How do you make fabric water repellent? I want to make the cotton/poly fabric of an outdoor canopy I made water repellent. Scotchgard is somewhat expensive for a spray can. Any help is appreciated. Thanks.
Back in the 1970's I remember reading an old Army Survival manual from WWII & they had an old fashioned waterproofing formula from the days before we had all these chemicals from the oils companies (like silicone). I must warn you that it sounds VERY flammable and somewhat dangerous to me & you'd have to be very careful & not barbecue or smoke around or under it. The recipe called for only 2 ingredients, Kerosene & Paraffin Wax.
They put the wax into the kerosene & waited until it melted. They then either dipped 100% cotton fabric into the well-stirred mixture or brushed it on with a natural hair paintbrush then waited for about a week for the kerosene to evaporate which left only the wax bonded to the fabric. I don't know the exact recipe of how much kerosene to how much wax but you may want to go to a large library & take a look at the old books. Or, better yet go to a large book store & look at the books that have ideas & survival recipes from the old days. Also, check out Army Surplus Stores & survival sites on the web like these below & also post your question there.. Another good idea would be to search the Mother Earth News site. They have listings of old articles. You can also Google "Tent Waterproofing".
Here's a great listing of info & survival web sites:
Preparedness & Survival:
PS. You may be able to find a large container of silicone then thin it down with rubbing alcohol (which will evaporate) then paint this silicone on to your fabric with a natural fiber paint brush.
I have used "Thompson's Water Sealer" for decks on all type of fabric for outside use. I have even used it on a tent and silk flowers I placed in my garden. Worked great for me! I just pour some in a spray bottle and toss out the bottle when finished with the project. Good Luck!