If you are living in the EU then extremetextil.de might be a good choice.
I first wanted to purchase a complete ultralight kit, but after I did the math I didn’t… Why? In the EU we must pay VAT + customs tax above 150 Euro value. In many western countries the package most likely will not pass the customs. In the Netherlands the amount of tax is 35%, in other words around 60-70 Euro plus. However I like the fabrics Matt offers in the shop, this was no-go for me.
Extremetextil is a German company. If you have got a valid EU VAT number than you can save 19% VAT from the price. They ship for 7.95 Euro.
I found the 70den Nylon TPU-coated one side (170g/sqm) and the 210den Nylon TPU-coated one side (275g/sqm) heat-sealable fabrics best for packraft building.
Did some similar tests with the 70D nylon like I’ve seen in Matt’s fabrics comparison video. I could not pull/tear the fabrics apart by hand. However if I made a small cut, then it was very easy to pull apart.
The 210D taffeta is obviously stronger.
The drawback is the color range… the 210D is available in yellow, grey, orange and blue, but surprisingly there is no black. The 70D is, well.. black. There is a blue option but be aware the TPU side is BLACK!
Since I wanted to make my packraft from 70D tubes and 210D floor, it is going to be black with blue floor. Odd combination, I rather would like to have the opposite.
The positive side: it looks like that the raft is going to be under the 900 grams (medium size)!
I found the boston valve in amazon.de and in kitemania.nl (Netherlands). TZIP I only found so far in England…