The material, the weight — and the wait

Work has been stalled for a few months. After taking the time to review the state of this project, I realized what the sticking points were. They come in three forms:

  • Our hot tub has been out of commission with a leak.
  • I’ve been struggling to choose the perfect material.
  • I’ve been struggling with the unforgiving nature of Sketchup.

Finally, I’ve made decisions on all three uncertainties.

Decision #1: The leaky hot tub

We purchased our tub second hand with a pre-existing hole. We patched it up, but the leak has re-emerged again this year. Thankfully, repairing a resin tub is quite easy. I cut a little strip of resin from inside the tub and melted it into our cracked shell. It seems to have worked without issue.

Decision #2: Material choice

It’s occurred to me that I’m not a plastic expert. For the manufacturing runs, I’ll consult the experts. As for right now, I just need the closest best thing to prove the concept.

Initially, I was hoping to use polypropylene, but the Prusa just wasn’t having it. Well, probably more like – I wasn’t willing to put in the experimentation time.

Now, I’ve discovered and settled on ASA, ABS’ flashier cousin. And… wow. It’s sturdy, relatively temperature-and-chemical resistant, and easy to print.

With all that being said, I just need something that is good enough to prove the concept right now. The design will change when we move to production.

Decision #3: Software

Sketchup has been a blessing and a curse. It’s got a relatively small learning curve that allows you to do a handful of things really well. My biggest frustration, however, has been it’s optionality. You make a model, print it, then need to make a change. Most changes are extremely tedious to make after the fact.

After exploring a few options and working with them, I found that Fusion 360 is leaps and bounds more useful for an in-progress model. Because it uses parametric modeling, you can tie certain changes to set characteristics (eg. angles, lengths, faces). To update the model, you can simply update the original parameter — and the model will completely rebuild for you without a complaint. Win-win.

AutoChlorinator™ Fusion 360

So, now, let’s carry on to completion of the first AutoChlorinator™ prototype.