Tents, tarps, patio chair cushions and other outdoor accessories benefit from a waterproof seal. This allows the rain to run off the fabric, thus keeping your belongings or you dry. Homemade waterproof sealants do not have to contain glue or other adhesive products to be effective. Make your own waterproof sealant and save money by not having to buy several expensive cans of waterproofing spray for large projects.
Set a bucket in an outdoor storage building, covered patio or garage area. Anywhere that is well-ventilated and away from children, pets and open flames or other combustible items is acceptable.
Pour 1 gallon of unleaded gasoline or turpentine into the bucket.
Shave 1 pound of paraffin blocks into the gasoline-filled bucket with the sharp knife. You can drop the block in without doing this, but shaving it or at least cutting it into smaller pieces enables it to dissolve faster.
Wait two or three days for the paraffin to dissolve. There may be some undissolved portions, but as long as most of it is dissolved, you can start the waterproofing.
Carry the bucket to an outdoor location.
Spread your tarp, canvas, tent or other item you want to waterproof on the ground.
Paint the paraffin mixture thoroughly over the material. Pay close attention to any seams, button-covered areas or the roof or floor section of a tent.
Work the solution into the material well with the stiff bristles of the paintbrush.
Allow the waterproof seal to dry thoroughly. The gas or turpentine evaporates and leaves behind a paraffin coating on the fibres, thus making it waterproof.
Flip the canvas, cushion or tarp over and sweep away any grass or other debris with a broom. Coat this side with the waterproof seal as well and allow it to dry completely before storing.
Commercial waterproof sealants are available in spray cans. There are many that are made for particular fabrics. If you are attempting to waterproof an expensive jacket, pair of fabric shoes or other types of apparel, it is advisable to purchase a commercial product. A simple method to waterproof a small piece of material is to lay it down on a flat, hard surface. Rub a block of paraffin up and down the fabric. Set the paraffin by ironing the fabric with a warm -- not hot -- iron.
Keep in mind that turpentine and gasoline are highly flammable. Never light a match or use the solution near any open flames.