Texturing clay

[Clemo1971]

Hello 

is there a way to texture clay to make it look like rocks , like a cement type look ? Wanted to make a reef aqua scape for a fish tank so needs to look textured like stone and rock 

thanks in advance 

[liambesaw]

Use a really groggy clay and when its leather hard you can sponge it off to make it look like sandstone

[Pres]

There are rollers out there that have all sorts of patterns for texturing a slab, at the same time you might try making squared coils of clay on a textured surface, cut the coils into clocks and assemble. I have often just had an "outline"  of what I wanted to just go with the flo, building with slabs or pieces until the pot was done. you could also incise the types of textures you are looking for in a finished piece by using a pointed tool to carve and create the decoration.

[blackthorn]

I use rocks and other natural objects I find to give texture. 

You mention cement , I've rolled slabs out on a particularly textured part of a driveway and streets.

But, 1) watch for traffic and 2) make sure to clean off any junk that the clay picks up.

The first step, though, is to start trying things. Lots of good stuff mentioned by Liam and Pres.

[oldlady]

try rolling a peach pit into the clay.  the part that would separate the pit into two halves makes a great impression like tree bark.    a piece of ledge rock with the layering ridges works well, too.  there are lots of textures in the environment without buying something every other potter has also bought.   use your eyes and imagination instead of cash.

[Magnolia Mud Research]

Adding to the list of approaches: 

I have been working with surface textured ware for the last couple of years.

Another way is to embed "sand and rock" into the surface of a lump of your favorite clay body that has been shaped to your own design.  

My current method is to get the shape close to final, spray the surface with water contaminated with baking soda (say a teaspoon of baking soda to a cup of water), then spread and compress the "sand and rock" particles into the surfaces, and let every thing dry some (at least past the sticky stage) for cleaning and final tweaking of the surface.  then dry and fire.  
Keep in mind that putting glaze over the "sand and rock" will somewhat change the "natural raw" rock and sand surface effect.  

Another alternate is to use you normal clay body to make your form and then apply a slip made by adding rocks and sand to your clay body and apply the slip on the areas where you want the 'rock and sand' look.  after the slip stiffens wiping of the surface to remove excess clay and show the sand and rocks.  

timing of the steps is important in either approach and is determined by trial and error for your materials and environment.  

I have two test pieces that applied sand/gravel over "wet glaze" on bisqued ware and then fired.  Got a textured surface held in place by the glaze, but have not yet worked on how to control the effects.  

Start making small simple forms and try various approaches.  Then build up from there to the items that you have in mind.  Test your rock and sand sources to be sure that the materials don't make problems such as shattering or melting from the heat of the kiln.  

 

LT

[Pres]

Perlite and vermiculite added to clay will burn out, leaving a pitted surface, as will sawdust.

 

best,

Pres

[liambesaw]

1 hour ago, Pres said:

Petalite and vermiculite added to clay will burn out, leaving a pitted surface, as will sawdust.

 

best,

Pres

Perlite I think you mean?

[Pres]

Good call Liam. . . Perlite. . . Been many a year since I used it, We had a one day workshop for making using the Perlite in a ^6 clay, that night they bisqued them, and then we glazed them the next afternoon. Interesting project as I did a lot of summer sessions that it would have worked for. However, I had downdraft tables as I mentioned before, and they did the same job without having contaminated scraps.

 

best.

Pres

[Clemo1971]

Hi guys thanks for the replies , what sort of clay would you use , as it would need to be waterproof as it’s going into the tank so I’m guessing would need to be Fired 

[blackthorn]

We've all been concentrating on your original inquiry about applying texture and not the final placement of your piece.

Yes, firing is an essential. Especially since you'll have the piece in water. Otherwise,  it'll just melt in the bottom of the aquarium.

Not good to look at. Or for fish.  And after firing, well,  fish, that's another consideration.   

I've kept aquariums at times and I've done ceramics as well, but never put the two together.   I'd advise caution in doing so.

I just googled "ceramics" and "in an aquarium" and the few things I read confirm my doubts about the safety of your fish, although some seem to have done so without issue.

Here's just one post, with varying opinions and I recommend you find and read others.

I hope that helps.

 

[liambesaw]

Most commercial aquarium decorations are slipcast earthenware, and do just fine.  I wouldn't bother glazing them.

[LeeU]

I use porcelain for features in my freshwater tank. I like it, the fish like it, and no problems. These are cone 6 electric.

[blackthorn]

Good to know.  Nice work Lee.