Restoring a 3-bar grille

[Shaun 69 E]

Just finished restoring a 3-bar grille. These were only on late 68 and 69 cars, Porsche had to add in the 2 extra bars for 70 with these things getting wavy just with butterflies landing on the ribs. Long process but really rewarding.

Grille I started with.

[Shaun 69 E]

The bars are held together with solid rivets. I found the best way to separate them was to drill them out from the back.

[Shaun 69 E]

Here you can start to see how bent and wavy these grilles can get. The bars have tabs with little ridges that the ribs press onto and get locked in place. Porsche was very helpful by numbering each of the ribs so you can't mix them up.

To get the ribs off the bars I made a little pry tool to widen the rib slightly on either side of the tabs.



















These "grab marks" were on several of the ribs and were too deep to sand out.

[Shaun 69 E]

Some pics of the bars with the tabs and ridges. Center bar was bent from close to 50 years of pushing down on it to close the decklid.

Black is just paint. Oddly enough the top bar was anodized and then painted. The bottom bar was left bare aluminum, it wasn't anodized.

[tcsracing1]

very nice.

i have two of these grills!

[Shaun 69 E]

Here are the ribs straightened and recurved. I had some male/female tooling made and pound on each rib with a 2lb sledge hammer. It's not for the faint of heart. Even with pounding these out, you can see they still aren't perfect. Part of that is I don't try to make them perfect as these are worked on a lot after being recurved and the law of diminishing returns kicks in.

Then the anodizing is stripped off and they are all sanded by hand on a jig I made to hold them. For days, can be 2-3 days of solid sanding the tops and sides. You have to pay very close attention to and feel the gentle curve of rib's profile which is not symmetric. The "front" of the rib has a different edge than the "back" of the rib. And then they are polished, tops and sides, for a day or two. What I've found is you can get most scars and pits out by sanding but there are some that are too deep and will never come out. And of course you can't locally sand out a scar or pit, the length of the rib must be evenly sanded otherwise you'll have localized low points. A perfect grill is attainable but you may have to add and subtract some ribs.

[sithot]

This is a thankless job for sure. I admire your courage.

[Shaun 69 E]

Well, anyone who wants an excellent original grille is thankful, so I have that.

Courage is just another word for not knowing what you can't do.

[Shaun 69 E]

I go through 3 rounds of polishing. What's always fun is finding a few pits that get hidden in the sanding stage. Here I have to make a determination to go back and sand them out or they are too deep and have to leave them. 9 times out of 10 the fact that they are hidden in the sanding stage means I can get them out so I have to.

Once the ribs are polished they have to be anodized so I made a rack that the ribs fit over dog-eared tabs for good conduction. This warps the ribs sometimes but well before plastic deformation so they spring back. My anodizer likes because they don't have to tough the ribs. Took a month to get a procedure down for handling door frames.

The anodizing layer is very thin as anodizing gets cloudy the thicker it is like the outer lips on Fuchs.

[Shaun 69 E]

Screens get de-anodized and I try to fix localized imperfections. Problem is the aluminum is so old and thin you end up breaking the mesh some times. It is interesting that Porsche painted the bars but anodized the screens. This grille I Cerakoted the bars, rivets and screens but I will try to brighten up the screens and then anodize them on the next grilles in line.

Even though these are anodized I am still careful so the pics of all the ribs together and the numbers shows some gaps which is more due to pressing them together very lightly.

Some of the assembly is on done on a nice decklid.