Fact or Myth - Conflicting Info- Rubber Care and Silicon

auburnryan · 05-07-08, 11:29

So I bought into the school of thought on NOT using Silicon product on tires etc. a few years back.

I still see some info (very littel factual info) on detrimental effects of silicon based products on rubber online...

I also see conflicting info that silicon based products (like di-electric silicone grease) are the best way to stop wear from ozone wearing on your weather stripping and rubber seals. On such contributor says he lead a GM rubber division for ~10 years.

Now I'm concerned with trim and weatherstripping specifically. Trying to relieve some cracking on some exterior rubber which is cracking. Wurth is now selling some marketed silicone-free stuff. 1z has Gummi Pfledge that is no longer really a grease, but more liquid.

So - is Silcone good or bad for protecting rubber?

2002 Z06 · 05-07-08, 11:37

I am torn myself. I see that the silicone makes the rubber look good for a while but whne it dries it ends up brownish colored depending on the silicone used.

CleanFreak2 · 05-07-08, 11:38

Subscribed....

DETAILKING · 05-07-08, 12:03

The following is from an article that David B wrote:

Your bike's tires have several formidable enemies: water, formaldehyde, petroleum distillates, ultraviolet light, and ozone. Water washes away the natural oils in rubber that keep it elastic. Formaldehyde and petroleum distillates act as a solvent, eating rubber on contact. When ozone, an odorless gas which is part of the air we breathe, is combined with ultraviolet (UV) light, a reaction occurs that attacks the tire and its polymers (the agents that bind the rubber).

To protect against ozone and UV damage, a stabilizer molecule called a competitive absorber is blended with the tire polymer. Competitive absorbers work by capturing and absorbing UV radiation and converting it to heat which is dissipated harmlessly. All tire manufacturers use the same competitive absorber, called carbon black. This is why all tires are black.

These absorbers are sacrificial; they expend themselves in performing their function of converting UV light to heat. However, as carbon black loses its ability to perform, it turns gray. This is one reason why black tires discolor as they age.

To protect from further ozone damage, tire manufacturers add a wax compound to their formulas. Tires flex when they are in motion, causing the wax molecules to migrate to the surface. This forms as a protective barrier between the air (ozone and oxygen), water and the tire polymer. In the tire trade this is called blooming. When tires are parked for extended periods, blooming does not occur and ozone quickly attacks the tire polymer. With UV light and ozone working in concert, the degradation is accelerated, resulting in drying, discoloration and cracking.

To combat the negative effects of water, solvents and UV light on tires, the bike care industry has created tire dressings. These dressings condition the tire, restoring essential moisture. Tire dressings fall into two groups:

1. Liquid Silicone Oil Dressings – These penetrating-type silicones form a flexible protective shield on rubber. Liquid silicone seals small openings with a film to prevent penetration of moisture and dirt. Most silicone dressings leave a never-dry gloss film. There are many myths regarding silicone, specifically the negative long-term effects of silicone on rubber and vinyl. The fact is, silicone is an inert material. The benefit of silicone is its ability to easily penetrate the tire’s surface and not evaporate. Some silicone-based dressings contain petroleum distillates as a cleaning agent. Petroleum distillates are harmful to rubber and vinyl, and will cause rubber and vinyl to crack. If you decide to use a silicone oil tire dressing, make sure it does not contain a cleaner.

2. Water-Based Dressings – The water-based dressings do not contain silicone oils, petroleum distillates, waxes, or other dangerous solvents that can harm and dull the surface of rubber and vinyl over time. Most water-based dressings use a water-based silicone, which offers a non-greasy, satin finish. The best products contain UV blocking agents to help keep tires and rubber from cracking, fading and hardening.

auburnryan · 05-07-08, 12:37

Thanks King - Curious - have you used any of the Gummi Plege products on your BMW? He used some here - http://www.autopia.org/forum/589734-post39.html

#1 - refreshing me that petroleum distillates are the harmful portion, not really silicone. Here's and excerpt of what I'm seeing online " For the weather-stripping, use a non-solvent based, silicone lubricant or grease. Mequiars Vinyl and Rubber Cleaner and Conditioner is one example and GM Goodwrench Dielectric Silicone Grease (part no. 12345579) is another. If you choose to use the silicone grease, apply a small amount to the weather-stripping using your fingers. Wipe off any excess with a clean rag."

Now for #2 - skeptical of the "water-based silicone" - Impossible I say... but anyways the problem here is the ability to last. My 303 just won't stand up to extended exposure to the elements.

Setec Astronomy · 05-07-08, 12:41

I'm curious about what the 10-year GM guy had to say--got a link?

auburnryan · 05-07-08, 12:53

Quote:

Originally Posted by Setec Astronomy

I'm curious about what the 10-year GM guy had to say--got a link?

Had to find it...I hate you for wasting more of my time - I'm so Obsessive-Compulsive on this stuff

And it was 10 -year old info, not 10 year "rubber man" - oops

Cadillac Owners Group - View Single Post - Silicone grease to condition weatherstrips

My father was the manufacturing engineer in charge of making weatherstripping for GM (then Delphi) at his plant. He then moved to be the global manufacturing engineer manager for engine mounts, so my info is at least 10 years old, but he said to use silicone lube (when he was at my house he bought some Penske lube stuff I still use). But you need to spray it on a rag or paper towel. If you spray it directly on the rubber the propellent in the lube will dry out the weatherstripping. The main thing is to make sure what you use is silicone based, since it is silicone rubber. Siloxane is what they soak them in after extrusion to moisten them, so if you can get that (which I could at my old job), use it.

Setec Astronomy · 05-07-08, 01:02

I talked to Dow Corning about this maybe 20 years ago, and they recommended DC 7, which is a light silicone dielectric grease, for weatherstripping, and I think for tires.

auburnryan · 05-07-08, 01:18

I am thinking this (silicone dielectric grease) is a good product for those rubber seal "covers" around the windows and other trim. Mine are cracking, due to exposure I imagine (not garaged).

Thanks for the input folks - considering this "researched" in my mind...

SuperBee364 · 05-07-08, 01:50

Great stuff here... subscribed

RTexasF · 05-07-08, 02:51

Here's what Honda uses for rubber weatherstripping and to stop squeaks. It's expensive but amazingly effective in my usage of it.

stigg · 05-07-08, 05:57

Quote:

Originally Posted by DETAILKING

The following is from an article that David B wrote:

Your bike's tires have several formidable enemies: water, formaldehyde, petroleum distillates, ultraviolet light, and ozone. Water washes away the natural oils in rubber that keep it elastic. Formaldehyde and petroleum distillates act as a solvent, eating rubber on contact. When ozone, an odorless gas which is part of the air we breathe, is combined with ultraviolet (UV) light, a reaction occurs that attacks the tire and its polymers (the agents that bind the rubber).

To protect against ozone and UV damage, a stabilizer molecule called a competitive absorber is blended with the tire polymer. Competitive absorbers work by capturing and absorbing UV radiation and converting it to heat which is dissipated harmlessly. All tire manufacturers use the same competitive absorber, called carbon black. This is why all tires are black.

These absorbers are sacrificial; they expend themselves in performing their function of converting UV light to heat. However, as carbon black loses its ability to perform, it turns gray. This is one reason why black tires discolor as they age.

To protect from further ozone damage, tire manufacturers add a wax compound to their formulas. Tires flex when they are in motion, causing the wax molecules to migrate to the surface. This forms as a protective barrier between the air (ozone and oxygen), water and the tire polymer. In the tire trade this is called blooming. When tires are parked for extended periods, blooming does not occur and ozone quickly attacks the tire polymer. With UV light and ozone working in concert, the degradation is accelerated, resulting in drying, discoloration and cracking.

To combat the negative effects of water, solvents and UV light on tires, the bike care industry has created tire dressings. These dressings condition the tire, restoring essential moisture. Tire dressings fall into two groups:

1. Liquid Silicone Oil Dressings – These penetrating-type silicones form a flexible protective shield on rubber. Liquid silicone seals small openings with a film to prevent penetration of moisture and dirt. Most silicone dressings leave a never-dry gloss film. There are many myths regarding silicone, specifically the negative long-term effects of silicone on rubber and vinyl. The fact is, silicone is an inert material. The benefit of silicone is its ability to easily penetrate the tire’s surface and not evaporate. Some silicone-based dressings contain petroleum distillates as a cleaning agent. Petroleum distillates are harmful to rubber and vinyl, and will cause rubber and vinyl to crack. If you decide to use a silicone oil tire dressing, make sure it does not contain a cleaner.

2. Water-Based Dressings – The water-based dressings do not contain silicone oils, petroleum distillates, waxes, or other dangerous solvents that can harm and dull the surface of rubber and vinyl over time. Most water-based dressings use a water-based silicone, which offers a non-greasy, satin finish. The best products contain UV blocking agents to help keep tires and rubber from cracking, fading and hardening.

Everything in this post corresponds to things I believe to be true. good stuff.