Concrete lawn mower questions (Making)

:The width does not have much to do with whether it will be heavy :enough. If you make it 2 feet wide, all the weight will be on a 2 foot :wide piece of lawn. :If you make it 4 feet wide the weight will be on a 4 foot wide piece of :lawn. Exactly the same amount of weight per foot. : :If I were making one I would make it bigger in diameter. Probably :about 16 inches in diameter. I would make it longer than 2 feet, but :probably not 4 feet. I might have a problem pushing one that was 4 :feet wide. : : Dan

Reply to
David R Brooks
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I bought the things to try to make one of these:

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(concrete roller). The tube form is 8 inches wide by 48 inches tall. This guy cut it in half to make a hand push roler. If I wanted to make one to pull behind a small tractor like the cub, would it be benificial to not cut it in half and just use the hole form? (All 4 feet?) Would the form be able to take this weight standing up? I have a one inch black iron pipe to go down the center and a 1/2 inch black iron pipe to go inside that for the axle.

I am just afraid that it wont weight enough with it just being 2 feet wide for an existing lawn.

Reply to
stryped

The width does not have much to do with whether it will be heavy enough. If you make it 2 feet wide, all the weight will be on a 2 foot wide piece of lawn. If you make it 4 feet wide the weight will be on a 4 foot wide piece of lawn. Exactly the same amount of weight per foot.

If I were making one I would make it bigger in diameter. Probably about 16 inches in diameter. I would make it longer than 2 feet, but probably not 4 feet. I might have a problem pushing one that was 4 feet wide.

Dan

Reply to
dcaster

First, if you make it wider but not larger in diameter, the effect of the weight won't change. You'll still have the same number of pounds per square inch pushing down on the dirt, and that's the issue. You'll just cover twice as much ground in one pass without putting any more pressure on the dirt.

If you want to calculate the weight of a chunk of concrete, regular concrete has almost the same density as aluminum, which is around 2.7 grams/cubic centimeter, or roughly 168.5 pounds/cubic foot.

An 8-inch-diameter cylinder of concrete will contain a cubic foot of material for every 2 feet, 10 inches of length. So a two-foot section will weigh approximately 118 lb. A three-foot section will weight about 177 lb. And a four-foot section will weight 236 lb.

FWIW, that's 2.7 times the weight of an equivalent volume of water, and roughly 1/3 the weight of an equivalent volume of cast iron or steel.

-- Ed Huntress

Reply to
Ed Huntress

The widest form they had was 8 inches. Also, I would pull with a small tractor.

Will the form hold 48 inches?

Reply to
stryped

Regarding those figures I gave for concrete density, they're a little high for plain concrete. They're more accurate for ferrocement or heavily reinforced concrete.

Plain concrete is closer to 2.3 g/cc. So, multiply the weights I calculated by 0.85. That means a 2-foot length is around 100 pounds, and a 4-foot length is around 200 pounds.

-- Ed Huntress

Reply to
Ed Huntress

True... except when you go over a bump in the lawn! >;-} David

Reply to
David Courtney

You can get them bigger. As a matter of fact I picked up a 12 inch one from Lowes yesterday for another project. Heading over to the commercial side of the house you can get them even bigger than that.

It just dawned on me that if you were to start with a 55 gal drum and put the form inside it so you had a tube made of concrete rather than a cylinder, you could go big with not quite as much weight, but as always, that's a bit more complex.

Something else I remember seeing was three shorter concrete rollers (I'd say they might have been concrete pipe filled with more concrete, but it's been awhile) of the size you mention two wide up front and one in the back rolling over the middle gap. Total width maybe four feet or so.

Reply to
carl mciver

Yup - Average pressure versus spot pressure which is why the thing actually flattens lawns. Ken.

Reply to
Ken Davey

Forget about th lawn ROLLER, I want to hear about the Concrete lawn MOWER !!!

(see the title to this thread !).

Reply to
Scott Moore

... but if you had a concrete LAWN, why would you need a MOWER? I could see using a concrete lawn roller (to keep painting it green) Ken.

Reply to
Ken Sterling

Yeah, I read the original message under false pretenses, too. I was looking forward to reading about a lawn mower that needed 15 hp, with 10 hp just to drive the wheels...

-- Ed Huntress

Reply to
Ed Huntress

That was the other possibility -- a mower for concrete lawns. The blade would last forever, and there's be no mess getting rid of clippings.

-- Ed Huntress

Reply to
Ed Huntress

Well, you would want to put some reinforcement steel mesh or rebar of some sort in your homemade concrete lawn roller, or it'll soon crack and split into large and unusable parts.

A simple ring of 4" welded wire, with the cut ends welded into a continuous tube would be my first thought. And weld it into position relative to the center axle pipe with some 1/4" rod, or it will try to shift as you pour the concrete into the mold. This will also keep the axle tube from spinning inside the cement of the roller.

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Reply to
Bruce L. Bergman

Already did one for smoothing out a model flying field.

55 gallon drum, weld in a center pipe to put an axel through.

Cover the two grooves on the inside with strips of roof valley flashing and duct tape in place.

Add some mesh for reinforcement and fill with concrete.

Cut drum off of harden concrete and add a pull frame and axel.

Pulled it with a John Deere 110 10 HP while mowing for years.

Now 25 years old and still in good shape.

Hugh

Reply to
Hugh Prescott

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