Red Crackle

R-20

🔥 RakuDiscontinued

Red Crackle is a satin raku from Amaco's Raku line, fired cone 05.

SatinOpaqueTexture-friendlyCone 05
Available at The Clay HoleNo Amaco has discontinued this line and it is not in circulation here. Kept on record because the chemistry is worth knowing.
Test tile
Find it on the glazes shelves Shelf 6, Row 5
Show me where

The quick version of Red Crackle

TypeRaku
FinishSatin
OpacityOpaque
Shows textureYes, good on carving
Glaze fire toCone 05
Bisque toCone 04

What this glaze does

Copper reds over a surface that is meant to break. The crackle is not something in the glaze, it is a network of fault lines opened by the cold air, and the smoke from the can settles into every one of them as soot.

So the pattern you end up looking at was drawn by temperature and filled in by fire. You will hear it happening: the fine ticking as it crazes starts the moment the pot leaves the kiln.

Clays that suit Red Crackle

B-Mix with Grog, 52 Buff, or Berlin Gray. Those are the three bodies we raku on, and the coarse particles in them are what let a pot survive going from 2000 degrees to open air in four seconds.

Raku clay is not optional and it is not a preference. The pot goes from near 2000 degrees to open air in about four seconds, and a body that is not built for that will come apart while you are holding it.

Use one of these threeB-Mix with Grog, 52 Buff, or Berlin Gray. Those are the bodies we raku on here. If your piece is on anything else, it is not going in this firing.
Why grog and sand matterThe coarse particles give the thermal shock somewhere to go. A smooth, tight body has no give in it and cracks on the way out of the kiln.
Build for the shockSoften interior corners, reinforce every seam with a blended coil, compress the floor properly. An uncompressed floor cracks in a normal glaze firing and stands no chance here.
Think before you close a formNarrow necks and sealed forms trap steam and pressure with nowhere to go. Those are the ones that burst.
Decide earlyThis is the one firing where the making decisions happen weeks before the glazing does. Ask an instructor before you build something specifically for raku.
Blocks of clay in the studio at The Clay Hole The complete guide to clay bodies What each body is made of and how it behaves under a glaze. The clay bodies we stock at The Clay Hole The clays we carry Every body on our shelf, with bag sizes and prices.

Applying this glaze to your work

Three brush coats onto cone 04 bisque, stirred well first. Amaco says thin with water or add their gum solution if you need it to brush better. Thin coats give the reduction too little to work with, which is the usual reason a raku pot comes back looking like nothing happened.

Across the Raku line

For the record, Amaco brushes this line in three coats onto cone 04 bisque and fires it to cone 05, about 1911F.

That is a hotter finish than the raku glazes our firings run, which is the reason this line is not in our rotation.

From The Clay Hole University

More info about Red Crackle below, but first... Everything we teach about glazing, written down and taught properly. These are the glaze lessons, and they are a small corner of a library that runs from centering your first pot to selling your work.

Raku Firing: Techniques, Tips and How It Works RakuRaku Firing: Techniques, Tips and How It Works Glaze Brushing Techniques, Coat by Coat GuideGlaze Brushing Techniques, Coat by Coat Glazing Big and Intricate Pottery Faster GuideGlazing Big and Intricate Pottery Faster Getting the Most Out of the Mega Glaze Tool GuideGetting the Most Out of the Mega Glaze Tool Making, Logging and Dialing in Test Tiles GuideMaking, Logging and Dialing in Test Tiles Glaze Problems, Causes and Fixes GuideGlaze Problems, Causes and Fixes Glazing on the Wheel for Even Coats and Clean Bands GuideGlazing on the Wheel for Even Coats and Clean Bands Oxide and Carbonate Washes GuideOxide and Carbonate Washes When to Use Celadon Glazes GuideWhen to Use Celadon Glazes How to Use Dipping Glazes GuideHow to Use Dipping Glazes How to Use Underglaze: Techniques, Rules and Firing UnderglazeHow to Use Underglaze: Techniques, Rules and Firing Mishima: How to Inlay Slip and Underglaze into Carved Lines UnderglazeMishima: How to Inlay Slip and Underglaze into Carved Lines Wipe-Away Texture: Underglaze and Oxide Washes on Bisque UnderglazeWipe-Away Texture: Underglaze and Oxide Washes on Bisque
Browse all 170+ lessons and guides

Firing Red Crackle

Fired to cone 05, about 1911F, then pulled glowing at around 1700F and dropped straight into the reduction can. Our firings run hotter than the book, closer to 2000F by the time the lid comes off.

If you are a member here

None of this is yours to manage. We handle everything on the kiln side, and every glaze on our shelves can be fired safely in our studio.

Common problems with Red Crackle

Why is the crackle black?

Because it is soot. The cracks open first, then the smoke gets into them.

Why did I get more copper on one side?

Direct contact with the combustibles reduces harder. That is where the strongest reds and flashes come from.

Food and function

Not food safe and never will be. The body stays porous, the glaze is crazed on purpose, and this line carries soluble copper. Decorative work only.

Across the Raku line

Raku is not food safe and never will be. Not with a sealer, not with a liner glaze, not if you are careful.

The body is fired hundreds of degrees below vitrification so it stays porous, the glaze is deliberately crazed so it has a network of cracks running through it, and this line carries soluble copper. It is not watertight either. Water passes through the body over hours or days, so a raku vase full of flowers is a slow leak sitting on your furniture.

Test tile pots lined up on the glaze shelves at The Clay Hole

Our test tile pots

This family does not have a test tile pot. The colors and results come out close enough to what the book shows that a pot would not tell you much more, so work from the printed Glaze Bible and the tile above.

More ways to pick a glaze

The Mega Glaze Tool Every glaze we carry, filtered by level, color, sheen and more. The Glaze Finder Type a name and see exactly where it sits on our wall. Clay Hole University Glazing lessons, from brushing to dipping to layering. Download the Glaze Bible PDF The whole printed Bible, in one file.

Membership levels that may use this glaze: Raku

Not sure whether this glaze suits what you are making, or how it works with our system here? Ask an instructor. That is what we are here for, and a two minute conversation at the shelf beats a fired pot you did not want.

How membership levels work Back to the Glaze Bible
About these images and what your pot will actually look like

We have done our best to represent every glaze here accurately, and you should still expect your pot to look different from what is on this screen.

Our glaze tile images are digitally created. They are built to show the character of a glaze, not to be a color match.

A screen is not a printout, a printout is not a test tile, and a test tile is not a finished pot. Each step in that chain shifts what a glaze looks like, sometimes a lot.

On top of that, the pottery itself changes the result: the clay body, how thick the glaze went on, whether it was brushed, dipped or sprayed, what was layered under or over it, where the piece sat in the kiln, how hot that spot ran, how fast it cooled, what was fired next to it, and how much texture the surface had. Two pots glazed from the same jar on the same day can come out different.

Treat every image here as a starting point, and treat a test tile fired on your own clay as the real answer.

Download the Glaze Bible PDF