Try a search on Inland Marine sealant.

Inland and DUX both make inflatable tube sealant for slow leaks. It is
air curing liquid latex. You deflate the tube, add the liquid through
the valve, squish it around and reinflate. Then spend the next few
hours rolling and tilting the boat to get all the interior coated.

However, it will only give you another season or two of use. Once
applied real professional interior patches are not possible so even the
vendors recommend that it be used only as a last resort and only on the
tube that is leaking.

andrea wrote:

My old inflateble has become porous. It's made of the neoprene, not hypalon.
Have heard about some liquid that impregnates the rubber from the inside.
One is supposed to sip it into the chambers. Please if anyone knows where to
find it (web address). Any experience?
Thx in advance.



--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com