Hello forum!
I need to cast a step into a living room in an old stone house. The step is situated in a half-spiral staircase and will be cast directly on an old tile floor.
I can't drive supports into the floor, of course, and the design of the staircase makes it difficult to create any reasonable counter-supports as an alternative. How can I best stabilize a casting mold during the casting process?
The mold will be only about 12cm high, 25cm deep and maybe a meter wide, is it possible to dimension around the problem by using stronger wood in the mold? Or how would you have done it?
Thanks in advance!
I need to cast a step into a living room in an old stone house. The step is situated in a half-spiral staircase and will be cast directly on an old tile floor.
I can't drive supports into the floor, of course, and the design of the staircase makes it difficult to create any reasonable counter-supports as an alternative. How can I best stabilize a casting mold during the casting process?
The mold will be only about 12cm high, 25cm deep and maybe a meter wide, is it possible to dimension around the problem by using stronger wood in the mold? Or how would you have done it?
Thanks in advance!
Yes, weights are always good and stabilizing so that the mold doesn’t float up and move…S slerker said:
An image would help to understand the problem, but generally speaking, double-sided tape of better quality is an effective way to temporarily attach things to flat surfaces. Since the height is only 12 cm, it should work, I think. Maybe you could tape some 45x95-reglar perpendicular to the edge of the form as support? I realize it doesn't sound very professional when I write it, but it surprisingly becomes strong.
Buy a thicker sheet of Styrofoam that you cut to fit exactly. Some glue on the bottom might be sensible depending on how tightly you manage the rest.
fatsug said:
S slerker said:
Thanks for the good thoughts, everyone! 🙏🏻AXS said:
I'm too far from the construction site at the moment to get pictures unfortunately, it will be a few more weeks.
If I calculate correctly, the weight of the concrete shouldn't exceed just over 70kg, so a few concrete bags as support might suffice? The idea with double-sided taped planks was also interesting, I will investigate that.
AXS - I'm not entirely sure about what you mean by "how tightly you manage to fit the rest"? Because you meant to use glued styrofoam as form material, right? What then is "the rest"?
The tighter you get the shape, the less important gluing becomes. Double-sided tape can also work on styrofoam!
Styrofoam is just because it's easy to work with, just cut with a knife. You can obviously do the same thing with wood.
Styrofoam is just because it's easy to work with, just cut with a knife. You can obviously do the same thing with wood.
Skip styrofoam and glue etc., go with a wooden frame and weights...
I did something similar about 25 years ago when I had to cast two small bases for my boiler because the mason had made the flue pipe hole at the wrong height.
I made two wooden molds that I screwed together (easier to take apart during formwork removal) and placed them on the concrete floor. I marked on the floor where the casting was to go and made the concrete surface rough for better adhesion of the cast base. The mold was then placed and held in place with the help of some heavy objects. I don't remember if I used any concrete bags or stones, but it doesn't matter much what it is, as long as it's heavy enough to prevent movement during casting and curing. A tip is to equip the mold with some kind of shelf or similar so that it's easy to add weights that hold it in place; the weight should press on the mold so that it seals tightly against the ground. After that, I cast in the molds and covered the casting with plastic and kept everything moist during curing. After a week, I removed my form and these bases have not yet come loose from the concrete floor.
I made two wooden molds that I screwed together (easier to take apart during formwork removal) and placed them on the concrete floor. I marked on the floor where the casting was to go and made the concrete surface rough for better adhesion of the cast base. The mold was then placed and held in place with the help of some heavy objects. I don't remember if I used any concrete bags or stones, but it doesn't matter much what it is, as long as it's heavy enough to prevent movement during casting and curing. A tip is to equip the mold with some kind of shelf or similar so that it's easy to add weights that hold it in place; the weight should press on the mold so that it seals tightly against the ground. After that, I cast in the molds and covered the casting with plastic and kept everything moist during curing. After a week, I removed my form and these bases have not yet come loose from the concrete floor.