I was just about to buy some Thompson's! The boat cover seamstress said it works "as good as any". Previous years I have used 3M spray cans. Now I'm not sure. The dust/dirt trap theory may be just a sail/sales ploy. As I recall from archives, lots of people swear by the cheap deck spray. Are we opening up a can of worms here?
Andy,
This stuff is NOT a ploy. 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 Sunbreall is only in your best interest.
One of my very good friends owns a very high end canvas buisness here in Maine. I have done lots of consulting work for him over the years and know his buisness quite well. I have seen first hand on hundreds and 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 pievce 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.
Just this month in 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 the manufactureres DO suggest the absolute best products for use with thier products so they can build and keep thier reputation. Use of sub par products can severly shorten the life of both Sunbrella and dodger glass. I have seen this time and time and time again with teh access I have to the marine canvas business.
You, or anyone else for that matter, are more than welcome to hear it directly from a guy with nearly 30 years in the marine canvas buisness. I will be working with Seth at the Maine Boat Builders Show manning his booth as I have done for the last 10 years. Oh and he believes so stromgly in these products that he gives them away with each canvas job. When owners need more he sells it to them at cost.. A scam? I think not it just works!!
Marine canvas is very expensive $$$$$$ yet folks will go to any length possible to save just two bucks to six bucks on a product they use maybe once per year? I just don't get the mentality??
My dodger glass is now 8 years old and have only ever seen Imar products. I have seen these same windows destroyed in one season..
Go ahead and spray a silicone based product on your marine canvas and let us know the outcome.

I already know what it is as I have seen the piles of junked Sunbrella in the dumpster at my buddies shop...
Please use what the manufacturer recommends.