Silicone or Proflex?
- Thread starter RVRAC
- Start date
The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Gizmo
Well-known member
I would first apply butyl tape between the vent and sidewall, then use Proflex over silicone around the outside edges.
Gary RV_Wizard
Site Team
What Gizmo says. Silicone is ok for that application, but Proflex would be my first choice.
zulu
Well-known member
RVRAC said:
Well, the vent should get hot and probably expand the butyl tape. I just used butyl tape on an RV window replacement, and the tape oozed out for a couple of months under normal temps.
If the vent cover rests against gel-coated fiberglass, then stay away from straight silicone. Maybe rubberized silicone, but Proflex is probable better.
Gary RV_Wizard
Site Team
The butyl tape goes between the flange of the vent outlet and the sidewall, so I don't see how it could interfere. At worst it oozes out at the edges and looks unsightly (too much applied!), but that is easily removed with a plastic blade. But if you don't want to use vinyl, a thin bead of the Proflex or other caulk between the flange and the sidewall is fine. Whatever it takes to keep water out of the hole.
What is the source of this advice? In the Splendide instructions for the kit, or some unofficial source?
What is the source of this advice? In the Splendide instructions for the kit, or some unofficial source?
The advice comes from someone who installed on and put it in youtube. I emailed Splendide service and they said they have no advice in doing it either way. They don't think it is a problem either way. If I don't use butyl tape, I will use only Proflex. I have both Proflex and Silicone at hand but not butyl tape. The cover snaps between the top of the vent and the MH sidewall, maybe this is the rationale for not using butyl tape, but I don't really know. It has two holes in the bottom for two provided screws. No instructions came with it.
Gary RV_Wizard
Site Team
The exit spout with the flapper cover has a flange that butts to the sidewall. That's where you seal against water intrusion through the wall. The cover snaps on and I would run a bead around the top and sides (not bottom) to help keep water away from the flange underneath.
cic317
Well-known member
Just a reminder if you use silicone, it tough to re caulk if ever needed. Silicone prevents materials ( even silicone) from binding to it or the surface it was applied to. The only option is to mechanically remove some surface material.
Gary RV_Wizard
Site Team
Silicone isn't impossible to remove and most RV manufacturers use it for some of the external sealant needs, e.g. around window frames and such. Just need to wipe it down with a solvent after peeling the old stuff off. Mineral spirits is usually good enough solvent if the silicone was old and dried out.
As with most things, there are places where silicone is appropriate and others where it is not. It's a really poor choice for roof seams and openings, or for joints that flex a lot, e.g. sidewall seams and such. It works well, though, for sealing around the edges of things applied to vertical surfaces, e.g. window frames, water or electrical ports, that sort of thing. Those already have another sealant behind them, so the edge sealer is an extra preventative and trim seal.
Another point: don't confuse pure (100%) silicone sealants with silicone blends, e.g. silicone-acrylic. Any silicone-based sealant that claims to be paintable will NOT have the oily residue that makes silicone unsuitable for some uses.
As with most things, there are places where silicone is appropriate and others where it is not. It's a really poor choice for roof seams and openings, or for joints that flex a lot, e.g. sidewall seams and such. It works well, though, for sealing around the edges of things applied to vertical surfaces, e.g. window frames, water or electrical ports, that sort of thing. Those already have another sealant behind them, so the edge sealer is an extra preventative and trim seal.
Another point: don't confuse pure (100%) silicone sealants with silicone blends, e.g. silicone-acrylic. Any silicone-based sealant that claims to be paintable will NOT have the oily residue that makes silicone unsuitable for some uses.
