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imdying
26th April 2007, 11:12
Built a muffler, out of 304 stainless, it work quite well. Want to build another, out of aluminum, any reason why I shouldn't?

It's under the seat, so things like heat radiation etc are important, weight, less so. For what it's worth, the stainless one under the seat has caused no issues with heat at all.

Other alternatives are welcome, but carbon is out, and I have been unable to find anyone to weld titanium for me.

Ideally, I want a list of the pros and cons of stainless vs aluminum, from people who know about mufflers and/or metals.

degrom
26th April 2007, 11:28
If they can weld aluminum they can weld titanium. Same process... :)

Crisis management
26th April 2007, 11:46
It is certainly possible, it's only metal after all....

Aluminium will expand faster than steel or stainless which may be an issue at the junction to the exhaust pipe however the greatest difference is that aluminium is softer and weaker than stainless so you will need to either design carefully or use heavier section material to gain the neccessary strength. This will be most obvious on mounting points as the loads will need to be spread over a greater area to avoid cracking the aluminium sheet (body of the muffler)

I tend to think aluminium is a bit overrated as a fabrication medium due to this weakness but its lightness, maleability and pleasant finish are advantages.

Give it a shot, should be interesting.....

Don't bloody radial mount it tho!

imdying
26th April 2007, 12:06
If they can weld aluminum they can weld titanium. Same process... :)Please tell me more?! I was under the impression it needed some sort of chamber to weld it in? I wonder who has Ti stock?


maleability and pleasant finish are advantages.These are the bits that interest me the most. Stainless has proven to warp just a little more than I'd like, when welding large flat sections. I do have an alternative design in stainless which has less of those large flat sections and more curves, which should mitigate that somewhat, but still investigating my options :yes:

Heh, it already is radially mounted somewhat :lol:

Babelfish
26th April 2007, 12:21
Whats the prob with carbon out of interest?

Radial mounting? I had a girl that liked that once...but in engineering terms how does this work on exhausts?

imdying
26th April 2007, 12:26
Carbon, cost mostly. One day though. That and the twin would blow it up, unless I used a whole heap of it.

Pumba
26th April 2007, 12:32
So you just got it al finished andlooking good to rip it apart and start again:scratch:.

imdying
26th April 2007, 12:35
So you just got it al finished andlooking good to rip it apart and start again:scratch:.It's evolution baby :rockon:

imdying
26th April 2007, 12:37
Another question... as I understand it, you can only anodize parts made from billet into nice colours. Something to do with the composition of the metal taking to the dyes, where cast doesn't. As I undestand it, sheet metal will anodize nice colours also.

What would happen if you were to weld up a box from sheet and anodize it? Would it all go a nice colour, except for the welds?

/edit: It would appear that die cast alloy has a lot of silicon in it, making it nearly impossible to anodize.

Crisis management
26th April 2007, 12:53
Bloody spank, he's fucked up all the user names now.....

Not an expert on anodising but a quick Google shows anodised welded aluminium is ok...

I've certainly seen anodised cast aluminium so a closer look into that might be needed....it melts at @ 700 so not beyond the capabilities of a good gas axe? Lost wax process anyone?

degrom
26th April 2007, 13:24
Please tell me more?! I was under the impression it needed some sort of chamber to weld it in? I wonder who has Ti stock?

These are the bits that interest me the most. Stainless has proven to warp just a little more than I'd like, when welding large flat sections. I do have an alternative design in stainless which has less of those large flat sections and more curves, which should mitigate that somewhat, but still investigating my options :yes:

Heh, it already is radially mounted somewhat :lol:


Well I am busy with a Tig welding course at the moment. What I have learned is that NON FURIOUS
metals like BRASS, COPPER,ALUMINUM and TI needs AC current to weld. So if you can do the one
you should be able to do the rest.

The Tig process uses gas as a shield that prevents the metal from reacting with air(Hense your
airless environment to work in). Some gasses also work better with certain metals.

If you know a bit about electricity you will know that AC flicks polarity every few seconds.This has
a huge effect on your welding because with AC it cleans you metal and penetrates it on each cycle.

Aluminum is a funny metal to work with. It does not change colour with heat but it has a lower
melting point than steel. Aluminum is a lot like an Ogar/Onion they have layers!!! You need to
break thought the outer layer before you can start welding it. With AC Tig welding you do that with the
cleaning part of the cycle. With Mig welding you normally do it with a special flux that sit's
inside your wire. In the past they use to do it with the flame but you had to use a lot of ugly
stuff to clean it.

Anodizing is a process that takes advantage of the layers. It can harden the metal to almost 10 times
its original strength but it's only skin deep. Anodizing can only be done to Aluminum as far as I know
and it also needs to be a very clean type of aluminum. It works the same as any other plating process.
(Basacally it Uses a DC current that shocks the metal and sort of burns it into the metal)

When you colour anodize an item you basically open up its pours, add the colour and then seal it again.

TI welding supplies you should be able to get from BOC.(Or they will help you get it...)

degrom
26th April 2007, 13:25
Bloody spank, he's fucked up all the user names now.....

Not an expert on anodising but a quick Google shows anodised welded aluminium is ok...

I've certainly seen anodised cast aluminium so a closer look into that might be needed....it melts at @ 700 so not beyond the capabilities of a good gas axe? Lost wax process anyone?

I am sure you can anodize it... Problem is it might have stains on it.. :P

degrom
26th April 2007, 13:27
Another question... as I understand it, you can only anodize parts made from billet into nice colours. Something to do with the composition of the metal taking to the dyes, where cast doesn't. As I undestand it, sheet metal will anodize nice colours also.

What would happen if you were to weld up a box from sheet and anodize it? Would it all go a nice colour, except for the welds?

/edit: It would appear that die cast alloy has a lot of silicon in it, making it nearly impossible to anodize.

Depends on what you use to cast with(Old scrap or expensive stuff)... And how clean you casting environment is...

imdying
26th April 2007, 14:16
In other news, carbon fibre pricing:

155gm twill, $101.75 per sq/m
4L resin, $67
Vac film, $6/m
Breech unit to connect vac to, $68

/edit: Apparently the Airbus A380 has a lot to do with its unavailability at times of late.

imdying
2nd May 2007, 10:17
Still after comments...

Has anyone built there own carbon fibre muffler? I'm thinking a combination of stainless and carbon might be ok.

If carbon isn't strong enough, I guess I can just add more layers?

Has anyone ever tried to vac bag a tube? I've a few ideas on how that might be accomplished, but would be interested in talking to those that have done it.

Anyone got an opinion on how many layers to use? 3? 5? Can you vac bag 5 something 5 layers thick? Or do you have to do each individually? Can you make the tube with one layer, and then add more after the first has cured? Or do all the layers have to be 'wet' at once to ensure adhesion between them?

Anyone got an opinion on what sort of minimum corner radius you would have to use for 3-5 layers?

What about sealing the metal ends to the carbon tube? Just use maniseal at the join, then rivet it up good?

What about what sort of rivets to use?

Packing? Where would I get glass pack suitable for one? Or could I used fibreglass chopped strand? Or get some fibreglass cloth and 'loosen it up' (tear it apart some) before packing the muffler?

imdying
2nd May 2007, 10:41
I'm not totally against a sandwich contruction either... it's pretty easy to get some say 1mm alloy sheet, roll it into the shape I want, and then cover that in carbon... less carbon required in that case, just using it to add strength. Not sure about the dissimilar expansion rates though :/

geoffm
2nd May 2007, 22:31
Still after comments...

Packing? Where would I get glass pack suitable for one? Or could I used fibreglass chopped strand? Or get some fibreglass cloth and 'loosen it up' (tear it apart some) before packing the muffler?

I used layers of chopped strand and mat, wrapped tight around the core. Use packing tape to pull it tight so you can slide it in.
Geoff

imdying
3rd May 2007, 09:12
Cheers for the reply mate :yes:

moT
3rd May 2007, 14:21
just do it man make it. my muffler is diy and its fine, just gut out ur old factory one it means they cant fail you on ur warrents because its a factory exhaust

imdying
3rd May 2007, 14:32
Sadly going back to the standard muffler on my bike is completely impossible. I don't have the factory headers in one piece anymore for starters :/

Going to visit a man who makes mufflers in his spare time tomorrow, he's done some pretty nice stainless work in the past, so I'll have chat with him... would like to learn more about carbon for mufflers though still.

moT
3rd May 2007, 14:43
good on ya

Thenaughtebucket
4th May 2007, 16:29
Hey,

Freakshows brother here,

There could be a few issues with making an aluminium(al) can, i presume you would just make the cylindrical part of al and add stainless end caps to it, in which case there can be issues with electrolysis between dissimilar metals, and basically the al will corrode, there are ways to slow it down with basically a sealant between the joining surfaces, but when you rivet it together, it makes this a bit of a waste of time.

the other thing would be the different rates of expansion that each metal has, but i don't think it would be that bad.
But to be honest, i luv making stuff out of carbon so i wouldn't even bother with the al one.

The only major hurdle with making a can out of carbon is finding some high temperature resin, i have seen a home made one that was made with just run of the mill epoxy resin, and it pretty much shat itself.
any ideas at what sorta temp the can gets up to, if so, theres sum guys at a company called "Adhesive Technologies" in Auckland, that are gurus on resin.

As for some of your other questions,

Making a tube bag for inside the can is pretty straight forward, just need some "tacky tape" and some vacuum bad and just fold it back on itself. here are sum manufacturing pics, the steering wheel at the bottom was made using some pretty small tube bag, http://www.fsae.co.nz/nav/buildpic.htm

Do you have a vacuum pump?
Corner radius, if you have a vacuum pump, then you can often get the carbon to bend around sum pretty tight radii, and it can depend on what weight carbon you an get, 200g is pretty sweet to work with.
3 layers of 200g cloth would be more than strong/stiff enough, and you can basically layer it all up at once and then vacuum bag it,

Do you have a spare can that you can take a mold off?

Thenaughtebucket
4th May 2007, 16:31
forgot to read the second page of ya thread.. ohwell good luck.

imdying
4th May 2007, 17:00
Yeah, have a vac pump, was thinking 155gm twill.

The current stainless one is about 50-30 degrees on the outside... no idea how to measure the temp of the inside of it.

Teflon
4th May 2007, 17:58
If you use the right grade ali it should be fine.

316 stainless is the material i would use to build a end can.

Teflon
5th May 2007, 07:20
These are the bits that interest me the most. Stainless has proven to warp just a little more than I'd like, when welding large flat sections. I do have an alternative design in stainless which has less of those large flat sections and more curves, which should mitigate that somewhat, but still investigating my options :yes:

You can minimize distortion by clamping Ali to the job, this sucks heat out of the stainless. Dressing the weld with a hammer and dolly removes tension..

It really depends on what you doing.. but prestressing before welding helps. Air, water can be used to take heat out of the material, alternate welds, bracing the job before welding.. any gaps in your joints will increase distortion..

imdying
5th May 2007, 20:46
Yeah, 316 is what has been suggested to me... the current one is either 304 or 316, but I'm not sure which.

classic zed
7th May 2007, 21:19
Hey,

Freakshows brother here,

There could be a few issues with making an aluminium(al) can, i presume you would just make the cylindrical part of al and add stainless end caps to it, in which case there can be issues with electrolysis between dissimilar metals, and basically the al will corrode, there are ways to slow it down with basically a sealant between the joining surfaces, but when you rivet it together, it makes this a bit of a waste of time.

the other thing would be the different rates of expansion that each metal has, but i don't think it would be that bad.
But to be honest, i luv making stuff out of carbon so i wouldn't even bother with the al one.

The only major hurdle with making a can out of carbon is finding some high temperature resin, i have seen a home made one that was made with just run of the mill epoxy resin, and it pretty much shat itself.
any ideas at what sorta temp the can gets up to, if so, theres sum guys at a company called "Adhesive Technologies" in Auckland, that are gurus on resin.

As for some of your other questions,

Making a tube bag for inside the can is pretty straight forward, just need some "tacky tape" and some vacuum bad and just fold it back on itself. here are sum manufacturing pics, the steering wheel at the bottom was made using some pretty small tube bag, http://www.fsae.co.nz/nav/buildpic.htm

Do you have a vacuum pump?
Corner radius, if you have a vacuum pump, then you can often get the carbon to bend around sum pretty tight radii, and it can depend on what weight carbon you an get, 200g is pretty sweet to work with.
3 layers of 200g cloth would be more than strong/stiff enough, and you can basically layer it all up at once and then vacuum bag it,

Do you have a spare can that you can take a mold off?


Just a quick note to say that there is no such thing as a Vacuum pump, a vacuum is nothing therefore you cant pump it. :nono:
You can however exhaust the air inside something thus creating a vacuum.
So the pump is actually an exhaust pump :yes:

aahh I used to have hours of fun discussing this point with my lecturers :killingme

imdying
8th May 2007, 12:01
It's a vacuum pump. That it pumps air is neither here nor there, the end result is a vacuum. A bicycle tyre pump doesn't pump bicycle tyres...

vifferman
8th May 2007, 12:07
Just a quick note on CF cans: litre v-twins tend to be rather hard on CF cans, shaking them to bits fairly rapidly, apparently because of the exhaust pulses. Doesn't mean you can't make them out of CF, just that you'll need to make them rather sturdy.

imdying
8th May 2007, 12:17
Yeah, this is a pretty small can, and thus pretty high internal pressure... not sure I want to risk carbon fibre (or use as much as would be required).

vifferman
8th May 2007, 12:39
Yeah, this is a pretty small can, and thus pretty high internal pressure... not sure I want to risk carbon fibre (or use as much as would be required).
You could just skin it with Cf, and have something more robust inside, like an aluminium or s/steel tube.

jonbuoy
8th May 2007, 12:57
My old VTR pipes were stainless caps with alloy wrap - never saw any corrosion though its never been on a salted road. I think you can buy muffler packing from supercheap, or an exhaust shop - they might have some of that universal baffle pipe as well? I'm thinking of making an ally pipe myself, Ulrich have some extrusions and pipes. I've found it pretty hard to bend even 3mm ally plate in big sheets so far - it might not be so bad of you had a wooden mold to form it around. Allys not cheap either.

imdying
8th May 2007, 12:59
I think you can buy muffler packing from supercheap,

it might not be so bad of you had a wooden mold to form it around. Allys not cheap either.

Cheers for that. Easiest way to bend the sheet is with a roller :yes:

classic zed
8th May 2007, 13:29
It's a vacuum pump. That it pumps air is neither here nor there, the end result is a vacuum. A bicycle tyre pump doesn't pump bicycle tyres...

No but it pumps air into them:yes:

imdying
8th May 2007, 13:36
Into, out of, and?

classic zed
8th May 2007, 13:55
Into, out of, and?

Into the tube

Out of The air pump

And therefore creating positive air pressure withing the inner tube

:dodge:

imdying
8th May 2007, 14:08
So what you're saying is that it should be called an 'exhaust sucker'? :lol:

Thenaughtebucket
8th May 2007, 18:34
Its merely a pump that creates a vacuum, therefore its a vacuum pump?? No??
anyways silly arguement.

I really dont think you will need asmuch carbon fibre as you think, ive made sum light bodywork that is pretty much just one laye of 200gm, the fact that the can is kinda small and the fact that is supported at each will mean that just due to its geometry it will be strong.

unless ofcourse they use structural exhausts aswell as engines these days???

imdying
8th May 2007, 19:20
unless ofcourse they use structural exhausts aswell as engines these days???Yikes! Don't get me started on that idea!

worm
9th May 2007, 22:33
carbon fibre will hold up fine. The issue with the exhaust pulse will be the movents between the end caps and the carbon sleeve.
I made a carbon exhaust sleeve for my R6 recently, heat was fine. I just used a Nuplex ployester resin. (but would recomend using a high temp vynalester). The resin will need post curing when product is finished. but just taking the bike for a light ride will do this.
U could use 2 layers of carbon double bias. and 1 layer of twill. As double bias is cheaper.
good luck.

sAsLEX
10th May 2007, 02:20
Into the tube

Out of The air pump

And therefore creating positive air pressure withing the inner tube

:dodge:

http://en.wikipedia.org/wiki/Vacuum_pump

degrom
28th September 2007, 14:24
Yikes! Don't get me started on that idea!

On the topic of exhausts... How do they round the tips on exhaust pipes?

http://www.neptunemufflers.co.nz/textureb.jpg

(Not even sure what you call it when you do that to a tube? Or what tool you use to do it? (Have tried Google with no luck...))

imdying
28th September 2007, 15:23
Probably just roll them.

degrom
28th September 2007, 15:39
Probably just roll them.

LOL... That part I figured.

But how is the question!?!?

It does look nice.

GSVR
28th September 2007, 17:05
On the topic of exhausts... How do they round the tips on exhaust pipes?

http://www.neptunemufflers.co.nz/textureb.jpg

(Not even sure what you call it when you do that to a tube? Or what tool you use to do it? (Have tried Google with no luck...))

Could be a variation on a tool plumbers use call a "Crox Tool" Basically it has ball bearings that expand out. You turn the tool and the bearings expand the metal.

Or could be rolled between two formers.

Better rolled can end is on Yoshimura exhausts as they are rolled right over to form a perfect bead.

tommorth
28th September 2007, 20:07
you can buy carbon fibre tube in varying sizes nt sure on how much $ or if it would be thick enough save a bit of stuffing around though just cut to length and put end caps on

blade1000
28th September 2007, 20:10
warren of virgin mufflers can weld titanium

imdying
28th September 2007, 20:19
you can buy carbon fibre tube in varying sizes nt sure on how much $ or if it would be thick enough save a bit of stuffing around though just cut to length and put end caps onNot that is thick enough or can take the heat :( That's the NZ places at least, don't know about overseas... probably just make it myself anyway now.

warren of virgin mufflers can weld titaniumMmmm, haven't been tempted to try any more muffler places... Neptune wasn't interested in helping me, and that sort of tempered my enthusiasm. Had trouble now and then with tradesman that can talk the talk, but not walk the walk, so now I try to make what I can myself. However, if you know this guy, ask him if this is up his alley, and a rough ballpark on dollars :yes:

It's 440mm long, 200mm wide, 100mm tall.

Pancakes
29th September 2007, 09:16
Still after comments...

Has anyone built there own carbon fibre muffler? I'm thinking a combination of stainless and carbon might be ok.

If carbon isn't strong enough, I guess I can just add more layers?

Has anyone ever tried to vac bag a tube? I've a few ideas on how that might be accomplished, but would be interested in talking to those that have done it.

Anyone got an opinion on how many layers to use? 3? 5? Can you vac bag 5 something 5 layers thick? Or do you have to do each individually? Can you make the tube with one layer, and then add more after the first has cured? Or do all the layers have to be 'wet' at once to ensure adhesion between them?

Anyone got an opinion on what sort of minimum corner radius you would have to use for 3-5 layers?

What about sealing the metal ends to the carbon tube? Just use maniseal at the join, then rivet it up good?

What about what sort of rivets to use?

Packing? Where would I get glass pack suitable for one? Or could I used fibreglass chopped strand? Or get some fibreglass cloth and 'loosen it up' (tear it apart some) before packing the muffler?

I played around with one and it looses a little bit of bottom end and gains a ton of top which is pretty predictable for a freeer flowing pipe on a little twin. Just haven't done enough testing to be happy to run it on the bike all the time, not sure about the mixture etc and cos I mainly commute bottom end is nice. I'll go to the shed and take some pics of it in a mo'. It's not pretty cos its just a dummy right now. Carbon can be had at reasonable prices from Kilwell in Rotorua, almost all of the carbon in NZ comes from there (rolled) or pre-preg and the blank sheets which are better for home use cos you can lay it up then epoxy from something composites in William Pickering Dr, Albany. Mine is just fibreglass and takes shitloads of heat, You can order glass with one layer of carbon over from Kilwell, cheap, light and looks carbon. I tried the proper stainless wool packing but needed more muffling and used some pinkbatts. Lighter, goes white after being hot the first time. Smells funny and smokes as it comes up to temp the first time and I wouldn't smell it tho I don't know exactly what it's giving off. Probably smoldering spiders. Wanted to put it under the bike Buell style but no room so as it's high and behind the rear axle I wanted a lighter option. it is straight thru 2" perf pipe so friggen loud and makes the Hyo sound like a big grunter at low revs then screams like a 4 stroke MX bike up high.

Pancakes
29th September 2007, 09:27
Oh yeah, this is an off cut of a mast, got it free.

imdying
29th September 2007, 13:00
Yikes! Mill that puppy out and make a muffler :D

Pancakes
29th September 2007, 15:40
Those holes you can see on the end match up to a Hyo exhaust flange. It's a bit shorter than a std Hyo' one, about 310mm. Is 90mm OD, has been on the bike for some commutes and a few rides around the place so has been up to temp enough to see if it'll die or not. Is 8mm wall so plenty light but should take a fair whack. the wrap and end caps would make more of a difference (I guess) than the outright wall thickness. I got the end plates cut out of standard rolled steel cos it's just the tester, tacked a pipe on the inside that fits snug, used some exhaust silicone on it and the caps are held together just by the 2" perf tube.




(down there, what I did this morning)

edit, never looks as ggod when your mate takes the pic late a, good riding tho and there's a restaurant in Unitech with cold beers!