Waterproofing cob/mud ovens with wax

[ratbagradio]

This is an experiment but I've used the technique in the past in making and colouring (and waterproofing) puppets and theatre and dance masks.

Rather than cover my mud oven to protect it from weathering, I've graffitied the dome shape with crayons. There are many types of crayon available but I use the commercial brands that are used to mark timber. These are very waterproof.

You burn a fire in the oven and when the exterior heats up a bit start drawing with your crayons. They'll melt a bit and become like lipstick as the wax is applied onto the surface.

Washable crayons -- eg:Crayola -- won't do, of course, and you could use bees wax but that will cost you a bit. The principle is to think candles which are a waterproof medium that melts and remelts in line with heart generated on the wick. Something like an oven....

So far so good.

It would have to be redone at some stage but I get a pretty fancy coloured oven to look at, especially when I swab the colours together with a brush. I guess it's something you could get the kid's to do.

Another way to apply the crayons is to use a hair dryer to heat the surface as your draw on the oven . If your oven is cool outside even with a fire going --as a good part of mine is -- you may have to use the hair dryer or heat gun.

If the wax catches on fire I don't think that's a big deal -- I'd call that patina. (At what temperature the wax will fire I don't know

While this may seem bizarre and way out of left field -- the ancient Greeks waterproofed their boats with wax which they'd colour and work into decorations.

How thick the wax layer needs to be , or whether coating the exterior granules is sufficient I don't as yet know.

[Archena]

Re: Waterproofing cob/mud ovens with wax

Hmm, I dunno. Wax won't allow water to get out if it cracks and lets water in. That's the problem with concrete as a render. It sounds like something that would require a lot of maintenance.

But, heck, why not give it a try? Let us know how well it works.

To burn wax must first convert to vapor. It's the wax vapor that actually burns when you light a candle. If the outside of your oven gets that hot your walls aren't thick enough!

Now, the colorant and/or fragrance are completely different chemical animals and may burn more - or less - readily.