What is the best INTERIOR Spray Seam Sealer?

[ts8501]

I would like to know what others have used as a successful Interior Spray Seam Sealer. Stopping any water penetrating seams also at or around screws or rivets is my priority #1. Because this will be on the interior, I am also considering a less toxic solution, due to off gasing. For ease of installation, I would prefer a spray.

What have others used with success?

[Inland RV Center, In]

Originally Posted by ts8501

I would like to know what others have used as a successful Interior Spray Seam Sealer. Stopping any water penetrating seams also at or around screws or rivets is my priority #1. Because this will be on the interior, I am also considering a less toxic solution, due to off gasing. For ease of installation, I would prefer a spray.

What have others used with success?

Seams are sealed from the exterior, unless the inside is totally gutted. Then you can seal the seams from the inside of the exterior shell.

Spray sealers usually have a life limit.

Sealers such as Vulkem, Sikoflex and Parbond, all used by Airstream, have a life expectancy in the decades, based on pass performace.

Andy

[Dave Park]

And preparation is key. Realize that if you have access to the interior of the outer skin, you need to degrease it before applying vulkem or sikaflex. This removes any finger grease and waxes (if water could get in, so could greases and waxes)... With both of these products, a box of nitrile gloves will come in handy - not just by keeping your fingers clean, but protecting you from a few sharp edges too.

[ts8501]

Just to clarify; I do have access to the inside of the external skin, as I am pulling the interior panels and end caps. I guess I could use Vulkem, but I thought I had read that others have used a spray on material. My end caps are all sprayed with a black material at the factory, but I assumed that was to allow the fiberglass to adhere, at least that is what I think. I thought I read where some people used an automotive product, and in at least one case, someone used a heating duct spray of some kind. I of course will do everything I can to seal from the outside, this is just the extra precaution.

[ts8501]

I am now convinced that anyone who said Vulkem is right. I like the low cost factor and life expectancy in decades. Thanks Inland Andy, Dave Park and Brad S.

[Dave Park]

Furthermore: on the inside, there is no UV. It's a weather and light protected area, and you do not need to tape or clean off excess.

[wahoonc]

I work in the water penetration prevention field...

Sealants work best when put on the outside to prevent water from getting into the system.

Seeing how you have access to the inside, see if you can locate the specific location of the leak then repair the location from the outside, if it is a loose or missing rivet you can replace it and make sure to get sealant under it. If it is around a window frame you can clear and seal the frame to the skin, however it may be necessary to remove the window and reseal the frame to the body.

Sprays and coatings are limited in their effectiveness and prep work is critical.

I use Vulkem, Sikaflex or Sonneborn sealants and not much else. For the Airstream you want the polyurethane based versions on the exterior, for concealed use you can use a butyl based version.

Vulkem was what was used at the factory in the 1970's. Somewhere along the way they switched over to the Sikaflex.

Aaron

[Dave Park]

Originally Posted by wahoonc

I work in the water penetration prevention field...

I read that and got a mental picture of you in a white lab coat, studiously examining a leak in a porta-potty, and the mental sub-title was "...if only they knew!"

What you say is absolutely right, of course. Preventing the capillary action of the water into the gaps in the first place is the most effective way to prevent leaks. However, if you have access to the inside of the seam too, and you have a box of tubes of "affordable sealer X" - is there a reason to NOT seal the inside, in addition to the outside?

[wahoonc]

Originally Posted by Dave Park

I read that and got a mental picture of you in a white lab coat, studiously examining a leak in a porta-potty, and the mental sub-title was "...if only they knew!"

What you say is absolutely right, of course. Preventing the capillary action of the water into the gaps in the first place is the most effective way to prevent leaks. However, if you have access to the inside of the seam too, and you have a box of tubes of "affordable sealer X" - is there a reason to NOT seal the inside, in addition to the outside?

Waste of time and caulking in my opinion. But it probably won't hurt. Biggest issue to me is the freeze/thaw cycle when water gets trapped in between layers of stuff. If you have caulking on both sides and water gets in between, goes through a thermal cycle you can create even more leaks and with all the caulking in the way, they can be harder to find and repair.

FWIW my field is primarily industrial roofing and siding, but I have a strong background in architectural sheet metals.

What we do for sealants on metal is a butyl in the lap with polyurethane on the outside. Butyl is not UV stable and works best when in compression.

Aaron