I made my own silicone water proofing using GE silicone II and Coleman camp fuel.I mixed the fuel and silicone till it was a kind of thick consistency then added more fuel to thin it out to the consistency where i could use a sponge mop and paint brush to apply it.I used the room divider that came with my tent to test it on.I stretched it out tight and used the sponge mop to spread it on.The fuel drys very fast.Over the course of the next four days I sprayed it with a garden hose several times a day.Not one drop came through the fabric.I put my tent up,which is a large 235 sq ft.Used the sponge mops and paint brush and covered the whole tent in about thirty five minutes.i only notice a very slight color change but consistent.Its been up in my yard for three weeks now with periods of heavy rain and wind(Irene and Ivans aftermath)The only spots where water came in were some zippers but nothing through the fabric.I applied some bees wax to the zippers and have almost totally eliminated all the leaks.The total cost for what i used was under twenty five dollars and still have enough left to do two more tents of the same size.It cost me under nine dollars to water proof this big tent.If i had to purchase cans from a local store it would have cost me over forty dollars for one application.Cheap,easy and durable.

The tent you used it on, was it PU coated to begin with? Does the coating stay on with repeated packing and unpacking? Photos?

I've done similar with mineral spirits instead of Coleman Fuel

Coleman Fuel is so flamable

The only problem I've had is the floor. On the surface against the ground, it peels off after a few trips. On the surface I sleep on, it peels off after many trips.

the silicone might not delaminate as much if it were heated and applied liquid as such. would help it penetrate all through the fibers, pressing would likely help as well, to force the silicone into the fibers. an iron might do the trick, though I havent tried it.

what type of solvent is used to keep the silicone in the tube flowable? thats what should be used for the thinning