Back to Step 4 – Bonding Tubes to Floor
Before we seal up the center seams on our packraft, let’s install a valve while we still have access to the inside of the tubes.
Start by deciding where you want to locate your valve. I put mine near the top of the right-rear tube so it will be out of my way when I’m paddling but still accessible if the air pressure drops while I am out on the water.
Mark a circle 4 cm (1 9/16”) in diameter in the spot you have chosen, and cut this out with a pair of scissors.
Unscrew the one-way valve from the flange and gently force the plastic ring off of the flange. Then use a piece of sandpaper to roughen the “top” side of the flange (the side opposite the three raised bumps). Clean off the dust and then spread some all-purpose plastic cement onto the roughened surface and insert the flange through the hole from the “inside” side of the fabric. Press the fabric onto the glue, working out any folds or bubbles, and then place some weight around the valve to hold the fabric in place while it dries (a roll of packing tape works well for this).
Once the glue has cured, pop the plastic ring back onto the flange and screw in the valve and you’ll have an airtight seal.
2 Comments
Henri · October 24, 2016 at 6:22 am
I just ordered your plans. Thanks for the great work!
I’m going through the how-to section and wanted to point out that this valve istallation procedure works if the fabric has TPU/PU coating inside. If the inside is nylon it may not be possible to glue the rubber flange of the boston valve to the fabric (with any glue!). I have no idea what “all-purpose plastic cement” is, but I know you can make a bond between rubber and PU with PU-glue. If the fabric has no PU backing one may need use a valve that is attached mechanically to the fabric (e.g. a Leafield D7 or C7 valve). Or possibly glue the valve to the side that has TPU coating (and sandwich the flange between an other layer of TPU coated nylon).
Matt (Admin) · October 24, 2016 at 9:38 am
Thanks, Henri! Of the two fabrics featured in the video, the yellow fabric does not have a PU or TPU coating on the side that the valve is glued to, and the white fabric does. Both bonds have held so far, but yes, one might be stronger than the other. The plastic cement I used is LePage “Flexible Plastic Adhesive”. It is probably not the best option, but it works for now.
I like your idea of sandwiching the valve between two layers of fabric+glue – I will try that in the future. Thanks!
Note that the valves are made of PVC, so any adhesive you try should be compatible with PVC.