This time, I wanted to build a full-size surfboard.

But before I could do that, there were still a few problems to solve.

Until then, I had made the entire cardboard framework by hand, using nothing more than a utility knife and scissors.

Even the small surfboard core had taken quite a while to make.

How long would it take if I made one full-size?

And cardboard comes in many different strengths and thicknesses.

I wanted to ask an expert which type might work best for a surfboard core.

There was one more thing on my mind.

Could the full-size framework be cut accurately by machine?

If so, I could save time and improve the accuracy at the same time.

So, using the Yellow Pages and the internet, I began contacting small cardboard manufacturers nearby.

I thought that if I could speak with someone there, I might find a useful clue.

But things didn’t go as I had hoped.

I couldn’t find anyone who could really help me, and time just kept passing.

“I can’t just sit around like this. I’ve gotta keep this project moving, even if it’s only a little.”

So, while continuing to contact cardboard manufacturers, I decided to try building a full-size surfboard using only the skills and tools I already had.

200 cm long, 80 cm wide, and 8 cm thick.

It was time to build my first full-size core.

I designed it so that the nose and tail would curve naturally upward, using the surfboard I normally rode as a reference.

First, I cut short pieces of cardboard and taped them together to make long sections.

Then, one by one, I cut slots into them so they could be fitted together like a yotsume-ami lattice.

Cut.

Tape.

Cut again.

Over and over.

It felt like it would never end.

Still, little by little, the pieces began to take shape.

And when I finally fitted them all together—

a huge rectangular core stood right in front of me.

I picked it up.

It was much stronger than I had expected.

And yet, it still had enough flexibility to bend slightly in a diagonal direction.

“All right. I think this might actually work.”

Next, I needed to fill each opening in the lattice with a piece of Styrofoam cut to exactly the right size.

But then—

another problem appeared.

I needed to cut a huge number of Styrofoam pieces, all the same size.

Using a utility knife was slow, and cutting every piece to exactly the same dimensions was extremely difficult.

“There’s gotta be a better way to do this.”

While wandering around a home improvement store looking for an answer, I spotted something.

A hot-wire cutter made for foam.

I tried it.

A beautiful, clean cut.

“That’s the one.”

There was just one problem.

The cutter was small.

It could only cut a little at a time.

I needed something bigger.

But I couldn’t find a larger one anywhere.

So—

“Maybe I’ll just make one myself.”

Using the small cutter as a guide, I decided to build my own large hot-wire cutter.

The Styrofoam sheets were 910 mm wide.

So why not build a cutter that could handle the entire width in one pass?

The next problem was the power supply.

I needed an AC adapter with just the right voltage to heat the wire enough to melt through the Styrofoam properly.

I visited secondhand parts shops again and again, collecting parts and running test after test.

Too much power wouldn’t work.

Too little wouldn’t work either.

Test it.

Change it.

Try again.

And finally—

I found just the right AC adapter.

My homemade large hot-wire cutter was complete.

I fed a large sheet of Styrofoam through it.

And it sliced through with surprising ease.

“Hey, this thing cuts pretty darn well!”

The job that had taken so much time and effort suddenly became much easier.

I had faced a problem, thought about it, built my own tool, and found a way through.

That gave me a real boost of confidence.

But—

the celebration didn’t last long.

I laid out all the Styrofoam pieces I had cut.

At first glance, they all looked exactly the same.

But when I looked more closely—

their dimensions were slightly different.

I tried fitting one into the lattice.

It wouldn’t fit.

Another one.

That wouldn’t fit either.

And another one.

All those pieces I had cut so proudly were refusing to fit into the framework.

“Why the heck...?”

Just when I thought I had solved one problem, another one appeared.

It seemed that building a surfboard wasn’t going to let me move forward quite that easily.