Weatherproofing footwell floor patch

You've identified it's not ideal but I'd be tempted it wallop seam sealer over it then underseal it. the seal sealer will remain flexible and repell most moisture. The underseal will make it look cosmetically normal again. A brush over with oil twice a year will then keep the underseal moist and prevent cracking.

It's alot of work to do the job properly but worth it in my opinion. The only down side is that alot of repair pannels will have to be made yourself as once you progress from the footwells then the likes of sills and lower door pillars will also look scabby. Sills can be bought but I never found a supplier of door pillar repairs other than for the early 3 door which need alot of refabrication to make them fit a 5 door which has a totally different profile.

Lee D.

Hello Lee

Am I correct in understanding that you think it _might_ be OK to patch the inside and then force (lots of) seal sealer into the holes in the original floor, i.e. from the outside, followed by plenty of underseal? What worries me is the void between the old floor and patch. I _know_ that I will not be able to completely fill that void with anything which is applied by brush or other tool.

Regarding the actual welding; I'm going to use MIG, apart from disconnecting the battery is there anything else necessary to protect the electronics - its an 88 EFI model.

The overriding factor is, of course, how long I expect the vehicle to be economically viable especially if Road Duty becomes stratospherically high.

Cheers

Richard

Patching in my opinion is false economy. You are leaving the rust there to get a hold of the new metal and continue its crusade into the rest of the vehicle. You have a MIG welder, cut the rust out completely, then put a plate in to fill the hole. I always butt weld the plate, not overlap as this will create a void in which the rust will start again. It only needs welding on one side then and i usually do this from above where possible as MIG welding from underneath is a pain at times. A little grinder works wonder if a tidy job can't be achieved. Plenty of primer/topcoat for inside and a rustproof covering for outside afterwards. I used to "patch" little pieces with fibreglass or filler but when after a few years i braked hard only to find the footwell tore away from the floor. I was lucky so now i don't cut corners. As for making repair panels, cardboard cut to shape and size usually works for me. For the more difficult/intricate panels, i build them in sections or strips, making sure each piece is fully welded and the correct shape before fitting the next. I always try to make the pieces slightly oversize and trim to fit as precisley as poss, this saves any gaps being filled and unneccesary welding.

Wolfie

Thanks Wolfie

I must confess that I have never done any butt welding - especially using the thin sheet that matches the RR floor, all my previous welding has been on 4 mm + RSA used in the resurrection of my trailer - maybe now is the time to start (after plenty of practice). I'm a very wary of the plate falling out. I suppose that I could bolt a few substantial straps across the hole (on the underside) to provide definate structural security then make a patch to fill the whole - as you suggest - and butt weld it in place. Does that sound truly awful or fainthearted?

Richard

Sounds like you're making it overly complicated. Cut the rotten bit out, cut a patch to fit into said hole nicely, offer it up and tack the corners, then tack along each side every couple of inches to stop it moving when heated. Now just weld the thing in, remembering of course that where MIG/MAG welding is concerned, cleanliness is next to godliness.

I usually tack the corner first then one side, then the opposite side, then work my way round at 2" intervals. When i weld, i weld between the 2" tacks and then move to the opposite side, then back. Sometimes I use a pair of mole grips with crab leg pincers (that's what i call them anyway :-) ) to hold the piece of metal in place but more often than not a simple tack is ample. I don't usually have any probs with thin 2-3mm sheet, only with the thicker stuff but then I am not a qualified welder. Some of the thicker items i've welded have actually warped and i've had to apply heat to straighten it again....

Wolfie

Lots of encouraging thoughts - thanks guys.

I guess that a little bit of marquetry practice using sheet steel and butt welding practice is due.

Getting everything spotlessly clean is going to be a problem - I can't get a clear run at the whole of the underside of the rotten area.

Any further thoughts regarding protecting the electronics - in additon to battery disconnection?

Rgds

Richard

Just disconnect the battery and you will be fine. Also make sure there is a good solid earth for your MIG clamp, clean and dry, preferably as close to the job as possible. I usually clean a patch of metal near the job and spot tack my clamp there. Good luck with the job, any probs don't hesitate to ask cheers Wolfie

Thanks Wolfie

Rgds

Richard

You're welcome Richard. Also as its basically your first time doing this, make sure you cover all interior cloth/wiring/underlay with damp cloths or cardboard or remove it completely to save any stray sparks. You will find that MIG does spark a lot with rusty or unclean metal and will cause a lot of dust & mess so a good hoover is also advisable. Anti spatter spray is another handy tool, cover welding nozzle and gas shield liberally with the spray which will save any build up of particles in the nozzle which leads to electrical shorting, also when covering work area with the spray, don't overdo it as it will make a mess when mixed with the dust.

Cheers Wolfie

On or around Tue, 22 Aug 2006 20:20:13 GMT, snipped-for-privacy@howl.com enlightened us thusly:

someone told me that plain CO2 is better than the various mixtures for welding rusty steel. I have noticed that the coogar 5 which I use spits and farts a lot on rusty stuff, but whether it does so more than with plain CO2 I don't know.

I use CO2 for mild steel, to weld dissimilar or different to mild steel metals it is better to use either an Argon or Argon/CO2 mix also when the metal to be repaired is galvanised. most car spares shops carry the small bottles for little jobs but for an overhaul on a classic or the like, it is actually cheaper to buy the valve and either rent a bottle from BOC or AP or if your local landlord is friendly, he may "sell" you the gas as it is CO2 which is used in the pub trade.

Wolfie

On or around Wed, 23 Aug 2006 07:22:43 GMT, snipped-for-privacy@howl.com enlightened us thusly:

pub gas is getting more problematic - the breweries are more keen these days about where their bottles end up - but if you're on good terms with the landlord you can sometimes work this.

hmmm. wonder what would happen if you got nitrogen instead?

Extreme weld porosity. Not only do all the experts say so, but being of an enquiring (and cheap) mindset I tried it and confirmed this.

Sounds like when I first had a mig welder & used it outside on a windy day. Ended up with sponge-like blobs everywhere.

These days I prefer gas welding with the DHC-2000 kit - it'll practically weld two aluminium beer cans together. Could, if I was better at it, I'd say.

They're not bad... but the automotive repair industry here will not recognise gas welding of any sort for structural repairs so mine doesn't get a lot of use.

I prefer using my TIG, but i get funny looks when using it to weld exhausts.

On or around Thu, 24 Aug 2006 23:49:09 +1200, EMB enlightened us thusly:

DeLorean...

and mild steel plus galvanising is still cheaper... mild steel plus paint is cheaper yet.