How to glue Mylar

I’ve been for more then a month wondering on how to properly join Mylar sheets together. The first attempt with Blimpy was practically a failure as it was leaking like a colander and it was a serious relief when that balloon (so so) flown away.

To prevent this I’ve discussed this with Vlada and he suggested a heat impulse welder or classical iron. Long story short it was a setback after setback. Mylar has a melting temperature starting around 250C and cotton ironing is around 205C. Even pushing Veronika’s iron to the max – Mylar was still happy – in sheets.

So I went to gumtree and bought a “hair straightener” – same result. Mylar simply didn’t get what I want it to do! Full of disappointment I came with a destructive idea and tried welding it with a soldering pipe – and it was holding!

However it also came with so many holes that whole procedure sort of lost its purpose. I’ve kept exploring and thought of some sort of RC model covering iron like this below, but it apparently won’t go over 220C.

At the end I came back to Serge and asked him for another advice and … it was working! Serge suggested to use a simple adhesive cement (like I did before), but use a can instead of spray to better control thickness of the glue layer.

Critical part is where you need glue both parts and patiently wait till they are no longer “touchy”. Even 5+ minutes. What a surprise … when those touch they instantly stick together and form excellent joint!

I did a stress test and couldn’t believe how strong it is, so I gave it to Sebi to have a go as well.

It passed our Q&A! Now we know how to make very strong sews and that being in hurry may not be always the best. Thank you again Serge! 🙂