Welcome to Hypertufa. In this thread you will find basic recipes and techniques for hypertufa.
Do not post anything other than a hypertufa technique or information. If you have a question, Please start a new thread.
If someone has Terms or information to add to what I have placed in this post please feel free to Dmail me and I will edit it in :)
If you have info or helpful hints that aren't covered here please feel free to add a post :)
Thank you and Happy Tufa-ing
PC = Portland Cement
Releases for Molds:
wd40 - posted by hostajim1
Perlite, Peat (the dark stuff that is used for soil amendment), Vermiculite
To make additives finer :
Put perlite into a plastic bag and roll with rolling pin until at desired consistency
Push peat through a screen to seperate and make finer
you can use perlite, it might be an extra thing to do but you can put some perlite in a ziploc bag and use a rolling pin or something to pound the perlite into powder, or at least smaller pieces. I use vermiculite instead of perlite. I don't like the the texture of the perlite. I use port, sand, pete, and vermiculite as my mixture. It make a good consistancy and the texture is good. If you don't want to use the perlite you can put it in your garden or make your own potting mixture for you tuffa pots.
Concrete hardens ... not the same as curing ... in a few hours in the summer, and overnight otherwise. Working in freezing weather is bad practice. Wet the surface often, for several days. Wrapping the casting in wet burlap is recommended, as this will help retain the moisture essential to the concrete's curing. It will keep strengthening over time. Its strength is commonly measured after 28 days (although it will keep getting stronger for years, if kept moist).
The optimal temperature range for curing cement and concrete is from a minimum of about 50 up to around 90 degrees Fahrenheit (F). Below 50 degrees F the chemical reaction slows to a crawl. Below 40 it often comes to a halt. Below freezing, the water in the mix forms ice crystals, expands and results in total failure. In one theory, if the water in the mix freezes before hydration is complete, the process comes to a halt simply because the water is isolated in those crystals and is therefore not available to combine with the cement.
ONCE the curing/crystallization process is slowed by low temperatures it can not be regained by longer curing.
Have been googling for info this morning
The reason all the concrete and tufa have these proportion in there mixes is to assure a minimum shrinkage (not noticeable for the eye) and cracking and also durability.
Try not to use chlorated water or any water that they have added chemicals too, that will make all PC mixes weaker and they will crack easier if they are thin
The less water you can add to the mixes the better as long as its workable. the less water the less shrinkage but you HAVE to water your project (keep it wet) to assure its durability if you cut down on the water
The most important curing period is the first month but the curing can go on for years as long as the " item " is kept wet/moist the mixes gets stronger, so after the initial curing on around two week, its good to hose your project with water every day you can.
About the styrofoam, there is some treads in here where people have made waterfalls and boulders that way by putting some tufa or concrete mixes on the styrofoam. BUT I wouldnt use it for making a chair. the coat have to be so thick since the styrofoam isnt strong enough with a thin coat of mix to sit and lean back on.
The plastic chairs is something I have been thinking about too, but havent desided yet to test it. I can imagine that it would work if you sand the plastic with a sandpaper with the biggest graines. But the only way to find out is to test it.