When fabrics, from a canvas tent to a pair of hiking trousers, become exposed to rain and wind they can begin to disintegrate to the point of being rendered unusable. The fabric waterproofing sprays sold at camping supply stores contain chemicals that might harm the respiratory system. It is not difficult to make your own safe, effective waterproofing spray to protect your clothing and equipment.
Pour 0.454kg. of powered laundry soap into a plastic bucket.
Add 1 gallon of warm water and stir the ingredients until the soap is completely dissolved.
Pour the solution into a plastic spray bottle.
Lay the item that is to be weatherproofed flat onto a plastic tarp and spray the entire surface with a generous amount of the dissolved washing powder. You may need to refill the spray bottle several times if you are waterproofing a large item or several pieces of clothing.
Allow the item to remain in the sun for 24 hours, or until it is completely dry.
Combine 0.227kg. alum, or hydrated potassium aluminium sulphate, with two gallons of hot water. Alum has several applications, from pickling to the production of deodorants and as a treatment for canker sores. The alum should be handled with care as it can be toxic when ingested.
Place the item into the dissolved alum and allow it to soak for one to two hours.
Remove the item, wring out any excess water and hang it out to dry completely. The item is now ready for use.
Wear rubber gloves when working with the alum and keep the mixture away from pets and children.