[harald]

There’s currently a sell-off of a 100 Liter (no idea much this is cubic inches) inflation bag on German eBay and similar sites, for around 5 Eurones. Just in time,  as I anyway wanted to build an XXL inflation bag. The Produkt is called Fluxbag: https://www.google.com/search?q=fluxbag&rlz=1C1CHBF_deDE790DE790&source=lnms&tbm=isch&sa=X&ved=2ahUKEwiAztLe-ezpAhU-QUEAHUhRADIQ_AUoA3oECB8QBQ&biw=1920&bih=888
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[harald]

I recently learnt that a good dishwasher fluid to detect leaks is Fairy Ultra diluted one plus ten. This is what people use in homemade formulas to blow giant soap bubbles. Works better than the no name stuff I used before. You have to cover the whole raft in detergent and wait a while for all leaks to show up.

 

 

 

 

 

[harald]

Someone must have read your post :-). This feature is now available in the Nortik Duo Expedition packraft. The raft has two internal bags which are sealed with watertproof zippers. I guess that the internal pressure on the bags keeps air and water out. Found no reviews on the performance, but here’s a pic: https://www.faltboot.de/fileadmin/_processed_/1/3/csm_nortik_raft_Tasche_integriert_6b109150e1.jpg

[harald]

Hi Christian,

here’s everything on one photo.

– The collar of the bottle is sandwiched for stability between two circles of fabric. The flap (in red) can be any type of tissue. As a valve this works the better the higher the pressure. I use it only to assist with manual inflation, so high precision was not my goal. (The dirt on the blue circles is glue residues. I could have protected the surfaces with tape, but these are from some prototype). On the inflatable seat I don’t use flaps on the “valves”.

To keep the threads of the caps tight, I use the TIZIP silicone grease for now, which to me looks like simple silicone vacuum grease.
– To secure the bottle cap I made a hole with a Swiss Army knife, secured the cord with a knot and E6000 (from China) glue inside and outside. E6000 adheres well to polypropylene, is a bit elastic and acts here more as a sealant than an adhesive. I assume many other adhesives/sealants would work as long as they stick to the polypropylene.
– as a bonus I show the garden hose adapter which connect’s Matt’s inflation blag to the bottle valve. Works really well.

[harald]

Since my inflatable seat was developing leak after leak I glued one together using vinyl cement and some cheap (20 Eurones) white 500g/sqm vinyl (PVC tarpaulin) from ebay. Works like a charm, no leaks, I did not even bother to add seam strips.

Since the seat worked so well I decided to build a packraft prototype from the rest of the vinyl. The build process was a bit less orderly than what you see in Matt’s videos and completely different since everything was glued, not heat sealed – today I took the raft out for a succesfull bikerafting test.

It weighs exactly 3 kgs before adding attachment points, the seat weighs 600 g. I used bottle cap valves for both the seat and the raft. I like them better than the boston valves since it is easy to make adaptors like one for the inflation bag, another one for an inflation tube etc. There are two “valves” on the raft: one for inflating and one for deflating.

I also added a DIY Packaft logo using the good old “rubbing accetone on a laser print” technique, but unfortunately it was on a position that was later needed for an attachment point 🙁

Here are some photos of the loaded raft:

 

 
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[harald]

It might interest you that a similar technique was used in olden times for field repairs of wooden folding Kayaks with a PVC fabric skin: PVC was scraped with a heated knife from PVC patches (or fabric they carried for that purpose) and then the hot PVC was smeared with the hot knife on the area to be patched. Requires obviously some skill.

[harald]

There’s a Russian packraft boutique who uses this valve hack on their packrafts:https://www.birdypackraft.com/. There’s actually a lot of packrafting going on in Russia, if you know how to use Google translate or Deepl. Personally, I don’t like the Boston valve much. Its too bulky and too protruding. I would go for a bottle cap opening for bag inflating and deflating plus a topping up valve if I ever build a new raft.

[harald]

I got a sample of a transparent TPU sheet from a German shop: https://www.diekleinewerft.de/TPU-Folie-152cm-breit-038mm-dick-semitransaprent

(They also have TPU tubes for making bladders.)

Unfortunately, this TPU has a much higher melting point than Matt’s fabrics. Since the material has not a fabric backing it warps if its heated and the warps stay if it cools down.

So in order to use this as a sort of patch you would want a TPU with melting point similar to your fabric TPU, heat it uniformally until it melts then press down until it recristallizes to prevent warping. In my opinion there’s no upside compared to using a single coated TPU fabric as a patch.

In theory one could try to melt this TPU until it liquefies and then paint it piping hot. In this case the high melting point of this material might be an advantage since it would easily bond to Matt’s TPU.

[harald]

Hi there, greetings from Germany.

[Author]

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