Planning on making some concrete flowerpots

[FJ and G]

using a wood form for the outside and a smaller wood form for the inside (to squish the concrete between the 2 forms. I'll add clay plug(s) in bottom for drain. Might add some latex to color the cement.

Just curious if anyone has tried this and what results you obtained. The forms will be screwed together so I can remove them. The outer form should be easy to remove but if the inner one isn't I'm just going to leave it in place and let it decay or remain intact. Might get fancy with the outer form and put some designs in the wood.

I'm thinking I may need some chicken wire or something to reinforce the cement, which I'll likely make about 2 inches thick for a small pot and thicker for larger pot.

Purchased stone or concrete planters can be pretty pricey, so I guess a bag of cement is worth the trouble even if it doesn't work. 

likely leave the cement in the form for about 4 days before striking the mold. I might not use vaseline as I've not had problems in the past striking wood molds. The inner mold might be more problematic so I think it can stay put. The clay plug will likely extend thru the wood bottom of the inside mold as well.

[ttrigg]

Did a few of that a few years back.  Except the mix was 50-50 cement and spaghnum moss.  They seem to last according to their thickness.  If it can be move easy: break in 3 years, hard to move: 5 years, so heavy that it must be built in its permanent position: last forever.  The moss helps hold moisture within the pot, rather than just soak through and out.

[FJ and G]

Hi Tom,

Thanks for your tips. I got motivated today (15 minutes ago) and went out and did a test pot (first photo). Quicrete to oatmeal consistency. 2 plastic pots. The outer pot has some nice rib designs running around it. I ensured there'd be no mold lock.

The inner pot wanted to float up! So I had a steel water cover lying around (who doesn't) and used it to weight it down. One side wanted to pop up so added a rock on top of that. Found a fairly level place for it to settle. Now it's wait and see. No reinforcement added. Didn't even add the drain plug so I'll drill that out later (see how lazy!). Since concrete is porous, I wonder if the water will just flow out on its own? No? So probably need to drill a hole.

 

While I was outside, snapped some photos to show how little work I've been doing on ROW maintenance. The 3rd photo down is 7/8n18 and the rest is 7/8n2. (Am I the only one on the forum who posts photos of work gone wrong or laziness?)

 

 

 

 

 

 

 

 

 

[FJ and G]

Here's the pot after 12 hours. It slipped easily out of the 2 pots, but it is still green. Should have probably left it in for a few days but I'm impatient.

The holes from aggregate can easily be filled in about a minute with vinyl patching cement. But they kind of look cool like swiss cheese. I poked some holes in the bottom for drainage. The pot could be painted or rubbed with Durham water putty to give it an adobe sort of look

[Rastun]

David,

Usually when pouring a 2 piece mold for something like that you would invert the whole thing so the inner mold is on the bottom the outter mold around it, this keeps the inner mold from wanting to float up on you. This will also allow the cream to rise to the outer mold leaving you a better finish.

Another thing you can use as a mold release is a good brushing of diesel fuel.

Doing conrete molds in a small setting like this you may wish to use a combination of sand and portland cement instead of quickrete. That eliminates the problem of the large aggregate.

There is also a product out that can be mixed into concrete that will allow you to not need the chicken wire it's a fiber that's strands help bond all the concrete together. I can't think of the name of the stuff but maybe call a ready mix company and they can tell you.

Jack 

[FJ and G]

Thanks! Great idea about the inversion. I just didn't want the stuff dumping out on me, but maybe it would stay put. My buddy said I should try adding trickets or golf balls to the batch to give it some character. Maybe even beach glass.

Re: the fiber, that sounds like something that would be worthwhile if it doesn't cost much. My goal is to make stuff for pennies.

As you can see where all of this is leading, not just to flower pots, but is giving me experience so I can create structures and stuff for the garden RR. I've already torn out 30 feet of bridgework to make a concrete viaduct when my skill level increases with flower pots.

[altterrain]

David,

Nice looking pot. From what I have read on making concrete pots, its best to cover them up with plastic, keep them moist and sit them in a dark place for a month to let them cure and strengthen.

The fiber Jack mentioned is fiber mesh. Its just fiberglass shreds that add a strengthening matrix to the mix. Its not expensive but usually only comes in a big bag. Once done you can burn off any of the fiber that sticks out with a torch.

-Brian

[ttrigg]

David;
I think the aggregate holes add character.  So long as you did not add any type of water retarding agent the water should "wick" through the concrete with little problem.  Caution needs to be taken when watering as the concrete will slurp up the water from the soil in the pot, you might consider using an "insulating" layer of moss between the soil/potting mix and the walls of the new pot, to help maintain moisture in the soil.

[FJ and G]

Thanks guys,

Brian,

I'll look into the fiberglass material (maybe fiberglass insulation will work). The next pot I may design as a modified hypertufa,adding a lot less peat moss shreds than recommended to make it partially organic. I may make a bunch of these pots just to see the various qualities obtained from differing proportions of aggregate, sand and so on. I'm not really sure what purpose the aggregates serve; maybe to somehow strengthen the pot? If that be the case, then using straight portland would definitely require reinforcing

 

Tom,

 

I experimented last night. Plugged the hole, filled partially w/ water, and within an hour, the water had oozed thru the cement! Deciding to leave the holes around the pot. BTW, since yesterday, a very tiny red spider made its home in one of the holes. I found out when I filled the pot with water and it floated up.

I planted a hardy local mint in the pot. I may plant plants that love dryness like sedums in these pots.

 

Once I see the characteristics of all of the pots, then I'll use whatever formulas I have for buildings, walls, abutments and so on for the railway.

 

Cheers 

[ttrigg]

David;

Well, looks like you definitely didn't add any use any type of water retardent.  Let the little guy set up house keeping in one of the outside holes, he'll keep down the insect count.

[FJ and G]

Here’s the finished concrete pot. Used a ramp to hoist it up, as I used 120 lb of concrete, plus with the water mixed in, I didn’t want to hurt my back. It's about 4 inches thick.



Tree tunnel



Here’s some photos of some trackage that needs rehabilitation: