How to turn a 5" pipe into a 3" pipe?

[Shewie]

I've got some lengths of 5" stainless flue pipe, I want to reduce the 5" down to 3" so I can marry up a new main flue. I cut my stove port to 5" so can't do much else unless I try to put another plate on top.

Effectively one of these but without the £30 price tag ..


Any suggestions on how I can butcher a length of 5" pipe and make an adapter? I've no welding gear but I'm pretty handy with a rivet gun

If I can't use the stuff I've already got, any other ideas on how it can be done? It's going at the base of the flue so it's needs to handle some serious heat.

 

[Jared]

First thought, is a jam funnel?

 

[BearInTheWoods]

Don't quite follow, if you've got 5" pipe and a 5" port, what's with the 3"? Have you got another stash of 3" that you want to use as well?

If you're intending to have a 3" main flue, are you sure that will provide sufficient draw? You don't want to take chances with CO, and to be honest I'd include bodging a reducer as 'taking chances'. On the one hand, a purpose-made, tested fitting for £30, on the other hand, an increased risk CO poisoning. Money well spent in my opinion.

 

[belzeebob23]

Hi Shewie
What you need to do is measure the circumference of your 3" pipe , mark it onto your 5" pipe with a little extra for and edge to rivet. cut a v shape out fold over, basically forming a cone and rivet you will need some sort fire rated sealer . but tbh most fitters would only do this as temp repair but it can be done, BUT since it is so close to the fire base I would buy the reducer so much less hassel. Just like Bear said money well spent

Bob

 

[Firebow Swagger]

for the sake of £30 buy one . if the one you make leaks ,its free carbon monoxide for everybody...I don't know about you but it tends to make me a bit sleepy

 

[Bluebs4]

Get a galvanised one from lindab uk should cost about a fiver for a small reducer .

 

[BearInTheWoods]

Get a galvanised one from lindab uk should cost about a fiver for a small reducer .

That should be good when it gets hot enough to make the zinc burn off. Zinc poisoning by inhalation makes death by carbon monoxide look a treat in comparison.

 

[BearInTheWoods]

Actually I'd like to add something. Two of my friends at University died because a landlord had bodged gas fire flue installation - incidents like that are why mandatory testing of gas appliances in rental accommodation was brought in. It may be tempting to try to save a few quid, and after reading something off the internet or looking at a book/video, we may think we're competent. Trust me, we're not.

This is why they have qualifications, certification, refresher training of professional installers - that's why they're called professionals. Unless you're a qualified installer or have been properly trained by one, it's not worth the risk of DIY installation of anything to do with gas or carbon monoxide. Pay a pro.

You can replace money by earning more. You can't replace your life or the lives of your friends and/or family.

 

[shaggystu]

Can you find a 5" stainless container of some sort (wilko's tea caddy/biscuit barrel/swing top bin etc...?) and make a 3" inch hole in the bottom?

Cheers,

Stuart.

 

[Shewie]

Thanks for the ideas folks, and a special thanks to BITW for the H&S lecture

I'll check out the other links and see what comes up

 

[BearInTheWoods]

a special thanks to BITW for the H&S lecture

You're welcome. Popping round to a friend's house for a brew, only to find two of your chums sitting in front of the telly, stone dead, tends to leave an impression. If the gas meter hadn't previously used up the 50p they'd cranked into it, the room would still have been full of the stuff and I would probably have joined them.

 

[Shewie]

You're welcome. Popping round to a friend's house for a brew, only to find two of your chums sitting in front of the telly, stone dead, tends to leave an impression. If the gas meter hadn't previously used up the 50p they'd cranked into it, the room would still have been full of the stuff and I would probably have joined them.

Sorry to hear about your friends BITW but this is for a wood burning tent stove rather than a domestic gas appliance, messing with that stuff is asking for trouble and should be left to the pros. I've acquired some 0.1mm shim steel to make a roll up flue rather than my solid pipes I use now, the problem being my stove port is cut to 5" and the new pipe will be 3"

A bit of background here

 

[mrcharly]

I think you can make a conical fitting as suggested. I'd use Wynns gasket maker to fill the joints (if they aren't welded or soldered).

 

[ged]

Richard, I can weld it up for you if you cut the bits to the right sizes/shapes. Getting the sizes of the fittings might need a bit of experimenting however, stainless shrinks quite a lot when you weld it.

Carbon monoxide has to be a serious concern with any wood burner. A five inch flue would be big enough for many stoves used in houses, three inches will probably be fine for a small tent heater but obviously you need to ensure that it draws well and that you have proper ventialtion for the tent. My instinct tells me you know that. Even with all the right design and sensible precautiions, I personally wouldn't leave one burning while I slept.

 

[drliamski]

Google jam funnel on eBay mate. There are stainless ones available for under a tenner.


Sent from my Nexus 7 using Tapatalk 2

 

[drliamski]

Check out this item I found on eBay:

End time: 3 Oct 2013 19:42:28

Item: jam funnel effect SHAPED STEEL PRESSING see desription

URL: http://pages.ebay.com/link/?nav=item.view&id=300944611090

Alt URL: http://www.ebay.co.uk/itm/jam-funnel-effect-SHAPED-STEEL-PRESSING-see-desription-/300944611090

(Sent from eBay Mobile for Android)
Sent from my Nexus 7 using Tapatalk 2

 

[Teepee]

Old stainless vacuum flask?

I'm sure I've got one cut up with those dimensions.

 

[belzeebob23]

Yeah they are not to expensive the galva ones, could ask in the office how much one is tomorrow if you like Stewie, as for the zinc burn off a good burn in the open before use in the tent sorts that out.

bob

Get a galvanised one from lindab uk should cost about a fiver for a small reducer .

 

[wingstoo]

Sorry to hear about your friends BITW but this is for a wood burning tent stove rather than a domestic gas appliance, messing with that stuff is asking for trouble and should be left to the pros. I've acquired some 0.1mm shim steel to make a roll up flue rather than my solid pipes I use now, the problem being my stove port is cut to 5" and the new pipe will be 3"

A bit of background here

Shewie, can you get a flat plate to fit directly to the flue outlet on the burner, so the flue is a constant 3"/75mm rather than reducing it down?

BTW it isn't only gas that causes CO poisoning, it is the incomplete combustion of any carbon based fuel. So good ventilation and good extraction of products of combustion is essential, especially in any space that might be described as confined.

If in doubt a chat with HETAS installer (Heating Equipment Testing & Approval Scheme)

http://www.solidfuelinstallation.co.uk/ has some useful info.

 

[Shewie]

Yeah they are not to expensive the galva ones, could ask in the office how much one is tomorrow if you like Stewie, as for the zinc burn off a good burn in the open before use in the tent sorts that out.

bob

If it's not too much trouble Bob a price would be great

Shewie, can you get a flat plate to fit directly to the flue outlet on the burner, so the flue is a constant 3"/75mm rather than reducing it down?

I think that's the way I'll probably go, the reason I wanted to use the 5" is so I could use my 45* adjustable elbow.

I know with the Kni-co stoves the flue just gets pushed into a hole in the top of the stove, no collar or junction at all, I'll maybe look at that when the shim steel turns up.