Acrylic Render question

[THX1138]

Has anyone used prepackaged acrylic render as their final coat? I am tossing up using this instead of making up my own bagging or cement stucco mix.

I used this same material for my base, but am not sure of the heat rating although it wont get too hot as I have 3" of ceramic fibre blanket & 3" vermiculite

I was thinking the acrylic would give me a more flexible final layer

Regards,

Phil

[dmun]

Re: Acrylic Render question

I have 3" of ceramic fibre blanket & 3" vermiculite

The outside of your oven shouldn't get much more than warm to the touch with that much insulation except right around your opening.

[Les]

Re: Acrylic Render question

Phil,

Thats the route I went - I used a product made by Dryvit. Survived one winter here with no problems.

Les...

[Johnny the oven man]

Re: Acrylic Render question

Final coat , with the acrylic render, with colour added should be fine.

[chrisbouw]

Re: Acrylic Render question

Thanks Johnny, others. I'm in Melbourne too, preparing for the final coat. I've seen Australian Builders (or something similar) brand acrylic render mix and colour. Do you know of it? I'm planning on a couple of coats to wrap things up. Does it need waterproofer too?

cheers. Chris.

[THX1138]

Re: Acrylic Render question

Many thanks,

I thought it would be ok with some tinted acrylic, I just checked the outer vermiculite layer as it is drying and it is setting fine after 1 day, I should be able to render it next weekend and finally start the curing process, low & slow

Regards,

Phil

[Johnny the oven man]

Re: Acrylic Render question

Phil, DONT render and then dry. Dry it out first. If you render, it becomes waterproof, therefore you cant push the moisture through the render. Fire it FIRST thoroughly several times until it is dry, use it a couple of times then render.

[david s]

Re: Acrylic Render question

Totally agree about firing before render. I use a 4:1:1 sand, cement, lime render first. Wrap for a week to keep it moist and make it stronger. Then start your cooking firings, do at least four good cooking firings before the final acrylic render. I find it best to apply by watering it down and paint it on in a number of layers- great finish. The stuff is waterproof, that's why you must make sure that the moisture is out of the oven before applying it otherwise you are locking the moisture in. A hand held to the outside of the oven should tell you if there's moisture in it. It will be hot to the touch if there's moisture there.

[THX1138]

Re: Acrylic Render question

Good point, I was wondering about that.

I know I would have done that with a brick job and was going to double check anyway with the castable so thanks for the heads up

I plan to light some low slow fires for a week or two and you say to ark up a couple of big ones also before rendering

Regards,

Phil

[Johnny the oven man]

Re: Acrylic Render question

Heat Beads are a good way to spread the heat evenly over the entire area of the base of the oven, and are a very manageable source.

[THX1138]

Re: Acrylic Render question

That is what I am using, I remember you saying that

Lets see what happens

Regards,

Phil

[THX1138]

Re: Acrylic Render question

Had six firings so far, gradually built up temp to this point, 250celsius yesterday & 350celsius today. Still using heat beads added to kindling mix and spreading around interior to different spots, chimney is drawing well, even had some flamage out the ceiling & up the chimney tonight which is spectacular, amazing how much heat you get from such a small quantity of fuel, dome is still cold to the touch

Looking forward to having a couple of cook offs over Easter at full temp prior to adding the final layer.

With the final render layer, is it better to do a few thin coats as opposed to one or two thicker coats, the vermiculite has a few spots where I need to add more material to give a uniform shape particularly after drying the stuff out

Phil

[david s]

Re: Acrylic Render question

You will find that the more you use your oven, the better it seems to get. Faster heat up, less fuel used, better heat retention. I think it's due to the elimination of moisture, a fair amount of energy is required to turn the water to steam and of course any moisture in the insulation area reduces the insulation value. You're in for a treat, keep firing.

[sarah h]

Re: Acrylic Render question

I used a product made by Dryvit.

Les,

That's exactly what I want to use to finish my base. We watched contractors apply Dryvit to the exterior walls of a house down the street from us last year and I figure if it's suitable for exterior house walls around here, it'll hold up well on the base of my oven - trouble is, it seems only contractors can get their hands on it around here.

Were you able to buy it at a Lowes/Home Depot/ or similar type of store?
It may be time for me to take a run to Syracuse again ...

Sarah

[wlively]

Re: Acrylic Render question

You can purchase DryVit at a plaster building supplier. I bought mine here.

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