Rusty problem - advice from welders?

[triplecustard]

erm, the rust will continue to spread behind your fibreglass bodge. Fibreglass is indeed strong, although not as strong as steel, but it has no strength as a repair when stuck to rusty steel. Have you ever pulled on a wheel arch with fibreglass in it? Lumps of it will come off in your hand. As I said, I cant believe anyone would recomend such an idiotic bodge.

If you value your car, repair it properly or not at all. This area ties the ends of all the adjacent panels together. Do you really think Toyota put a bit of extra steel in the car when it was'nt neccessary?

I hope you let your passengers know about the awfull standard of your work before you give them a lift, I certainly wouldnt want to travel in a car you had "repaired".

[MR2sRuleTheRoad]

Fibreglass and filler have gained a bad reputation over the years by people who fill sills and other important areas with it or apply it with a trowl and use it to "tart things up" instead of fixing it properly, usually as a quick fix to sell it on. My car has small amounts of both but only to make repairs invisable or for cosmetic reasons to finish something off. my routine for repairing body work goes like this if possible:

cut out dead steel treat any remaining rust with Jenolite
fabricate new panel/patch from good steel
weld it in and grind the welds back smooth'ish
skimming of filler or fibreglass to make it look tidy
then waxoyl the inside and paint/underseal/weatherproof the outside
That for me is how a decent repair should be done

[b2hbm]

FFS are people reading things right!!! fibre glass is super strong
what do you think alot of cars have been made of over the years?

Sorry, but this is misleading. We're talking of using grp to repair rusty steel so it's the bond interface that's critical, not how strong the repair material is.

Yep, cars have been made of grp and without being a smartass I own 3 grp bodied cars and the construction is markedly different from a steel monocoque car. They all have a seperate steel chassis or sub-frames to take suspension, seat belts, etc and 2 of the bodies have steel stiffening bonded inside the grp. Mounting points are usually steel or Al bobbins and in places of loading the grp can easily be 8-9mm thick. You just can't equate a grp design with using the same material to repair a steel construction.

The fact that the panels are double skinned at that point is a hint to me that it's more than purely cosmetic. Car makers don't weld in steel for fun, and if the internal panel (complete with it's stiffening ribs) wasn't needed then I think they'd have made the outer wing single skinned like they did for the front wings.

fabricate new panel/patch from good steel
weld it in and grind the welds back smooth'ish
skimming of filler or fibreglass to make it look tidy
then waxoyl the inside and paint/underseal/weatherproof the outside

ditto that's exactly what I do as well, my welding isn't pretty enough on it's own and the grp ensures that it's leak-tight !

[triplecustard]

cut out dead steel treat any remaining rust with Jenolite
fabricate new panel/patch from good steel
weld it in and grind the welds back smooth'ish
skimming of filler or fibreglass to make it look tidy
then waxoyl the inside and paint/underseal/weatherproof the outside
That for me is how a decent repair should be done

Exactly.
The important bit is cutting out all traces of rust, think of rust as like cancer for cars - if the slightest bit is left behind it will grow again.

[widster]

Just to let you know that i had the car MOT'd in the week. I left the rusty area uncovered and untreated and i even pointed it out to the mechanic. They are a trustworthy garage and i like to think they do things properly, not a dodgy back street place. Anyway, it passed! He said that as it was an inner wing it was a 'grey' area whether to pass or fail but he did not think it was unsafe and he was happy for me to fill it and paint over it to prevent it from getting worse.

So, my car is now back on the road, at just the time of year that many are putting theirs away for the winter. Can't wait to have a blast though.