Im about to start building a tube out of MDF for a sub box, but before I needed to test things out to see if I could. I also decided to take pics of it for a little tutorial if other people are wondering how to do this.

I started of by finding the inner diameter I need. Im going to use this for an 8" sub with a 7" cut out. so my inner diameter is 7"

Now outer diameter: I'm using 3/4 MDF so my outer diameter is 1.5 + the inner diameter' 7+ 1.5=8.5"

Now I can find out how long I need to cut my board: take the outer diameter multiply times pi to get the circumference, which will equal the board length: 8.5 * 3.14 = 26.7"

Board length is 26.7"

Now I need the inner circumference: 7 * 3.14 = 21.98 or 22"

Now I can find how much wood I need to remove in order to bend the wood completely around.

outer circumference - inner circuference: 26.7 - 22 = 4.7"

Now I have to remove that much wood distance with a 1/8 inch table saw blade.

So I need to know how many cuts that will take. so I divide my distance needed to be removed by my table saw's blade width: 4.7 / (1/8) = 37.6 = 38 cuts

Now I have to spread these cuts out evenly across the board. I need to find the distance between the cuts by dividing the original board length the number of cuts: 26.7" / 38 cuts = 0.7" apart.

To make it easier to cut evenly down the board i cut alot of pieces of wood 0.7" wide

Pic time

Board 26.7" long

all my pieces 0.7" wide

before cuttin I needed some prevention for MDF boogers

set the table saw blade where it almost goes through the wood

lining up all my little pieces to make the cuts even

Leave a small gap to start with so the first cut isnt right at the end of the wood

First cut

showing how deep it goes

half the cuts down

it Bends

all of the cuts done

I used wood glue to fill in the gaps it took alot. but most of it with squeeze out

Now bend it together, I couldnt take any pics of this process because I was by myself it was kinda hard to do this part. I just used a rope, but an easier way would be tie down straps for a trailer. That way you can rachet it down easily, because the last inch of completing the circle was tough. but here it is

checkin the dimensions. inner diameter

outer diameter

I let it set for a day to cure

took the rope off, and it stayed together...yes!!

Final Product

Thanks for watching, hope this helps some of you guys.

If anyone can add anythin I may have missed feel free.

nice if i had a table saw i would sure try this :/

reminds me of the Bass Tubes I made for my Van

Im goin to be makin a tube inside a tube about 4ft long.

Came out very nicely.

Are you gonna fiberglass the inside of that?

thanks.

Im not fiberglassin this one. but im debatin on fiberglassing the outside of the actual enclosure I'll build, but i really dont think it needs it.

thanks.

Im not fiberglassin this one. but im debatin on fiberglassing the outside of the actual enclosure I'll build, but i really dont think it needs it.

It would reduce turbulence...

thanks.

Im not fiberglassin this one. but im debatin on fiberglassing the outside of the actual enclosure I'll build, but i really dont think it needs it.

It would reduce turbulence...

would there really be any, if there was it would be easier to just pour resin down the inside. since bein almost 4ft long it would be hard to fiberglass.

thanks.

Im not fiberglassin this one. but im debatin on fiberglassing the outside of the actual enclosure I'll build, but i really dont think it needs it.

It would reduce turbulence...

would there really be any, if there was it would be easier to just pour resin down the inside. since bein almost 4ft long it would be hard to fiberglass.

I doubt there would be much, but resin on the sides wouldn't hurt.

thanks.

Im not fiberglassin this one. but im debatin on fiberglassing the outside of the actual enclosure I'll build, but i really dont think it needs it.

It would reduce turbulence...

would there really be any, if there was it would be easier to just pour resin down the inside. since bein almost 4ft long it would be hard to fiberglass.

I doubt there would be much, but resin on the sides wouldn't hurt.

I don't think that would help too awful much unless he fiberglassed it.

BTW fritosaregood are you 'Tony B'?

thanks.

Im not fiberglassin this one. but im debatin on fiberglassing the outside of the actual enclosure I'll build, but i really dont think it needs it.

It would reduce turbulence...

would there really be any, if there was it would be easier to just pour resin down the inside. since bein almost 4ft long it would be hard to fiberglass.

I doubt there would be much, but resin on the sides wouldn't hurt.

I don't think that would help too awful much unless he fiberglassed it.

BTW fritosaregood are you 'Tony B'?

yea thats me

and if its just to smooth out the inner surface resin would do that. I think

Edited November 17, 200816 yr by fritosaregood

Nice job!

Looks good, nice job. I have yet to build a box using the "bend" method. One day maybe, lol.

Nice job on those cuts.

I've found out it's a bit easier to cut even deeper than that. Especially when it comes to small radiuses.

sticky....?it would nice to find this easily..never tryed to bend mdf but i would like too

Nice job on those cuts.

I've found out it's a bit easier to cut even deeper than that. Especially when it comes to small radiuses.

most cuts only left 1/16 inch of wood, but then about 5 cuts on one end went up to 1/8 inch, I don't know what happened there, but it being thicker at the end definately made it harder to bend

Im going to try this...

When I kerf MDF like this I usually cut almost all the way through. It makes it considerably easier to bend and less likely to crack. Nice job though.

And what works for me is using resin instead of wood glue when you bend it. Wood glue doesn't fill the gaps like resin will. When you fill all these gaps the wood cannot flex and the entire structure becomes fairly strong.

When I kerf MDF like this I usually cut almost all the way through. It makes it considerably easier to bend and less likely to crack. Nice job though.

And what works for me is using resin instead of wood glue when you bend it. Wood glue doesn't fill the gaps like resin will. When you fill all these gaps the wood cannot flex and the entire structure becomes fairly strong.

Would it not run out everywhere. Ive used bondo before too, and it worked alright

lol, mdf ports ftw, lol

lol, mdf ports ftw, lol

i might be tryin that soon. i was lookin at a 7"port for a comp box. and make soem flares on each end with fiberglass.

Edited November 20, 200816 yr by fritosaregood

Nice, What is the smallest one you have made?

Nice, What is the smallest one you have made?

the only one so far

When I kerf MDF like this I usually cut almost all the way through. It makes it considerably easier to bend and less likely to crack. Nice job though.

And what works for me is using resin instead of wood glue when you bend it. Wood glue doesn't fill the gaps like resin will. When you fill all these gaps the wood cannot flex and the entire structure becomes fairly strong.

Would it not run out everywhere. Ive used bondo before too, and it worked alright

I think you can use some duct tape on the ends but it's going to be a bit more difficult than with wood glue.