Unless like Rick and your canvas is so old it does not matter don't use Thompson's. Thompson's Water Seal is a big no, no on Sunbrella. It contains silicone. Silicone attracts dust and dirt and traps it in the fibers of the Sunbrella. As the wind moves the fabric these grains of dirt & dust act like sandpaper on the fibers cutting its life and also making it permanently dirty. The silicone residue also runs off over your dodger windows then the sun hits it and can ruin them.

I have had lengthy conversations with the Glen Raven Mills rep (Sunbrella) and they have thoroughly tested just about every "claimed" waterproofing treatment known to man. The hands down consistent winner, and the only one Sunbrella recommends is 303 High Tech Fabric guard. Glen Raven stakes their reputation on this product and no other.

Please do not mistake this for 303 Aerospace Protectant for 303 Fabric Guard they are not the same.

Keep in mind that once Sunbrella has sold you the product their only investment is to see that it lasts and up holds their hard earned reputation. They have thoroughly tested many products and seen the results. They, Glen Raven Mills, have no stake in the 303 company what so ever so by recommending the absolute best product for use with Sunbrealla is only in your best interest as they have zero financial gain other than a good reputation.

One of my very friends owns a very high end canvas business here in Maine. I have done consulting work for him over the years and know his business quite well. I have seen first hand on hundreds of occasions where folks have tried to "cheap out" and save a few cents yet the end result was the destroying of a very expensive piece of work.

For years & years I have suggested the use of Imar products on dodger glass. Many have called what I suggested as being un-wise and complained that it was too expensive and that products like Pledge worked fine. A few months ago Practical Sailor tested a myriad of products for dodger glass and guess what? Imar was the hands down winner in both the cleaner and the polish. I have known this for years now finally everyone else does. Sometimes what the manufacturer recommends actually is the best.

Sometimes the manufacturers do suggest the absolute best products for use with their products so they can build and keep their reputation. Use of sub par or the wrong products can severely shorten the life of both Sunbrella and dodger glass. I have seen this time and time and time again with the access I have to a marine canvas business.

Seth believes so strongly in these products, and his reputation, that he gives them away with each canvas job. When owners need more he sells it to them at cost, 0% mark up.. A scam, no, it just works and keeps his customers happy.

Marine canvas is very expensive $$$$$$ why go to any length possible to save just two bucks to six bucks on a product you'll use maybe once per year? My dodger glass is now 8 years old and has only ever seen Imar products. I have seen these same windows destroyed in one season, mine are still crystal clear..

Applied correctly 303 Fabric Guard does not change the color, does not attract dirt, does not bleed off onto the glass and re-waterproof and protects the fabric from staining.