Fire cement cracking

[leakingroof]

Twice now the fire cement has cracked on the join between the flu and my wood burner. I imagine this is down to the flu expanding and contracting during and after use.

Is there a more suitable cement or putty that is flexible and withstands very high temperatures?

Thanks

 

[Nige F]

High temp silicon in a tube

 

[leakingroof]

Wow used high temp silicone now house filled up with smoke and silicone is bubbling away!

 

[Norcon]

If its cracking then the fit between the stove spigot and flue must be excessive.
First job is address this issue.
Post up an image.

 

[leakingroof]

Untitled

• leakingroof
• 6 Apr 2013
• 1

Untitled

• leakingroof
• 6 Apr 2013
• 1

Untitled

• leakingroof
• 6 Apr 2013
• 1

 

[Pigeon85]

Twice now the fire cement has cracked on the join between the flu and my wood burner. I imagine this is down to the flu expanding and contracting during and after use.

Is there a more suitable cement or putty that is flexible and withstands very high temperatures?

Thanks

what did you do step by step to apply the cement?

 

[leakingroof]

It was pre mixed so I just put it on my finger and rubbed it into the gap around the flue

 

[Pigeon85]

Try wetting the surfaces first, it may well be simply a case of it drying to quick

 

[leakingroof]

The cement dried hard though so when the flue expands it crackes causing gaps. I tried the silicone as I presume it would of been flexible

 

[Norcon]

You must use fire cement here. Black is available.

The flues must be separated and cleaned and a coating of fire cement is applied to both " contact" surfaces of the "male" spigot and "female" socket ends.

When they are connected enough should squeeze out to form a neat capping. This will not crack if properly done and will not leak.

You need to wear latex gloves for this operation.

HT silicone is very dangerous in this situation. Your hetas installer should be doing this work.

 

[leakingroof]

Very dangerous in what way?

I have found some high temp silicone that will go to 1200 degrees c will that be ok?

 

[Norcon]

It can go on fire. At the very least it will emit dangerous fumes and then mix with the leaking flue gases to make an altogether much more dangerous toxic mix.
Your playing with fire. Literally!


What silicone have you found that is rated at 1200c? Have you a link?

I still wouldn't use it though.

 

[leakingroof]

http://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=1200 silicone&_sop=15

 

[Norcon]

That won't have hetas approval.
Fire cement is the only option.

 

[leakingroof]

That won't have hetas approval.
Fire cement is the only option.

Is it going to be ok though or do you think it is w waste of time?