Steel pipe - scrap bus exhaust, perhaps?

[vulgalour]

Internal diameter of 17cm (not less than 16.5cm)

Total length of 12cm OR two lengths of at least 6cm each

 

I gather this is the same diameter pipe as some sections of bus and lorry exhaust.

 

Must be steel, not stainless, as I'll be welding it to other regular steel.  Not had much joy trying to find pipe of this diameter in small enough quantity as of yet, but I have only just started looking.

[beko1987]

Tractor pipe for the Princess?

[vulgalour]

It is for the Princess...

[lisbon_road]

I think you'd be better off going round metal fabricators yards or something.  That is so short that it hardly merits the name 'pipe'.  You could even roll and bit of flat sheet and weld it together  Where I work there is a some of this sort of stuff done so I will have a look but I don't think we have anything that big diameter.  Good luck.

 

How thick do you need? 

[vulgalour]

I have had zero luck rolling sheet into a tube so it doesn't have flat spots and kinks.  It only needs to be thick enough to match car bodywork.  It is little more than a scrap that I'm after, just annoying I don't have anything close to that diameter kicking around.

[Inspector Morose]

Pop on over to your local small coach company. They're sure to have a scrap bit lying around the yard somewhere.

[alf892]

Get some from a (proper) factor? I got a couple of 3" diameter bits for my truck and it was only about six quid a metre.....

[M'coli]

Am I right in thinking that 17cm - about 6.5 inches - is rather large for a bus exhaust pipe...?

[Bobthebeard]

Am I right in thinking that 17cm - about 6.5 inches - is rather large for a bus exhaust pipe...?

I did wonder about that...

But because Vulgalour I didn't question it!

[vulgalour]

I thought it was a bit on the big side too, but various components purpoting to be this diameter were popping up for use on bus/lorry exhaust systems in my searches.  all far too pricey though, especially given what I need.

[vulgalour]

As likely as that sounds, no.  I am not building Anne Hathaway's wedge.

[vulgalour]

If I say yes will that stop you making suggestions that are making me feel like a creative wasteland because the intended purpose for this pipe is so dull on comparison to the ones you're proposing?

[twosmoke300]

I'm guessing something to do with headlights .

What about stove flue pipe . You would need to grind off the enamel first obviously

[seth]

I reckon you should have another go at rolling this from sheet if its only got to be 'bodywork' thickness.

 

FInd something solid that is the right diameter (16.5 -17cm) and not too brittle.  Even a plant pot might do it.  Or maybe you could cut a disk out of some wood or something.

 

Get a strip cut that is 6cm wide or whatever and carefully cut it (with nice square ends at 90 degrees) to the length of the circumference of whatever it is you have found/made.  (ie PI x diameter).

 

WIthout using the former curve it round till the ends touch and it is pretty much a circle but not necessarily perfectly so.

 

Weld the ends together.

 

It should now fit reasonably well on to your former which you can use as a guide or dolly to bend/hammer against to get it as round as you need.

[vulgalour]

Daft question, but how do I stop it sliding/springing off the former?  When i've tried this in the past the welded bit ends up with a V where the ring has tried to pull into a teardrop.  The other thing I really struggle with is getting the metal to curve evenly, is there a knack to it?

[vulgalour]

EPIPHANY:  If I get a relevant sized hole saw I can cut a hole out of some wood with a sheet-metal-thickness gap when the circle is put back in the hole in the wood.  Would this work as a decent former?

[explosive-cabbage]

Small gas bottle from a scrapyard? And cut a section out of that.

[Christine]

series land rover air filter.. are you gunna  french in round  tailights?

[vulgalour]

@Christine:  not a bad call that but an expensive way of solving the issue (or not, on looking at some prices, can anyone confirm dimensions?).  You guessed correctly.  The Viva lights are beyond my skill set to install, the shapes are just too complicated.  I'm reverting to the BMW 2002 pie dish lights I bought which are much easier to install, a good size and contain all the lights I need.  Won't look quite as smart as the Viva lights but it will still work and I can always change them in the future when my skills have improved.

[chodweaver]

Is sewer pipe too far from the required bore to be used as a former? I'm thinking the plastic stuff, as a short piece of that is not expensive iirc.

 

Sent from my GT-S5830i using Tapatalk 2

[vulgalour]

Plastic is unsuitable for purpose, which is a shame because getting plastic pipe of the correct diameter is easy.

[michael1703]

Try

 

http://www.stgperformance.co.uk

 

Or

 

http://exhaustsuk.com

[panhard65]

Just ring the local steel stockist. I needed 3 bits of box section to make an adjustable bracket for my bike rack each length was 50cm and the whole lot was about 7 quid. It is so cheap there is no point messing around trying to bend bits of sheet steel.

[seth]

Daft question, but how do I stop it sliding/springing off the former?  When i've tried this in the past the welded bit ends up with a V where the ring has tried to pull into a teardrop.  The other thing I really struggle with is getting the metal to curve evenly, is there a knack to it?

 

Curve the metal round something with a diameter a little smaller than the finished ring will be.  Gas bottle?  Saucepan?  Just do it gently a bit at a time so as not to put in a sharp kink.

 

No need to weld it while on the former or when it is perfectly round.  By cutting it to the length of the circumference you know there is the right amount of metal there so once it is welded you can then use the former/guide to help you get it round, tightening/relieving the curve where necessary.

[castros_bro]

Daft question, but how do I stop it sliding/springing off the former?  When i've tried this in the past the welded bit ends up with a V where the ring has tried to pull into a teardrop.  The other thing I really struggle with is getting the metal to curve evenly, is there a knack to it?

 

If using a former or, better, a set of rollers  (homemade ones work)  you must anneal the metal before shaping.

[catsinthewelder]

You will also tend to end up with a flat bit at each end.

[Des]

I reckon you'd knock this up from a piece of flat using a rolling pin, cardboard or mouse mat on your flat surface will help with the curling, go for a couple of inches longer than the desired circumference and trim off the inevitable flat ends.

 

Now I worry that Vulgalor from plates creates a brace to replace the space of misplaced displacers, because that would be a disgrace.

[vulgalour]

But if I could replace that brace of displacers with minimal effort (thus not losing face) that would be ace.

[vulgalour]

Guess what, cake tins are made of steel and come without silly coatings and are exactly the size I want.  Cake tins.

[vulgalour]

I just found two in the cupboard that are *useless* for making cakes in but exactly the right size for what I want to do.  I didn't even know I had them.

 

 

They even have removable bottoms so I can make good baseplates too.  Happy about that.