Any opinions regarding tamping (jitterbugging) concrete flatwork? I’ve always done it but a mason friend says never, it always causes the surface to flake.
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There's an art to jitterbugging. I only do it initially to levl the surface to screed, no heavy pounding. You don't want to weakin the surface by pounding the aggragate away.
Most times lately I don't use it much since I started using a self leveling 10" slump 8)
Are you talking about a power float http://www.multivibe.com/floating.htm a power screed http://www.multivibe.com/screeding.htm or what?
Edited 10/29/2005 11:19 am ET by Matt
Me thinks he means a vibratory screed.It's Never Too Late To Become
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no , he means a jitterbug, its a fine screen wire mesh on two handles that pushes the rock just under the mortar. 15 years ago everybody did it. I have not seen anybody use this method in over 10 years. I guess it doesnt matter.Edited 10/29/2005 11:44 am by brownbagg http://www.howibuiltmyownpool.com/images/decking-2nd-tamp.gif
Edited 10/29/2005 11:45 am by brownbagg
We call them jutes(sp?)
15 years ago everybody did it.
Oh yeah, now I got it.
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We have way better floor mixes now than even 10 yrs ago, and with concrete placing by pumper being the most common method of placement, jitterbugs have become unnecessary.
Pump mixes typically have more " fat " which allows the concrete to be pumped, and aids in placement workability.
Jitterbugs may still be necessary for " chute " mixes as they can be much harsher.
By harsher I mean that the mix contains a higher percentage of "rock aggregate" than a typical pump mix.The jitterbug is used to force the aggregate down allowing for the " fat" to be surfaced, allowing for easier finishing. Because the jitterbug is labor intensive, most placers leave it at home.
Good results can also be had with a vibrator which also causes the " fat " to rise somewhat. MagicScreed and Vibratestrike incorporate vibration to "flatten" the concrete, however accurate raking must be done to achieve good results with these tools.
A good screed man with a 2x4 hand screed, a lazer man, and 2 rakers are still a high perfoming group if they are experienced and work together,and the conrete is a suitable mix design.
I was typing when you posted and you answered some questions I had, Thank you. I mostly do small jobs out of a chute so I guess I'll keep my jitterbug, but I'm wondering if the 2x4 vibrator screed is a worthwhile tool
Tom
I think the rental yards don't keep vibrating screeds because of the clean-up hassle, with the customer.
It is certainly worth the investment and you could rent it to your friiends.
A 7 ft blade would be useful for basements and 10ft for outside slab on grades.
I your RM supplier is sending you harsh mixes , ask for a little "air" to aid workability.This will also cause the mix to remain more homogenous and let you leave the jitterbug at home. Better yet, sell it and get a long handled darby with the money.
Placing floors fast can be critical in hot weather. Why jitterbug and expend the energy, when you can save some juice for hangin on to your power trowel ?
I do mostly small concrete jobs too, often mixed on site. Thanks for all the feedback. I have used a screed vibe on a 2x with success, haven't been able to justify the expense of buying one. Still haven't heard anyone say a jitterbug will cause the slab to flake. Of course we're talking about just using the tool to settle the big rocks and work up the fat. I don't (nor do the clients) like seeing the aggregate shadow on a finished slab which is often the case when no tamping occurs
a bunch of things can cause the surface to flake or scale. Excessive jitterbugging is one of them, but just an intitial tamp doesn't hurt a thing.
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I have used a screed vibe on a 2x with success, haven't been able to justify the expense of buying one. I have used a screed vibe on a 2x with success, haven't been able to justify the expense of buying one.
I have 3. You around here (fill in your profile)?PAHS Designer/Builder- Bury it!
I'm one hour North of Santa Fe, NM
Built my own vibrator for flat work years ago. flat plate bolted to 2 horizontal 2 x 4 or 2 x6 or later, 3 x 3 aluminum, bolted small gas motor, honda 5 hp, with a mandrel and a plulley with a piece of rebar welded to it, did a good job, 14 ft. coverage with the aluminum. just pulled it over form or screed bars. 1 pulled, couple of rakers, makes job 'easy' ( if there is such a thing with concrete placing ! )
IF IT WAS EASY, EVERYONE COULD DO IT !
1 pulled, couple of rakers, makes job 'easy' ( if there is such a thing with concrete placing ! )
That's why I bought the four at auction. These are commercial units similar to what you copied. My cost was $40 for the bunch. Sold 1 for $200. Should put in fresh gas and advertise another. Like vibrators, I want a spare around anytime I'm doing a pour.
Taos, or wherever, is a tad far for delivery.PAHS Designer/Builder- Bury it!
VT,
I might want one of those extra screed vibrators, how much you looking to get and what kind of shape is it in? We have borrowed them before and they really help.
MC
Got $200 for the last one, quickly. They're all the same. Run well, but certainly not new. And you're gonna ask the brand, which escapes me at present. I'll look tomorrow. Something Tool Crib sold. IIRC, good to 16'. Looks like a lawn mower.
You travel this way? PAHS Designer/Builder- Bury it!
Flake and scaling is caused by too much water in the mix , not having some "air entrainment" in the mix , or not allowing the initial bleed water to evaporate before commencing power trowelling.
If you trowel in the bleed water you can pretty much guarantee flaking.
Improper curing, improper sealing, or having your salty car dripping on your newly poured floor can also play havoc with the finish.
Too much "air entrainment" by wetting down a rich mix will also cause peeling during the finishing operation, but I don't think you are dealing with that here.
The most common problem is pouring too wet,period.
It is the easiest thing to do when mixing yourself onsite...adding too much water.
Not a mason, but I do misc flat work on occasion. I've found that when I dont jitterbug I hit rocks when I finish. I try to be an artist as Jagwah suggests. Set the jitterbug down, work the rock down with a little bit of arm motion, and then move on. Or so I was show by an old timer anyway. I have seen finishers beat the suface with the tool.
I've been curious about the vibratory screed. On the job with one once and it seemed to work well but I wonder if it settles the aggregate too much. Rental yards here wont carry them which makes me suspicious.
Tom
I had my 24x36 garage floor poured in august, and the finisher used a vibratory screed to level it. He just made one pass, presumably to avoid having the aggregate drop out. Nice stiff mix (except for the last 3 yards, which came in sloppy from the plant).
I wasn't really thrilled with how flat he got it - there's one puddle about 3/8-1/2" deep and a few others not as bad - but acceptable for a garage/workshop. Not sure if he normally gets it flatter. Concrete was delivered late, so the sun must have started baking the slab just after he screeded, plus his helper was his approx. 12 year old son. I'm guessing he had to really hustle to get it trowelled before it set up too much, so maybe he didn't get a chance to really play with the levelling. Got a nice finish, though, and no sign of cracking. (No control joints)
Don