Rebar Trellis

Length of Project:
Project theme:
Suitable for grades:
Tools & Materials
Material List
  • blank paper or graph paper
  • two pieces of 20' 10mm rebar
  • painter's tap
  • ~10' tie wire
  • heavy work gloves
  • safety glasses
  • ear protection
  • welding helmet
  • long welding gloves
  • non-flammable clothes
  • ~five 7018 welding rods
  • dish soap
  • spray paint for metal/rust
  • Optional

  • pipe cleaners
  • sidewalk chalk
  • scrap box cardboard
Tool list
  • pencil
  • ruler
  • black felt pen
  • tape measure
  • hacksaw
  • metal file
  • vise
  • ~3' pipe, inner diameter >15mm
  • ironworker's (rebar) pliers (or Linesman's pliers)
  • stick welder
  • end cutters
  • chipping hammer
  • water bucket
  • scrub brush or sponge
  • Optional

  • calculator
  • grinder with cutting wheel
  • wire wheel for grinder

    Design your trellis

  1. Use a pencil, paper, ruler, tape measure, and calculator to design a trellis of your chosen shape to the following parameters. Hold the tape measure up to visualize the actual size of the dimensions you are sketching. Make the dimensions easy by drawing 1”:1’ (or 10cm:1m).
  2. Parameters

  3. You will be working with TWO 20’ lengths of rebar, 40’ in total. Try to design your trellis so you have NO extra waste rebar.
  4. Leave a minimum of two vertical sections of 10” rebar at the bottom, these will be driven into the soil and hold the trellis upright. These should be a minimum of 12” apart.
  5. The technique used to bend rebar in this project result in sharp angles like a “Z”, not long curves like an “S”. Keep in mind that bends more acute than 90°, as well as any large-radius curves, can be difficult to execute with the methods given here.
  6. When you are done the designing, ask a friend to double check your work and math to ensure the parameters are upheld before you start cutting!
  7. Optional prototyping

  8. Make a small 3D model prototype with tie wire or pipe cleaners. You could also use sidewalk chalk to do a life-size sketch of your trellis to make sure you like the overall dimensions.
  9. Make a cut list with the different lengths of rebar you need to cut (make sure you have two cut lists that add to a total of 20’. Ex, the first piece of rebar will be cut into: 72”, 66”, 60”, 42” and the second piece into: 66”, 60”, 40”, 38”, 36”)
  10. Helpful hint

  11. The store where you purchase the rebar will have a rebar cutter, and you can use this to cut your rebar into manageable lengths. Bring your tape measure and a felt pen and mark out your cuts on each of the two pieces of rebar. Make the necessary cuts you need to (on your marks) in order to fit the pieces into your vehicle, and cut the rest when you get the rebar to your workshop.
  12. Cutting rebar lengths

  13. Put on your safety glasses and work gloves, then use a hacksaw (or a grinder with a cutting wheel, and some ear protection) to cut your rebar lengths. Clean up any sharp edges with a file.
  14. If the rebar is dirty or oily, you can wash it with dish soap, water, and a sponge or brush before moving on to the next step.
  15. Lay out the rebar on the floor according to your diagram. If you can’t leave the trellis in place (eg, you need to clean it up in between sessions), you may want to number each piece on your sketch, and use painter’s tape and felt pen to label each piece.
  16. Bending rebar

  17. If you have planned to bend the rebar, make sure you bend in sequential order down each piece, as you will be using a pipe for leverage. It will only work if you still have a straight piece of rebar to slide it over.
  18. Choose one curve to start with. Slide a piece of cardboard under your rebar and draw the angle (bend) you want the rebar to take. Determine where you want the middle of your curve to be and make a mark with your felt pen.
  19. Secure the rebar horizontally in a vise with the mark approx. ½” outboard of the vise (this is where the middle of the curve will occur – if you line the mark up with the vise jaws, the curve will happen a little too far along the rebar).
  20. Slide the pipe all the way onto the rebar until the end is touching the vise, then push it sideways to make the bend.
  21. Use the cardboard template to check your angle and adjust as necessary.
  22. Place your rebar back in place on the floor and repeat the above steps for each curve.
  23. Tie the trellis together

  24. Use your pliers to cut several 5” pieces of tie wire.
  25. Put on work gloves. At each cross-over point, slide a piece of tie wire diagonally under both pieces of rebar, and bend both ends upward. Cross the ends to make an “X” at the top.
  26. Pinch the “X” with the tip of your pliers, then hold the pliers vertically and twist them three or so times to twist and tighten the wire around the rebar.
  27. Make sure the rebar is snug and stable, then push the wire ends down to the side. Note: this might take some practice until you learn how to twist the wire until it tightens securely. Use as many pieces of tie wire as you need to practice this – it can be tricky at first!
  28. Repeat the above steps for each place where one piece of rebar overlays or crosses another.
  29. Your trellis is not “tied” together! It may not be completely solid, and your pieces may twist, so be gentle with it at this point.
  30. Tack the trellis together

  31. Put on all your welding gear: non-flammable clothing, helmet, gloves, ear protection. Follow the directions in your welder’s manual, or have a welder show you how to use the machine. Tack each tied junction on your trellis with the welding rod, then let your trellis cool.
  32. Use end cutters to clip or pull away any loose pieces of tie wire.
  33. Use a chipping hammer or a grinder with a wire wheel to remove any slag from your welds.
  34. Paint the trellis

  35. Wash your trellis again with soap and a scrub brush or sponge to remove any oil, dirt, or debris.
  36. Suspend your trellis in a well-ventilated space and apply 2-3 coats of spray paint.
  37. Your trellis is ready to place in your garden!
Extension Challenges
  1. Place your trellis in a sunny spot, and plant pole beans, snap peas, cucumbers, squash, sweet peas, clematis, or any other climbing plant at the base. Tie netting to the back of your trellis if the plants need a smaller framework.
  2. Look up some different ways to bend rebar and redesign your trellis with larger-radius curves, or try making one with a single piece of rebar!
  3. Try making a 3D trellis, like an inverted cone or an arched ladder shape.
  4. Interview a horticulturalist (or a gardener) and make your trellis a design challenge with them as the end user.
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