Buy the gas and do it yourself, you wont regret it and you will then be looking for the next welding job to do.


Here is how to do it courtesy of our friends at www.xkec.co.uk

 

RD - please explain the 4 partial holes that were drilled (1st picture).
Is that trying to find good metal?
Also the black stuff in the 4th picture.
Is that seam sealer? - do you use this?

So, drawing on your XK8 welding experience, what do I need for a welding setup (I already have a Sealey MightyMig XL with cored 8mm wire), is the following suitable -
Hobbyweld 5 (93% Argon / 5% Carbon Dioxide / 2% Oxygen) Optimum weld depth 1mm to 5mm
6mm MIG wire

What replacement steel sheet (type and thickness) would I need and where am I likely to buy it from?

Thanks Mark

 

Please explain the 4 partial holes that were drilled (1st picture).
Is that trying to find good metal?


This is where they have drilled out the spot welds. You should get a spot weld drill like this one.




Also the black stuff in the 4th picture.
Is that seam sealer? - do you use this?


It looks like it, I always use seam sealer over welds in case there are pin holes. As you can see this area is a 3 ply sandwich, best to also put weld through etch primer between the layers.

So, drawing on your XK8 welding experience, what do I need for a welding setup (I already have a Sealey MightyMig XL with cored 8mm wire), is the following suitable -
Hobbyweld 5 (93% Argon / 5% Carbon Dioxide / 2% Oxygen) Optimum weld depth 1mm to 5mm
6mm MIG wire


Spot on, well almost, it is 0.6mm wire.

What replacement steel sheet (type and thickness) would I need and where am I likely to buy it from?


I am not sure what the thickness is here could be 1.5 to 2mm mild steel (cut a bit off and check), you can buy mild steel sheet metal at local metal merchants or you can buy small sections on ebay.





Good luck!

 

Before cutting new steel, make sure the corrosion is cut back enough so you can get a good weld, rather than just burning away rust. This is most important and saves a lot of frustration as there is nothign worse than taking the time to make and fit a repair piece only to find there is nothing to weld it to!

Angle grinder time! use a thin cut off wheel to achieve a straight boundary to the area to cut away, then grind away the rest with a regular grinding wheel. The repair piece can be developed using a card template cut and bent where needed to fit. Only when the template fits perfectly, think about cutting steel.

Steel can be bought from your local steel stockholder. best to get some 1.5 and 2mm. (16 gauge and 14 gauge) They will usually will cut it to a manageable size for you. If you have no joy locally, let me know. Most body panel suppliers stock much thinner (0.7mm) and this is too thin for what you are doing and much more tricky to weld.

Cutting the stuff - snips are tough at this thickness. bandsaw is perfect, or a jigsaw set at a low speed with the right blade will do the job well. This is where a good template pays off as you are not trying to cut a repair piece lying under the car!

When the repair piece is cut and fit is good, bevel the edges to give a good bit of "weld prep" This means there is more surface welded and a stronger, flatter weld results. Don't bevel to a feather edge as this will be burned away.

Then make sure the repair piece is securely held in place before going near it with the welding torch. A few lengths of wood can usually be contrived to hold the repair piece in place.

If you are welding around the wheelarches, the heat from the weld will cause the glue to burn. Be ready for this.

When all is secure, tack the repair piece in place, and then tap down any areas that are not fully home before welding it all in.

When building up multiple layers, it is easy to plug weld subsequent layers.

Also, use seam sealer on all unsealed seams to stop the water getting in there and causing trouble again.

 

Your certainly getting the advice. Just think when you have finished you should have a car that will be great for a couple of decades.

If you get your welding kit you will be able to tackle all those nasty expensive jobs and offer to do work for other forum members in the local area.

 

looks like its the spline shaft leaking were the nut is.

may as well replace the seals while your at it!

 

I have just spent a couple of days under-sealing my car. Oh what fun. I wont bother you with 'before' photos as I am sure you know what rust looks like. But this is after, its in the passenger side wheel well.

 

Nice job Frank - bet the underseal went more places than just the car.
Messy job indeed!

 

Cut away the rust bit by bit and eventually found some good steel.



As others have pointed out, there are three layers here -



I will cut out the small square section where the hole is with a jigsaw and weld a piece in, grind down and then weld in the middle piece then finally the top piece -



I'm using the lid off a Dell rack mount server for the steel and will be wire brushing the galvanizing off first for a better weld (and health!).

I now have my argon mix coupled up to my MIG and after 5 minutes setting the wire speed etc. seem to get reasonable welds (well the one on the left isn't too bad!) -



BTW - my car isn't brown underneath, I think that is a white balance issue arising from my halogen flood light

 

Great to see your progress, how does your weld penetration look and what is the steel thickness?

 

RD - unfortunately I don't have a micrometer but the the steel I am using looks similar thickness to the top skin of the chassis section , however I'm not sure if the bottom layer is different - I will know better when I jig-saw it out tomorrow.
My test welds look the same either side of the steel so I presume penetration is good.

I did think whilst painstakingly removing the layers that I bet there are some cars with just the top layer replaced or plated as nobody would know but obviously it would weaken the chassis.

 

I can tell you one thing though, if I ever finish this I think I'll only take her out on dry days, just to make sure she doesn't rust again

 

Well it feels good to know that you have done it right, you will have covered the cost of the gas set up conversion by not getting someone else to do it, you get to know your car more intimately and your are set up for the next welding job.

It almost makes you feel good that you found the rot in te first place!

 

That looks familiar! Just to point out to people who use such threads to make out the XK8 as a "Rot box" , this corrosion is from the "outside in" due to unsealed seams and should be very localised, where water/salt has collected and done its worst. Best of luck with the welding!

 

Your doing a great job. One thing I would say though is try that Rustcure stuff. I was impressed with the effect on the rust after leaving it overnight. Just thinking of those connections I can see in the background.

Anyway keep up the good work

 

Just to answer your original question - have you asked the tester exactly why it failed and where the areas are which attracted his greatest concern? In my experience testers are usually very helpful if you ask their advice rather than dispute their findings. After all they see far more cars than we do and are simply making sure we do not drive around in a death trap.

 

I appreciate that your post was some four years ago but my local garage has told me I have bad rust on the front chassis legs. Welding would be needed. I do not want to "cover up" and hide the rust but I just cannot work out how to get to this rust. I have a 2004 XKR Convertible. I see you did yours. How do you get to these rusted legs? Any guidance and pointers would be appreciated.

Thanks!

 

The rust is probably behind the front subframe, you will probably need to remove the subframe to do a good job.

 

Sorry I did a double post. Is there any photos or diagrams I can look at to actually see what and where these "legs" are?

 

FrankC told me to ask you I thought he was talking about car tuning. Duh!. The bits the garage showed me on the photo the garage took were " coming down from the interior bulkhead" and it looks like its sandwiched between two bits of metal covering it? Been sitting on this problem for a month or so and cant find the answers. From what I can see it is a common problem?