A number of years ago, I decided that I needed something large and eye catching for my Maker Faire booth, since all my display items were small decorative knots. If you were just walking past, there was not much to draw you in to look at the specimens on the table, especially with flaming robots right over there.

What is large, colourful, bends, and wouldn't be a pain to carry around? Foam pool noodles. The problem with tying knots in pool noodles is their length. The blue 3 eared cloverleaf knot above required 3 noodles to tie. The red 5 bight 3 lead turks head knot needed 4, so key to tying knots in pool noodles is joining them.

Supplies

pool noodles

duct tape

3d printer (optional)

Step 1: Duct Tape

The first thing I tried to join the noodles together was sewing, but the yarn ripped right through the foam as soon as the join was stressed in any way.

Duct tape, works reasonably well, but the colour matching duct tape (brand forgotten) was far less sticky than other versions and the knots I tied with those soon fell apart. My only surviving example of knots tied with noodles joined by duct tape is with this clear duct tape I found.

Align your pool noodles, wrap the join evenly with one layer of duct tape, then with one edge of the duct tape barely overlapping the join wrap left and then wrap right. Press the tape firmly to the surface of the foam.

Step 2: 3d Printed Connectors

Since even duct tape is not that reliable for dealing with foam, the imagination turns to 3d printed connectors. Most pool noodles seem to be of the especially long donut variety, so a short rod type object for the holes, and a claw type object to grip the sides and prevent the ends of the noodles at the join from fanning apart. For ease of printing, the claws were separated into 2 plates, and the centre post was also divided into 2 parts that would screw together through holes in the claw plates and create one spiky barbed object.

As you can see from the full sized image, the claws are not perfect. I believe that if I had not experimented with tying a few different knots, stressing the foam more than necessary, and I tied just one, the connectors would have done a better job. Also, for join camouflage, I had intended to use coloured markers to dye the print to match the noodle, but ran out of white mid-project. While, I might have been able to nail polish the black prints...

The claws in the models provided are meant to go on the outside of the noodle. In one instance, the claws were forced into the foam instead, but that did not perform better. An experiment I did not have time to attempt would have been to shrink the claw plate to be smaller than diameter of the noodle and redesign the claws as barbs to see if that would better grip the foam.

Note that the spikes on the centre posts are very spiky! I used kitchen towels to protect my hands while screwing the connectors together.

Step 3: Tying Knots in Pool Noodles

The 3 eared cloverleaf knot is the smallest decorative knot I habitually tie and that required 3 pool noodles. Any knot you choose to tie will always require more length than you'd expect. Even though the foam noodles will bend, they don't want to stay bent. Also, unlike string and cord, all parts of your knot will vigorously resist sliding through any other parts of your knot. All aspects of your knots must be deliberately shaped and wrestled into place. The relatively genteel handcraft of decorative knot tying becomes a full body contact sport (my forearms are still aching!)

I thought I had enough length for the 5B4L THK above. It kind of looks like I might, but the inability to tweak and slide slack around the knot, not to mention constantly fighting join separation as stressed foam starts to shred made me give it up in favour of a 5B3L THK.

Lastly, eagle eyed readers will notice that I called the Fusion 360 file "pool doodle connector kit". That's not a typo as such, I've always called the items commonly known as "pool noodles", pool doodles. I have no idea if this is a regional thing or just me. What do you call them?