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How to bend a pipe in an even arc?

husbandman's picture

I'm wanting to make some pieces of bent pipe to support plastic over garden beds.

I've used pvc before and, while it's easy to bend, it doesn't work well for me. (flimsy)

I'd like to be able to bend 3/4" EMT into an even arc about four feet across at the bottom end. Sort of a steel hoop (think Splitergroupies hoophouse) instead of plastic.

I could probably bend the piece numerous times with a conduit bender, but I could never make repeated pieces that were entirely matched. Plus, I'd wind up with a somewhat bumpy outside rather than the even arc I'd like to have.

Anyone know how to do this?

(post #88225, reply #1 of 43)

Have Rosie ODonnel stand in your yard, brace one end against a tree and wrap the other end around her waist. Probably the right arc.

No thanks needed

(post #88225, reply #3 of 43)

leave the socialists ouy of this

Is anybody out there? 

(post #88225, reply #25 of 43)

>>leave the socialists ouy of this

so, that leaves rush as the form and ann as the lever, I guess





"Man's capacity for justice makes democracy possible, but man's inclination to injustice makes democracy necessary."
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======================================== "Man's capacity for justice makes democracy possible, but man's inclination to injustice makes democracy necessary." Reinhold Niebuhr: 'The Children of Light and the Children of Darkness' http://rjw-progressive.blogspot.com/ ========================================

(post #88225, reply #4 of 43)

I'm trying to think of a rigid form that you could use, a large tree, for instance, and run a steel cable through the pipe, then pull it with your truck.


I've straightened farm harrows this way, with a chain to a tree, gentle pressure from the tractor. 


Greg 

(post #88225, reply #9 of 43)

I like the steel cable idea and I have a bunch of it on hand, but I'm not sure how I'd get the hoops to be very even.

(post #88225, reply #11 of 43)

Wagon wheel rim, of which I have two or three - clamps or cable. 


 Seriously, if you have many to do, you could either have someone weld up a jig similar to a wheel rim, or go shopping at the junk / antique shops.  Around here, wagon wheel rims are common, folks buy them for flower beds.


Greg

(post #88225, reply #2 of 43)

If you are doing a bunch make a form to bend them on. Cut the arc you want out of 3/4 ply and then cut 2 slightly larger arcs out of ply for the top and bottom guides. Sandwich the whole thing together with a bunch of deck/drywall screws. Put a pipe strap on one end to hold the pipe and bend away. You may need another 1" pipe slipped over the other end for leverage.

Greg

(post #88225, reply #5 of 43)

Seriously, I checked your profile for location. You probably don't have an aeroator for your well [ fact of life here in TrailerlandFlorida ] but it would be perfect for the bending form. With the arc you propose you might not get kinking, but if it is a problem, fill the pipe with sand as you bend. With EMT I don't think you would need a cheater bar.

(post #88225, reply #6 of 43)

How about with 3 bends.


Mark the center first, then '45 up' on each end and '45 up' in the middle. (I think that math works)


That way you could make steel plate feet with studs sticking up to hold each section, or just drive two smaller pipes into the ground to slide each section onto.


It would look like a pup tent with side walls.


You could also do that gluing up PVC, adding extra tubing (PVC or EMT) inside the sections for stiffness


Regards Rich

(post #88225, reply #7 of 43)

The top on my boat lift is 3/4" PVC bows with 1 12x24 silver tarp.(10' span with a center ridge on "+" fittings) and it has lasted years, including Charley and Wilma.

Greg

(post #88225, reply #8 of 43)

Thanks for your suggestions.

I could still use pvc, but it degrades the plastic sheeting (or has to be painted) and I'd like to be able to have a neat stack of the things when they are not in use. I have a jumbled pile of used pvc sticks now. I also want to be able to bend it so that the open bottom of the arc is only about 4'. A ten foot stick of pvc doesn't do that well, I tried. Yes, I could cut it shorter, but then I lose height inside and waste some material.

(post #88225, reply #10 of 43)

Have you tried cpvc? much more flexible... or pex w/ wire in it?

We'll have a kid
Or maybe we'll rent one
He's got to be straight
We don't want a bent one
He'll drink his baby brew
From a big brass cup
Someday he may be president
If things loosen up

www.tvwsolar.com

The Village Woodworks, Inc

Chapel Hill, NC

 

We'll have a kid Or maybe we'll rent one He's got to be straight We don't want a bent one He'll drink his baby brew From a big brass cup Someday he may be president If things loosen up

(post #88225, reply #14 of 43)

As someone else said use a conduit bender and put in 3 discrete bends. Maybe 4. The basic shape would be that of a gable end of a house.

I can't remember the details, it was 55 years ago. But when I was a kid we had rows and rows of temporary plastic house supported by conduit. Had hear plastic and "black cloth" on then to control the light to custom grow mums for florist. Also to keep the frost off. Had some white gas "pot heaters")

Since he had been an electrician I suspect that they where EMT bent with a bender. But, as may as he had, after making a template he might have gone to a muffler shop to use their power benders.

If you do need it in a even arc use a tubing roller.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=99736

junkhund would probably have the parts to make one.

Basically 2 fix rollers and adjustable one.

Muffler shops might have one.

Also I don't remember what splinty (where has she been) used for her hoop house.

.
William the Geezer, the sequel to Billy the Kid - Shoe
. William the Geezer, the sequel to Billy the Kid - Shoe

(post #88225, reply #16 of 43)

Good call Bill.


 I have a small version of that, but it will only fit 3/8" maximum thickness stock.



 

 

(post #88225, reply #20 of 43)

Thanks, Bill, but I'm way too cheap to buy a tool like that for a purpose like this!

(post #88225, reply #13 of 43)

My gut tells me you'd need 3@ 60* to do that, or similar. 180 in half circle or a triangle. Or say a 120 and 2 @ 30...

Spheramid Enterprises Architectural Woodworks


Repairs, Remodeling, Restorations



www.richmondrenovationsandrestoration.com  

(post #88225, reply #17 of 43)

How would a guy named Sphere just know that automatically?

(post #88225, reply #12 of 43)

I've used the following trick to custom bend pipe around whatever's handy in the past:


Cap one end of the pipe, fill tightly with sand, cap the other end, and bend it around whatever you have that's the correct radius. (The sand keeps the pipe from kinking.) Uncap, empty out the sand, and yer done.



Mike Hennessy
Pittsburgh, PA
Everything fits, until you put glue on it.


Edit: You could also just use a conduit bender and just "tweak" it along its length into the arc, but you'd have to be careful to get it even.


Edited 10/29/2009 5:35 pm ET by MikeHennessy

Mike Hennessy
Pittsburgh, PA
Everything fits, until you put glue on it.

(post #88225, reply #15 of 43)

3 wheels mounted in a triangle formation with the top single wheel movable, will make a roller jig that will bent any radius. Start the feed and each pass tighten thegap , like a tubing cutter works, till you get the desired bend.


BTW Hasbeen, I made my hoop covers for lumber and peppers with the GREY Ele. conduit ( PVC) and snapped the next size up keepers over the plastic.


Just band saw a 2" hunk so ya keep about 2/3rds of the pipe, it  them clips over the hoop pipe. I used 3/4" and 1" respectfully.


Spheramid Enterprises Architectural Woodworks


Repairs, Remodeling, Restorations



www.richmondrenovationsandrestoration.com  

(post #88225, reply #18 of 43)

My old hoophouse was made with plastic elec conduit, but it sunburned as bad as any pvc.

(post #88225, reply #24 of 43)

I was trying to get my hooped green house up before the first frost, to save the late peppers.


Didn't git er done in time and we had a freeze..bummer.


But for a lumber cover I used Colleen's method, but the cover isn't clear, its a silver tarp..looks more like a conestoga wagon in the side yard.


That 3 wheeler Marty showed is what I'd find....Ohhhhh brain storm time...I might use halves of round cattle hay feeders!.


Anyway, my Greenhouse won't be a true hoophouse, I intend to attach one end of the ribs to an existing shed at about 8' high, and the bottoms to something like a concrete parking stop.


These hoopsters, will flank a center section of sliding glass door front wall, tilted at 38 degrees, and a roof of Lexan Poly carb, twinwall.


Might be able to exten the growing season, and create storage for our gardening supplies.


Now ya got me thinking about metal pipe, thanks, I may dodge a future bullet.


Spheramid Enterprises Architectural Woodworks


Repairs, Remodeling, Restorations



www.richmondrenovationsandrestoration.com  

(post #88225, reply #27 of 43)

Can you believe that this thread has political sniping going on? Geesh.

(post #88225, reply #19 of 43)

I've done that with copper in the past, but wasn't sure about EMT. The copper I just crushed and folded the ends... back in the day of cheap copper!

With a ten foot stick of EMT, I'm not sure how I'd seal in the sand.

(post #88225, reply #21 of 43)

I made an arbor by drilling holes in 4"x6" and inserting 1/2"x20' rebar in one side and bending it by hand to stick the other end in.
Over my gate I slipped 1/2" rebar into 1/2" emt and bent it around a plywood form by hand. The spring back required about 2 1/2" radius form for a 5' radius arch.

 

 

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(post #88225, reply #26 of 43)

Very nice.

(post #88225, reply #22 of 43)

if you did it in steps/increments a pipe bender from HF would be the tick...



12 Ton Hydraulic Pipe Bender
Central Hydraulics
32888-0VGA


$109.99

make yurself a three rollered radis bender and go for it..


look at the head set up...






Current Special!

 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!



Forget the primal scream, just ROAR!!!


 



"Some days it's just not worth chewing through the restraints"
"Some days it's just not worth chewing through the restraints"

(post #88225, reply #23 of 43)

it just occured to me...


you want to borrow my three head...


how many tubes...


what radius...


 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!



Forget the primal scream, just ROAR!!!


 



"Some days it's just not worth chewing through the restraints"
"Some days it's just not worth chewing through the restraints"

(post #88225, reply #28 of 43)

Thanks for the offer.

I'm working on a plan that I can replicate with reasonable ease. I want to be able to reuse my concrete form to add more growing beds whenever I can get to it, so I need to be able to bend a few pipes here and there i.e. I don't know how many yet. Thus, I need to be able to bend pipe on into the future, too.

I went out yesterday afternoon and cut the pieces of ply for the form.

Turns out that 24* and windy is colder than it was twenty-five years ago!

(post #88225, reply #29 of 43)

okay....


and yes it is...


 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!



Forget the primal scream, just ROAR!!!


 



"Some days it's just not worth chewing through the restraints"
"Some days it's just not worth chewing through the restraints"

(post #88225, reply #30 of 43)

 


http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=99736


Tubing Roller

Tubing Roller

 


Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming


WOW!!! What a Ride!



Forget the primal scream, just ROAR!!!


 



"Some days it's just not worth chewing through the restraints"

"Some days it's just not worth chewing through the restraints"