Rear shroud repair

[robolab]

I want to repair the edges of the rear schroud of my BJ8. I must manufacture edges stripes as represented in the picture.
I will try to bend the Alu-stripes between hardwoodparts as shown in the example picture. Is it possible and which Aluminium-alloy should I use and which sheet metal thickness I am supposed to choose.

Gerd

 

[Keoke]

Gerd !

I forget the thickness but the aluminum is very close to pure which I think is # 6000.

Man that repair strip looks great--

 

[BoyRacer]

The alloy you want is 3003 and the thickness is the same as your shroud... .060". I am assuming that the aluminum in your photo is a very light gauge if you can form that tight of a radius using only wooden forms. I would offer two tips. First, anneal the aluminum as it will make working the aluminum much easier. Secondly, using a shrinker will help you get that tight radius.

 

[andrea]

https://picasaweb.google.com/112770...MayJune2011endMayJune2013#5814069361356709250
https://picasaweb.google.com/112770...ATIONAUSTINHEALEY10061958#5605071715312162146
Having my 100/6 rear shroud in the same conditins-My opinion is that welding the aluminium with TIG, wire and gas is the better and strong solution
my coachbuilder Mauro was very shillful in this - use a professional in this operation

 

[vette]

What you are trying to accomplish is very much possible. As suggusted by "boyracer" the shape of a new flange is easily done with shrinking jaws. Even relatively inexpensive ones such as bought from Eastwood Co.
You may be able to do it in the wooden form you have made, but the requirement of shrinking the flange as it bends still needs to happen. As you hammer it over the wooden form the edge will buckle and pucker up like a ribbon. Just keep hammering on the ruffles and the metal will be crushed into itself which accomplishes the shrinking. Annealing the aluminum will help the process but if the shrink or stretch is not drastic it may be done without the annealing. If you can't get the shape you want on the wooden form then you will have to get some shrinking jaws. About the thickness of the meta. I don't work with aluminum much, but when I do steel, I like to work with 19 gauge. Recently a metal supplier talked me into trying 22 gauge. I don't like it, it's just a tech too thin. 19 gauge steel holds its shape really well. So I would suggest 19 gauge for the aluminum because I think that will be enough and will be able to be worked fairly easily. Here are some pics of the possibilities. The last pic is a stretched flange because it is an outside radius. Dave.

 

[vette]

Here's a pic of welding the flange back on. I had to cut the flange off the new fender to rework the radius because it did not match the car. I then had to weld the flange back on with the fender bolted up to the car because every time I tried welding it off the car, I distorted the fender too much. I eventually made a barrier out of a 6 inch piece of copper so that when I welded i did not burn into the aluminum shroud. Of course this is steel, I have been using a tig welder from my son-in-law but had to give it back. Here I am using a mig. But for aluminum you really need tig. Dave.

 

[BoyRacer]

Thin steel is a lot easier to weld than thin aluminum. The rear shroud alloy is actually .062 inch thick. That's approximately the same thickness as 16 guage steel. And that's fairly difficult to weld with TIG even at that thickness. I would not recommend trying anything thinner for those flanges.
But, I have an idea. Forget about trying to do the entire flange as one piece. Do it in sections. Clamp the 1" flange part in a curved hardwood form and bend over just enough material that you can weld into the existing shroud material. I hope that made sense. Without a shrinker, you're gonna have a heck of a time creating that rear section tight radius... instead, trace the desired shape of the flange onto a big piece of aluminum and then you only have to worry about creating a very small flange to weld to.

 

[robolab]

Thank to everyone for the answers.

Roger, your proposal is exactly what I have planned. The first trials with a 15-inch long piece of 16 gauge aluminum have been very successful. So i will order the necessary aluminium and hardwood.

Gerd

 

[andrea]

Richard
I can confirm your procedure - I have saw on a flat plate 1,5m tich of aluminium, some segments of my shroud profile, re-copied on hard board ,
then Mauro TIG welded the segments over the oldest rest of aluminium of the shroud, not easy but I can follow the original shroud profile and in some cases I can also have the same bolt holes traces-
At the definitive rebuilding, I put over the conection a lot of Lityum grease (water resistent)to insulate the different metals,and avoid eletrolitic reaction

 

[robolab]

After a first test, I decided to make the side pieces of two parts. The first parts of the side pieces (LH and RH) I have bent in the wooden template The photos show the wooden template and one of the manufactured Curved sections.

 

[BoyRacer]

That sure looks pretty. Questions: What kind of wood are you using for the forms and is the alloy .062" thick?

 

[robolab]

I used an existing 2 cm thick beech plywood board, but i think you also can use other hardwood boards. The alloy material thickness is 1,5mm (0,059"), that is a common thickness in Germany.