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Super crumbly, didn't work

Posted by ms_minnamouse 7a (My Page) on
Sat, Jan 18, 14 at 19:50

So I bought a 10 lbs back of Quikrete portland cement mix to try out hypertufa. Um, yeah, it didn't work. Even though I followed the recipe on the Q&A page on here. I even added some rope fibers for further strength to the cement, peat, and perlite.

It developed cracks while drying and also is very loose and crumbly. It's not going to hold up at all.

? What could I have done wrong? Did I buy the wrong cement mix? I don't know of any other Quikrete portland cement pre-mixes that come in the 10 lbs bags.

Follow-Up Postings:

RE: Super crumbly, didn't work

In my part of the world, Portland cement doesn't come in 10 Lb. bags, only 94 and 47 Lb. bags. We use Portland cement not cement mixes.
Just went to see what recipes you were talking about. Did you buy sand mix instead of straight Portland cement? I couldn't find the recipe using the rope fibers so hard to say what went wrong. Could you tell us the recipe that you followed and if you followed it exactly. As I said, I couldn't find the rope fiber recipe.

RE: Super crumbly, didn't work

I made this recipe found in the FAQ section.

"I encourage anyone who is STRUCK by the hypertufa bug and unsure if this is for them, to seek out the pre-mixed sand mix. Lowe�s (in my area) carries the Quikrete sand mix in the smaller 10# bags; they also carry a 60# and 80# bag. If you get the smaller size, you can try it without a huge investment in supplies. Dependent on the size of the bag, you may actually be able to carry it!

Recipe #5

1 part pre-mixed sand mix
1 part peat moss
1 part perlite or vermiculite

Mix the dry ingredients first, then slowly add water so that you can gently squish the mush with little water coming out. Now add a little bit more water and walk away for about 10 minutes. Check your mold set up or think about your next project. Then, back to the mix. Check it with your hands (of course they are gloved!) and add a bit more water, if needed."

Rope fibers aren't part of the recipe but it's still super crumbly and weak with or without them.

RE: Super crumbly, didn't work

Did you add anything else besides the rope fiber? How much rope fiber? how much water? Was the mixture too wet? What did you do exactly? Not trying to be funny but people say they followed the recipe exactly and they didn't and what they added caused the problem.
You asked on the papercrete thread what the paper was for. It's papercrete and that's one of the ingredients. Just like peat moss is an ingredient in Hypertufa. Hope that helps.

RE: Super crumbly, didn't work

Okay, I think I wasn't adding enough water. My dad showed me the "slump test" so I think I have a general idea of how much water to add now. I also mixed up the cement mix (dry) so that it's all evenly distributed just in case it settled.

I'll have to see what it looks like tomorrow after some curing.

I didn't measure the rope fiber, I just shredded and added like a teaspoon or so.

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