Rick, Thanks for the info. I'd read on one of the concrete sites that Portland is ground fine enough to flow through a screen/sieve that would hold water. Now thats fine. So it's no wonder that it grabs onto moisture like it does. I've got mine in 5 gallon buckets with lids that have rubber seals. Again thanks for the update from the rep.

Clumps are a constant problem for me in white Portlands.
I use a standard flour sifter and toss the lumps.
Strength is not a problem for me and my white portland test bricks are not weaker than the grey.
White flecs in the final product however are a constant pain however, so I decided white flecs are a feature and have learned to live with them.:)

tufaenough-read my message.The clumps are a problem with the supplier.Ask them the age of the package.I've not had problems until recently.And,again,from one supplier!

Rick unless I want to drive 250 miles I have access to only one brand, one supplier.
The lumps are only a problem for me none of the contractors buying the stuff are complaining so I have to shut up and bear it.
The lump problem is in the bag before my supplier even get's them. Turnover is not the problem.
I suspect my lumps are a different problem than your lumps.:)
I've only had one good bag.

Hello!
I´m trying to study White Cement problems, because I´ve been required to in a Subject of Industrial Engineering, and I´d be very pleased if some of you could tell me more exactly what these "clump problems" are.

Thank you very much!!

Plopplop --- I'll jump in here too. I used to routinely use white Portland for sculpting and what I call "micro-clumps" are both a consistent and aggrevating problem. Yes...Houston, Texas tends to be a little on the humid side ( as in 140% humidity, year 'round), but I've bought two different brand-name products from high-volume commercial distributors who turn their inventory quickly...and it's still a problem. Especially with any mix that employs integral or surface applied oxide colors. The annoying little white clumps show up on the surface uncombined with the integral color. ARRRGHH! I spent a month or so running controlled tests before I could confirm the source of the problem...and it definitely is the white Portland. I've just about given up on it as it seems to be insurmountable by any of my mixing methods.

So...if anyone has a fix for this...please let us know what it is. Otherwise, I'm sticking with my (very) light gray.

Tango

I am trying to make a white cement whiter, I am using Portland white cement but it is not white enough for me. Should I be using white sand instead of regular sand? If so where can I buy this in the Vancouver, Canada area?
Are there any ways to or tips to get whiter looking finish. This mixture is being used to make white cement railing outside.
Luc

Luc, there is a listing of BC suppliers at thegardenartforum dot com, if you look under the forums for work areas, materials and tools you should find it.

What is the additive used to make white concrete whiter? Not sand, but a whitening agent or type of filler.

I can't find my bookmark for it, IF I bookmarked it.

Any help is appreciated.

Sue

You might try metakaolin, which is quite white; Advanced Cement Technologies in Blaine, WA has it. Google their name. It looks like it might be easier to use than silica fume; both agents are used to make high strength concrete. I haven't used either one, since my 'tufa abilities are still at the extreme newbie level. If you try the metakaolin, please post your results.
Good Luck!

white cement supplier from China

Here is a link that might be useful: white cement

What cement to use to Make Hypertufa? Can also be used for fake rocks. I tried cement from home depot it doesn't still, crumbles. I have spent quite of bit of money getting all the ingrediants and so far it all crumbles,