MIDAS MK 3 REAR SIDE WINDOW

[justamin]

Has anyone got a side window (preferably an offside but both or either would do) for a Mk 3 Coupe for sale please?

[Hans Efde]

I once built my own perspex rear side windows. Cut from perspex and made a sort of clamps that screwed into place. They were watertight and looked quite racy. I had built them because I needed to do work on the car, but it was parked outside. Now I could easily unscrew them, work on the body and then put them back in again. Later I glued the original windows back in again. I sold the car with the perspex windows, so they may be lingering somewhere. Car is in Sweden and the owner is reading this forum so who knows they pop up.

[justamin]

Thanks Hans, I will give it a day or two and hope one shows up. Otherwise I could also be getting the Jigsaw out. Mine were glass but had been direct glazed with a polymer.

[Hans Efde]

Thanks Hans, I will give it a day or two and hope one shows up. Otherwise I could also be getting the Jigsaw out. Mine were glass but had been direct glazed with a polymer.

The original way to bond these windows in, was to place a U-shaped rubber over the GRP edge and then use Sikaflex o.e. to bond the windows to the rubber. Usually this would leak, then the gap between the window and body would be filled with sealant. Biggest mistake of the factory in the days was not to apply an edge of UV protector etch primer at the inside of the window. As a result the glue would turn brown and come off the window. I noticed this on my first car when -standing outside- closed the door and the window popped out.

[DavidL]

When I bought my car, the rear windows had a strip of black insulating tape around the perimeter, on the outside, and I assumed that this had been applied to protect the sealant from UV.
However, the tape started to peel off, so I removed it altogether, to find - not sealant - but double sided foam tape holding the windows in place. Another job to add to the list.

Is it possible to apply UV protector etch primer to the glass retrospectively, or is that a factory-only job?

Also, is the U-profile rubber strip necessary, or can the glass be bonded directly to the GRP shell?

[Stuart]

Also, is the U-profile rubber strip necessary, or can the glass be bonded directly to the GRP shell?

I'm fairly certain that the bonded in ones are bigger than the earlier ones that went in the rubber seal.

[Hans Efde]

When I bought my car, the rear windows had a strip of black insulating tape around the perimeter, on the outside, and I assumed that this had been applied to protect the sealant from UV.
However, the tape started to peel off, so I removed it altogether, to find - not sealant - but double sided foam tape holding the windows in place. Another job to add to the list.

Is it possible to apply UV protector etch primer to the glass retrospectively, or is that a factory-only job?

Also, is the U-profile rubber strip necessary, or can the glass be bonded directly to the GRP shell?

You can buy this UV etch primer and apply yourself just as regular paint. It's expensive and comes in rather large bottles. Try a Carglass or equivalent company to buy/borrow/beg a small amount in a jar. You need only a small amount say 200cc. I wanted to pay for it but the guy this gave it to me.
Bonding directly to the shell would be possible provided the bead of sealant is thick enough, there should be no contact between hard materials (just like using silicone sealant to make a leakfree aquarium). You need tape to keep the window in place until it is fully dry.
It would be nice to bond in the windscreen of the coupe this way as well (convertible windscreen has always been bonded in). It looks so much better than the gastly H-seal. Many years ago I suggested Alistair to provide a mod. kit for coupe's. This can be a simple strip that must be bonded to the monocoque and can be taken from the convertible mould (in theory).

[DavidL]

You need tape to keep the window in place until it is fully dry.

Is this to maintain the lateral positioning of the glass, or to maintain pressure on the adhesive while it cures?

[Hans Efde]

You need tape to keep the window in place until it is fully dry.

Is this to maintain the lateral positioning of the glass, or to maintain pressure on the adhesive while it cures?

It's for positioning, else it may slide out of its position. You don't apply too much pressure, else you'll squeeze everything out. You apply light pressure when placing the window, just to be sure the kit adheres and has good contact with the window all around. Any voids will cause leaks (carglass companies even have ultasonic equipment to find these voids). Then leave it in place with tape. Any rubbish sticking out can be removed with white spirit while the kit hasn't dried. You can even smooth it, just like the silicon kit edges in the bathroom (if you ever placed tiles).

[DavidL]

You need tape to keep the window in place until it is fully dry.

Is this to maintain the lateral positioning of the glass, or to maintain pressure on the adhesive while it cures?

It's for positioning, else it may slide out of its position. You don't apply too much pressure, else you'll squeeze everything out. You apply light pressure when placing the window, just to be sure the kit adheres and has good contact with the window all around. Any voids will cause leaks (carglass companies even have ultasonic equipment to find these voids). Then leave it in place with tape. Any rubbish sticking out can be removed with white spirit while the kit hasn't dried. You can even smooth it, just like the silicon kit edges in the bathroom (if you ever placed tiles).

Thanks Hans.

Now all I have to do is to work out how to feather the inner edges of the UV etch primer, to make it look like production line windows...