Rust repair before paint, The quest for solid metal in the driver side Long - 73 narrow body/4 rebuild thread Options

[Montreal914]

Edit: I might as well make this my rebuild thread...

Original post; I got side tracked on my Microsquirt build as I have decided, after 11 years of ownership, to finally get my car painted to get her ready for her upcoming 50th birthday. (IMG:style_emoticons/default/smile.gif)
Knowing these endeavors can take a lot more time than initially planned, I hope to make it in time... (IMG:style_emoticons/default/wacko.gif)

Originally bahia red 73 1.7. The goal is a narrow body 2056 Microsquirt, VW Tornado red, 5 lugs conversion with 16" Fuchs.
Front: 914-4 A arms with rubber bushings, 911 3" pin struts, Bilstein inserts, Alfa Brembo, vented rotor, stock torsion bar, 19mm sway bar, turbo tie rods, and 19mm master cylinder.
Rear: Drilled hubs, 914 PMB stock calipers edit: 914-6 calipers replica, 914-6 solid rear rotors, 140lbs springs, stock sway bar, rubber bushings.

But before I get the pleasure of installing all of these beautiful fresh goodies, I need to tackle the not so fun stuff... (IMG:style_emoticons/default/headbang.gif)

I have already started fixing some of the rust issues and will share that progress in the near future but right now, I wanted to post some of the issues i have on the passenger side front fender. (IMG:style_emoticons/default/sad.gif) I have searched and read many of the builds here but I would like some inputs from the people who have gone through this mess.

I am trying to understand the construction of the rear part of the fender, more precisely the area joining the front cowling.

Below is a sketch of how I think it is made but i would like someone to confirm...



Having removed the seam sealer in the upper rear area, I have discovered "this" (IMG:style_emoticons/default/dry.gif) which is not really unusual, but clearly a pain to fix. I am not sure though what I am looking at. If my sketch is correct, I guess the inner rusted layer is from the fender rear bulkhead that actually becomes an inner layer on the rear upper point of the fender by the door and cowling junction.





I might be able to cut this from the underside preventing me from cutting the outer surface of the fender. But I would like to better understand what is happening at the junction to the body.
How many layers are there from the fender, one or two?
Is the metal peeling off at the joint to the body the metal from the bulkhead/inner layer, or is it the outer fender layer?

As a reference, this if the situation of the channel, surface rust, but how bad? Is there a way to better know without destroying? Maybe poke with a screwdriver? (IMG:style_emoticons/default/confused24.gif)



Comments appreciated (IMG:style_emoticons/default/smile.gif)

[nathanxnathan]

Coming along nicely. (IMG:style_emoticons/default/smile.gif)

I'll have to take another look at the back of the trunk seal area to see how that ties in with the rear panel above the tail light.

Other areas to think about... the bottom of the door jamb, how to tie that to the sill. The factory I think gas welded that joint with bronze, as there's an overlap of the 2 panels.

The top of the sail panel where the flange goes I think under the top of the targa bar. Plug welding that seems like the best option. It's a tricky area because you can't back the weld.

The other area to think about is the fresh air inlet. The ones I've seen, the factory mig welded the lip of the 2 layers. I've removed one, and was able to just grind off the lip/weld and carefully separate the tube inner from the flanged hole in the inner fender.

What are your thoughts on prepping the inner fender before mounting it? Areas like behind the sail panels or the area where the foam is at the rear of the fender by the tail lights aren't going to be accessible once the fender is in. The factory I think there's just primer there.

I've thought about this for my front cross panel project on my car. My thoughts are 3M Weld Thru Primer on both surfaces of the seams where it'll be spot or plug welded. ... tape off the flanges that will be welded, epoxy primer, then tape off and spray weld thru primer on just the flanges — seems like the best way. I'm not sure what others do?

[Montreal914]

@nathanxnathan Thank you!

My comments in italic in your post (IMG:style_emoticons/default/smile.gif)

Coming along nicely. (IMG:style_emoticons/default/smile.gif)

I'll have to take another look at the back of the trunk seal area to see how that ties in with the rear panel above the tail light. Yes, that will need further investigation. My donner fender insn't 100% complete on the rear end either and there will be some butt welds needed there. So overall the installation will be a composition of spot and butt welds.

Other areas to think about... the bottom of the door jamb, how to tie that to the sill. The factory I think gas welded that joint with bronze, as there's an overlap of the 2 panels. I was thinking just weld and grind. This gets hidden by the aluminum door sill.

The top of the sail panel where the flange goes I think under the top of the targa bar. Plug welding that seems like the best option. It's a tricky area because you can't back the weld. Yes, plug welding seems to be the only option as the fender flange does go under the Targa bar panel. I made sure I didn't drill through the donner fender when I prepped that area. On the car those spot welds are more of an elongated shape instead of round and they are at an angle (Pictures below). Not sure yet how I will proceed to remove that part. I might try to grind from underneath to leave the Targa piece exempt from holes. Then, planned holes could be done for the plug welds.

The other area to think about is the fresh air inlet. The ones I've seen, the factory mig welded the lip of the 2 layers. I've removed one, and was able to just grind off the lip/weld and carefully separate the tube inner from the flanged hole in the inner fender. The donner fender came with all of this and I had to proceed in grinding the factory weld to clean it up. I plan on doing the same on the car when removing its fender. I didn't do the cleanest job (IMG:style_emoticons/default/rolleyes.gif) (pictures below) but it is done. Once the "new" fender is in, I will put a few tacks.

What are your thoughts on prepping the inner fender before mounting it? Areas like behind the sail panels or the area where the foam is at the rear of the fender by the tail lights aren't going to be accessible once the fender is in. The factory I think there's just primer there.

I've thought about this for my front cross panel project on my car. My thoughts are 3M Weld Thru Primer on both surfaces of the seams where it'll be spot or plug welded. ... tape off the flanges that will be welded, epoxy primer, then tape off and spray weld thru primer on just the flanges — seems like the best way. I'm not sure what others do? AHHH YES! That is a great question that I have been asking myself... (IMG:style_emoticons/default/wacko.gif) How to prep the inner fender. If I was to apply epoxy paint, it would have to be with a brush or roller. I don't have a compressor/gun and any experience in painting. For under the car, I have been considering using those truck bed liner product and roll it on. Could this be used for both the inner fender and the fender back side? (IMG:style_emoticons/default/confused24.gif) I have seen that some can be colored to match(!) the car color. A lot of questions to be answered on everything prep and paint related... (IMG:style_emoticons/default/unsure.gif)

Here is the sail panel top flange when I was cleaning up the extra metal from the donner fender.




And this is the top of the Targa corner on the car.




As for the vent tube, this is what I started with on the donner fender:




During the dismantling (IMG:style_emoticons/default/wacko.gif) A bit of a wrestle... I will try to do better when removing the fender from the car.




Once free and reshaped, this is what I am working with.