Note: This step can be done at any point during your packraft’s construction. It will be easiest if done before the tubes are completed, but can also be added to a completed packraft with a single-layer floor. If you are doing this step before your tubes are completed, remember to leave at least 5 cm unsealed around the perimeter of both floor pieces so you can attach the tube pieces!
If you have purchased the double-layer floor option with your DIY Packraft kit, you may want to make your floor inflatable to insulate your legs from cold water and to provide some extra padding.
There are two different methods for making the floor inflatable:
- Sealing the floor pieces directly together in strips
- Adding baffles between the floor pieces
Option 1: Sealing the top and bottom floor pieces together in strips
The quickest and easiest method is to follow the normal construction procedure, but instead of using a full-size clothes iron to laminate your floor pieces together, use your heat-sealing iron to seal the two floor pieces together in strips (following the pattern in the diagram above). Install a Small Valve on the upper floor piece so you will be able to inflate it. Between the heat-sealed strips (where the floor pieces are not heat-sealed together) will inflate when you add air through the valve. (Remember to leave gaps between the sealed strips to allow air to move between them!)
Option 2: Adding baffles between the top and bottom floor layers
Note: Fabric for making baffles is not included in the kits but can be purchased separately. Scraps will work fine, as the baffles do not have to be made from continuous pieces.
A more elegant (but also more time-consuming) method of making an inflatable floor is to install baffles in a similar pattern to that pictured below. (Baffles are strips of fabric that span the vertical gap between the bottom and top floor layers. High quality sleeping bags and camping air mattresses feature baffles because they provide a more consistent thickness and better insulation.)
The heat-sealing procedure for installing baffles is illustrated in the inflatable seat video and instructions, and it basically makes your floor into an inflatable mattress.
I got pretty fancy with my baffles and had them tapered so the floor was 7 cm thick under my butt to 4 cm thick near my feet, and 3 cm thick near the front and rear of the floor. I also made the center baffles taller than the outer baffles, so the side-to-side cross-section of the floor looks like a squashed diamond. (This level of complexity is not required.)
I recommend making your baffles no more than 5 cm tall (excluding the parts that are sealed to the floor pieces) because as you inflate the floor it draws the sides of the packraft together somewhat, and the thicker your floor is, the more pronounced this effect will be. (Adding more baffles and making the outboard baffles shorter than the central baffles will also help to minimize this ballooning effect.) For this same reason, do not inflate your floor fully – it will pull the sides in less if it is only partially inflated. (If you stand on the floor, your feet should rest on hard ground, but when you sit on it, you should be elevated on a cushion of air.)
High strength and puncture-resistance is not required in the baffles, so they can be made from either 210D or 40D fabric.
Tip: When you bond the baffles to the first floor piece, orient them all with the TPU facing in the same direction – this will make it much easier to bond them to the second floor layer (see Make an Inflatable Packraft Seat for for details).
Tip: You can cut holes in your baffles to lighten them and improve air flow.
Making the floor airtight
Whichever way you choose to make your inflatable floor (with baffles or by sealing the floor pieces together in strips), you will need to heat-seal a perimeter 2-3 cm wide around the inflatable part of the floor so it will hold air (if you are making the inflatable floor before your tubes are finished, remember to leave at least 5 cm around the outer edges of the floor pieces unsealed so you can attach the tubes).
When sealing around the edges of your inflatable floor, be sure to keep the top and bottom floor pieces aligned, and avoid creating wrinkles or folds in the fabric, as air could escape through the fold if you seal it in place.
Tip: If you find that your floor is ballooning too much after you’ve sealed it up, you can still heat seal the top piece to the bottom piece in some extra spots or strips.
Questions? Please leave a comment below.