duburban

Hey countertop guys. I'm working on getting away from quickrete for more custumizable mixes. Please send me some recipes your using for certain qualities. I just tried a mix that came out too dry, too many voids. I'm on the verge of being able to mix ok. Any help, ideas would be great. Also, all i could find on the big island of hawaii for 3/8 gravel was crushed rock, not pea gravel, although looking through the quickrete mix it looks like they have crushed rock in there too.

Also, How are you customizing colors affordably?

genecarp

What are your complaints with quickrete, what do you want to accomplish with a custom mix?

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Jayrek

I am not all that familiar with hawaii, but arent your options limited ??

You cant order spec-mix can you?

Being an Island and all.

gallerytungsten

Check out the Concrete Countertops book by Cheng, he gives lots of detailed mix ideas.

duburban

I have been through Chengs book but he gives only one example of a custom mix. I just tried a mix with white cement to broaden my color options. Quickrete is fine, but it has its limitations ie, color, agg size...

Hawaii can get anything you want to pay for. I just found a supplier that carry's buddy rhodes mixes. I'm not looking to buy a prebagged custom mix. I want to buy all the ingredients and mix it based on the project needs.

I'm only into custom mixes for the sake of understanding it thoroughly for future projects that need tweaking, like a pure white peice. And if i was ever to get into GFRC, I would definitely need a strong background in mix design.

Just curious what you guys are playing with. How about colors?

duburban

And... what are you using for vibration?

I've had great success clamping a sawzall blade to the table and rocking out on it. Hell on the saw but serious vibration... palm sander doesn't seem strong enough. Oh... and i also use a rotohammer on hammer only and put a block on the form and hit it with the hammer. Works good too.

GunitePoolGuy

We make our own precast concrete swimming pool coping and ive done about a dozen countertops for friends and friends of friends. If youre getting too many voids/bugholes use more cement. Everyone gets bugholes so dont worry too much about them cause youll drive yourself crazy trying to cast a perfect piece. as a general rule, the more cement, the higher the psi. silica sand and pea gravel are great for psi as well. also, use more sand. like, 3 parts silica, 1-2 parts gravel and 1-2 parts cement. You'll be hard pressed to find a concrete countertop man share his mix design.