Make an Inflatable Packraft Seat – Kit Instructions

To avoid mistakes, be sure to read and understand these instructions fully before you begin.

The completed ultralight (40D) seat made in this demo. The standard (210D) seat kit is the same, but the fabric is thicker and somewhat less pliable.

Step 1 – Identify Kit Parts

Baffles A, B, and C, and the seat top and bottom showing baffle locations. Note: In newer kits the dashed line has been left uncut and should be folded. Semi-circular tabs (“ears”) have been added to the top+bottom to make tie-down points. Holes have not been cut in the baffles and are not required.

 

Each 210D (standard) seat kit includes:

  • One small valve.
  • Three pre-cut rectangles of 210D fabric for making baffles. We will call these rectangles A, B, and C.
  • Pre-cut top and bottom piece(s) of 210D fabric – early versions of the seat kit had separate top and bottom pieces; newer versions have a single piece that will be folded over to make the top and bottom. A 2 cm hole is cut in the top piece to fit the included valve.
  • Fabric scraps for reinforcing the heat sealed joints.

Each 40D (ultralight) seat kit includes:

  • 40D fabric with the shapes marked in pen, ready to be cut out with scissors.
  • One small valve.

 

Step 2 – Separate and Label Fabric Pieces

Use scissors to separate the seat pieces from the surrounding scrap material in any areas that aren’t fully cut.

You may wish to label baffles A, B, and C to differentiate them and indicate the top and bottom of each piece. (You can use a permanent marker, because these will be invisible from the outside of the seat.) Identify the baffles as follows:

  • Baffle A measures approximately 23 x 15 cm (9 x 6″) and the long edges will be attached to the top and bottom
  • Baffle B measures approximately 20 x 18 cm (8 x 7″) and the long edges will be attached to the top and bottom
  • Baffles C measures approximately 15 x 18 cm (6 x 7″) and the short edges will be attached to the top and bottom

If you like, you can reduce the weight of the seat by a few grams if you cut holes in the baffles, but the more material you remove from the baffles, the less the seat will keep its shape.

 

Step 3 – Mark Baffle Locations on Top and Bottom

Seat top and bottom indicating positions of baffles A, B, and C. They should be positioned symmetrically, and perpendicular to the long axis of the seat. The dashed line indicates a fold (some kits have a cut here separating the top and bottom pieces).

Lay out the seat top and bottom piece(s) on your work surface with the TPU coating side up.

Use a pen to mark the location of the baffles on the TPU sides of the top and bottom pieces, as in the diagram above. Note that the positions do not have to be exact, so do not spend a tremendous amount of time marking the locations – a single dot will do, if you feel comfortable “eyeballing” the position from that.

 

Step 4 – Install the Valve

Before sealing baffles in place, the inflation valve should be installed. (It is possible to install the valve after the seat has been sealed up completely, but it’s easier to do while you still have access to the inside surface of the seat top.)

Cut a circle of scrap fabric roughly 7 cm or 3″ in diameter, and then make a hole in the center approximately 1.5 cm or 3/5″ in diameter, as below.

Cut a ring of scrap fabric to fit under the valve flange. Outside diameter ~7 cm (3″), inside diameter ~1.5 cm (3/5″).

Apply glue such as Aquaseal to the top and bottom of the valve’s flange, taking care to make sure there are no gaps in the glue.

Being careful to avoid making a mess with the glue, press the bottom of the valve’s flange to the TPU side of the fabric ring, and then insert the top of the valve through the 2 cm hole in the seat top. Press the seat top down around the valve’s flange to ensure the glue will form an airtight bond around the valve, and then allow the glue cure (overnight is best).

Valve glued to the inside of the seat’s top and the fabric ring, as viewed from inside seat (before heat sealing the ring to the seat top).

 

Valve as it appears from outside the seat.

After the glue has cured, heat seal the fabric ring to the seat top (around the valve flange).

Seal fabric ring to seat top after glue has cured.

Step 5 – Bond Baffles to Top Piece

Sealing baffle B to seat top.

Align one long edge of rectangle A in the position you marked. Note that the baffle must be oriented so that the unsealed free edge hangs towards the fold between the top/bottom piece (the fold is indicated by a dashed line in the diagram above).

Use the edge of your iron to seal an area approximately 1 cm or 1/2″ wide near the edge of the baffle piece. Press firmly to make a strong bond. Don’t bother trying to seal it perfectly all the way to the edge of the fabric, because this joint will be on the inside of your seat so it won’t be visible, and you could compromise the airtightness of the fabric if you accidentally melt the TPU surface on the larger piece. (If you do happen to melt an area you didn’t intend to seal, simply patch it by heat sealing a small scrap of fabric over the hole.)

To avoid accidentally bonding more of the baffle to the seat top, place piece of parchment between the area you do not want sealed (fold the parchment paper in half a few times to increase its thickness to slow the heat transfer through it).

Seal rectangles B and C in the same way as you bonded rectangle A. It is very important to keep all three oriented in the same direction with the free-hanging part of the baffles pointing the same way – if you do not, it will be difficult to seal them to the bottom piece!

Fold back the baffles and cut some scraps of fabric to seal on the other side of the joints to increase their strength, as below.

Bond a strip of scrap fabric along the TPU side of the joint to increase its strength.

Step 6 – Bond Baffles to Seat Bottom

Because it would be too difficult to add reinforcing strips to the joints after the baffles are sealed to both the top and bottom of the seat, first seal reinforcing strips to the bottom of the seat, taking care to orient them so the TPU side will face the TPU side of the corresponding baffle.

Adding a reinforcing strip to the bottom of the seat before bonding baffle A. Be sure to orient the reinforcing strip as shown so the baffle can bond to it.

Add reinforcing strips for baffles B and C, making sure to orient them the same way.

After the reinforcing strips have been added, fold back the reinforcing strip for baffle A and use the edge of your iron to bond the free edge of baffle A to the seat bottom piece and the reinforcing strip at the same time, as in the picture below.

Bonding baffle A to the seat bottom and reinforcing strip. The baffle is already bonded to the seat top (right).

Do the same for baffles B and C; then the three baffles will be attached to both the top and bottom of the seat.

Step 7 – Seal the Seat’s Perimeter

Cut several fabric scrap strips 2-3 cm (1″) wide and bond them around the perimeter of the bottom of the seat, as shown below, so they can fold over to bond to the top piece later. The center of the strip (i.e. the fold) should be approximately 1.5 cm from the edge of the bottom piece, and only the inner part of the strip should be bonded to the bottom piece.

Note that you can use several short reinforcing strips to make up a side – it doesn’t have to be one long piece per side.

Joints between these strips need not be airtight, as the airtightness of the seat will come from sealing the top of the seat to the bottom – these reinforcing strips merely keep that airtight joint from peeling apart under pressure.

Fold a section of reinforcing strip over so the TPU side is facing up and align the edge of the top piece with the bottom piece. Heat seal the top piece to the bottom piece and the reinforcing strip. Repeat this procedure all the way around the perimeter of the seat. (If your top and bottom pieces are connected, you do not need to seal the fold.)

Fold a short section of the reinforcing strip over and align the top piece with the bottom piece.
Heat seal the top piece to the bottom piece and the reinforcing strip.
A finished section of seam.

Not pictured here are the tie-down tabs (semi-circular “ears” extending from the sides of the seat). Before sealing these areas together, insert a small piece of scrap packraft floor material (420D or 1000D fabric with TPU on both sides) between the top and bottom tie-down tabs. By sealing this heavy-duty fabric between the tabs you’ll create a reinforced area that you can tie to (make a circular hole with a hole punch or drill so it’s less likely to tear).

The seat with the entire perimeter sealed.

 

Trim the excess fabric from the edges of the seat for a cleaner finished look.
Inflate the seat and test for leaks.

If you have questions, please leave a comment below!

9 thoughts on “Make an Inflatable Packraft Seat – Kit Instructions”

  1. I have found that a stainless steel ruler with cork on one side works much better than parchment paper for placing on the back side of straight seams.

  2. Hi Matt,

    I just received the V3 kit and I noticed that the seat piece has two small ‘ears’ on the side that do not seem to be described in the instructions. What is the purpose of these and how should I deal with them.
    Thanks in advance and also for the great site and resources!

    cheers

    Kaspar

    1. Hi Kasper – the newer seats have tabs added to the perimeter to make tie-down points. You can heat seal them together when you’re sealing the rest of the perimeter, then cut holes in them (or use a hole punch) so you can tie the seat to your packraft. I’ve updated the text above, but please let me know if it’s unclear what to do. Cheers!

  3. Hi

    I’m currently working on a folding version of the seat kit.
    I have been following you instructions point to point, however i found that the installment of the valve was a bit troublesome.
    After the baffles are bonded to the top and bottom there is very little room left to work with the valve.
    I believe it would be easier to have the valve fitted before finishing work with the baffles.
    Install valve as step 4 or 5.

    Cheers
    Fred.

    1. Thanks for the tip – I wrote the instructions for a previous version of the seat in which it was easier to install the valve after the baffles were finished, but I see now why you had trouble. I have re-ordered the instructions to make it easier. Cheers!

  4. I am just starting my new packraft build. I have the standard kit (210D). Do the baffles need the holes cut in them? Also. Can the valve be installed before sealing the baffles as stated in an earlier post?

    Thanks,
    Matt

    1. Hi Matt,

      The holes are not required – I had originally been adding them to help people orient the pieces, but since you still have to measure them to figure out which one goes where, I decided it wasn’t really worth the time I was spending on it.

      And yes, the valve can absolutely be installed before the baffles if you prefer.

      Cheers,

      Matt

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