The Steamboating Forum

Can anyone give me advise on what specification to build a funnel.
It’ll have a 4” internal diameter and be double skinned.
I have considered twinwall, bit I can’t say I’m too impressed with the appearance.
A bit of advice on how to finish the top (so it looks good) and how to fix it to the top of the boiler would be appreciated too.
TIA
Ian

ianrichards wrote:Can anyone give me advise on what specification to build a funnel.
It’ll have a 4” internal diameter and be double skinned.
I have considered twinwall, bit I can’t say I’m too impressed with the appearance.
A bit of advice on how to finish the top (so it looks good) and how to fix it to the top of the boiler would be appreciated too.
TIA
Ian

I have a stub funnel about 10 inches high to which I welded to a square plate . This is held in place by the outside casing. A stainless steel flue which has a sort of taper on the last 2 inches fits into the stub and over the whole lot I have a enamel outer funnel which stops the inner from wobbling too much.
The outer funnel is topped by a 5 inch band of mild steel just screwed to the funnel and painted black.

Thanks for that Mike.
How is the outer enamel tube spaced and held in place?
Thanks
Ian

Mike Cole wrote:

ianrichards wrote:Can anyone give me advise on what specification to build a funnel.
It’ll have a 4” internal diameter and be double skinned.
I have considered twinwall, bit I can’t say I’m too impressed with the appearance.
A bit of advice on how to finish the top (so it looks good) and how to fix it to the top of the boiler would be appreciated too.
TIA
Ian

I have a stub funnel about 10 inches high to which I welded to a square plate . This is held in place by the outside casing. A stainless steel flue which has a sort of taper on the last 2 inches fits into the stub and over the whole lot I have a enamel outer funnel which stops the inner from wobbling too much.
The outer funnel is topped by a 5 inch band of mild steel just screwed to the funnel and painted black.

It is all very simple, the inner flue has 3 stainless sticky out bits riveted to the top. just a bent L shape. Slide the outer over the inner and the bottom of the outer just rests on the casing. not fixed. Held in place by its weight. The inner does have a slight force fit into the stub as the bottom of it is sort of a corrugated taper.

Got it !
I was thinking of something unnecessarily complicated
Thanks
Ian

Mike Cole wrote:It is all very simple, the inner flue has 3 stainless sticky out bits riveted to the top. just a bent L shape. Slide the outer over the inner and the bottom of the outer just rests on the casing. not fixed. Held in place by its weight. The inner does have a slight force fit into the stub as the bottom of it is sort of a corrugated taper.