Proper concrete cure time ?

[SnoopDog]

I want to make some concrete plugs, or even aggrocrete plugs for some mushrooms that i will frag. The molds will have toothpicks embedded in them. What would be the proper cure time for the concrete ? Also what do i cure it in.

 

[liquid]

I'd let them cure for 24-48 hrs in the air then I'd submerge them in tap water for 5-6 weeks changing the tap water every week or so. If you don't do the water soak you could run the risk of spiking your pH depending on how many you put in your tank.

Shane

 

[wade1]

Since they are plugs, curing can be accelerated greatly by using acid. Give them a couple days to totally solidify, then put them in a 10% acid solution (muriatic or the like from a pool supply area) for maybe 30-60 minutes. They'll bubble some as the outermost layers of lime burn off, then put them into clean fresh water again or even quench it with lye or kalk. That removes a great deal of the readily accessible (and unbound) lime. And since they are plugs, even a little bit of leaching won't matter unless you dump 100 of them into a tank.

Wade

 

[liquid]

If you do go the acid route I'd recommend white vinegar over anything else. If you use muratic or something like that you'll have to use dechlorinator to remove any residual chlorine.

Shane

 

[wade1]

Actually, using muriatic does not require the use of dechlorinator. HCl breaks up into H+ and Cl-. The Cl- in seasalt is the same. The only risk is the production of chloramines, which some dechlorinators do remove. But, if you use lye or kalk to neutralize the acid, you will just form salt.

Vinegar does work, as it evaporates over time and will drop the pH as well, but its not as cheap. Basically, no matter what you do, use alot of clean water to wash it in afterwards.

Wade

 

[liquid]

Good point Wade. Man, it's been too long out of college.

Shane

 

[Anonymous]

Since they are small plugs you can also stick some in the water tank of your toilet. The water gets changes frequently and easily plus you have the added benefit of conserving water.

 

[SnoopDog]

OMG never thought of toilet, what an idea.