make your own sil.

[Knotty]

Denatured alcohol might be worth a try but only with the dunk and squeeze method. Would probably evaporate to fast for brushing on.

I think that even when we use mineral spirits the silicone caulk doesn't actually dissolve into it. I believe what we're really doing is making an emulsion, which is why thorough mixing is key. Think salad dressing...oil and vinegar don't mix but but you can make an emulsion from the two in order to keep them from separating for a little while.

I there a chemical engineer in the house...MacEntyre?

[MacEntyre]

I think you are correct, Knotty, because silicon we use for waterproofing is really a silicon polymer called Polydimethylsiloxane (PDMS) or dimenthicone, an inert, non toxic, non flammable substance with unusual flow properties. It's used everywhere... silly putty, caulk, adhesives, polyurethanes, shampoo, food, contact lenses.

Aqueous solvents, like alcohol, do not dissolve or diffuse into silicon polymer. Organic solvents don't dissolve silicon polymers, but they do diffuse into it and make it swell, some to a greater extent than others. So, we are making a slurry, as you said, but solvents that diffuse into the silicon will take longer to evaporate out. Mineral spirits are not among the organic solvents that swell PDMS a lot.

[Knotty]

Mac - You're the man. That's one solid answer. Thanks.

[1022]

I think you are correct, Knotty, because silicon we use for waterproofing is really a silicon polymer called Polydimethylsiloxane (PDMS) or dimenthicone, an inert, non toxic, non flammable substance with unusual flow properties. It's used everywhere... silly putty, caulk, adhesives, polyurethanes, shampoo, food, contact lenses.

Aqueous solvents, like alcohol, do not dissolve or diffuse into silicon polymer. Organic solvents don't dissolve silicon polymers, but they do diffuse into it and make it swell, some to a greater extent than others. So, we are making a slurry, as you said, but solvents that diffuse into the silicon will take longer to evaporate out. Mineral spirits are not among the organic solvents that swell PDMS a lot.

Now that is an answer !
very informative, thanks

[cosmicmiami]

That's because denatured alcohol (ethanol) and mineral spirits (petroleum distillates) are totally different things.

I'm familiar with the differences between the two, polar solvent vs. hydrocarbon. One gets 3% foam the other 6%

[MacEntyre]

So, cosmicmiami, did you use denatured alcohol or mineral spirits?

[cosmicmiami]

I think you are correct, Knotty, because silicon we use for waterproofing is really a silicon polymer called Polydimethylsiloxane (PDMS) or dimenthicone, an inert, non toxic, non flammable substance with unusual flow properties. It's used everywhere... silly putty, caulk, adhesives, polyurethanes, shampoo, food, contact lenses.

Aqueous solvents, like alcohol, do not dissolve or diffuse into silicon polymer. Organic solvents don't dissolve silicon polymers, but they do diffuse into it and make it swell, some to a greater extent than others. So, we are making a slurry, as you said, but solvents that diffuse into the silicon will take longer to evaporate out. Mineral spirits are not among the organic solvents that swell PDMS a lot.

For a minute I thought I was watching BTTF and listening to Dr. Emmett Brown.

I'll try the denatured on a small patch and see what happens.

[cosmicmiami]

So, cosmicmiami, did you use denatured alcohol or mineral spirits?

I used spirits first. Worked pretty well. Need to go back and do the seams.

[harrell79cj5]

Anybody that did this to a tarp or some other gear a while back have any report on longevity of the treatment?

[Rain Man]

It's used everywhere... silly putty, caulk, adhesives, polyurethanes, shampoo, food, contact lenses.

Okay, you've got my interest piqued!!! How do I make some DIY contact lenses with this stuff?! I could save tons in the long run, I bet!

Rain Man

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