I think if you check the prices of pvc pipe and pvc fitting in larger sizes (like 6 inch) you'll probably find it way cheaper just to go buy a canister.
I don't know if places that sell pvc pipe in less than 10 foot lengths either, so you'll spend money and have leftovers.
4 inch pcv is $6 to $7/ ft; 6 inch is over $10/ft.
A 4 inch 90 degree fitting will run around $9 and a 6 inch 90 would be over $20 EACH.
There are some places online that sell pvc, but UPS won't ship over 4 foot lengths. A few will sell by the foot, but the cost usually goes up quite rapidly that way.
Oops, Rex, you and I were typing at the same time.