Anyone Know Which Alloy for Body Skin?

[cpcooper]

I have a '78 Caterham 7 that's suffered a bit of a bump to the rear on the spare tire; not enough to bend any structure, just distorted the alloy skin. I have a competent metal man ready to repair it, but he needs to know which alloy was used. Does anyone know, or can anyone suggest where I might find out? Thanks, Craig

[Jon W.]

3003 H14 is most common. 5052 also works well.

 

Check the existing thickness. Probably .050" or maybe .040.

 

("Competent" metal man should know this.)

[WestTexasS2K]

I second the 3003 h14 it is mailable and available in many thicknesses.

[slomove]

I had the rear end repaired a few years ago with 32 mil 3003 alloy and was not happy with the result, it came out not even but kind of a wavy surface. Then I had another rear ender last year and repaired this myself with 40 mil 5052H32 alloy. This looks so much nicer (see below). The 5052 should be a bit more resilient to future damage, because it is 1/4 hard but it was still quite easy to work with. With a pneumatic nibbler, riveter and various rubber and wood mallets it took only a weekend to replace the skin. I bought the aluminum from Aircraft Spruce and used half of a "half sheet" for approx. $50. They sell it cheaper and in much better condition than e.g. McMaster Carr. But I could pick it up locally.

 

Edited April 20, 2013 by slomove

[sdaddy]

I had the rear end repaired a few years ago with 32 mil 3003 alloy and was not happy with the result, it came out not even but kind of a wavy surface. Then I had another rear ender last year and repaired this myself with 40 mil 5052H32 alloy. This looks so much nicer (see below). The 5052 should be a bit more resilient to future damage, because it is 1/4 hard but it was still quite easy to work with. With a pneumatic nibbler, riveter and various rubber and wood mallets it took only a weekend to replace the skin. I bought the aluminum from Aircraft Spruce and used half of a "half sheet" for approx. $50. They sell it cheaper and in much better condition than e.g. McMaster Carr. But I could pick it up locally.

 

 

Wow, that look fantastic! Where's the local pickup?

[slomove]

Wow, that look fantastic! Where's the local pickup?

 

Corona, CA is their West Coast warehouse.

They supply the aluminum sheets with protective plastic cover films to reduce the scratching. Shipping by truck is quite expensive but if you don't live close by what can you do?

Edited April 21, 2013 by slomove

[JohnK]

Check out

http://www.airpartsinc.com

for both a good description of the different alloys and what I've found to be very good service. Haven't compared prices.

On another matter, found it much better to get almost all my steel tubing from them, rather than my local Metal Supermarket. Their 4130 is " normalized" to aircraft spec.

[speedwagon]

Thanks for the info. After de-hairing the belly of a bovine, I may have to build a new hood, after repairing the nose. Needed to do some mods to house the oil cooler, larger radiator and inter-cooler, but would have rather started with a good base. With timing set by me.