Remove silicone from calking

Phil & Stephie wrote:
Wasn't aware that silicone might cause some problems. Excuse me for not knowing, but what is wrong using silicone as a sealant?

Thanks.

Silicone is problematic at best.

It often sticks where you don't want it to and where you want it to stick it flat out doesn't stick :M causing lots of unseen leaks.

Silicon has another "issue", removal. While you might be able to remove the "rubber" part of silicone caulking it is near impossible to remove the silicone residue left over. This residue makes adhesion of other caulking or even paint spotty at best if you fail to remove it.

On edit.. I should also mention another pitfall of silicone, it doesn't stick to its self once hardened. In other words you can not apply more silicone over top old silicone. The new layer will never stick...

If you have ever had the "joy" of painting an automobile which had "wax" which had silicone as a ingredient (Turtle wax was famous for this) you would understand the shear frustration of getting the paint to "flow" without getting "fish eyes" (looks like little holes in the paint due to silicone).

For RVs there are PLENTY of non silicone caulking which is far superior and does not have bad side effects of silicone..

On edit.. one of the other pitfalls of silicone caulking is silicone won't stick to its self. In other words new silicone put on top of old silicone will not stick..

Wasn't aware that silicone might cause some problems. Excuse me for not knowing, but what is wrong using silicone as a sealant?

Thanks.

In the past, I've tried just about everything I could think of to remove silicone with very little success. But, I've found that regular old gasoline, when applied and is allowed to soak for a bit breaks down the silicone and allows it to crumble so that it can be removed. I've also had success with Mekanica silicone remover that I bought at Ace Hardware. It's a little slow but will eventually remove the stuff. I also understand that Permatex markets a silicone remover but I've never tried it. Good luck with your project, you've got a mess on your hands!

gregwest wrote:
Thanks handye9

If I miss some silicone chances are the Dicor will not adhere properly, thus eventually cause a leak somewhere.

What about sealant removal by 3M? Any experience with such products?

There must be a way, other than maybe silicone should be banned.

I have used 3M sealant remover, but, only on a bath tub. It took a lot of time, made a big mess, and didn't get all the silicone off.

There won't be any silicone residue under the old dicor. Shave, scrape, or peel that. Biggest part of the silicone will come with it. Then wipe area with wet (denatured alcohol) towel. Let it dry (10 - 15 minutes) and caulk with dicor.

I've removed it from aluminum but not from rubber. What worked was Goof Off Heavy Duty Degreaser. I had to let it soak. HOWEVER I know from personal experience that the Goof Off will bubble a rubber roof!

From what you have written, if you want to go after it, it sounds like the best approach would be to remove the existing Dicor lap sealant, because you applied the silicone on top of it. If you go on your roof on a warm sunny day, you'll find that old stuff can be shaved pretty readily with a putty knife. If you knock it down below the silicone layer, you then would have a nice surface for applying new lap sealant. At least that is how it sounds to me.

Thanks handye9

From all the posts I have read on several different forums, it doesn't look good for removing silicone from existing sealant.

If I miss some silicone chances are the Dicor will not adhere properly, thus eventually cause a leak somewhere.

What about sealant removal by 3M? Any experience with such products?

There must be a way, other than maybe silicone should be banned.

Carefully scrape, cut, and peel as much as possible. Don't cut the roof itself.

Removing some, or, all of the original sealant, may be the best option.

An alternative to mineral spirits is denatured alcohol, but, even this may not get it all.

Proper sealant for flat roof surfaces would be Dicor self leveling lap sealant.