Crimping steel pipe for stove flue

[Moondog55]

Rather than buy new I want to use what I have
Anybody here with old fashioned plumbing experience who can help me with getting the galvanised pipe to sit cleanly inside the stainless?
The gal needs to fit inside the SS or I will get tar and creosote running down onto the stove; don't want that it's an extra fire hazard
Of course the SS is Metric 4 inch ie: 100mm and the gal is 105
When I sold the other stove to Old Piscatore I didn't envisage needing more 4 inch flue and included it in the sale Stupid mistake
The coupler I had made didn't work
If there is no easy way I'll just have to buy 2 more sections of course and take them up with me in June but I'd rather spend the $70- on bacon and eggs

[Strider]

Try an exhaust joint MD.

[Moondog55]

Now that's a thought, but I tried that last season, and an adapter's the same cost as a new flue section.
I'd have to drive to Melbourne to find an exhaust place with the 105 to 99mm mandrel
OK I'll save for some new flue and forgo a months bacon and eggs, just as well I like porrige

[Strider]

They should just be able to expand the end of one section to fit over the other. I don't think you'll need an adaptor.

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[Moondog55]

Need to make the gal pipe smaller to fit inside the stainless
This is old pipe not the modern LW zincalume stuff, it's more than a millimeter thick and really hard and tough
It's probably older than either of my plumbers
Strider I think I'll stop stressing about saving a few dollars and just buy new flue sections and forgo a few cooked breakfasts over the ski season
it being far more important to avoid cold stress in camp than eat out

[RonK]

Your local sheet metal shop should be able to put the pipe on a jenny and enlarge it to fit in just a few minutes.

[MeanderingFlyFisher]

There are lots of ways to do it including making adaptor,cutting slots in pipe lengthwise and flaring in(weld up if required),expanding smaller pipe but your info is a bit vague.
I personally wouldn't use gal pipe for a flue.Tube is measured as outside diameter and pipe is measured as a nominal bore which isn't true to size.Wall thickness changes your options.
Not trying to put a dampener on what you are trying to achieve but would have to see it or at least a photo or sketch to put forward suggestions that would work.

[Moondog55]

Thanx fellers but I'll just bite the bullet and buy
I'll keep the gal pipe/tube for something else
I have no problem at all using gal pipe for a flue, it only has to last me 4 months; I'll just make sure I don't breath in any zinc fumes while they are burning off
Very few small sheetmetal shops around here now and the big ones don't like doing small one-off jobs so charge appropriately that is like wounded and angry bulls

[bmak]

Can you give me exact dimensions of what you're after and I can maybe roll and weld up some thin stainless. Better not to use gal

[Moondog55]

Can you give me exact dimensions of what you're after and I can maybe roll and weld up some thin stainless. Better not to use gal

PM coming

[Moondog55]

I went in to Pivot and bought flue sections and the angle
I'd just paid for my seasons pass and I had the money so this will save time
Now to drill all the holes needed and put in all the 6mm Brownbuilt set screws to hold it all together in the wind, somewhere I should have enough fencing wire

[Moondog55]

Burning the zinc off and making sure the bipod support is OK
Not using the baffle shelf here and it really does need it to work best
Also there is a breeze blowing robbing heat from the lower section of flue, I won't need the heat exchange perhaps but I'll take it up anyway
The cheap gal flue isn't as precise as the SS but I'll fix that on the hill with some stove gunk
I'll fit the cap as soon as it cools down