Sunday 24 November 2019

To bead or not to bead

I have read quite a few posts on forums where MG Midget owners have discussed replacing the rear wing beading. As it is a common rusting point where moisture gets in under the beading and silently rots away the joint where the rear wing meets the main section of the chassis. 

I am extremely lucky in that the wings are in very good shape around that area, but there is a little rust bubbling around the beading and in one small section it has come away. With further probing with a screwdriver found that this beading needed to be replaced. 

There has been a few debates about the best way to tackle this problem. The more pure enthusiast will suggest that originality is vitally important and certainly in the restoration guides it gives a very good description of how to attached a new beading strip with soldering techniques. 

There is another view though that the beading was a cheaper alternative during the manufacturing process than making the seam between the wing and the chassis seamless. Today this gap could be filled to make a smooth and impenetrable fix by using the lead loading process, which uses molten lead to shape the desired finish, or just some filler if you preferred.

This is a highly skilled job to get this perfectly correct as you can see in this video: YouTube - Lead Work and on my MKII the beading is a lot longer so there is more to get right.

So far I have removed the beading and cleaned out the joint with the grinder and a metal cutting disc to remove the rust, which thankfully is limited and then applied rust converter to stop further corrosion. I'll have a further thought about which way to go.

After a little over a year later I decided to replace the beading. The Midget had beading and the rust took it away and I still feel that it is important to try to restore the car to as best that I can get it.

I purchased a new beading strip that is designed to be fitted when you are attaching the outer rear wing to the main chassis. Although I have no idea how you can weld all those parts together as access is a nightmare.

Here is the new beading and as you can see the flange is quite deep and certainly a lot deeper than the gap that is left behind. The Haynes restoration manual suggests cutting the flange to fit the depth of your gap and then fit the beading using soldering techniques.

I really wasn't comfortable trying to solder this in and so I had a thought after watching a programme on TV that was demonstrating the strengths of modern adhesives. After some internet research I came across this product.

Mannol EPoxy Metal adhesive claims to have many properties that really felt like it would be a good solution to work with for this repair. Things like fillings cracks and cavities, can be painted over and has high mechanical strength all sounded perfect for the job.

Apart from the "hardens in 4 mins" section! That didn't leave me with much time to apply the mixture and force the new beading into position. But it did mean that if I was quick enough and applied the right force evenly along the beading I wouldn't have to wait very long for the adhesive to set.

Preparation was the key. Isn't it always! First up was to clean the gap up and strip the primer back to bare metal.

Next job was to cut the beading to size and check how much depth I needed on the flange. Too much and it wouldn't sit flush and too little and I was worried there wouldn't be enough metal for the adhesive to bond to.

It took a while but after a lot of measuring I was happy to go for it.

It took even longer to get the beading to sit flush. Cutting the flange created some heat which caused the beading to bend, but the groove also mends downwards towards the rear. I wanted to get this to fit as best I could without any pressure as I only had 4 mins to set it in place and hold it there.

Getting ready to mix. I wasn't expecting the syringes to be so hard to squeeze, but eventually it came out and then panic started as I began to mixed the two compounds together.

I didn't have time to take photos of my method, but using a metal spatula tool I worked the adhesive into the gap and then placed the beading into the gap and used a clamp at each end and a strip of wood about the length of the beading to lean on. I had to keep checking that the beading was sitting flush. After about 5 mins I could feel the adhesive setting which then allowed me to double check everything was sitting right. I also used a hammer to very lightly tap the beading down. 

The good thing about this adhesive is that it can also fill which helped to make a seal between the beading and chassis. I then left it over night to fully cure.

Once cured I could then sand down any excess and prep for a coat of primer.

I had to weld up each end and file that down to finish. There is some very light surface rust around parts of the lip by the beading that will need some filler before paint, but it has come out really well. Glad I chose this option, it all seems really solid.

Saturday 23 November 2019

Left Rear Wing Repair

Getting this rear wing done was one of those major milestones that I have been looking forward to for some time. 

I had to look back through the blog to remember how bad it was rusted and the poor attempt to repair it.

Which all needed to be cut out

You can see the damage behind which was all fixed a year ago in this post: Left-hand-rear-wheel-arch-repairs

Certainly looks a lot better now behind the wing, which leaves the next job of lining up the new replacement panel.

Needed the usual preparation of weld through primer and holes for the welding.

Then make sure it lined up ok. This took quite a bit of fine adjustment with the angle grinder to make sure that the panel fitted just right, but also left a small gap between the new and original metal to weld into. About 1mm to 2mm is normally about right.

Then a final spray of chassis paint to cover the parts that the sandblaster probably won't reach.

And then it was time to weld it all and grind to a smooth finish.

It will certainly need a thin coat of filler to make perfect but considering the extent of the damage I'm very happy with this result.