Vulkem not holding up

[Journalist]

About six or seven years ago, Vulkem was used to reseal a few pieces on the roof of my AS. Much of the 40-year-old original stuff is still on the trailer and going srong with no leaks. However, the newer stuff is drying up and rotting away at an alarming rate from sun exposure. I don't remember exactly which Vulkem product was used, but it was recommended to me by Jackson Center when I called to ask what I needed. Anyone else had this problem? I made the natural assumption that when I used the stuff recommended by the factory that it would hold up on par with the original sealer.

[Inland RV Center, In]

Originally Posted by Journalist

About six or seven years ago, Vulkem was used to reseal a few pieces on the roof of my AS. Much of the 40-year-old original stuff is still on the trailer and going srong with no leaks. However, the newer stuff is drying up and rotting away at an alarming rate from sun exposure. I don't remember exactly which Vulkem product was used, but it was recommended to me by Jackson Center when I called to ask what I needed. Anyone else had this problem? I made the natural assumption that when I used the stuff recommended by the factory that it would hold up on par with the original sealer.

Vulkem sealer easily lasts and bonds for decade.

BUT it must bond to a good surface.

Applying Vulkem over the clearcoat on your Airstream, does not provide a good surface for the sealer to bond to. In fact, that's a very poor surface.

The factory appliied Vulkem sealer, before they clearcoated the trailer.

With today's clearcoat, no problem. With the older clearcoat, big problem, as the paint itself only lasts about 5 years, and then starts to peel off, without any assistance from anything else, except the sun.

Andy

[dwightdi]

Airstream engineering does not have a materials engineer on their staff. It is doubtful that they have the facility to do long term environmental exposure testing. From what I have heard they depend on what the supplier's salesmen tell them the supplier engineering department has tested and Airstream short term performance testing. Vulkem, from what I understand is a urethane based sealant. Urethanes adhere to almost any solid surface and have excellant toughness but only fair long term resistance to the sun exposure and can be degraded by long term exposure to soaking in water. In most climates the trailer is usually dry and they add pigment to the caulk to prevent the sun penetrating into the bulk of the fillet of caulk. The actual sealing between the sheets of aluminum is accomplished by another material which I can not remember right now but has a low viscosity to wick in between the sheets.