Inner arch trouble & Bonding/Welding Qs

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dunketh
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Inner arch trouble & Bonding/Welding Qs

Post by dunketh »

I did the whole 'digging' thing at lunchtime.

Managed to dig out a large hole at the foot of my rear inner arch and it appears the arch is rotten a fair way across til it meats a previous repair panel. :(

Fun fun fun!

The sill area and the floor area are both very good and the box section I can now see 'inside' is very good so I guess its not all bad news.

Its got me thinking about repair methods again though.
Purely because of its proximity to the spring hangers, and the fact it forms a 'box' when closed, I think welding is the way forward but I keep looking at panel adhesives.

There's not a lot of decent information on the web on this topic. Most places seem to really rate adhesive bonding but only for door skins and the like, not for structural joins. Some places claim adhesion 'can be' stronger than welding!
I don't get it? Welding effectively makes 2 panels into one doesn't it?
How can a substance sat on-top of both surfaces result in a stronger bond?

Any of you bodyshop types looked into this?

I guess the 'big' question is can adhesive be used for bigger jobs, say replacing the sills and floor edge panels? I'd guess not for crash safety reasons. But, has anyone carried out any real world tests on this stuff?

(I don't count new lotuses and the like, those cars are designed to be bonded from the start)
What would Macgyver do..?
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chickenjohn
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Post by chickenjohn »

This is within 12" of a load bearing part of the car (suspension mounting point) so the MOT man will fail the repair if its not continuous welding.
Cheers John - all comments IMHO
- Come to this years Kent branches Hop rally! http://www.kenthop.co.uk
(check out the East Kent branch website http://www.ekmm.co.uk )
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Alec
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Post by Alec »

Hello Dunketh,

as John says you really have no choice.

Certainly adhesive joints can be made but I suppose that the design of the joint will be critical, as will preparation, cure temperature, clamping etc? I have seen some joints that are both riveted and glued but it is really academic in your case.

Brazed joints are also not allowed despite brazing being an accepted joining method. (Jaguar used a brazed frame for the front structure of the E Type, and on tubular construction is stronger than a pure weld if the correct brazing material is used) I do wonder how a MOT tester can tell if it is a brazed or welded joint once it has been painted, I'm think particularly of an inside corner joint.

Alec
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MoggyTech
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Post by MoggyTech »

Current MOT standards mean a continueous weld has to be used.

As for the panel adhesives, i've tested a few, and under ideal conditions the bond is extremely strong. Probably best used for cosmetic repairs, where MOT standards regarding distance from critical component in not a factor. Very handy for cosmetic repairs where a weld would mean stripping out interior to avoid fire risk.

The area you found corrosion is a common rot spot. My traveller has 3mm steel plate in that section (fitted by previous restorer)
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