Dinghy Repair ... not one you'll see in a magazine.

 

This is a not so good patch.

I had a very slow leak in the starboard tube, and had hunted diligently for it. Soapy water etc. I could not find it, and decided to try to seal the tube from the inside using a latex sealant. These usually work well for very small leaks.

As an aside, I'm not that happy with how many times I've had to fix leaks in this dinghy - it was very expensive (Zodiac 2.4 m), and I thought it would be more robust. It hasn't had rough treatment.

Anyhow, I removed the valve body and squirted in a good helping of latex fluid - more than would normally be necessary. Maybe half a litre. After sloshing it around a good deal ('tumbling' the fully inflated dinghy) I noticed a tiny scratch that was bubbling faintly. What I couldn't find with soap was revealed by the sealant ...

I painstakingly prepared the area (cleaned with solvent) and the patch - three thin layers, five minute gaps between the first two, fifteen minutes after the third, and applied it. At first, everything seemed fine.

Then it became clear that the pressure in the tube was driving air into a bubble under the patch. I immediately opened the valve and tried to press out the bubble, but it was too late. The adhesive was setting up well, but the blister looked like it might progress.

I carefully lay the dinghy in a position that made sure the latex was flowing into the leak. Then I had a think. I really needed to get rid of the air bubble, and it wouldn't be persuaded to go back where it came from ...

I decided to puncture the bubble carefully from the outside - near the edge, with a needle, at a very shallow angle. I put two small holes in and got rid of the air. Unfortunately, the adhesive in the centre section wouldn't grip properly now - either because it had set up, or because the latex was lubricating it.

I reinflated the tube and put it in back in the position that let the latex flow towards the puncture. After an hour or so, it was clear that the latex had filled the bubble and was coming out through the pin holes. No more air.

It all now seems to have set up, and the tube is still firm after 24 hours.

This is definitely not a technique I would recommend, but it seems to have worked. We'll see.

Since getting the patch off again would probably do further damage, I don't have much choice.

The mucky finish is from an excess of rubbing and manipulating.