Beginner tackles arch. Help!

[GJM]

Hi,

Getting around to tackling the rust on my Hillman Imp.

Have been to a 9 week night class to learn how to weld half decently in a stright line on 2mm plate but replacing a wheel arch seems like a totaly different bucket o' frogs to me!

First time i'll have touched the car with the welder.

Essentialy i'm wanting some pointers as to WHAT TO DO NOW?! As currently im a little clueless and daunted as to the scale of the task.

Heres where i'm up to on the passenger rear wheel arch:

Have sanded the arch down. Rust has gone through both outer and inner arch in a number of places. In other areas it does not look to bad.

So, what now?

Firstly i suppose i need some replacement panel sections.
Obviously i'll need an outer arch replacement.
I also guess im going to need an inner arch as well? Or do you think i can attemp to build up what left myself?

So when i get the panels i need then whats the process?

I'm guessing I then take an angle grinder to the whole of the outer arch cutting it off taking as little good metal as possible.
I presume originaly the outer was spot welded to the inner via the arch lip, i suppose i'll need to tease outer from inner with cutter/grinder as well.

If i have a new inner section do i then cut what i need out of that and weld in repair sections or do i cut out the whole original inner and weld in the whole new inner?

Its seems I can then either butt weld the outer into place or have a slight overlap sliding new outer under original wing a tiny bit. Then lap weld.

Obviously distortaion is a problem so tack it into place plenty. Then do short seams a different locations around the arch letting it cool.

How do you connect outer to inner??? Some websites seem to say use auto seam sealer, the gungy stuff that goes hard. Apply to lip of inner then put outer section into place, squeezing the lips together.
Or you you drill and spot weld?


No doubt i'll think of some more questions but thats enough of my babble.

Essentialy where do i go from here?

Thanks
Graham

 

[Tigman]

If you can get parts for it then start there !If not you can fabricate them , you need to cut out all the rot and then clean back to good metal , i would tackle the inner first then the outer ! good luck

 

[tux]

That's about the size of it. Cut away the rot and see what is left. Outer arches are still available I believe but I suspect you will struggle to get an inner. May be wrong.
Butt welding is preferable to overlap as it eliminates any moisture traps.
Seam sealer is just to seal out moisture when you have finished. If you want to bond outer and inner arches together something like Sikaflex or Tigerseal would be best, but I would be tempted to drill and plug weld.

 

[mike 109444]

Hi GJM If you can't get inner and or outer, Before you start chopping make up some cardboard templates of what is there. One starting point is get the car on an axle stand. Then you can get that wheel out of the way. I know it's stating the obvious but DON'T just use a jack. Check whats above/inside from the wheel arch that might catch light. Also having owned 2 Imps in the past, rember there is an engine just behinde that panel. oil/petrol ect. If you have not yet done it, get a heat gun and scrape off the underseal from the inner arch, cos you will only wish you had once you get going with the welding. Just think the welding is only about 5% of the work. The rest is grinding, scraping, cutting, rust treating, preparing patches/panels, fitting up, clamping. Then you get to weld.Then grinding, paint protection, filling, sealing, finish painting. Oh the joy of car restoring now that spring is in the air I think you will find that because of the work involved in the above (timewise) is why welders on cars charge so much. Best of luck with it. Will lookout for your up dates

 

[Engineer]

If you can get outer arches, then take them along to your nearest body parts supplier, and ask if they have any inners for other cars that are anything like the same shape.

After you have sorted out the inner arches, which can be very time consuming if they are bad, you need to fit the outers.

Best way to fit outer arches is to get hold of joddler/punch tool, and after you have cut away all the rusted metal, leaving a neat curved edge, fit the arch under the edge of the original panel and clamp it in place, then scribe a line onto the new arch.

Next cut the new arch adding the width of the joddle to your scribed line, its generally easier to joddle the new panel rather than the original bodywork, and you need to do this next. Then punch a series of holes along the edge of the original bodywork.

The holes you have punched can then be used to plug weld the new panel in place. Its essential that panels are help very close together when you are plug welding, and a combination of welding clamps, and self tapping screws will often work ok.

When all your plug welds are in place, linish the welds off with a flap disc, then lead load the repair to prevent corrosion. Its quite possible to finish the whole thing completely with lead, but this can be time consuming, so most will skim with lead, than use polyester filler.

You can butt weld arches, but this often results in quite a lot of distortion, which makes final finishing to a reasonable standard a very time consuming job.

 

[GJM]

Thanks for the advice so far guys. Been very useful.

Panels arrived today. Inner and outer. Got a joggler and some 'slitter' discs on order.

Question:

When plug welding the inner arch to outer where do i put the welds? At A or B?

Rubbish mock up.

If you plug weld at A how do you stop moisture getting into the inevitable gap at B? Just fill it full of sealant, Tiger sealant or something?

And if B...well...upside down welding it is

Graham

 

[tux]

I'd be plug welding at B personally. I know its more difficult but it will minimize the tidying up afterwards. Wallop some weld thru primer on the panels before putting them together as rust proofing after they are welded in will be difficult. Not the best corrosion protection, but better than nothing at all.
Must confess that I am surprised you were able to buy inner arches. I thought they were NLA. Makes the job easier though.
Keep us updated with your progress.

 

[Chickenjohn]

Great news that inners and outers are available!!

I agree with Tux- would plug weld at point B, drill a 6/7mm hole for the plug welds, or if you use the hole punch side of the hole punch/ joddler, then enlarge the holes slightly with a 6 or 7mm drill to help the plug welds easier.

I would also use Zinc weld thru primer on all the inside, would butt weld the new inner arch section to the old part. Drill out the spot welds to remove the old outer arch, then scrible the cut line using the new outer arch as a template- deduct ~10mm to allow for the joddled overlap.

Then offer up the inner arch repair section and scribe the line using that for cutting the old inner wing. You want to butt weld the inner as it will be exposed to water and you want a butt weld and seam sealer here. Take lots of measurements and keep a record of them so you can check the fit of the repair sections before final welding.

Good luck and post some photos to let us know how you get on!

 

[chunkolini]

I think you are all mad.
I admire vehicle restorers, but every time I see a mate dabbling in vehicle repairs I repeat my vow to never ever get involved.
The horror stories that unravel, and the gumption to stick with it and finish the job amaze me.

Good luck, you will learn a lot via this process..
Chunko'.

 

[Engineer]

You need to plug weld at B, make the plugs quite close together and make sure the panels are well clamped when you are welding.

Some MIG sets have a spot weld setting and using this in conjunction with a nozzle which puts your torch at exactly the right distance from the panel, will after a little practice mean perfect spot welds every time.

As to sealing I would think when the car was originally made, there was some sort of weld through sealant between the panels, but not sure whether something like this would work with plug rather than spot welding?

 

[tux]

......... As to sealing I would think when the car was originally made, there was some sort of weld through sealant between the panels ..........

This is Rootes engineering, second only to British Leyland in terms of shoddiness. I suspect there was ****** all between the panels when it was built!

I would probably go with the weld thru primer before assembly and then apply Waxoyl/Dinitrol/Dynax/whatever as best as possible after its finished.

 

[GJM]

Minor teeny weeny update. No welding as yet. Waiting till I have a few days off work next week.

Got some 1mm cutting disks however so started to cut away the outer wing. See wood for trees and all that.

Looks like im going to have to replace the majority of the inner arch lip. Do you think i should cut it out in sections and weld in new inner in small sections also bit by bit. Or weld in the whole inner arch in one go.
Need to take a bit more metal out of the wing to make room for butt welding in new metal.

Looking down the inside of the sill was a relief, looks very clean.

Been having a look at the repair sections. They seem to be hand made rather than pressed. Inner does not seem to match up very well with outer. An inch or so out in some places. I can see its going to take some bending/self tapping screwing and lots of tacking to get it all together. :|

Hopefully will get round to some welding after the weekend.