Opening up a tube of worms. (caulking debate)

[Rwethereyet]

Ok two years ago when I rebuilt the top of my camper I asked for advice on what type of caulk to use to reseal the top. The most popular choice seemed to be butyl caulk so thats what I went with.

Well this weekend as I was scraping off all of the cracked and seperating butyl caulk from the camper top after only two short years I decided that perhaps I should reopen the debate.

So what is the best caulk to use and is Silicone really all that bad as I was led to believe.  I hope to get 10 years out of this camper and I would prefer the next caulk job be done by the next owner.  

[wavery]

Ok two years ago when I rebuilt the top of my camper I asked for advice on what type of caulk to use to reseal the top. The most popular choice seemed to be butyl caulk so thats what I went with.

Well this weekend as I was scraping off all of the cracked and seperating butyl caulk from the camper top after only two short years I decided that perhaps I should reopen the debate.

So what is the best caulk to use and is Silicone really all that bad as I was led to believe.  I hope to get 10 years out of this camper and I would prefer the next caulk job be done by the next owner.  

If you have an ABS top, you may be stuck with re-caulking periodically.

IMHO, 3M 5200 Marine Sealer is by far the best sealer to use in full sunlight. It adheres stronger than anything that I have ever seen. The downside......once you put it on and it cures, you will have a VERY difficult time removing it.
http://solutions.3m.com/wps/portal/3M/en_US/Marine/Home/Products/Catalog/?PC_7_0_4S4T_root=GST1T4S9TCgv&PC_7_0_4S4T_output=html&PC_7_0_4S4T_gvel=QH8HT14PGTgl&PC_7_0_4S4T_vroot=GS4JK4Y166ge&PC_7_0_4S4T_node=GSWWSBSW85be&PC_7_0_4S4T_theme=en_US_marineproducts_portal&PC_7_0_4S4T_command=AbcPageHandler

When I outfitted my yacht, I used 3M 5200 for bedding all of the windows and deck hardware. In 14 years, I never had a leak or had to deal with it at all. That was with constant sun and sea exposure and 80,000 miles of hard sailing.

It cleans up with mineral spirits for about 2 hours. That makes it easy to do a professional looking job. You can apply it with a caulking gun then go over it with your finger or a rag, dipped in mineral spirits, to remove excess and smooth out the seam. It takes about 7 days to cure to the point of using the camper. After 30 days, it will be totally cured and will be almost indestructible but yet remains flexible.

Silicone does not hold up in direct sunlight. It is probably the least desirable medium for sealing your PU roof.

[AustinBoston]

So what is the best caulk to use and is Silicone really all that bad as I was led to believe.

I think Silicone is OK if you put a couple coats of black paint on it to protect it from the sun.  If you don't want a black roof, better go with something else.

Oh, and have fun finding a paint that will reliably adhere to silicone caulk.  Many will, but the only way to find out is to experiment, because they won't say so on the can.

Austin

[flyfisherman]

I re-calked the roof of my '99 Starcraft a couple of years ago (aluminum roof) using the Dow silicone that was recommended in the owner's manual and have never had a problem. And the camper sits outside year around. Really is not that big of a project. I know there are a lot of good sealants on the market today, but for sure, I like going with what the manufactirer recommends.




Fly

[wavery]

I re-calked the roof of my '99 Starcraft a couple of years ago (aluminum roof) using the Dow silicone that was recommended in the owner's manual and have never had a problem. And the camper sits outside year around. Really is not that big of a project. I know there are a lot of good sealants on the market today, but for sure, I like going with what the manufactirer recommends.




Fly

The manufacturers would never recommend a permanent type sealer like 3M 5200 because it is nearly impossible to remove, without damaging the roof, in the event that repairs are needed. JMHO.

Silicone sealers don't adhere very well by the very nature of the silicone that it is made with. Therefore, it is much easier to remove in the event that a molding or something needs to be replaced.

Using a permanent type of sealer is something that must be considered carefully. That is why I always tell people that this stuff is nearly impossible to remove. Although, with the skilled use of a heat gun, it can be removed. I just don't recommend trying it unless you absolutely have to.

[flyfisherman]

Not only can the silicone be removed successfully (to re-calk, repair or for  repainting the roof), but it has good adhession qualities when applied correctly and it will do a good job of sealing as well. Cleans up afterwards is easy, too. Considering that it will have to spend all it's time in the sun and the weather - not to mention rambling on down the road - and remain flexible to boot. Good product for the job. Contrast that with what holds millions and millions of automotive windshields in place, that black windshield urethane, which will out perform silicone by light years, but you'll NEVER get the stuff off! Also, when applying that black urethane, if you ever get it into your clothes ... a shirt or a pair of trousers ... it ain't EVER coming out! That is some nasty stuff ... but that will seal the roof, for sure, forever!




Fly