Does it matter? I bought a little thing of coleman's seam sealer. I've never used it. The last tarp I had was two sil nylon ponchos sewed together. The fabric leaked when saturated pffft! I used some waterproof spray from JoAnnes and seam sealed with silicone from the paint department at lowes disolved in denatured alchohol. This seamed to work.
Any pro advice on the subject would be appreciated. Or as allways I'll jump in the deep end and try to swim
If I have seen further, it is by standing on the shoulders of giants.