Advice required on welding holes in my Manta floor panel

[MSG]

I have a question or two:

My Manta has filed MOT because of fair bit of rust on the floor panels, so i have stripped the carpet and underlay, and chisseled off the bitumen stuff that just came off in brittle chunks and not as sticky gungy stuff, due to the age of the car (23 yaers old)

So I exposed the rsuty areas and can now see all the rotten steel and big holes, so the question is

1) Do I weld new material from below the floor or from inside the car?

2) or do I cut the new material just the right size for the hole so that it does not overlap the hole to be welded, hence it could be welded from either top or bottom, welding from top would be a lot easier as you won't have to get under the car and weld against gravity)

and what is the best welding method? Mig weld or gas welding ?

[hay_lewis_68]

cut all the way around the holes ensuring you remove all the rotten steel, otherwise it will just continue rotting, then cut a piece of steel that will overlap the hole by about an inch all the way round, then weld it from the outside of the vehicle, i.e. underneath. if you weld it from the top all you do is create a lovely moisture trap between the 2 pieces.

its not a good idea to try and butt weld the 2 panels, as it will be hard to get a good penetration due to the thin material and you will just blow holes in it all the time

welding upside down is a twat, but unavoidable in this case.


and MIG welding all the way, gas welding has no place in body repair

[Nemesis]

Mike I might be able to help you here... I have a brand new MIG you can borrow (and I am passing London soon - Gatwick via M25 - 27th )

I need a small bit of electronic wizardry sorting and you might be just the man!

[blueosis1]

check the jacking points and the swan necks on the chassis rails as well while your under,favorite places on mantas to rust.

[MSG]

Thanks everyone, yea I took out the floor carpets to see the true extent of the damage, it now needs a good deal of welding with lots of patient, garages unfortunately don't have that, they would somehow want to do bare minimum to get it through the MOT, whearas my plans are for a long term preservation, so it definitely needs to be done fairly soon as after the end of this month i won't be able to keep the car on the road without a road tax, which I can't get unless I have a valid MOT.

Nemesis, thanks for the offer mate, if you are heading my way on the 27th, it may be a bit too late as I need to get this sorted fairly quickly, a bloke down my street repairs cars and has a Mig Welder and I will hire it off him or he even said he might be able to carry it out for me if he gets some spare time. Neverthe less I truely appericiate your genorcity.

And I see your point Hay-lewis, makes perfect sense about welding from the bottom, and I should leave no cavity from inderneath for moisture or water to accumulate which would only encourage rusting.


blueosis, yes the rust is stretching from all the way from the front area near the accelerator pedal and runs along towards the mid way just by the front seat mounts, and passes through the jacking point, which itself is fine except all the material around it is effected.

[8valve-craig]

I wouldnt agree that overlapping and welding from outside is the best method. Its a much better job if you can cut out all of the bad metal (dont be shy) and make sections of new steel exactly the same size to fit in. This way you can weld a continuous seam from insided the car, This will be a butt weld and completely elliminates any moisture traps.

Blowing holes wont be a problem if you use a kind of "pulse" method, Welding a spot and watching the heat cool off before welding another (approx half a second).

I am no expert but have been dipping my feet in the welding of my mk2 astra recently and am finding that its a pretty simple skill to learn quickly. Ive put a few pics up in my thread "mk2 astra floor and sills" Take a look and you may get a few ideas.

[MSG]

I wouldnt agree that overlapping and welding from outside is the best method. Its a much better job if you can cut out all of the bad metal (dont be shy) and make sections of new steel exactly the same size to fit in. This way you can weld a continuous seam from insided the car, This will be a butt weld and completely elliminates any moisture traps.

Blowing holes wont be a problem if you use a kind of "pulse" method, Welding a spot and watching the heat cool off before welding another (approx half a second).

I am no expert but have been dipping my feet in the welding of my mk2 astra recently and am finding that its a pretty simple skill to learn quickly. Ive put a few pics up in my thread "mk2 astra floor and sills" Take a look and you may get a few ideas.

Yes I have been seing your thread with a ;lot of interest, as i said i wish i could do somthing what you did, but have not played around with a mig weleder before, so i guess I will have to start somewhere, but like your astra which looks absolute immaculate from the outside and when you look underside its another story, same goes for my Manta, although mine also needs a lot of attention to the body as well.

[blueosis1]

you own a manta ,you then will become an expert with the welder.
good luck with the project.post some pictures up

mark.

[MSG]

here some pictures of the floor panel with rust showing, ignoring the two bung holes.










And the Bonnet repair (Not finished fully, still needs to fill up more and rub down until it gets perfect, just the first initial fill and rub down....course finish so far)

[MSG]

The bonnet was repaired using the fibre glass stranded resin, fortunately the holes had another panel underneath so the resin would not just fall out and was held in place, after hardening it for 24 hrs i rubbed down and filled a layer of P38 and roughly sanded it down and primed the area to see where it needs the next filling and grinding or rubbing down, atleast for the time being getting the floor is my main priority due to MOT, the bonnet repair makes it look more acceptable than it was.

Whilst doing the bonnet P38 mix, I mixed too much and was left with surplous mix so started to fill up the cracked bay window sill, and suddenly last 3 weeks i have been restoring the outside of my house, i start one job and never finish it properly and jump to another task, thats how bad i am, never finish one thing before starting another,

[blueosis1]

what model have you got,hatch or coupe

[MSG]

coupe GTE 2L, the headlights failed 2 years ago and I used cooking foil to make the reflector coating by sticking that with a glue, so its been redone again to keep the shine on, but the MOT tester made a comment about it not being spot on, he might be comparing it with modern cars with far clearer lenses and loads of refletive areas, but I will get around this problem by sending in the inner rectangular reflectors for a recoating or mirror coating from a buisness that does telescope mirrors locally.

[Gaz86]

you just fillered the bonnet?

PS who owned that before you ? captain birdseye!

only issue I see is what looks like a chassis rail near one of the massive holes, all that lot is easily sortable for long term but good looking restoration is gonna be tricky if that's what you're after.

[MSG]

Funnily, the bonnet only had what looked like some minor perforations along the lip, , but when I ran a screw driver through the perforations then all became clear! after clearing away the crumbling material, it became aparent how bad the rust had taken hold!!

If i had access to welding gear, i would have welded a complete strip of new metal along the edge, but had no choice but to fill in, the bonnet can always be replaced., so just for the time being i didn't want it attracting the wrong sort of people who might consider it an eye sore and remove it for the crushers, the local councils do have descretionary powers to remove cars that look eyesore despite having a road tax.

as for who owned it......i am the second owner now for about 21 years!! The company i worked for provided me that as a brand new company car and then i bought it off them when they went down !

captain Birds eye!! lol

[blueosis1]

will dig upthe adress of a german firm that do jacking points ,cills and other bits for you if you need it.m&mdrotten if i spelled it right.give it a google.
got a 16v hatch on r1carbs myself,so now about welding the bottom of the legs

[MSG]

will dig upthe adress of a german firm that do jacking points ,cills and other bits for you if you need it.m&mdrotten if i spelled it right.give it a google.
got a 16v hatch on r1carbs myself,so now about welding the bottom of the legs

that looks like Martian terrain with a crater!! (lol)

I know of one German firm able to supply a new bonnet for around 600 euros, but I think its a bit over the top, no way that sort of money is worth spending on mine as othyer body panels don't merit it unless the whole car was rust free and in a pristine condition.

[MSG]

My roof also has a similar perforations all around the hatch area, so down will come the head lining and all rust treated and fillered job again unless the holes were bigger than a 10p pice then it will have to be weld patched.

i did use Halfords rust treatment on the bonnet before filler job. Its a white milky thing and turns purpleish.

[Nemesis]

What are your plans for the car long term mate?

[Frisco]

This has to be the biggest waste of a manta coupe ever. MOTd every year just to block a parking space! does it even do 100 miles a year?

[MSG]

This has to be the biggest waste of a manta coupe ever. MOTd every year just to block a parking space! does it even do 100 miles a year?

sadly, we all have our difference of opinions about various cars, yes a while back I was contaemplating sending it to crushers, then realised it may be worth keeping it alive even if just used for blocking parking, now that it costs very little to insure, even though the road tax has shot through the roof, been sent a renewal notice for the tax at £205.00, whilst the insurance is merely 135 quid! I might put in a 36V electric motor after removing the engine and install series of lead acid batteries and convert it to all electric car, capable of running short journies on a single charge, and at speeds no greater than say 3- to 40mph, just for town use only, thus do away with the road tax altogether!

But yes if offered a reasonble sum i will let go to a dedicated owner, Grim reaper has already indicated some interest in it, but now looking at how much rust it has may well put him off his plans!

[MSG]

What are your plans for the car long term mate?

If the overall exterior wasn't so badly dented here and there, some rear impact it suffered when staionary at the lights was never sorted out even though the bloke hitting it exchanged details, because it belonged to a company at that time and the company went bust within a wekk so it got left.

truely, the amount of work on this car is horrendous, it needs lower rear panel, a slight buckle to the rear N/S panel just above the rear wheel arch, some rust perforation around the rear panels behind the rear wheels, both front wings have dings, someone heavy walked on the bonnet caving it in, at the moment its been knocked back out hence why i wanted a cheap good condition bonnet, area around the roof hatch now has major rust , so if it was one small thing or two, I could have dedicated to repair it properly, both front headlights have lost chrome reflective coating, both rear light clusters are cracked through teh rear impact, engine doesn't sound aweful, probably stuck hydraulic tappets, but there you go mate its only use as a parking blocker!

[8valve-craig]

Looking at the rust in the floor i wouldnt consider it un-repairable atall. The only real question is do you want it to be solid and functional or do you want it solid and to look as it did when new? A proffesional restorer would take a lot of time fashioning sheet steel and shaping them to how they originally were whereas someone like me or you would simply weld in flat and vertical sections of steel with just a little shaping more for convenience.

This could theoretically be done over a few weekends to a good standard by DIY welder and providing you were reinstalling the carpets nobody need know, However if your long term plans were for a "concourse build" Then i would simply say look for a better shell or be prepared to spend a lot of time and money. My thinking is that you will opt for the latter.

Also once you have cut the sections you intend to renew out you will be left with a MUCH clearer view of whats required and the whole task will seem a lot less daunting

Oh and yes. You can imagine my Horror when seeing my GTE so mint from the outside just how rotton it really was, Thankfully a lot of that rust has now gone.

Set small goals and concentrate on one thing at a time. And keep the pics coming

[MSG]

I have unearthed the passenger side footwell, it is real bad around the jacking point, and at foot rest part of the wheel arch side so i will get some more pictures taken, I have to expose everything in order to enable it to be evaluated for welding by experts if I can, see how much they would quote me, otherwise it will have to be straight panels welded just to get by for now, better to do that than to have the car scrapped, someone can at a later date restore it fully with proper floor panel sections if they are still available and weld those in alng with new chassis runners, can't see me going to that length though. Cause of the rset of the car isn't in a good shape like your Astra GTE.

[mantasport]

Rusty floors are not uncommon with manta's.
If you're lucky you can catch it before it spreads into the chassis rails under the floor.
When it comes to cutting back the rust you really do need to go all the way to good metal
Which can result in quite a large hole


But if you catch it before it gets into the chassis rails fully it can save an even larger hole in the floor


That shell has been repaired and the only genuine panels i used were sills and a rear arch.
So just find yourself a decent guy who can weld that you're confident will remove all the rot, so you won't have future issues.

Oh and i would stop using that Halfords Rust killer and buy some from Bilt-Hamber
I tested a load of rust killers and the halfords stuff doesn't work for more than a couple of weeks.
The bilt hamber stuff has been on a sheet of metal in my back garden for 8 months (including being buried in snow) and still isn't rusting

[MSG]

wow man, those are excellent pictures, that is just like where my manta has also gone. for those who think i have let the rust built, but sadly, the car floor is undersealed with a layer of some material, and you cannot see if there was any rust being formed underneath it until such time as the rust really has taken full grip, and has then perforated through the protective layer, and again the same senario from inside the car, there is a carpet layer, then a thick rubber underlayer, then you have the bitument layer stuck on the floor, so how the heck can you see where any potential problem is developing, and you won't know until it is too late,

The MOT tester poked my car underneath with a long heavy instrument and it started to poke holes through this protective layer, so whereas he did not do this last year and so it got un-noticed last year, and hence he passed the MOt last year, but this time he did a proper job by poking all around to expose danger rust spots.


I will put some pictures of ho0w bad my passenger side is in a minute.


secondly bear in mind, i am not priveledged enough to take my car off the road or has a gargae to do proper un hurried repairs! I wish!! ( I am carrying out all repairs along a roadside!! what a disadvantage it is., as you can't leave a car half stripped on a road, it will be considered as an eye sore and removed promptly!!