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Re: terracotta = clay flower pot?

From the WFO board

Posted by Rado (211.29.202.200)

In Reply to: terracotta = clay flower pot? posted by Jerry

Jerry,
Sorry for delay, it was very hectic this week. Here goes:

Broken terracotta clay pots are fine too, I use mostly old broken roof tiles or offcut pieces from firebricks - all of these will work well. Dip small fragments in bucket of water and start to work with them when soaked, 3 minutes in water will be good then just pour all out on grass. Use as many pieces as you can fit in and you can do it in long layers reaching the angle, less mortar between pieces the better (it is good fun to do this and it's effective.) As you ask, you can also use heat resistant concrete but use a good mix. You can also cut firebricks into desired angle.

Yes use sieve to separate small stones if you do thin mortar application. Mix all dry ingredients then add water and mix it to paste. After mixed to paste I always wait 15 minutes, add a bit more water and remix it ones more because clay takes water making it dry at start time. When firebricks are well wet mortar will dry slowly:

I dip firebricks in water so mortar won't stick and dry fast while working. I don't recon your masonry skills are lucking, I don't think so. Firebricks are like the dry clay ground, drop water on it'll do cheeeest and the drop is gone in a moment. Fill buckets or wheelbarrow with water and dip firebricks in for 5 mins, they love water it'll soak in fast, you will hear that "cheeeest". Fireclay based mortar needs wet firebricks, and it is harder to apply for 1mm space in flat joint between firebricks - I would do 3 to 4mm - and it is very easy to use for "V" gaps in oven arches! Water from bricks is dried out later.
Then there are ready mixed refractory mortar types some of which will work with drier firebricks and these can be applied in 1mm thickness. r