On the relative costs of extruded aluminum components.

So I just ordered up some aluminum parts for a project I’m working on, and I was shocked to see that 6" x 2.5" channel costs $13.20 per pound. For comparison, 4" x 1.5" channel costs only $3.36 per pound. Why does the price go up so rapidly? With products like wood, I can understand: a 16’ length of lumber has to come from a much larger tree, it takes longer to grow, etc. But all of these aluminum shapes are extruded through a die; a 6" die isn’t any harder to make or use than a 4". Is it simply a matter of supply and demand, that there’s not much call for the larger pieces, so less of it is made and it needs to be pricier to ofset the production costs?

(six years in the extrusion biz) Well, the larger shape may need to be run on a larger press using a larger die and a larger billet of aluminum or, on that same press, you could probably fit two of the smaller channels into the same die diameter, giving some economy of scale, and for a given wall thickness it would be harder to hold tolerances on the larger piece, but mostly I assume it’s demand (they sell more of the smaller one) and that they found out they can get $13.20/lb from the people who need the larger one. Are you sure that’s the per-pound price and not the per-foot price?

It’s definitely per pound. I weighed it myself.

I used to be in the aluminum extrusion business.

I got canned.

(high and mighty voice) I quit!