3:1:1:1

[wotavidone]

I know this very interesting post was from years back, have you read this article The Myth in the Mix, The 1:3 ratio of lime to sand, by Gerard Lynch

https://www.buildingconservation.com...ix/mythmix.htm

Yes, I did years ago.

[Alomran]

Re: 3:1:1:1

I accidentally broke the cubes, they were too big to move easily. Both stayed adhered to one side, I will see how soft they are when they cool down.

I know this very interesting post was from years back, have you read this article The Myth in the Mix, The 1:3 ratio of lime to sand, by Gerard Lynch

https://www.buildingconservation.com...ix/mythmix.htm

[Tscarborough]

Re: 3:1:1:1

I tested it like it would be used in an oven, i.e. direct heat from cold to full flame.

[david s]

Re: 3:1:1:1

The reason I asked is that around 500-600 there is a big change in the expansion rates of different materials and they're all different. In addition clay undergoes the quartz inversion change. Although we usually sneak in under this temperature range, when we fire the centre of the fire will be hotter. I once killed a whole kiln full of pots in a wood fired kiln by taking this temperature range too fast. The pots were full of little cracks. Wood firing is hard to control and I think that is probably what killed your sand/clay sample. Castable refractory manufacturers state that the stuff is unstable in this range and recommend a rise of only 50c/hr from memory.it is possible to fire pottery by gently heating it and pushing it gradually closer to the fire and finally pushing it right it, but expect more than 50% failure rate even when done really carefully. Hope this helps.

[Tscarborough]

Re: 3:1:1:1

I didn't but they were hotter than it reads anyway (999 degrees F).

[david s]

Re: 3:1:1:1

Time to test the homebrews.

Did you read thr surface temp of the bricks with an IR. if so I suspect the reading would be quite high as it appears you have them right in the hottest part of the fire, probably hot enough to fire the clay (573 C+)

[vtsteve]

Re: 3:1:1:1

If you taper the bricks in the critical, near-vertical areas, and rely on the mortar only as 'chinking' to fill the gaps, bond strength is almost irrelevant. Although "disintegrated completely" sound bad for the clay/sand mix... if you have enough residual strength to keep the mortar from trickling out the gaps, almost anything should work (with tapered bricks). I'm a big fan of tapered bricks. Two years ago, I used Heatstop 50 -- next time I won't .

[Tscarborough]

Re: 3:1:1:1

I accidentally broke the cubes, they were too big to move easily. Both stayed adhered to one side, I will see how soft they are when they cool down.

[Tscarborough]

Re: 3:1:1:1

Time to test the homebrews.

[Tscarborough]

Re: 3:1:1:1

OK, that didn't work. It disintegrated completely and did not even leave a residue on the brick, indicating zero bond strength.

[Tscarborough]

Re: 3:1:1:1

The fireclay has finally started to set, I think it may well work for a barrel vault, if not for a Pompeii. I am burning the test cubes today to see how it hold up, but I am sure it will be fine.

[stonecutter]

Re: 3:1:1:1

Yeah, but what a great discussion!

I agree..even if the participants don't see eye to eye, it helps broaden the scope of knowledge.

[david s]

Re: 3:1:1:1

Yeah it did go off topic didn't it. The OP probably ran off because a bunch of kooks were talking

Yeah, but what a great discussion!

[stonecutter]

Re: 3:1:1:1

No I didn't miss post #3

That answers the 1st part of the question!!

Yeah it did go off topic didn't it. The OP probably ran off because a bunch of kooks were talking about clay.

Why don't you enlighten him?

[stonecutter]

Re: 3:1:1:1

89 Posts later has anybody actualy answered poor Gianluca question????

Gian, I hope you have not hanging by your thumbs waiting!!!!

Did you miss post #3?