rendering woodburner hood - NEED ADVICE

[M1i2k3e4]

I have had a curved metal hood made to sit over a woodburner I've built and I will put a 3 foot chimney pot on top of hood. I want to put a 50 - 60mm render over this hood and then set small pebbles on the render.

How would I mix and lay the render?

I have been told numerous methods involving either Hydrated Lime or High Alumina cement or even Hydraulic lime mixed with rendering sand in various ratios ???

The metal will obviously get hot and ideally I dont want the render to crack and fall off - is it at all possible ??

I have tried to upload photos, but won't upload for some reason......would appreciate your thoughts.

 

[marshman]

lime putty render
you'll have to build it up in layers of about 1/2 inch, let each layer dry slow cover with a damp cloth and let the render and cloth
dry together.spread a coat over then lay rabbit wire netting in it so it can crack and move but won't come apart and you should
add hair to bind the layers, wet down each previous layer before adding the next.
Mix 4&1 sharp sand for the under layers
then use kiln died sand for the top coat if you want a smooth finish,
maybe 3&1 but cover it with a damp cloth take off cloth give it a little spray of water for a few days (putting cloth back)
to slow its drying out, the longer it take to dry the less shrinkage cracks you'll get.
at 50 to 60mm thick it will take you a month or so as each layer needs to dry and set before you add the next.

 

[M1i2k3e4]

Can I buy Lime putty render or is it a mix of different materials ?

 

[marshman]

you buy the lime putty, just Google it, lots of sellers, comes in big buckets with lime water on top, keep this until the end of the bucket
and pour it back on any lime left unused, when the bucket is empty use it in the mix.

 

[M1i2k3e4]

thanks for advice - not sure about the 4:1 sharp sand and cement, does this go on the initial coat over the metal hood or last ?

 

[marshman]

no cement just lime putty in all coats / mixes.