacking gently, didnt it ping as the tack cooled and crack grew another half inch or so!

The floor has been flexing under weight of  the driver and the  the sparkling acceleration would only add to this! I  do not think adhesives are the correct solution in this environment.    Regards     - - - - - steve

 

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To a man equipped with only a hammer, most problems look like nails

Thanks Bill for your advice. I will take my time this fall/winter and do as suggested. This is my first attempt and has always been my desire to own a British Sports Car. I have limited experience, especially in the welding dept. and hoped to do this project myself. I'm not in a rush to complete, as this is my new hobby. I purchased the MGB rest. manual, but do require more descript. instructions. Thanks again for the advice.

 

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The trouble with doing something right the first time, is nobody appreciates how difficult it was.

Just finished this job myself. One bad spot on the passenger side front outer corner, and the front half of the driver's side. Bought the driver's side after market pan and trimmed to fit the opening I made. Used rust-mort to kill any further rust, then primed the area and then wire brushed the seams. Then welded the pan (and passenger patch) using plug welds and seam welds. Followed by priming, then seam sealer (inside and underneath), then painted the seam sealer.

 

The end result is very study and looks quite good. I'm quite pleased with the result. The toughest job was learning to weld sheet metal to sheet metal (I mostly only ever welded 1/8" angle iron and square tubing). Lots of practice pieces.

 

Cheers,

 

-S

Glad to hear you got it done. I think you'll be fine with plug welds as long as you used enough and sealed it well with seam sealer.

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Bayless
Never express yourself more clearly than you can think
'48 Prefect
'67 Sprite (project)