Cardboard Creations - Perfect Circles

HOW-TO Cut a Perfect Circle Out of Cardboard

The simple answer is to trace something that is a circle; a cup, a plate, a pot, etc.  But what if you don't have something the right size to give you the circle you need?

Here is a simple tip I have used without fail many times over.

 

Tools

TOOLS:

Pencil

Measuring tape (flexible/fabric - not metal)
       - with an eyelet at the end
         (see the Tools picture)

Straight pin
Utility knife (not shown)

Cardboard :)

DIRECTIONS:

1. Determine the radius of your circle. (The radius = 1/2 the diameter.  The diameter is the measurement from one side of your circle to the other - see figures 1&1.1.)  For example: If you want a circle that is 6" across, the radius would be 3".

For this How-To I will use a 15" diameter (circle measures 15 inches across), so the radius will be 7 1/2". (see Figures 1&2)

Figure 1

Figure 1.1

2. The eyelet in my measuring tape is 1/4" from the end of the tape, so I add 1/4" to my radius measurement of 7 1/2" to get 7 3/4" and put a straight pin through the measuring tape at 7 3/4". Then, push the pin through the cardboard where the center of the circle is to be. (see Figure 2)  Insert the pencil into the eyelet and draw the circle.  NOTE: Be sure to keep the tape measure taught as you go around. (see Figures 2.1 & 2.2)

Figure 2

Figure 2.1

Figure 2.2

3. Cut out the circle with the utility knife.  NOTE: I usually make two cuts, going around twice. The first time I keep the cut shallow so I have better control cutting the contour around the circle. The second time I cut all the way through. (see Figures 3 & 3.1)

Figure 3
Shallow cut

Figure 3.1
Deep cut

FINISHED!

A perfect 15" circle
(ok, well nearly perfect :D)

-Jill

For the Stage - DIY LAMP POST

DIY LAMP POST

Yes, this is a DIY!! That fact was a surprise to many who saw it up close. They thought it had been purchased. I'll admit, I loved the compliments. I too was excited at how well it turned out.

Made mostly of cardboard making it light weight.
Comes apart for easy storage.

WHY I DID THIS:

Our church was doing a "Night On Broadway" event and I was asked to dress the stage with little time and a small budget. I took on the challenge. One of the things I needed for my design were a couple of lamp posts. Since I couldn't afford to rent any, as I had previously done for a wedding reception, and I couldn't find anyone who had one or two I could borrow I ended up making them.

WHAT I DID:
First of all, I got my initial idea from my sister who is an amazing artist and a creative genius! (Check out some of her art at http://www.mcfarlanearts.blogspot.com/) She had made some pretty amazing lamp posts for a project she was working on. (see picture below) I didn't need mine to be as fancy as hers so I scaled it back and went for it with the materials I thought would work. Most items I had on hand; left over from other projects I had done, or had attempted to do. (Not everything is a working success. "I have not failed. I've just found 10,000 ways that won't work."  -Thomas Edison :D)

My sister's lamp posts in use.

Materials:
Cardboard
Fabric bolt tube (empty)
Black Duct Tape
Copier paper or Melamine
Almost empty black duct tape roll
Low Temp hot glue sticks and gun
1"x4"x 4" piece of wood
PVC Plug
PVC coupler
A few screws
Flat black spray paint
Tape Measure
Straight edge
Pencil
Push lamp from the dollar store (you can see it sitting on the table next to the lamp post in the photo at the top of the post - the small white circle thing)

THE BASICS:
This is how I made it work for me with the materials I had.

The Lamp Box:

Figure 1

I designed this lamp box to open on one side for easy insertion of a push lamp. In my sister's design, the top came off for the same purpose.








BOX SIDES: Need 4 total. Paper or melamine for windows. (I used copier paper because it was what I had on hand). Cut them to the same dimensions as the box sides then trim (or just cut .25" smaller all the way around to begin with - see Figure 3.1).

Figure 2

Figure 3

MEASUREMENTS:
Top & Bottom: 7.5"
Width: 9:5" (gently fold along this line)
Height: 16"
Borders: 1"

Three of these remain all one piece.  For the fourth, separate the top section from the bottom section as shown in Figure 3.

Figure 3.1
Finished Lamp Box
showing swinging door.
(I used a couple extra
pieces of duct tape
for securing the door
when closed.)

BASE & TOP: (Cut 2)

Figure 4

          Base & Top: 7.5" square
          (Figure 4)















After I had all the pieces cut I taped it all together with the black duct tape. I thought about just taping the seams and spray painting the rest, but decided to put tape over the whole thing in an attempt to make it more durable.  I've been pleased with how well the pieces have held up with all the use they've seen.

I hot glued the mostly used tape roll in the center of the bottom of the lamp box. The tape roll would be the collar that would fit over the empty fabric bolt or "post". Since the tape roll was too large to fit snugly over the empty bolt I cut strips of cardboard, rolled them up to give them a curl, then coiled them around the inside of the tape roll filling the gap. (see Figures 5 & 6) Once I got the fit I wanted, I hot glued the coiled cardboard strips into place.

Figure 5

Figure 6

The Base & Post:

I would have preferred to use a 3" PVC pipe for the post of my lamp, but budget did not permit.  I happened to have an empty fabric bolt, so that is what I used. However, the bolt was not long enough to give me the height I wanted so I had to improvise.

I cut TWO CARDBOARD CIRCLES - 12" diameter and set one aside. TIP: See my "Perfect Circles" post at  http://jillscreativeumbrella.blogspot.com/2013/12/cardboard-creations-perfect-circles.html) On the other one, I found exact center of the circle and drew a circle the diameter of the bolt tube in the exact center.

TIP for finding exact center

TIP: Trace the end of the bolt onto a piece of cardboard, then cut it out. Find exact center on the small circle and match it up with exact center on the 12" circle. Trace around the small cardboard circle.







I then cut the center circle 1/2" from the edge of the drawn line for the small circle. (see Figure 7 - drawn line is the solid line - cut line is dotted line). NOTE: It is always easier to cut more off than it is to add cardboard back when you've cut too much off. I always err on the side of having to trim again. I then cut small wedges out around the edge of the small circle creating small pieces of cardboard that I could gently fold down to fit the post into place. (see Figures 7.1 & 7.2)

Figure 7

Figure 7.1

Figure 7.2

After I made certain the small circle in the center was going to work with the bolt tube, I taped the 12" circle to one end of my base piece (see below), wrapping the base piece around the circle.

THE BASE PIECE measured approximately 38.5" wide x 31" high - (lines in the cardboard running 31" inches, top to bottom). Initially, I just taped the two together to get them to stay in place. Once it was taped in place, I used hot glue from the inside around the entire bottom edge of the 12" circle for stability. After the glue had cooled and the circle was firmly in place, I went around the top outside edge with black duct tape to give the tape the finished look as seen in Figure 7.2.

Preparation of the post and inside circle:

I prepared my second 12" circle by determining the exact center of the circle and the exact center of a 1"x4" piece of wood. I then attached the plug, (see figure 8) which had previously had a hole drilled in it from another project, in the exact center of the piece of wood with a screw. I used a fiber washer to make sure the head of the screw wouldn't slide through the hole in the plug. After attaching the plug, I hot glued the piece of wood in the exact center of my circle. (See figures 9 and 9.1) 

Figure 8
PVC Coupler and drilled Plug

Figure 9

Figure 9.1

Next I prepared the post by cutting strips of cardboard and wrapping them around the outside of the PVC Coupler until I had the right fit, then hot glued the cardboard and coupler into place in one end of the bolt tube MAKING SURE THE SMOOTH END OF THE COUPLER WAS CLOSEST TO THE END OF THE TUBE in preparation to slide over the plug. (See figure 10)

Figure 10
Bottom end of bolt tube
coupler and cardboard
glued inside - smooth end
of coupler toward edge
of tube - slips over plug
inside the base

Figure 11
Looking at base from the bottom
-Second 12" circle glued in place

From there, I determined how tall I wanted my finished lamp post to be and after preparing the second 12" circle, hot glued it, wood and plug side up, inside the base at the proper height. (See figures 11 & 11.1)

I had to glue in small sections and hold the cardboard in place until it was cool/set enough that I could let go and have it stay.

I then taped the base piece along the seam to secure it in place around the circles. I made sure all tape was securely in place I assembled the post and base together then spray painted the two pieces.

Figure 11.1
View of base from the top.
You can see the second circle
with the wood and plug.

After it was dry I added the lamp box to the top. Done! Ready to insert the push lamp for lighting affect.

Finished
&
Unfinished

-Jill

For the Stage - Broadway Sign

CARDBOARD CREATIONS: THE BROADWAY SIGN

Finished size: 3'3" x 10'3"

The Broadway sign ended up being in the way of the lights when hung at the location shown in the photo below. It was relocated; hung in line with the scrim suspended above the skyline and opposite the moon. Looked great! (Unfortunately, I didn't get a picture after the sign had been moved.)

WHAT I DID:
This 3'3" x 10'3" piece of cardboard was made by taping three fairly good sized pieces of cardboard together with clear heavy duty packing tape. Duct tape sticks better, however, I didn't want the bulk of duct tape for this piece because I anticipated it being close to the audience and was concerned the tape might be seen in the reflection of the light. NOTE: When I painted the clear packing tape the moisture from the paint caused the tape to peel back a little. After the paint dried, I just carefully pressed it back down again and it seemed to work fine.

Front of Broadway sign painted.
Back not entirely painted
(Notice: left side curling,
right side straight - see tip below)

Back side of cardboard
now fully painted
(Notice: You don't have to
go to the very edge.)

TIPS:
-When painting on cardboard, you will need to paint BOTH sides to keep it from curling. (see "The Science Behind Curling Cardboard - The reason to paint both sides" at the end of this section of the post.)
-I most often use a brush when painting cardboard as a roller tends to get too wet and can deform the cardboard. 

Broadway sign with "lights"

The white circles were cut with a 2" circle punch out of regular printer/copier paper and attached using an adhesive strip roller.

Letters were penciled in using a straight edge where possible then painted freehand with small paintbrush. No need to erase errant pencil lines as they cannot be seen from a distance.

PROVIDING LIGHT WEIGHT STABILITY:
To provide stability to the lengthy cardboard sign while not adding a bunch of weight, I attached a PVC pipe (about 8 feet long) along the back from left to right strapping it down with duct tape. I did NOT use this for hanging, just for stability.

HANGING THE SIGN:

I used duct tape, staples and a key ring to create 3 fasteners to put on the back side of the sign. First, I tore a piece of duct tape about 4 inches long and folded it in 3rds lengthwise to create the strip you see the folded around the ring. (Duct tape is pretty tough stuff, especially when used in multiple layers.) Next, I folded the strip in half with the ring in it, held it in place on the back side of the sign and stapled it in place, stapling from both the front and the back to make it secure. The staples cannot be seen from a distance. Once stapled, I taped it on the back with a piece of duct tape as shown. I secured a fastener in each upper corner and one in the center for a total of three. I then used fishing line through the key rings in order to hang the sign. DONE!

CREATIVITY ABANDONED:  I thought it would be cool to create "light bulbs" and actually light up the sign. My thoughts went kind of like this: Use small baby food jars for the "light bulbs" by punching a hole to match the diameter of the jar opening through the cardboard in place of each white circle. The jar would then be inserted through the hole from front to back and the lid, with a hole punched through the center and a small white Christmas light inserted through the top, would then be screwed onto the jar from the backside of the cardboard, hopefully holding the jar in place. (not sure it would actually work since I didn't get to try it)  As I thought about all those jars it occurred to me that it might be necessary to reinforce the edges of the cardboard to handle the weight of the jars. My mind then went to building a 1" x 6" wood frame, drilling holes the size you would for a door knob or close to it to fit the jars, painting the frame black... This was where I had to put a halt to my thinking.  It was getting way to extensive for my short time frame and tiny budget, not to mention all the other problems the weight of the new design would create. So, I had to abandon my lighted sign idea and stick to white paper "light bulbs".

The Science Behind Curling Cardboard - The reason to paint both sides

...in case you wanted to know.

Two things:

Paper is made from wood and expands and contracts when exposed to moisture just like wood.

AND

Paint generally shrinks when it dries (at least the kind I use does).

The Explanation

When you paint a large portion of cardboard, that portion (the front) of cardboard shrinks when the paint dries. It also prevents the painted portion from being exposed to moisture in the air, allowing less expansion to take place. The unpainted portion of the cardboard (the back) remains the original size (not shrunken with paint), as well as remaining exposed to the moisture in the air allowing the cardboard to expand. This is why you may notice that a piece of cardboard painted only on one side might have more of a curl on a higher humidity day than on a drier day.

So, to keep the cardboard flat, you need to paint both sides, thus keeping both sides of the cardboard equal in size and equally exposed to humidity.  It's that simple.

-Jill