Hydroforming

Thought ill start a new thread on my attempts of Hydroforming. Got to admit it turned out really well with no creases or bends. Also when doing this the metal will "unbend/overbend" if that makes any sence.

Here is the template, you can see the original lines of where I wanted the pipe to "under/overbend" but I allowed 3/4" each side over for this. The orrange is the cut'off but I changed this before I cut.



This is the modded template, use layout blue then scribed. I got to admit I will never go back to using a marker pen to do layouts as the layout blue is amasing.



The two pieces were roughly cut then tacked together ready for the grinder to get the cut right.





All the edge was folded using a pair of mole grips then slowly pressed together and welded.



Both sides welded together.



Made some connections.



600psi later.





All cut off.



I will do the other side and finish hopfully this weekend.

I bet you had a smile lika a chesire cat after that! Looks good.

Good idea. Exhaust part?

Yep expansion chambers for my RD350.

You can all see why I ask the simplest and most stupid quiestions, just like to get it right first time and learn from other people mistakes.

Had loads of help of an exhaust builder called Martin77, he is not on this forum but does alot with 2T for alot of people. Im straying away from my design as I got a design from another exhast builder by the name of Kenny to my specs. Also another exhaust builder & tunner I deal with is Slinger. If you stumble accross any of these people you will get a whole load of good advice. Shame they dont use this forum though.

busa, how do you calculate the bend difference from 2d to formed 3d?

Tidy job..the last pic looks like it's a nice round cross section.

Do you reckon you'll stick with this way instead of cones, or a mixture of the two ?

Not sure Wyn,

Cones perform better, for this set I think im going to cone roll the 2 defusers & belly but Hydroform the Baffle cone as that will have a bend in it.

Think my next set of pipes I will have a go at doing a compleate pipe.

Still alot of work but easyer than cone rolling.

Got to figure a way of squaring out both ends.

Lovely work! Maybe an alternative to mandrel bending for smaller sections?

Very impressive for your first attempt!

Thanks,

Ive decided tonight that im going to Hydroform defuser 2+3 & belly in one and then the baffle, so three sections all in. No cone rolling at all, now thats straying away from how I was going to do it.

The pipe is a 3 defuser tunned pipe or it can be called a two stage header & two stage defuser pipe.

The header you can see in the pic includes number 1 defuser, or can be called a two stage header. Should peak at 10250 rpm with a fat curve, quite peaky.

What do you use to apply the pressure, is it a hydraulic pump ?

Like that ! Ive never seen anything like it , nice one !

Pedro, I used the Clarke PTP100 Preasure test pump, much cheaper than the Rothernburg. Bought it from Machine Mart for about £105.

Tigman thanks, Ive seen clips on youtube, I know of a few people doing exhausts like this BUT getting the relavent infomation sure is hard as not many people do it. Think im the first on the forum to have a go and post up, just hope it can help others.

There are very slight ripples in the steel but nothing worth worrying about, there are no creases, some times ive been told you need to tap the thing with a hammer for a fair bit with preasure in the tube. Another thing is they are slightly oval, not by much but they are, going to use some dies/discs just to knock onto the ends to round them so they meet.

Lucky enough I asked enough stupid questions to get around the little mistakes you can make first time out, even down to the template sweep, bend, streach I asked advice on. The strange thing that confused me was these BSP fittings, untill you have delt with somthing its hard to picture it but the thread sizes as different to standard metric.

For anyone rubbish at fabrication like me and attempting 2T chambers I would recumend doing it this way as cone rolling is very hard and takes a certain skill to get it right. Saying that I do have the other sections to finnish now and they may go pair shape, lol,,, also held back by running low on gas and back in work soon so may not be finnished for another week or so.

What gauge material did you use,as looks very thick ?
Allways liked the sound of thin gauge as gives a more crisp rat a tat sound !

Using 0.8mm, standard size straight from the local Motor Factors, under £11 a sheet.

Today I realised I have made a compleate b**s up.

The down pipe & 1st defuser, I did the correct lenths BUT I did the diameters of only the down pipe. So it doesent mate with defuser 2-belly section.

I always measure twice and cut once, even when I ask Wyn to do one off stuff my measurements have always been bang on even if its from memory. I know its work, hours all over the place, no time to do things so im rushing and constantly tired.

So downpipe & 1st defuser got to be redone

Still I did get the 2nd, 3rd & belly section done today (only one of them mind)

Same way so no need to explaine all over again, still pics do all the talking:









Now lack of time is putting it all on hold again, think a week sicky I need to pull.

That's a great result right there. That looks very impressive. We did hydroforming in my welding class as it's a good 'performance welding' project rather than just sticking metal together, if that makes sense. One project was to weld a cube from 6 pieces about an inch square, then pop it into a section of tube and weld caps on each end. When pumped up, if you did it right, the inner cube should be crushed and the outer cylinder puffed up sort of round-ish. There was a bit of puffery around whose work reached the highest pressure.

I have been thinking about this one for years.
I remember a feature in some bike mag aeons back with some amazing shots of hydroformed expanny's, beautiful things even though two strokes are the devils own spawn. I dimly remember them being made flat, welded round the edges, still flat, then blown with the oil, then sliced up and made into the bonkers curves to allow the to fit round sily things like engines and foot rests. The amount of 3D visioning(is that a word) in this process flabbergasted me then and that was before I even thought of metal bashing myself. I am sure they were done flat and the welds just ground off.

I can visionise some fantastic uses for this technique in my work. Obscene planty things, weird fishes, bodies, 3d forms made of flats then 'blown'.

More info please. What are you using, how do you attach the fittings? is it as 'simple' as it looks.
Busastars You are a Bad man, you have set me off on one. South Wales is not so far away, can I come have a look?

Chunko'.

Chunk,,,

This is the very first time ive done it, made a balls up with the dimentions for the headers so will be redone. I will be the first to admit im Rubbish at fabrication BUT im trying my best to learn.

If you look at my previous posts "How a preasure washer works" that wil give you alot of the information, also a few link there to what other people do.

Got to admit I would like nothing better than to have someone local droping in showing me how to do things and genuraly working with me here and there, ive got almost everything needed to do most things, larger stuff that needs turning and one off stuff Wyn does for me.

My problem right now is work, got to be 100% clean, shaven, bla, bla, bla, housr are all over the place and rearly get two days off together. BUT Baby Busastars is due 12th September and ill eather go part time or finish depending on if they let me go part time. If I do end up part time then ill have loads of time to play more.

For your 3D fish etc it would be a great thing to have a go at, I was reluctant to buy a preasure test pump because of the cost but now I think it may be the way.


Basic guide & parts ( I know nothing though )

PTP100 Clarke preasure test pump £105
2 x 1/2" BSP double ended steel union £2
1 x 1/2" BSP tap, ball valve £5
Water £free
I sure 1" OD steel tube to weld to the unions as I have this here.
Sheet steel 0.8mm £10.78 3x2'

For the header bend I under bent the design by 3/4" each side so 1 1/2" total as the shape will pull in. This however may change from shape to shape.

For the Belly/defusers, they needed around 700psi and a couple off attempts, little beating with a hammer to form the shape.

Ive learnt that the off cut depends on the shape. What I have done is run paralel / square around 200mm extra then tapered in for the 1" tube to be welded on.

I have also discovered that my Bird poo welding is very strong and leak free, had 3 pin holes tops. It not all about those little rings for me, my excuse for being rubbish.

Blown pipes are not as good as cone rolled for performance, loads of reasons why but thats all in 2T theory and would bore lots of people, however you can get very good results doing it this way.

Hope that helps, thats all my expereance from 3 parts so far.

As they say, nothing venture nothing gain. I'm impressed as a very impressed thing at the results so far. My last 2 stroke was a DT125R which I really enjoyed riding.

Also impressed and that means a lot from me.

Without giving the game away how do they determine the expansion and flow ratio and then reduce accordingly in to silencer? Must be a set of rules some where, 4 strokes dead easy straight through no back pressure.

Just had a look on one of my bikes, looks like they were blown 30 years ago on a production line. http://pic20.picturetrail.com/VOL15/728921/19827387/390025027.jpg

Cap it off with a nice carbon fibre or aluminium silencer on the end, sure i had one on above later repackable.