Blog — Slim Pack


The Foam Shop in the Shadow of the Tesla Factory

In the shadow of Tesla’s Fremont factory sits an unassuming business who does specialty foam work for a wide variety of clients. When National Geographic needs a custom case designed to protect equipment from the elements, these are the folks they call.

Bob's Foam Factory

Sitting directly between San Jose and San Francisco, most of Fremont is a suburban bedroom community that serves both cities. But it actually covers quite a wide area and has many industrial sections as well.

When I first visited Bob’s Foam, I still remember the awe I felt when opening the door to the shop area, seeing solid blocks of foam the size of camper vans and saws large enough to cut them.

Minimal backpack foam producer Bob's Foam Factory

I told the guy in the shop who greeted me about my backpack project and the kind of foam I was looking for… something that would hold its shape, protect the contents, and be thin enough to be integrated into the liner itself.

He quickly grabbed a yellow legal pad from the small desk in the corner of the shop and started making diagrams. Despite the fact that I had been researching different types of foam for weeks online, I learned more about foam from him in 5 minutes.

I showed him my prototypes and got out my sketchbook to take notes. 

Minimal backpack foam producer Bob's Foam Factory

There are two general categories of foam- open cell and closed. Open cell is most common and cheaper because a lot of the material is taken up by air. It’s great for many uses like couches but it’s spongy and can break down over time.

In order to achieve the curved back of the Slim Pack, I would need something more rigid. An open cell foam dense enough to do this would be too thick. So he recommend closed cell.

Even within closed cell, there are tons of materials, densities, and even processes used to make it. He showed me some of the ones he stocked and they worked okay but ideally I wanted something a bit stiffer. “Well, there’s also crosslink but it’s way more expensive,” he remarked. 

If you’ve heard of crosslink, also commonly referred to as EVA, it’s likely in the context of shoes since this is the type of rubber used in high-end running soles. It provides excellent cushioning and doesn’t break down over time. It also doesn’t take on any water and can even float!

Outside of $100+ running shoes, EVA doesn’t have many uses which justify the cost so it wasn’t something they carried. But he said if I can find it, they could make the parts I needed for the bag.

As I prepared to leave, I thought he must be the owner since he was so knowledgable. “Are you Bob?” I asked. “No, I’m his son- Rob.” Funny, another second generation family business to add to my partner list along with my printer, die cutter, and shipping house.

My hunt for EVA initially didn’t go too well. I spoke to a specialty foam supplier who did a lot of work for Nasa and when I asked for crosslink she said- “Oh, you want the fancy stuff, huh? No we don’t carry that.” If this stuff was too fancy for Nasa things weren't looking too good!

As I expanded my search I ran across a terribly designed website that seemed promising. It’s funny- sometimes with industrial suppliers a bad website can be a good sign. It can be an indication that they have customers already and they often times have very knowledgable sales folks… which turned out to be the case.

Just a couple days after talking to the foam supplier, a sample box showed up. Opening it gave me a similar feeling of awe as walking into Bob’s Foam… in front of me was a library of foam, arranged by increasing density, much of it even available in different colors. With this arrangement I immediately identified the perfect one… and I could even get it in black.

When I talked to the sales person about the thicknesses available, it took me a moment to realize that he was saying I could get it in any thickness I wanted. But that was because I had to buy a whole block and they would slice or “scythe” it for me to order. They would drop ship it to Bob’s Foam and then they would die cut the parts for the backpack.

Pricing everything out, this would be one of the most expensive parts of the bag if I divided it out by how many we were going to make. I thought it was worth it but I would also essentially need to buy three times more than I needed.

Minimal backpack foam producer Bob's Foam Factory

It was pretty exciting to see my block of foam arrive at Bob’s. There was no way to know for sure whether the final cut parts would have the properties I wanted before we made our pieces, but it turned out to be even better than I expected. It slides right into the liner but maintains the shape. And since it’s closed cell you can also collapse it flat like in the bottom of a suitcase and then it’ll rebound to its normal shape. 

From educating me about the right foam to use to precision cutting the final parts, Bob’s did a fantastic job delivering this custom part that makes the Slim Pack possible. I’m glad to add them to my list of local manufacturing partners and look forward to working with them to bring more products to life.

Slim Pack project complete!

It started with a simple question from my wife- What do you want for Christmas? When I couldn’t find a backpack I liked and heard from previous backers that they were also looking for a minimal backpack, I decided to make one.
Initial Slim Pack Sketch
After 2 years of designing and prototyping, I launched the campaign and the response was fantastic. But while folks loved the concept, there were also lots of suggestions for additional features and design elements. One of the great things about Kickstarter is that it facilitates a discussion directly between the customer and creator. When you walk into a department store, you can’t know who the designer behind a brand actually is, much less have a conversation with them. 
The first suggestion was to add just a bit more color… but not enough to distract from the minimal style. So I added two main elements: A bar tack accent stitch on the bottle pocket and some top stitching portions on the shoulders of the bag.
Bar tack close up
On the black bag, these top stitches are also black so it makes it more of a textural element than an overt color contrast. 
Close up of top stitching
The next main suggestion was to consider a charcoal backpack. As it so happened, I was already imagining this as a potential possibility down the road. It’s kind of a big deal to make a new color of Soft Shell since it needs to be custom manufactured and color matched, but I thought that our previous gray wouldn’t look as good for a backpack. So during the design phase of the Slim Pack, I defined a new darker gray and had already ordered it. It came in during the campaign, so I created a prototype Slim Pack. It looked so good, I decided to make this available during the campaign so folks would have the bag they most loved. And the Charcoal/Orange color combination ended up being incredibly popular.
Charcoal Slim Pack
There were also several functional elements that entered into the discussion… is there a clip for keys? What’s the handle like? Based on this feedback, I added a highly functional key clip with a rotating head so it doesn’t get tangled up and long leash so you can unlock a door without actually unclipping it.
Key clip addition
I also upgraded the handles to use an overmolded rubber grip, which is super comfortable in your hand.
Overmolded handle detail
Lastly, folks asked about the stability of the bag if they were active, such as while hiking or commuting on a bike. Some wanted a chest strap but others implored me not to add one since they hate how they dangle. So I came up with something I call Minimal MOLLE, which leverages the spacing of military webbing and allows things like a sternum strap to be added. Other things such as sunglasses or small pouches can also easily be attached.
Sternum Strap
By the end of the campaign, we had over 1,000 backers… which meant 1000 bags to make! This has been by far my most challenging project yet, from both a design and logistics point of view. Each bag ended up taking three times as long to make which also made the cost much higher. Even though we did all we could to make the process efficient, they’re made in a very small shop in San Francisco so are still essentially hand crafted one by one.
Slim Pack Components
The project has had more ups and downs than previous ones, but I can definitely say I’ve learned the most from this one. Sometimes I guess you learn more when things don’t go that smoothly. One of the things I learned was how supportive and understanding my backers have been throughout the process. With all the behind the scenes updates, folks began to feel like they were on the journey with me… and it was their comments along the way that encouraged me as well.
Kickstarter comment
Kickstarter comment
It took a bit of help from everyone to get the project done...
A little help from your little friends
But when folks got their bags, the positive feedback made it all worth it:

"Just wanted to send a quick thanks/kudos for the slimpack…. the air pressure from the plane popped open the person's water bottle…n Everything inside the other bag (nothing important fortunately) was also soaked. Slimpack contents though, including my laptop, were bone dry. So, thanks! Sure glad it arrived before my trip. :)"
- Nathan (Canada) 

"This backpack feels like the last backpack i'll ever own. Its attractive and understated, and i get compliments from people regularly, only to wax "and it's totally waterproof!” Anyway, i just feel like this is an incredibly functional object that makes essentially no compromises. Its the perfect backpack for me. Thank you so much!!"
- Greg W (Brooklyn, NY)

"My wife and I both love our backpacks! Mine works great when on my motorcycle, too. Love the fact that it rides high, not down on my waistline. Whatever difficulties you had in producing this project, just keep it up. This is the best minimalist backpack on the market, by a long ways!!"
- John M (Hixton, TX)

"Hi Dave: I don't like my bag. I absolutely LOVE it. It's so incredibly thoughtful in its design. Minimalist in appearance, but so functional, so light. Beautifully designed with function at the forefront, and yet so robust in its material and construction. You've done a marvelous job. I'm so impressed. This thing is beautiful. I was at the Airport earlier today, and I had 5 different people walk up to me and ask me about your bag. I unwittingly became a Slim Pack evangelist."
-Pablo (Durham, NC) 

"Hello! I took my backpack to our Canada Day Celebration in Ottawa and it poured rain all weekend. Everything in the backpack stayed dry as promised!"
-Evelyn (Canada)

"Hi Dave, I got your backpack and its amazing. Very light and stylish. Thanks a lot for this beautiful bag."

"Hello Dave, Just want to say, thanks for the bag and wallet, great products."
Alex A (Netherlands)

"Dear Dave, I just wanted to say thank you for creating the SlimPack.
It’s not an exaggeration to say that it has changed my life for the better: Since it’s arrival in late May I’ve used it as a daily commuter pack, used it as an on-board pack on international and domestic flights, used it as a conference bag, and it’s held up brilliantly—including soakings in foul weather where the contents remained toasty dry! I’m carrying both a Macbook Pro and a large iPad with far more comfort, and better posture, than with my previous backpacks."
-Andrew W (Australia)

"Will say, have never received so many compliments on a backpack before!"
-Amanda H (Massachusetts)

Now that the kickstarter bags have shipped, it’s a great feeling to have the project complete but I’ll also miss the process of creation.
Which leads to another question… what should I make next?

Accidental Slim Pack Water Test

When I worked as a UI designer, there were several times when I had the opportunity to design for entirely new hardware devices. During the process, we would usually have prototype versions of the devices at various forms of completion. These could cost in the tens of thousands of dollars per unit and there were a handful of times when someone on the team would accidentally have one one fall off of their desk onto the ground. “Drop test!” everyone would exclaim in a half-joking, half-panicked tone. Everyone would be very happy if it passed.

Slim Pack Perfect Backpack Waterproof

Water Test of the Slim Pack Commuter Backpack

Well, a backer recently had the accidental opportunity to put our waterproof commuter backpackthe Slim Pack, through its paces during a flight. As he described:

"Just wanted to send a quick thanks/kudos for the Slim Pack. As it turned out, I received mine the day before we left for a week-long vacation in Mexico.

I had already planned to bring my laptop, so naturally took the opportunity to try out the new pack. Used it as my carry-on, with laptop and some other supplies. What happened next was great. As the slimpack was stowed under the seat in front of me, the air pressure from the plane popped open the person's water bottle sitting in that seat. She didn't notice as it slowly leaked almost a liter of water out beside the seat, directly onto the slimpack.

When I eventually reached for it, I discovered that both it and another bag I had under the seat there were drenched. Everything inside the other bag (nothing important fortunately) was also soaked. Slimpack contents though, including my laptop, were bone dry. (The exterior dried off quickly too.)" -Nathan

In my testing, I can control certain variables such as water intensity and exposure time… but in the field, conditions are more realistic. So far with rain and now this in-flight water torture test, it’s shown to hold up really well in real world scenarios.

Another backer shared his experience:

"Dave, I received my backpack in the very first batch sent. It is incredible. It was put through its paces this weekend at the NAMM show in Anaheim CA during our crazy weather. It handled the rain with no problem, and for those not in CA, this was an exceptional amount of rain. I carried my DSLR and my iPad in it with no fear. Truly impressed with the comfort." -Sam

We’re making great progress on the backorders and they’re coming out great… looking forward to getting them in the hands of the rest of the backers!

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