Who knew vacuum forming could be so easy? Ok, so probably a lot of people, but I’ve been thinking and not taking action for a few years now because the necessary equipment just seemed so complicated. Enter Make SF’s vacuum forming workshop to flip my perception of vacuum forming’s difficulty on its head and offer up a fun Tuesday evening vacuum forming a ghostly bulbasaur to haunt my desk.

The Event: Peanut Butter Vacuum Former Workshop

Vacuum forming is a molding technology via which you can stretch heated plastic over a model by applying a vacuum beneath the plastic. The vacuum sucks all the air out the the space between the plastic sheet and a table covered in small holes, forming a tight and detailed shape over the model. Professional vacuum formers are expensive and even several of the hacks on Instructables require workshop space. So I was surprised and thrilled to learn that the only things I’m missing are a heat gun and some sheet plastic.


In this workshop, we each used a small plastic container and the top of a soda bottle to create a vacuum “table” on which we could place small objects on to be modeled. The first half of the workshop was spent building our “tables” and a frame to hold the sheets of HDPE plastic (think milk jugs) we would be molding.  The space was a little tight, but everyone was friendly and shared tools and tips easily. It was fun to see the variety of techniques people used to cobble their “tables” together. Some people installed their bottle tops inside of the larger plastic container, which was tricky but creates a studier form. Others, myself included, opted to glue the bottle top to the exterior, an easier and faster option, but probably one that is less stable in the long run.


In the second half, we each took turns heating up our square of HDPE and vacuum forming various objects. This was surprisingly simple, although you had to take care not to burn yourself with the heat gun or on the softened plastic. HDPE is easy to use because it turns clear when it’s hot enough. A more professional grade plastic would by styrene sheets. I had brought a small Dr. Who figure, but it had too many undercuts to mold without damaging the object or the molded form. Instead I made a mold of a bulbasaur. The details were so fine I could see all the leaf patterns and even the ridges of my fingerprint in the clay I used to fill a gap in the top of the toy.


After molding, we cleaned up and gradually dispersed. I always appreciate a workshop that makes me want to go home and try the project or technique again. This vacuum forming workshop did just that. Now I just need a heat gun.

The Group: Make SF

I discovered Make SF via a friend and Meetup, and consider it a phenomenal group to get involved with if you’re in the Bay Area and like to make stuff. I attend the occasional meetings and have enjoyed them all. Each monthly workshop is held in three different locations (Oakland, SF, and San Jose) and typically has a fairly low participation fee. Events range from fully hands-on to demos, but even the more talk-oriented meetings are worth it to learn about the technologies available for your projects. You can check out what Make SF is up to and join on Meetup.

The Space: RockIT Colabs

RockIT Colabs was a new location for Make SF’s workshops, but it was a nice one with a smallish “hardware” room perfect for the gluing, drilling, and cutting we did during the workshop. The majority of the space is a coworking area that one attendee referred to as the space for “software” people. While not as large as TechShop, the space was welcoming and friendly. In addition to workspace, RockIT Colabs offer a variety of regular workshops. I found it a little tricky to find and enter (you have to pass through 2 locked doors to get in), but I’m sure regular members have no trouble. Check out more about RockIT Colabs on their website.