Hello all! I’m playing around with making containers. I have some alumina/aluminous cement ordered, hydraulic cement, and a high-strength concrete mix on hand.
Anyone have tips for finishing/staining? Anyone have small quantities of stain on hand in the Portland area that I might be able to experiment with?
Here’s an example of what I’ll be coating: 
Having a dark color to begin with, you are not going to achieve any thing lighter than black.
Options for coloring concrete can be in the mixing stage, where you add colorant/dyes.
Or when a lighter colored concrete is set, then you apply a concrete stain.
There are many products on the market for both applications.
With the black color you have there you could apply a “top coat” of light colored concrete then stain or a dyed concrete “top coat”
Seal with a high quality sealer when you achieve the desired effect 
Thank you! Excellent points! I’m wondering though with a semi-transparent stain (indicating some of it is opaque/would show up on black) if layering it over black would actually produce a nice effect 
Looks like it’s time for an experiment
Lowes n Home Depo have dry additive colorants for concrete. Natural browns, darker reds, lighter sand yellows… used them in stucco to get a color I LIKED to match my siding. Mixed up and dried swatches to calculate dilutions.
Should work with silicatious concrete. Was going to do this for pots myself. Have not taken the time.
I like ceramics better, anyway…
Hi @zlessley. You can also add other substrates when mixing, especially if you use the white version of the alumina cement. Things like ground slate, marble dust or even different coloured stone dust. This will give you a similar finish to the substrate you put in, eg slate looks like slate etc. Most of these are freely available from stone masons or monumental (those who create grave stones) masons who are usually glad to let you take it away so they don’t have the cost off ditching it themselves.
Fantastic idea, Keith! Thank you so much!!!
That looks fantastic, any chance you could document or explain how you made that?
Yes! Please show us how ya done it. Looks great.
Hi, Jim!
This is just an extruded aluminum mesh, available from most larger hardware stores, with expanding foam, I’ve carved the foam into what you saw above, and here’s an example of the mesh from another one I’m making:
So… the top post photo is just expanded foam?
Yup. Carved expanded foam on an extruded aluminum mesh armature. Then I’ll put an alumina cement mixture on top of that and see what happens
What is the alumina cement mixture, is it hard to use?
Hi @jim.vogel. The only difference is it dries really fast -like plaster of paris. Best to only mix up as much as you can realistically use in a short space of time. It’s commonly called cement fondue and it’s used in refractories and often for lining kilns, but it is also used as a catalyst when mixed with ordinary cement on large construction jobs.
Is this something you can just set like regular cement, or still requires firing like a ceramic?
It is cement, just a different version. It does however set far quicker than ordinary cement. If it dries too quickly it doesn’t set properly and turns to powder. After spreading it on the frame (or whatever you’re covering) it is best to wrap it in polythene and keep somewhere cool to allow it to set slowly. I prefer to do a few thin layers rather than one thick one as it tends to give better contours.
For my ‘frames’ I use small gauge chicken wire with net curtain material glued onto it. This allows me to put a layer on one side followed by the inside and it avoids having air between the layers (which can happen when using fibre glass cloth).
I got the wrong stuff in the mail unfortunately. I got sort of a heat-cured product. Gonna try tossing it in the fireplace and seeing what happens 
I honestly can’t seem to find proper calcium aluminate cements in the US in a small volume. If anyone has recommendations, please let me know!!
I buy mine from a sculptor’s tools and model maker suppliers. Cement fondue is the trade name of Farage cement which sculptors use to make statues etc. May be worth a shot
