Some people like to use fiberglass strands for large projects, but I haven't found them that necessary. And, if I do use them, I just use a small handful in a large batch of mud.

Speaking of fibres, I was reading in the old book Concrete Pottery and Garden Furniture (from 1910) that they used goat hair for fibres.. Wondering if anyone has tried that or wondered if horse hair would work also? As mine are shedding now ...might come in handy....lol

Hey! tamahlee speaking of fibers-I have a bag full of dog fur from my (silky haired) Havanese, was planning on putting this out for bird nesting material-may have to keep some for my next project! Never could get excited about handling those fiberglass fibers-makes me itch just thinking about it. Guess we could all start trying different items for strength or even for a varied appearance and see what we get, 'hyperfurta' ?

I tried fibers after reading many post to various forums. They were purchased from a local cement batch plant. I don't think they offer any real benefit considering how difficult they are to use. If you do not want them to clump you have to "sprinkle" them into the mix - what a hassle. Then they write you can simply burn the fibers off the completed project - YUK! Why add more work? Why bother?

My next project will be a garden sphere. The first coat cement and sand, then a layer of fiberglass drywall joint fabric, and a final slurry of pure cement mixed with ½ water and ½ acrylic additive. I have no idea how it will come out but it should be fairly light..

In your case you so right on - you cannot get a smooth finish with fiber additives unless you use a slurry overcoat.

valolson1 is right: if it is not a "huge" project they are unnecessary.

My 2 cents.

I've run across two kinds of fibers -- some are little chopped up strands of fiberglss (without the itch). Don't know if they help, but I throw a handful in a fairly large mixture. Can't hurt. I figure the larger pieces need them for strength and they take the place of chicken wire - which is something that can be a real pain to use. The other kind of fibers are soft and you have to separate each and every last piece of the little blighters and are the absolute horrors to deal with definitely early cave -- they look like wet cats in the mix. Yuck.

The old timers used horse hair in their plaster, so why wouldn't it help in concrete (early version of the fiberglass fibers)? Would the concrete cause the hair to breakdown? There is lime in plaster so maybe not.

They do make your troughs look hairy and you have to take out the propane torch and blast them off. You are right it is another step.

Being neurotic about the larger troughs breaking, I use 'em and hope for the best.

Found some stuff on Google about curing:

"Improper curing can easily cut the strength of even the best concrete by 50 percent. Curing simply means keeping the water in the concrete where it can do its job of chemically combining with the cement to change the cement into a tough "glue" that will help develop strong, durable concrete. Good curing means keeping the concrete damp and above 50° F (10° C) until the concrete is strong enough to do its job.

Recommended practice calls for a minimum of seven days curing (except for high early strength concrete) or the time necessary to attain 70 percent of the specified compressive or flexural strength, whichever period is less.

All concrete must be cured to attain maximum strength.

Correctly cured concrete is best from every standpoint: It shrinks less, cracks less and dusts less. It is stronger, is more durable and is more wear resistant.

Start curing the concrete as soon as possible after it has hardened. Early drying &endash; especially in hot, windy weather &endash; must be prevented or the concrete will not attain its full potential quality.

If it's too hot, the water evaporates too quickly and weakens the mix."

Happy Pots.

DebraWPope,
Can you tell us which fibers worked and which were hard to use? I was about to order Fibermesh polypropylene fibers off Ebay until I read your comment.
Thanks,
David - Dallas

I stopped by my local cement batch plant and had a coffee can in my hand. I figured I could get some.. The guy gave me 2 1# bags of fibers.. they look like curly doll hair and is kinda in locks like hair.. I will try to break it up.. Not sure if it melts or burns yet. they were free. It says to add 1 # to 1 cu yd cement. So I think I have enough for my life.

I stopped by my local cement batch plant and had a coffee can in my hand. I figured I could get some.. The guy gave me 2 1# bags of fibers.. they look like curly doll hair and is kinda in locks like hair.. I will try to break it up.. Not sure if it melts or burns yet. they were free. It says to add 1 # to 1 cu yd cement. So I think I have enough for my life.