I decided to start my own thread on this subject rather than crash someone else's.
Gasket Sealant - Permatex 2B
Is for sealing a cork or paper gaskets from the deteriorating effects of engine coolant or hot oil. You "frost" both sides of the gasket before assembling the gasket to its assigned mating surface. I say "frost" because I don't mean a thin coat. Properly applied it will look like cake frosting. This compound is impervious to water and oil; however, it will degrade under the constant presence of gasoline; however, it can withstand brief periods of exposer to gasoline. Brake fluid is what dissolves Permatex 2B and nothing else. I find that Permatex 2B when properly applied with a gasket, to be a bullet proof seal. Some mechanics will refer to it as their best friend.
If however, your paper (fibrous) gasket has a bead of dried silicone applied to it by a robotic dispenser, do not use a sealant on that gasket; just simply assemble it to the part as-is. I have seen some thermostat gaskets utilising this feature.
The best part of using a gasket with Permatex 2B is that there's no cure time to wait for; you can run the engine right after assembly.
Rubber Gaskets -
I don't apply anything to rubber gaskets accept for maybe some dielectric grease to keep them from getting pinched during the assemble of the parts.
RTV Silicone -
This compound is not a sealant; it is used as a stand alone gasket. You apply it in the form of a bead of uniform width along the gasket surface. The manufacturer will prescribe the bead diameter they want you to use. The bead will always be applied along the the inside facing area of the bolt hole and not the outside. You will wait until the RTV "skins over" before assembling the parts. That means the very outside portion of the bead (skin) is dry, but the inside is still wet. A typical time frame for skin-over is 5-10 minutes. The manufacturer will tell you the exact time frame.
I find RTV to be finicky to use; therefore, I don't like using it unless the correct gasket is absolutely not available. It has to be applied in just the right manner or it will fail; in addition to that, RTV gives you very little room for error during the alignment of the two parts to be assembled.
There is a product called the Right Stuff that utilises an aerosolised can with a trigger. The RTV exits the applicator tube at a constant speed, making the task of applying a bead of uniform width much easier.
Cleaning Gasket Surfaces -
A gasket scraper is the first instrument you're going to use for removal of the old gasket material, followed by WD-40 and a purple Scotch-Brite pad. If the old gasket had 2B applied to it, then you would use brake fluid in place of the WD-40. After that, you will remove all traces of solvent or brake fluid by wiping the gasket surface down with either lacquer thinner or carburettor cleaner.
That's all I can think of for now.
Gasket Sealant - Permatex 2B
Is for sealing a cork or paper gaskets from the deteriorating effects of engine coolant or hot oil. You "frost" both sides of the gasket before assembling the gasket to its assigned mating surface. I say "frost" because I don't mean a thin coat. Properly applied it will look like cake frosting. This compound is impervious to water and oil; however, it will degrade under the constant presence of gasoline; however, it can withstand brief periods of exposer to gasoline. Brake fluid is what dissolves Permatex 2B and nothing else. I find that Permatex 2B when properly applied with a gasket, to be a bullet proof seal. Some mechanics will refer to it as their best friend.
If however, your paper (fibrous) gasket has a bead of dried silicone applied to it by a robotic dispenser, do not use a sealant on that gasket; just simply assemble it to the part as-is. I have seen some thermostat gaskets utilising this feature.
The best part of using a gasket with Permatex 2B is that there's no cure time to wait for; you can run the engine right after assembly.
Rubber Gaskets -
I don't apply anything to rubber gaskets accept for maybe some dielectric grease to keep them from getting pinched during the assemble of the parts.
RTV Silicone -
This compound is not a sealant; it is used as a stand alone gasket. You apply it in the form of a bead of uniform width along the gasket surface. The manufacturer will prescribe the bead diameter they want you to use. The bead will always be applied along the the inside facing area of the bolt hole and not the outside. You will wait until the RTV "skins over" before assembling the parts. That means the very outside portion of the bead (skin) is dry, but the inside is still wet. A typical time frame for skin-over is 5-10 minutes. The manufacturer will tell you the exact time frame.
I find RTV to be finicky to use; therefore, I don't like using it unless the correct gasket is absolutely not available. It has to be applied in just the right manner or it will fail; in addition to that, RTV gives you very little room for error during the alignment of the two parts to be assembled.
There is a product called the Right Stuff that utilises an aerosolised can with a trigger. The RTV exits the applicator tube at a constant speed, making the task of applying a bead of uniform width much easier.
Cleaning Gasket Surfaces -
A gasket scraper is the first instrument you're going to use for removal of the old gasket material, followed by WD-40 and a purple Scotch-Brite pad. If the old gasket had 2B applied to it, then you would use brake fluid in place of the WD-40. After that, you will remove all traces of solvent or brake fluid by wiping the gasket surface down with either lacquer thinner or carburettor cleaner.
That's all I can think of for now.
