Sealing a loco smoke box

[Tony MartyrParticipant @tonymartyr14488]

[Tony MartyrParticipant @tonymartyr14488]

Through the base of the smokebox comes the steam inlet and exhaust pipes which require a slot to be cut in the saddle and smokebox base.

Surely this slot needs to be sealed otherwise the draft takes this route rather than over the fire?

Also this part of the smokebox will be where ash gathers that would drop through the gap and make a mess of the linkages etc underneath.

So how is this normally achieved – I can find no reference on drawings.

I have posted a photo of the present state of the smokebox on my William album

[Jeff DaymanParticipant @jeffdayman43397]

It does need sealing up. I have successfully used hi temp automotive grade silicone sealer, but have seen references in ME to fireclay, auto exhaust patching compounds being used too.

 

[Jeff DaymanParticipant @jeffdayman43397]

 

 

Edited By Jeff Dayman on 03/10/2009 12:55:24

[AcrosticusParticipant @acrosticus]

I was advised to use Holt’s “Gun-Gum” (from auto accessory shops. It is sold for patching exhaust/silencer holes, and was still available four years ago), which I did and it has been entirely successful.

Yes the hole must be sealed up, or the smoke box vacuum will be defeated.

I have never seen it actually on drawings, but LBSC in his “words and music” says to use “asbestos string annointed with plumbers’ jointing“. Martin Evans advocated something similar in his “Manual” but things have moved on a bit from the 1960s!

[Tony MartyrParticipant @tonymartyr14488]

Thank you Gents – it is nice to get confirmation of one’s assumptions when working in a local support vacuum.

However I will carry out this sealing as the last possible moment because I fear that I will have to disassemble the smokebox more than once in future.  

[John Andrews 2Participant @johnandrews2]

When I built my “Marie E” 7 years ago I considered using some of the harder stuff like mentioned in the other posts, but was strongly advised not to because you need to get it out if you need to dismantle the loco.

 

I used Plaster of Paris.  Cheap, easy to buy, softish, should be easy to remove.  It does tend to absorb water vapour, and you could ge a bit of rust, but in seven years and nearly 1000 kms of loco travel, there are no smoke box leaks.

 

It’s what I’ll be using in my next loco too.

 

AND, DO leave the sealing till the last minute.  When you have tested everything, done the painting and you are ready to go on the track, that’s the time.

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