Shrinking Aluminum

[123pugsy]

I have no problem shrinking steel with heat or a disc, but what happens when I inevitably overstretch the alum panels I will be making for my hood?

And yes, paper patterns will be used. I haven't made any FSP's since reading up here about paper.

Got my initial check the shape buck started.

[Blue62]

Pugsy,
Block your shape out slowly.
Make up some profiles of the shape.
It's easier to guide your progress with the use of profiles then it is a buck.
Use plenty of Profiles of the shape to guide your progress.
Use the English wheel just for smoothing up.

If you over stretch an area and that area can be reached with your English wheel then that area can be let out with the English wheel.
I believe the "Shape in Shape out" exercise is the most important thing to learn about the English wheel and shaping in general.

Watch Peter's youtube videos on making the Austin Healey rear mud guard.
They are an excellent guide on how to block a shape out with the use of profiles as a guide.

How many pieces are you planing on??
Where will the welds be???
Pictures of progress please...we all like pictures

Edit:
After looking at more pictures of your project I see there is lots of low crown area on that hood.
So you will probably be wheeling most of the shape in... not blocking.
But the above still applies.
Any shape that can be put in with the wheel can also be removed with the wheel.
Any shape that you can reach with the wheel can be removed with the wheel.

[Chazza]

Things I have learned about aluminium shaping on the wheel for low-crown is to:

• Adjust the wheels on a piece of scrap to the point where the wheels grip the metal, just beyond the point of slipping. Pull on the test piece from the side.
• Space the passes widely so that not too much shape is put in.
• Check shape frequently with a straight edge.
• Adjust the pressure on the wheels and the spacing as required. Bugger-all pressure is required!

[Steve Murphy]

I haven’t tried it, but others have made shrinking discs with wood glues or bonded to the metal disc for aluminium shrinking that minimises galling.

[123pugsy]

Thanks Guys.

Wood shrinking disc?

I know 100% that I will go over and need shrink somewhere.
I'm not good at wheeling.

No idea how I will wheel the large top section.
It's gonna be tough.

[Chazza]

...

No idea how I will wheel the large top section.
It's gonna be tough.

Can you train a friend to hold the other end? Peter has a good video somewhere on how to do it with two people.

[123pugsy]

Can you train a friend to hold the other end? Peter has a good video somewhere on how to do it with two people.

Ya, I'm gonna need a sucker for sure.

Maybe take a day off work and have one of the guys from the shop come up to my house for an 8 hour shift.

[123pugsy]

Pugsy,
Block your shape out slowly.
Make up some profiles of the shape.
It's easier to guide your progress with the use of profiles then it is a buck.
Use plenty of Profiles of the shape to guide your progress.
Use the English wheel just for smoothing up.

If you over stretch an area and that area can be reached with your English wheel then that area can be let out with the English wheel.
I believe the "Shape in Shape out" exercise is the most important thing to learn about the English wheel and shaping in general.

Watch Peter's youtube videos on making the Austin Healey rear mud guard.
They are an excellent guide on how to block a shape out with the use of profiles as a guide.

How many pieces are you planing on??
Where will the welds be???
Pictures of progress please...we all like pictures

Edit:
After looking at more pictures of your project I see there is lots of low crown area on that hood.
So you will probably be wheeling most of the shape in... not blocking.
But the above still applies.
Any shape that can be put in with the wheel can also be removed with the wheel.
Any shape that you can reach with the wheel can be removed with the wheel.

Top in one piece and then 2 sides. There is a belt line to roll into the sides, so the small side pieces will help to get that part done easier.

I may still change my mind and go with 19 ga cold rolled.
I will calculate weight when I get the buck done.
Aluminum to me is ultra scary.

[123pugsy]

An idea on the size of this monster.
The front snout is 18" high and from snout bottom to rear corner about 64".

[Blue62]

An idea on the size of this monster.
The front snout is 18" high and from snout bottom to rear corner about 64".

Pugsy,

Big panels Very easy to get a twist in big panels like those
use plenty of profile gauges check shape often... you can do it.

[Chris_Hamilton]

Pugs if you have to do this by yourself, perhaps rethink making it in 3 pieces. Trying to wheel something 5+ feet in length by yourself is going to be difficult. Personally I'd split the sides into 2 pieces each, as well as the top pieces into 2 pieces. More welding and planishing but it would be manageable for one guy to wheel. JMO. Good luck.

[123pugsy]

Pugs if you have to do this by yourself, perhaps rethink making it in 3 pieces. Trying to wheel something 5+ feet in length by yourself is going to be difficult. Personally I'd split the sides into 2 pieces each, as well as the top pieces into 2 pieces. More welding and planishing but it would be manageable for one guy to wheel. JMO. Good luck.

Thanks.
Sounds like good advice. I will probably do this.

[Peter Tommasini]

Puggsy
make the bonnet in a few sections it's very important to have the welds in the right place all the lower crown sections can be wheeled (only ) , all the high crown block them first give them some shape and then wheel them up , so this is the way I would section and weld the bonnet

1 ( the two sides ) all the way to about 3 inches from the front , make sure to make the shoulders on to the side panels
2 wheel the whole top on the wheel , but work the SIZE of blank out so that it's JUST ! OVER THE THE SHOULDERS (use profile gauges for that )
3 for the nose well that is a bit tricky BUT ... CUT YOUR BLANK FROM THE PAPER PATTERN mark a center and wheel either side of the center ( about 3 inches ) till it's twice the shape than what it needs to be , next break the centerline on to the wheel by tipping the lower anvil , once you hav
Puggsy
make the bonnet in a few sections it's very important to have the welds in the right place all the lower crown sections can be wheeled (only ) , all the high crown block them first give them some shape and then wheel them up , so this is the way I would section and weld the bonnet

1 ( the two sides ) all the way to about 3 inches from the front , make sure to make the shoulders on to the side panels
2 wheel the whole top on the wheel , but work out the SIZE of blank out so that it's JUST ! OVER THE THE SHOULDERS (use profile gauges for that )
3 for the nose well that is a bit tricky BUT ... CUT YOUR BLANK FROM THE PAPER PATTERN just overlapping the two sides , mark a center and wheel either side of the center ( about 3 inches ) till it's twice the shape than it needs to be , next break the centerline on to the wheel by tipping the lower anvil , once you have the right angle (AGAIN USE PROFILE GAUGES) wheel and adjust the shape on the rest of the nose , then block a little on the top of the nose and shrink accordingly till you get your desired shape matching the top CHECK WITH YOUR PROFILES AGAIN .

As far on where to put the welds ...that is important ...so , the two sides complete with shoulders should be welded to the top panel where the top has some shape ,THE NOSE should be welded about 4 inches from the side panels and the top should be welded ( AGAIN ) WHERE THE TOP HAS A LITTLE SHAPE GOING DOWNWARDS TO IT.
Cheers
Peter T.

[123pugsy]

Thanks Peter.

I take it that would apply to steel or aluminum construction.

[Peter Tommasini]

Thanks Peter.

I take it that would apply to steel or aluminum construction.

Yes
Peter T.