Hello everyone,
I need help with a simple question about casting, but I don't know the answer.
I am currently casting decorative "concrete" tiles which I have done many times before.
I am casting these in fiberglass mix to make them thinner and thus reduce the weight.
Since the tiles have a slight load-bearing property, in previous castings, I have chosen to keep them in the mold as long as possible to make them as strong as possible. I have therefore kept them in the mold for 7 days and also watered them for 7 days with plastic on top to retain the moisture in them. This is because I have heard that the slower they cure, the stronger they become.
Now, however, I am going to cast quite a large number of these tiles and I need to get them out of the molds as quickly as possible WITHOUT losing quality and tile strength.
My question is as follows:
Would I get just as good strength in the tiles if I take them out of the molds after 3 days, BUT continue to water them and keep them wrapped in plastic for 7 days?
The difference here is that I would take them out of the mold after 3 days, but still continue to water them. In other words, how important is it really for them to stay in the mold for more than 3 days, provided they become hard enough that I can release them after 3 days? Does the mold have any function after the first 3 days?
I hope you understand what I mean, I don't know if I'm expressing myself clumsily. But if I can take them out of the molds after 3 days and then, as mentioned, continue to water and wrap them in plastic for 7 days, I could then stand them against a wall and thus free up floor space that I can then use to cast another tile.
Big thanks in advance. All answers appreciated!
e.
I need help with a simple question about casting, but I don't know the answer.
I am currently casting decorative "concrete" tiles which I have done many times before.
I am casting these in fiberglass mix to make them thinner and thus reduce the weight.
Since the tiles have a slight load-bearing property, in previous castings, I have chosen to keep them in the mold as long as possible to make them as strong as possible. I have therefore kept them in the mold for 7 days and also watered them for 7 days with plastic on top to retain the moisture in them. This is because I have heard that the slower they cure, the stronger they become.
Now, however, I am going to cast quite a large number of these tiles and I need to get them out of the molds as quickly as possible WITHOUT losing quality and tile strength.
My question is as follows:
Would I get just as good strength in the tiles if I take them out of the molds after 3 days, BUT continue to water them and keep them wrapped in plastic for 7 days?
The difference here is that I would take them out of the mold after 3 days, but still continue to water them. In other words, how important is it really for them to stay in the mold for more than 3 days, provided they become hard enough that I can release them after 3 days? Does the mold have any function after the first 3 days?
I hope you understand what I mean, I don't know if I'm expressing myself clumsily. But if I can take them out of the molds after 3 days and then, as mentioned, continue to water and wrap them in plastic for 7 days, I could then stand them against a wall and thus free up floor space that I can then use to cast another tile.
Big thanks in advance. All answers appreciated!
e.
The slabs do not cure more slowly in this way. The curing and strength gain are primarily affected by the temperature. The strength increases the most at the beginning of the curing time before declining. The concrete must have enough water during this process. If you want to get the slabs ready faster, you should increase the temperature in the room while still keeping them moist. You can even store the slabs in a water bath!
The simplest way to see if they can be removed from the mold earlier is simply to try.
If you have a suitable mold and also fiberglass reinforcement, I believe they could be removed even earlier than after 3 days. One method is to have a frame mold that lies (but is not attached) on a sheet (of, for example, sheet metal, plywood, or board). This way, you can cast many slabs simultaneously by moving the frame between them as soon as the concrete has set.
It sounds like a brilliant idea... too bad my slabs need to be cast in different sizes for the project.
But regarding curing, can we say that the form has absolutely NO function after the first 2-3 days? Simply put, as soon as they can be removed from the form, one CAN do so without losing any strength, provided that they continue to be kept moist, etc.?
Have I understood you correctly? If so, that's very good news!
Best regards
e.
But regarding curing, can we say that the form has absolutely NO function after the first 2-3 days? Simply put, as soon as they can be removed from the form, one CAN do so without losing any strength, provided that they continue to be kept moist, etc.?
Have I understood you correctly? If so, that's very good news!
Best regards
e.
Member
· Västerbottens län
· 18 051 posts
If you don't have too much water in the concrete, you should be able to cast twice a day if you use the described "cake mold."
The pros (precast concrete industry) remove the mold almost immediately, but then they have good concrete.
But water to keep the heat down.
Protte
The pros (precast concrete industry) remove the mold almost immediately, but then they have good concrete.
But water to keep the heat down.
Protte
That concrete is earth-damp. That is, a concrete that you barely get dirty from if you squeeze a ball of it in your hands. Compare it to building sandcastles in the sandbox with the kids. If the sand is too dry, it can't be shaped, and if it's too wet, it flows away. Additionally, the concrete is vibrated and pressed under very high pressure. I have worked a bit in a concrete goods factory, and we shaped it a few seconds after the vibrating and pressing stopped. The next day, we could stack the products on pallets. In some cases, we could handle the products after about 16 hours.prototypen said: