Can't find 7 inch pipe???

[TheBetterMethod]

Hey guys,

I'm in the planning stages of my next build and I'm trying to find a 7 inch diameter pipe or tube that I can use as a port.

I'm looking at a box that's about 3.8-4.1 cubic feet after displacement. It's for 2 12s. and I want it tuned to 30 hz.

The problem is that standard pipe sizes are 6in. or 8in. And if I use 6in. there won't be enough port area (>8in./cube).

And if I step up to 8in. the port area is a little too high and the port would be very long (13.5/cube @ 30in. long).

So it seems that 7in is the perfect compromise. Except that no one seems to make it.

So does anyone know of a source to get 7 inch tube or pipe? It would make this build so easy.

Thanks,

TheBetterMethod

[Namosh]

The inside diameter of 8" schedule 80 pvc is about 7 1/2". Would that be close enough?

[FroznBeavrBALLs]

thats not much port area. u want ~10sq inches of port. thats what a 7inch round port would be...

[TheBetterMethod]

I looked at the schedule 8*0 and the ID would be fine but the OD is very big and takes a lot of box volume, plus that stuff weighs about 8lbs/ft.

Since the port would be about 27in. long that would make the port about 20lbs. And I think I would have trouble heat forming flares on the ends

of schedule 8*0.

As for the area I want. It's going to be an aero port so from what I understand 9-12 per cube is ideal for daily. I may be wrong. But a 7in. ID

schedule 40 would be ideal for it's ID and OD and the length per 30hz tuning. But I can't find any.

Thanks for all your input guys!

[STEvil]

Go to local large hardware/construction store and get some cardboard tube (its used for cement piling forms), then just resin it. Or go to an irrigation company that supplies parts for center pivot irrigation. They usually stock or can point you to someone who does stock large diameter pipe and its a lot cheaper through them usually since they are bulk carriers.

[TheBetterMethod]

COOL!

Thanks for the info. I looked for cement forms and couldn't find the right size, but I'll keep looking. And I'll check on that irrigation thing too.

[STEvil]

take a tape measure when you go for the cement forms, they're not very uniform sometimes lol.. makes you kind of wonder about the footings under some buildings

[bass28]

Go to local large hardware/construction store and get some cardboard tube (its used for cement piling forms), then just resin it. Or go to an irrigation company that supplies parts for center pivot irrigation. They usually stock or can point you to someone who does stock large diameter pipe and its a lot cheaper through them usually since they are bulk carriers.

Agreed i have seen the cardboard ports used and they work great. He had two 18s with 2 10inch ports and damn did it move air. But he had the mags faced up.

[Watch the bass]

Long years ago i used something like this as pipe, worked well.

[TheBetterMethod]

Thanks for all the replies fellas!

I still can't find the 7in. cement formers, and the search I did for irrigation pipe was fruitless.

I came across the stove pipe a few days ago, and thought about it. Since you had good luck with it maybe it would be worth a shot.

Thanks a bunch!