I have used some failures in batches. What I do is just add more Portland - I have been successful with adding 1.5 times more then I would in a normal batch. Make sure you crush up the left overs so that they get evenly incorporated into the new batch

For the record... it did work, for anyone who tries this in the future. I did add a bit more portland this time, but it probably didnt need it.

I recycle as much as possible and that means all the "tufa residue" that comes off when I'm wirebrushing gets put in a bucket to be re-used. If for some reason the project breaks apart and it's still in it's "first cure", I just recrumble and put in the bucket. If you wait until the pieces are a few days old, they'll probably be too hard to crumble.

I mix this excess in my new batch and have never had a problem. Nothing goes to waste when it comes to hypertufa.

My tufa failure was too hard to crumble, even when I took a hammer to it. I decided to try to save it anyhow and added portland and water. As I stirred it in the wheelbarrow, I thought it resembled meat balls and sauce. Then I shoveled it into a large garbage bag placed into a large plastic garden pot. The unveiling was today and it still looks like meat balls. Maybe I'll make a saucer for it and call it a bird bath. I love this hobby. Sharon ;)