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Pin hole rot roof.

Posted: Tue Jan 10, 2017 10:16 pm
by cleverusername
Ah the dreaded rust has returned, in some areas my fault, not aggressive enough the first time. I have taken a 3 foot section out of one sill and replaced. I need to do an area next to the front wing on the scuttle panel, fortunately in a rare piece of forward planning the front end is only held on by bolts, so that should be easy.

The area I am not sure about is the roof, back edge there was a bubble, so I attack it with various tools and sanded it down. This has left me bare metal and a pin hole. For now I have covered it in zinc primer till the weather gets better.

I prefer welded repairs, because my experience with any other methods is they don't work. Am I safe to do a sneaky weld to patch the pin hole or will that set something on fire? The headlining for example?

Re: Pin hole rot roof.

Posted: Tue Jan 10, 2017 11:22 pm
by Carledo
Headlining material is highly flammable and there may or may not be a plastic bag stuffed with sound deadening stuff between the roof and the headliner, which burns even easier. DON'T RISK IT!
Unless you fancy the cheat fix of slapping a Vinyl roof over it, the way to do it is remove the rear window, seat and parcel tray (and anything else that comes to mind like door furflexes and drop the rear section of headlining carefully, superglue a small plate under the hole (or get an assistant to hold it in place with a screwdriver or similar) then Plug weld down through the hole and grind it flush after.

Steve

Re: Pin hole rot roof.

Posted: Thu Jan 12, 2017 9:55 am
by cleverusername
Carledo wrote:Headlining material is highly flammable and there may or may not be a plastic bag stuffed with sound deadening stuff between the roof and the headliner, which burns even easier. DON'T RISK IT!
Unless you fancy the cheat fix of slapping a Vinyl roof over it, the way to do it is remove the rear window, seat and parcel tray (and anything else that comes to mind like door furflexes and drop the rear section of headlining carefully, superglue a small plate under the hole (or get an assistant to hold it in place with a screwdriver or similar) then Plug weld down through the hole and grind it flush after.

Steve
I was afraid you might say that, I did once set a car on fire so I know the risks. Isn't the roof double skinned, how do you get a plate in? Is it only the bit round the vents?

Rear screen, is that like the windscreen? Remove sealing strip, push out from inside and pray you don't break it?

Re: Pin hole rot roof.

Posted: Thu Jan 12, 2017 12:10 pm
by misterp
Unless the car was undergoing a complete resto, Id avoid anything involving heat due what Steve has said with regards to setting light to the headlining and the risk of warping the roof if it gets too hot.

Personally Id get some of the metal epoxy stuff (QuikSteel type of stuff) and as long as you have removed the rust and treated it with a good converter and as long as the hole is no bigger than say 1-2mm then Id use that.
Its very strong when set, and can be filed flat then skim filled and finally painted over with whatever you are using. It will probably outlast some other areas on the car!

Look at it as the cold modern equivalent of braze and/or lead loading :D (if you ever see a car with lead loading and strip it away..you can see the mess they used to hide with it!!)

Re: Pin hole rot roof.

Posted: Thu Jan 12, 2017 12:52 pm
by tony g
You could put a dent where the pin hole is with a ball bearing to create some depth, then tiger seal it and knife it flush when dry. Just a thought

Tony

Re: Pin hole rot roof.

Posted: Thu Jan 12, 2017 3:38 pm
by mahony
About two years ago the bottom half of the channel above the wing where the chrome strips are ( A pillar i think ) had a small hole in it , i did not want to use heat in that area so i took it back to bare metal used a rust converter and used a metal filler then used a zinc primer then painted it, it has not changed since i did it, if it's only a pin hole i would fill it :D

Re: Pin hole rot roof.

Posted: Thu Jan 12, 2017 7:00 pm
by cleverusername
misterp wrote:Unless the car was undergoing a complete resto, Id avoid anything involving heat due what Steve has said with regards to setting light to the headlining and the risk of warping the roof if it gets too hot.

Personally Id get some of the metal epoxy stuff (QuikSteel type of stuff) and as long as you have removed the rust and treated it with a good converter and as long as the hole is no bigger than say 1-2mm then Id use that.
Its very strong when set, and can be filed flat then skim filled and finally painted over with whatever you are using. It will probably outlast some other areas on the car!

Look at it as the cold modern equivalent of braze and/or lead loading :D (if you ever see a car with lead loading and strip it away..you can see the mess they used to hide with it!!)
I am tempted by that idea, the problem is I have found such repairs blow through. When I cutout the metal on these repairs later I could see why, small hole on one side could conceal rust that had spread an inch or more past the hole on the inside.

Re: Pin hole rot roof.

Posted: Thu Jan 12, 2017 7:47 pm
by Carledo
Some areas of the roof are double skinned, mostly round the edges. Even so it is not complete skinning, it has holes in it in various places and you should be able to get a patch plate underneath easily enough.
Rear screen is exactly like the windscreen but easier, since it is toughened not laminated, so it is more bendy! Remove the plastic fillet first and don't forget to carefully disconnect the HRW terminals.
Like you, I prefer to do a job like this properly, then you only do it once!

Steve