So for a project I'm working on I need to expand from 1.75" ID pipe to 2.5" ID pipe, it will be over a height of 3 or 3.5". I couldn't really find any weld in pieces so I think I am going to have to make my own. What do you guys think of this idea:

Draw up a 2D template for the conical section (like making paper cones back in kindergarten). Then cut that template out of a piece of sheet steel. Then I'm planning on tacking the top corner to a piece of 1.75" pipe and heating the template and bending it/tacking as I go around to get the final shape I want.

Think it will work?


Or maybe someone knows where I can buy a pre-formed one that isn't like $30 a piece. I only need mild steel.

 

Here's what I'm talking about, only I need it in mild steel and inexpensive

 

Good luck finding the 1.75" ... I personally would use one of the following and then swedge the 1.5" end out to 1.75": http://www.drgas.com/store/pro...age=1

 

What I would do in this situation is take a 2.5 in pipe in whatever material and length you want. Now measure the circumference of a 1.75 in pipe and mark that on one end of the 2.5 in pipe. Obviously it won't go all the way around. Now you have 2 points on that end. On the other end of the pipe (in the middle of the 2 points from the other end) make your next point. Now cut out the triangle the length of pipe. Now take some hose clamps and put them on and start tightening the pipe shut. Make some tacks and remove the clamps. Finish welding it. Now it won't be a perfect cone or a perfect circle. You have to massage it to be perfectly round and cut the ends square to the pipe. It's really easier than it all sounds and I hope it makes sense. Hard to describe without a visual aid.

 

I need it to be perfectly conical, want to take advantadge of the venturi effect

 

You can round it really good but it would never be perfect. The only places I know that have cones are Burns, SPD, and McMaster

 

get one rolled

 

Burns can do you one in Mild steel for cheap. Something like 20$. It is the way to go.

 

i need one in aluminum... burrns? i want it to be at least 10" long from 3" to 4"

 

Get some 2.5 inch exhaust pipe, and cut it to the desired length. Then make a slit in the pipe lengthwise stopping about 1/4 inch from one end....this will be the big end. find something thats 1.75 inches in diameter (to use as a mandrel) and stick it in the other end, then use a hose clamp around the end of the pipe to squeez it down around the mandrel.. Take a marker and mark the overlap, then undo everything and cut out the extra peice, put the mandrel in and the hose clamp back on and weld it all together. You will have a piece with one seam down its length, it may not be to pretty, but you said CHEAP.

 

Do it yourself .Its easy

 

Hmm picture is broken

 

http://www.burnsstainless.com/....html

THis is if you don't want to fab it