Tin Worm

[Richard Lambert]

Hi all

I thought I would look at the small bit of corrosion only to find the floor inner sills and inner a posts have all rotted.

I have done a bit of welding ie seat brackets and boxes but nothing on a car should I attempt this task if so any recommendations on the work order 

[Guest]

Hello Richard,

That's not looking to serious !!

Some of this you will know:

1- clear the area of everything that is not metal - wires and that tape etc.

2- with a grinder you need to get rid of all the surface paint and rust, keeping going until clean metal is revealed.

3- with that out of the way you will be able to see exactly where the rust is and then taking each section separately carefully cut the rot out. Ideally you are looking to leave straight edge finishing as that will make it a lot easier to form cardboard templates to cut the metal which will be used for the repair.

4- ensure you use metal of the correct thickness.

5- where edges meet these are normally structural (certainly in your case) and as such those joins will need to be seam welded, starting with tack welds to ensure the new metal is positioned properly.

6- try to run 2x jobs, so that after welding 1x section you can do another area while the first tack welds are cooling off - too much heat and the metal will distort, this I am certain you know.

7- before doing any welding ensure you have thoroughly neutralised any remaining rust that is surface and the grinder cannot get too. Good prep is the key.

8- with that done spray the areas to be welded with a weld zinc primer or the like, this ensures that that neutralised areas of rust remain so.

9- do your work slowly and keep checking the new metal is fitting in correctly - hence the tack weld requirement.

10- when happy with that run the seam and then grind back accordingly.

Hope that assists ??

You can do it !!

Regards.

Richard.

 

 

[wayne Rollinson]

Go for it, just make sure you have a decent welder with gas, stitch weld so the heat doesn't build up in any one area,  Richards post above is spot on, regards wayne

[Richard Lambert]

Thanks for the advise the photos make it look better than it is the rot is the whole length of the sill on both the floor and sill I was considering  new floor panels and inner sills, is the floor welded to the outer sill, I see the cross members are spot welded 

All this because I wasn't happy with a patch the PO had done 

Rich 

[KevinR]

I would be concerned about the state of the sill strengthener that runs between the inner and outer sills.

To do the job "properly" requires the outer sills to be removed.

The bottom of the inner sill sits on the floor - the floor extends about 15mm outboard of the inner sill.

The sill strengthener runs between the top of the inner sill and the edge of the floor

The outer sill runs from the top of the sill strenthhener to the bottom of the sill strengthener.

At the top, you have a sandwich ....  Inner sill, sill strengthener, outer sill.

At the bottom you have a sandwich..... edge of floor, sill strenghtener, outer sill.

The normal build up sequence is : fit the floor, fit the inner sill and weld it to the floor (in the gap between the inner sill and the edge of the floor - these welds are between the inner sill and the sill strenthener), fit the sill strenghtener and the outer sill and weld the "sandwich" top and bottom.

With a spot weld drill, it may be possible to remove the inner sill on its own - its normally spot welded to the floor as well, but as this has rotted, it wont be a problem disconnecting it from the floor.

Beware, what looks like a simple job can quickly evolve into something much bigger.

[wayne Rollinson]

I am about to do my floor, A post, sills then cut the bulkhead out, i will post pics and description, it will commence this weekend so I can move things on then onto the wings 

[Richard Lambert]

Thanks Kevin

That diagram has given me a better understanding one side looks like it has had a new outer sill fitted and I can see the three parts sandwiched together but the floor has rotted at the seam  Drivers side however there are only two parts welded a new outer sill but no strengthener looking though the hole I can see the outer sill and paper thin rust piles but the floor looks better however this is before I set the girder to work.

If I cut out the outer sill do I need to make any kind of jig between the door 

I know this is going to turn out to be a big job but its got to be done and the only way I am going to learn is just do it. 

 

[Clive]

Are the door gaps good? If so you can buy/borrow a door gap tool. Or weld some wide steel bar across the doorgap. Or make something up that will bolt in. All sorts of things can be done.

Now, if the floors are largely sound (wire brush on a grinder finds out for you) I would be tempted to 

1. Cut off the outer sills.

2. cut off the strengthener (where it is still there)

3 cut the floor back in a straight line, an inch or 2 off the inner sill.

4 Cut an inch off the bottom of the inner sill.

Some L shaped repair sections, and the inner sills and floors are repaired ready to go. Super cheap and may be better than removing more. Then new strengtheners ad probably outers. Even there I have managed to use a thin cutting disc and recovered the outer sills. Oh, and the bottom front bit of the rear wing.

It all depends on budget and quality of new panels.....it is easy to do far more and the job is still no better.

Of course, all that is dependant on how the floor etc really is.

Now, a tip. If you don't own a spot welder (few of us do) a sheet metal punch saves a lot of drilling for spot/puddle welds. One with a step on the other side is ideal. Bought one 26 years ago, still in use...

This is the exact one I have. Others available...

https://www.ebay.co.uk/itm/Joddler-with-Punch-Joggler-Edge-Stepping-Tool-manufactured-by-TAMA-Denmark/261002525872?epid=3018580983&hash=item3cc4f67cb0:g:U~wAAOxyuOtRbZtP

[wayne Rollinson]

As Clive says, what are the door gaps like. If they are really good tack in a 25mm box section across the gap so the door still fits so you can double check before going ahead and properly welding if the gaps are bad you want a gap tool you can bolt in to hold the opening as is then once you take the sills off you can adjust the gap correctly by turning the nuts, here's one I knocked up but you can buy them, or maybe borrow one. I just paid £165 for the full floor, £10 middle sill then about £28 for the inner sill, I got lucky with a new outer sill and payed a tenner but i think they are normally about £45 oh and lower A post was £62, if your outer is good drill out the spot welds carefully to re use the sill, I would be inclined to do the full job as you can see the full extent