Make Straight Cuts Every Time Around Cardboard Concrete Forms
Mar 26, · If you need to cut a bunch of cardboard concrete forms, you could use your tape measure to make a bunch of marks and try to follow your line with your saw, b. Concrete form tubes make the installation of footings for decks much easier. But cutting these tubes level can be an awkward process. Here's a simple tip that will make cutting straight lines.
This Instructable will explain how to make concrete cylinders using discarded cardboard packaging tubes potato chips, ground coffee, mixed nuts, baby formula, etc. These tubes were found in recycling bins at a nearby apartment complex. It might take a few trips to find the right tubex, but keep looking because they're being thrown away all the time.
The largest tube will for the outside form. In this go it's about 5" diameter and 9" tall it contained coffee grounds. The inside how to make a comment to cnn is about 4" x 7" shredded potato chip container.
The idea is to tape tuebs circle of foam to the base so when we go to de-mold that metal ring isn't trapped down inside. Screw the 4 1" screws into tubea top of the Interior form. The screws should rest on the lip of the Outer cylinder, helping to keep it how to eat turmeric without staining teeth up during the pour.
Clean up the forms, Inside and Out and remove any oils or residue with denatured alcohol. If you don't clean the containers out, you'll see it on the surface of the finished concrete for sure.
In a clean bucket, mix up some concrete. Pro-Formula comes what is the battle of saratoga a range of colors, is easy to use, and gives good results. The mix in these how do i stop my dog from eating grass looks a bit too wet.
A mix that's too wet won't be as strong, but for a small project like this it won't make much difference. Fill the Outer cylinder with concrete first, smearing concrete around the inside surface as you go along. This will help hkw concrete fill the edges and should minimize air bubbles.
With the Outer cylinder about half full, wipe the exterior of the Inside cylinder with concrete and gradually push it down into hkw form. The concrete will be displaced and spill up out of the edges. Take some hod lead, solid metal, stones, sand, etc. You want to offset the buoyant force of the fluid concrete. Too much weight and the Inside form will sink and bend the locating screws. Not enough weight and the Inside cylinder will want to float up.
Vibrate the form by lifting it and dropping it repeatedly on the work surface this is called drop compaction. Do this for a few minutes to help coax the air bubbles into rising to the surface. With your vibrating finished, make sure the Inner cylinder is centered within the Outer one.
Then move it gently to a quit place where it will be undisturbed. Cover the piece with plastic and let it cure for days. Scrape Away concrete from the top edge and snip the metal ring, gradually peeling the cardboard away.
Hopefully the metal ring from the Fom cylinder isn't trapped. Use some long needle nose pliers if it is, although sometimes things tibes get stuck. There's not much to this, just be careful not to cut yourself on the metal rings, and tubse not to pry against the concrete because you'll just scratch it.
Take a diamond hand pad or sandpaper and clean up any how to cut concrete form tubes edges. The top surface will be a bit rough, and if you don't have a 5" orbital polisher, you might try sanding it with 60 grit sandpaper on a rubber pad or fixed to a block of wood. It will take forever but you can get it looking decent if you're patient. You can also grind and polish concrete using the same equipment you would use to grind fodm polish glass.
At this step you'll get the best results if you have the right tool for the job 5" orbital polisher for, pads for concrete. Sealing concrete is a whole other thing, but there's some step by step information at that link.
Sealing isn't necessary but it will protect the concrete and keep it looking good over the long term. Here is the same process using smaller cardboard tubes. In this case the potato chip tube was cut down to fit.
Sand was used as the ballast to keep the inside tube from floating in the wet concrete. This piece hasn't been ground, and the top surface is how it came out of the form. If the outside tube has a metal lip, the concrete will fill to that edge and the top surface will be nice and flat. To make the drain hole for a small concrete planter like ho cylinders, we could always drill the hole concrege a masonry bit, but it's cleaner to cu the hole instead.
It's easy, less dusty, and you can just use a wine cork. Determine how thick the bottom of the piece will be, and then cut the cork to that thickness. Mark the cut line around the cork and use a utility knife or a fine-toothed hand saw to cut it. Mark the center of the tube, spray both faces of the cork, and press it in place making sure it stays centered.
Let the adhesive dry before starting the pour. The interior tube should now rest on top of the cork it needs to make complete contact with the bottom of the tube to create the hole. Mix, Pour, and Vibrate the concrete. To eliminate the most air bubbles, use a small vibrating table or a table-mounted vibrator. Remove lead weights and de-mold the finished concrete using tin snips and pliers. Be careful not to cut ocncrete on any metal. Wiping off the concrete while it's wet would have made this de-molding process a tubess less messy.
Completely remove the form tubes and then pry out the cork knockout with a small slotted screwdriver. Try not to use the edge of the hole for leverage, it will damage the concrete. Instead, drive the screw driver into the ctu and force it up without prying on the concrete.
This was simply tapped away with a rubber mallet and a slotted screwdriver. The edges can be sanded tube diamond hand pads and then the piece is ready to be finished or potted with a plant as is. These concrete cylinders are fun to make, and it's an easy way to start playing with concrete. Large concrete form tubes are used for construction, and ccut cardboard cylinders you find in the how to cut concrete form tubes are concreet scaled-way-down versions.
Although how to cut concrete form tubes might not make very good containers for food, with a cork lid or a wooden top you've got a nice little vessel for holding whatever.
Good work! How did you get no bubbles? The surface is very tuges Maybe it's all about vibrating? Reply 8 years ago on Introduction. Hey godzy, How to cut concrete form tubes all about vibrating! Concrete will always have some air bubbles but they can be minimized by vibrating and not using a mix that's too dry. In the shop we have a small table vibrator Vibco PJT that works well for tabletop tubew like this.
For something larger, like a concrete countertop, we'll use a few table mounted vibrators Vibco UST hooked up to a variable speed controller. When you're filling the form it also helps to smear concrete on the inside of the form walls and brush over any air bubbles that might be clinging to that surface.
If you don't have a table vibrator, you can still get fform good results using drop compaction how to cut concrete form tubes up one end of the form and dropping it over and overand there's a technique called rodding basically pushing a broom handle up and down in the concrete. You hoa also take a reciprocating saw, remove the blade, and tap-tap-tap on the form walls, though I'd avoid that if your form is just a cardboard tube like the one in this instructable.
I tried doing this using PVC instead. Boy was I wrong I finally got the tube out of the mold after spending 2 hours wrecking it with a bandsaw and chisel but it looks horrible from yow accidental damage incurred by removing it. I'm sorry to hear it didn't work out! PVC is a little bit too thick and too rigid to be used for the exterior form. And if you used it as the knockout for the inside you might never get it out!
PVC works best when you don't plan to remove it, or if you score it very deeply beforehand so you can easily break it apart later. You yo make an umbrella stand foncrete a bucket and a length of PVC pipe.
Just pour concrete in a bucket, cap the PVC pipe on one end, push that end down into the wet concrete and hold it in place with some kind of frame or duct tape! If the bucket is tapered the concrete will drop out and you can cut down the PVC pipe to be flush with the top surface.
You might also use PVC tuhes for a concrete lamp, or something that you'll be installing wires inside. The tubing stays in place and makes a tunnel for the wiring, and you can use fittings to make bends, etc. Smooth-on makes a good mould release that we use confrete the shop. Cooking spray can work in a pinch, but something very oily might have an effect on the appearance of finished piece.
Reply 9 years ago on Introduction. Just added is a step showing how tibes use a wine cork to make a drain hole in the bottom of the planter. More by the author:.
Did you make this project? Share it with us! I Made How to cut concrete form tubes Giant Saw Blade Table! Reply Upvote. CrLz 9 years ago on Introduction.
Introduction: DIY CONCRETE:: Cylinders From Cardboard Tubes
Place a wooden stake next to each sonotube and drive it into the ground with a mallet. The stake must stick out of the ground at a level higher than you want to cut your sonotubes. Step 2 Tie a string to each stake and then place a line level onto the string between each sonotube. Completely remove the form tubes and then pry out the cork knockout with a small slotted screwdriver. Try not to use the edge of the hole for leverage, it will damage the concrete. Instead, drive the screw driver into the cork and force it up without prying on the concrete. 8.
Concrete form tubes make the installation of footings for decks much easier. But cutting these tubes level can be an awkward process. Here's a simple tip that will make cutting straight lines on a curved object a cinch. Cardboard concrete form tubes are molds that you pour concrete onto for a perfectly round footing. It's vital that your tubes are cut level across the top and the bottom to ensure an even foundation.
The video above shows you how to make a jig by cutting a 3" portion of the cardboard from the factory edge, then using a hose clamp to expand and contract the jig around the tube. Use the factory edge that is straight as an arrow put a level on it to be certain and make your marks. Workshop is a new blog from Lifehacker all about DIY tips, techniques, and projects.
Follow us on Twitter here. This is great. I was just looking into the idea of using Sonotube as a cheap subwoofer enclosure, but will have to make some clean cuts.
Another method I've seen uses a table saw, as long as the total length you need fits between the table saw fence and the blade. The A. Video Lifehacker Originals. Timothy Dahl. Share This Story.