Designing and manufacturing of exhaust pipes

**mr bucketracer** · 4th October 2015, 10:40

Originally Posted by Sketchy_Racer

Hand pumps sounds like hard work, i'm allergic to hard work.

I have an idea that might work, I was thinking that I could put an adjustable pressure relief valve on the fitting using a spring loaded plunger. I don't think I would bother with a pressure gauge for now.

With the pressure relief it would hopefully allow me to sneak up on the desired pressure without having to worry about splitting the seams uncontrollably

yip you get water comimg out of pin pricks in the weld and it drives ;you nuts , but you get strong arms after a wail lol

**Sketchy_Racer** · 4th October 2015, 13:43

So a little bit more work done. I've taken the dimensions from the FOS exhaust concept and created my chamber in Solidworks. So far it's looking good. I used the a spline tool to create very smooth transitions between the changing diameters.

I will have to wait until tomorrow evening when I can use the 2015 solidworks to generate the flat pattern from this but I think it should be fairly straight forward.

**Bert** · 4th October 2015, 16:59

Originally Posted by mr bucketracer

yip you get water comimg out of pin pricks in the weld and it drives ;you nuts , but you get strong arms after a wail lol

Here you go...

**Sketchy_Racer** · 4th October 2015, 20:23

Love it!!

You shoud take some detailed pics of it so I can "study" it.... and maybe copy it to make my own. I can see having to have a few attempts at the hydroforming......

**Mental Trousers** · 4th October 2015, 20:57

Title of thread changed as requested by the original poster.

**jasonu** · 5th October 2015, 04:58

Originally Posted by Bert

Here you go...
]

Nice machine.
You might want to watch just how close you get your shirt and hair to the top wheel...

**mr bucketracer** · 5th October 2015, 06:56

Originally Posted by jasonu

Nice machine.
You might want to watch just how close you get your shirt and hair to the top wheel...

thats what bert told me lol

**Sketchy_Racer** · 5th October 2015, 22:03

Well I had a fairly productive evening. So many other jobs to do but I couldn't get the Pipe out of my mind so I went and welded the flat pattern together.

With a bit of luck will pump it up tomorrow and see how it comes up.

**mr bucketracer** · 6th October 2015, 07:11

Originally Posted by Sketchy_Racer

Well I had a fairly productive evening. So many other jobs to do but I couldn't get the Pipe out of my mind so I went and welded the flat pattern together.

With a bit of luck will pump it up tomorrow and see how it comes up.

good stuff , warning it can become a obsession lol

**Sketchy_Racer** · 6th October 2015, 19:40

Well, not a bad start at all! It is remarkable how much the metal stretches through the center section!

I decided to simply do the template by multiplying the diameters by (d*pi)/2 and then took a stab in the dark regarding the header angle change.

Because the metal stretched so much through the center it made the material ripple a lot more than I was expecting.

I didn't bother putting a relief valve on the fitting for this attempt I thought I'd give it a go with out it. Needless to say I really need a relief valve as well as a pressure gauge.

Anyway enough with the words, here's the result. Time to have a measure up and a second attempt.

**Bert** · 6th October 2015, 19:52

Originally Posted by Sketchy_Racer

Well, not a bad start at all! It is remarkable how much the metal stretches through the center section!

I decided to simply do the template by multiplying the diameters by (d*pi)/2 and then took a stab in the dark regarding the header angle change.

Because the metal stretched so much through the center it made the material ripple a lot more than I was expecting.

I didn't bother putting a relief valve on the fitting for this attempt I thought I'd give it a go with out it. Needless to say I really need a relief valve as well as a pressure gauge.

Anyway enough with the words, here's the result. Time to have a measure up and a second attempt.

Looks great for first run.

Scotty suggested fulling with water again and tap with hammer or sealing and adding air ~30psi then heat the ripple areas and they will pop out...

Also note the belly will expand about 2-5% more the template/design.

**AllanB** · 6th October 2015, 19:56

Well done - that is very cool. Nice effort for the first time out.

**TALLIS** · 6th October 2015, 19:59

seem to easy. but seriously... looks good for the frist time!

**Tunisti** · 6th October 2015, 22:37

Nice job Sketchy!

Did you try the middle section support method, in the beginning of hydroforming? It´s somewhat dangerous method, if the vise decides to crack under the huge load... But that´s what the wrapping of vise with durable rope is for! With that method I´ve been able to get the belly streching somewhere bethween 2-4%.