Render ingredients without stucco, but wait...what about acrylic paint!

[Buzzlight]

It's interesting reading about locations and what people can and can't get locally. For me, in Winnipeg, Manitoba, the local stores don't sell white cement, they don't have bagged stucco, they only have type S mortar and so on. I managed to get ceramic blanket at a commercial cement place but I always feel intimidated going to these placed. A small pottery store had refractory mortar for sale, and I only needed a tiny bit since I am doing a steel oven. Perlite...found HUGE bags at a hydropnic store. Well, I think it's more of a weed store than anything but anyway. I can't find stucco.

So for my render, what is the best formula? Regular portland with sand, and clay? Will this be waterproof? Could I use type S mortar? I'm trying to get a layer of anything over the perlcrete before the snow comes any day now. It's already below freezing at night time.
And what about colour? Has anyone ever added acrylic paint to this mix to tint it? I read a little about it as an experimental use of waste paint and it seems the acrylic actually does the same job as the expensive additive you can by. thanks all....

[david s]

If you want to make your own stucco a mix of 4:1;1 works pretty well. Ie 4 sand, 1 hydrated lime, 1 Portland cement. This mix has nowaterproofing qualities, but some acrylic fortifier (equal parts water and fortifier will impart both strength and some waterproofing. If you can’t get it don’t worry, you can deal with waterproofing issues over the top of the stucco later. Go easy with any clay addition as it creates shrinkage (cracks)’ It’s a bit different where it’s close to the fire where it acts as a refractory material in the mix. The 4:1;1

[Buzzlight]

Is it ok to fill in small voids and depressions in the perlcrete with the stucco mix? Or is it better to mix a small batch of perl and build it smooth first? Do folks usually add a layer of lath or stucco or chicken wire between insulating concrete and render?

[david s]

It is easier to fill any low spots with a richer mix say 5:1 or even some render mix and vermiculite 50/50. If you fill with render only it will produce an uneven coating thickness and use up lots more render. Any high spots of 10:1 vermicrete can be easily shaved with a brick trowel.I use a network of thin wires against the vermicrete for the render to bind on to. These wires plus AR fibres in the mix have proved quite strong enough.