home made concrete bonsai pots/forest slabs

[penumbra]

Here are some example of the Portland expanding grout slabs/pots. All Painted.

Great pics, much appreciated.

 

[TinyArt]

Portland expanding grout slabs/pots.

And good to know there are different recipes for success in differing climate zones --

 

[Tibor]

Íme néhány példa a portlandi táguló fugázólapokra/edényekre. Minden festett.

boldog Karácsonyt

 

[PonderingSage:]

Nice!

 

[WNC Bonsai]

I am considering adding either glass microspheres or perlite to the concrete for a lighter slab. Any advice on mixing ratios for this approach? I saw one YouTube video that used them 1:1 but is that likely to be too much of the lighter material? I am using Quickcrete Vinyl Concrete Patcher.

 

[ShadyStump]

I am considering adding either glass microspheres or perlite to the concrete for a lighter slab. Any advice on mixing ratios for this approach? I saw one YouTube video that used them 1:1 but is that likely to be too much of the lighter material? I am using Quickcrete Vinyl Concrete Patcher.

I can't speak to the particular concrete you're using, but a 50/50 mix by volume of cement and filler is about standard.
I'm not 100% on how it would apply to pots, but my guess is you may want something harder than perlite to maintain structural strength.

 

[Tibor]

I can't speak to the particular concrete you're using, but a 50/50 mix by volume of cement and filler is about standard.
I'm not 100% on how it would apply to pots, but my guess is you may want something harder than perlite to maintain structural strength.

To mix different proportions in smaller portions, to test this, it would be good to do a bending test with them. It's a long process, but you would learn a lot from it.

 

[Frozentreehugger]

Been wanting to try it . Especially for a larger slap and or unique pit . 2 things will a concrete slab stand up to freezing and has anybody had any experience with fibreglass . I mean pot experience. With glass

 

[Tibor]

Ki akarta próbálni. Főleg nagyobb pofonhoz és vagy egyedi gödörhöz . 2 dolog, hogy egy betonlap kibírja a fagyást, és van valakinek tapasztalata az üvegszállal. Úgy értem, pot tapasztalat. Üveggel

Nem üveg, hanem műanyag.

 

[penumbra]

Concrete, perlite and fiber mesh.

 

[ShadyStump]

Actually, I believe @Tibor may be our resident expert in the matter.

What do you use for lighter cement pots?

 

[WNC Bonsai]

Concrete, perlite and fiber mesh.

In those proportions?

 

[WNC Bonsai]

Been wanting to try it . Especially for a larger slap and or unique pit . 2 things will a concrete slab stand up to freezing and has anybody had any experience with fibreglass . I mean pot experience. With glass

There have been a lot of folks who have used concrete slabs in freezing conditions, not a problem. My concern is whether perlite will hold up well and whether a 1:1 mix would in effect dilute the concrete too much?

Peter Chan has molds that he uses to make fiberglass slabs for his forests.

 

[penumbra]

Equal portions except fiber mesh which you use very little of depending on brand, follow directions. Probably only an ounce or so.

 

[WNC Bonsai]

Equal portions except fiber mesh which you use very little of depending on brand, follow directions. Probably only an ounce or so.

I guess you can just cut up and shred some old fiberglass curtains, but does anyone sell the stuff any more—maybe auto parts stores? But since I plan to use galvanized steel stucco mesh as a core base for the slab is the fiber mesh even necessary?

 

[penumbra]

I guess you can just cut up and shred some old fiberglass curtains, but does anyone sell the stuff any more—maybe auto parts stores? But since I plan to use galvanized steel stucco mesh as a core base for the slab is the fiber mesh even necessary?

Fiber mesh is a shredded additive that has been used for decades to enhance the strength of concrete. You use very little and you don't need the steel mesh. There are many ways to do it, pick what you like.
And look in the archives. This has been repeatedly discussed.

 

[moke]

Concrete Rock Pot/Slab?

Here’s a concrete pot I made for an elm forest in desperate need of new pot. I plan to repotting them into this in the spring. I’ll share pics in the spring after it’s planted.

www.bonsainut.com

Mokes Cement Rock Pot How To

Just wanted to share how I make cement rock pots. I promised @Silentrunning @Woocash & many other B-Nuts that I would take pics and show a step by step how to? So I hope this helps someone create their own :) First, I start with an idea in my head sometimes I draw it out but usually just...

www.bonsainut.com

Here’s a couple of threads I did awhile back that may have some useful info?

 

[Leo in N E Illinois]

Hypertufa - if you add peat moss or shredded paper or any organic to your cement to make a organic concrete blend, you will and I repeat, you will get spalling in winter. This is deterioration means that in the Chicago area, a hypertufa pot will decay to gravel in about 7 to 12 years. The decay process is part of the "charm" of hyper tufa. In southern, more mild climates, moss will grow on the exterior and it will look charming. Up north, it will look charming for a shorter period of time, but it looks charming. Hyper tufa is short lived.

Perlite - this will be a weaker concrete, Use perlite ONLY if weight is a serious problem. If the pot you are make is small enough to be lifted even if made with "normal" aggregate, then skip the perlite.

Do consider using attractive aggregates, colorful quartzites, or maybe crushed garnets, or nice color of crushed granite as your aggregate. Spray a thin film of sugar water over the outside surface of your form. When you strip your form, a soft spray will wash away the outer layer of cement paste (the sugar will have retarded the set) and you will expose the decorative aggregate. Or skip the retarding sugar, use a sand blaster to remove a layer of cement paste. Wire brush can work too.

 

[WNC Bonsai]

@penumbra I am using the wires mesh as a form on whihc to apply the cement. It provides the basic shape for the pot which is sort of a shallow ”S” curve.

@Leo in N E Illinois I will gove perlite a try on the large one I am building and hope the wire mesh holds it together.