Sealants: butyl tape, dicor, sikaflex, etc. - plugging holes

Ducstrom

Active member
I did a search but didn't find anything specific to comparing the different types.

I am going to need a sealant for the installation of a roof vent as well as camper jack mounts, door install, electrical outlet and inlet, light mounts, wire holes, etc.

Is there a general product people find superior for these purposes?

I've heard butyl tape and self leveling dicor for roofs. Sikaflex for vertical surfaces.
Is there one product that covers the range?
I'd like semi-permenant, something that I don't have to fart around with reapplying every year. I don't mind if I have to pay a little more for it. Although I'd like to avoid destroying a door frame if I ever have to remove it.

Surface is painted fiberglass.

If I missed something in the search, please throw in a link!
Maybe a list of products that people find work well for specific applications like EDPM, wood, fiberglass, vertical or horizontal surfaces. May help out folks in the future too.
 

john61ct

Adventurer
Avoid anything containing silicon.

Permanent flexibility is key.

Butyl rubber for where bolts clamping keeping pressure

And replacing the fixture in 5-10 years is important, e.g. 3M 5200 usually too much of an adhesive, 4200 better as a sealant.

Sika 291 vs 292 the same.

UV protection is key on top.
 

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Verkstad

Raggarkung
Urethane sealants are great. They are strongly adhesive too, so disassembly later can be extremely difficult.

Butyl never fully dries what makes disassembly easier.
Cheap butyl tape can, but it takes decades and loses its adhesive properties then also.
Butyl tapes are quite viscous what is great as gap filling, but dont use it for connections needing a high clamping force. It will seep out of the joint for weeks afterward as you need to tighten it up again and again.
Use butyl caulk or other gungrade caulk for those joints
 

Abitibi

Explorer
I'm a big fan of Eterna Tape. It also comes in 4" width so you can cover the edge of your roof fan and the roof at the same time.

I also use it to cover all the holes on my roof from removing all the ambulance antennas and light bars.

It's semi flexible and never really dries up which makes it last. I painted mine as well but too recent to know how well it will do.


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Jnich77

Director of Adventure Management Operations
Avoid anything containing silicon.

Permanent flexibility is key.

Butyl rubber for where bolts clamping keeping pressure

And replacing the fixture in 5-10 years is important, e.g. 3M 5200 usually too much of an adhesive, 4200 better as a sealant.

Sika 291 vs 292 the same.

UV protection is key on top.
3M 5200 is for things that you never want to move again...lol.
 

Alloy

Well-known member
Check product compatibility. The maufucture of my buddies trailer use the same caulking to seal the windows/door/edge of the roof. The caulking around the edge of the EPDM rood hardend and cracked in 15 months.

Butyl tape (1,2,3 layer) makes a fast long lasting gasket but it creeps so it is best to let is sit and cut off any extra after a year. If it needs to be sealed right away on a roof Dicor works great but Dicor never hardens so it needs to be checked/touched up every 6 months .

The Etenabond tape that Abitibi mentions is a great product. The excess Butyl has to be removed first. It's important to test fit and make sure there are no wrinkles. A small hand roller to install works best

I'll install doors and widows that have a parallel mounting flange/surface with acrylic tape then seal with clear Geocel Proflex. I preffer clear because leaks cannot be seen through colored caulking.

Test the Geocel Proflex first because I've found it does not stick to some types of thermo formed plastics if I didn't tape and Scotch Brite the surface before hand. FYI......never use steel wool it will make the surface rust.

When caulking any fiberglass it is important to make sure that all the mold release/previous silicone has been removed.

Sika does not bond to aluminum (without the use of primer) as good as 3M 5200/4200. I'll use Sika to make a gasket for aluminum.
 

Ducstrom

Active member
Thanks for the replies everyone.
- So it sounds like eternabond tape may be the best choice for under the stuff that has flanges.
- 3m 4200, sikaflex 292, or Teroson ms939 for under lights, wire holes, power inlet and outlet.
- 3m 5200, sikaflex 291 for the camper jack brackets.
- Then a Geocel Proflex to finish off the edges of the door, jack brackets, outlets, etc.
 

Abitibi

Explorer
Close, eternabound doesn't go under flanges but on top as you can see in my picture (fan) or to patch holes/seams...

Good to hear all options!

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Alloy

Well-known member
Be carefull combining products like urethane (Sika291 / 3M 5200) and Proflex. It should be tested beforehand.

....and don't get acetone near urethane. It will leave the urethane a sticky mess. Use denatured (rubbing) alcohol.
 

john61ct

Adventurer
Bedding and bonding (adhesives) is not the same thing.
Of course, butyl has nothing to do with adhesion, why I was talking bolts.

I thought the question here was sealing.

VHB tape works well with butyl, but needs very diligent surface prep, closely following the data sheets wrt to temperature range etc.
 
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