tireman9 Report post Posted April 23, 2018 I understand the Eternabond tape is good for seams that need something to hold the seam together but if you just want a bit of extra waterproofing like around the ladder feet that attach to the roof why wouldn't 100% silicone seal be OK? Comes in smaller, resealable and less expensive container than Dicor. Have also wondered about "Flex Seal" as advertised on TV ? Thoughts Share this post Link to post Share on other sites
wildebill308 Report post Posted April 23, 2018 20 minutes ago, tireman9 said: I understand the Eternabond tape is good for seams that need something to hold the seam together but if you just want a bit of extra waterproofing like around the ladder feet that attach to the roof why wouldn't 100% silicone seal be OK? Comes in smaller, resealable and less expensive container than Dicor. Have also wondered about "Flex Seal" as advertised on TV ? Thoughts One of the problems is geting the silicone to stick to the old sealant and being shure the old sealant is not compromised causing a leak path. I have no experience with "Flex Seal". Bill Share this post Link to post Share on other sites
kaypsmith Report post Posted April 23, 2018 Roger, I used Flex Seal spray on on my aluminum roof where some sealant was not doing a good job any longer. I cleaned thoroughly with acetone, made sure it was good and dry, then sprayed three coats of the flex seal where needed. It has been there for two years now, and no more leak yet. Keeping my fingers crossed. Share this post Link to post Share on other sites
jleamont Report post Posted April 23, 2018 Roger, is your roof rubber or fiberglass? I was told silicone products are harmful to the rubber membrane of a RV roof, thus requiring Dicor. Flex Seal I am not familiar with whats in it and if it would be the same as silicone. Share this post Link to post Share on other sites
richard5933 Report post Posted April 23, 2018 In my experience, the only really good place to use silicon sealant is around glass. There are also a few high-temp applications where it can be helpful. While it's kind of like the Duck Tape of the sealant world, there are many other more purpose-specific sealants better suited for other jobs. One big drawback to silicon is also that it will contaminate anything it touches with regard to future painting. I've been having good success with Dicor, which comes in both self-leveling (for horizontal surfaces) and non-leveling (for vertical surfaces) compounds. You can also get the Dicor in many colors to match what you're sealing, if that matters to the project. I'd rather use half a tube of Dicor and potentially throw away the remainder than use silicon if it wasn't the best sealant for the job. As it happens though, I can usually find a few other places that are in need of re-sealing if I have anything left in the Dicor tube. For the ladder feet, I'd imagine that one problem is going to be making sure that there is sealant not just over the top of the feet but also between them and the roof. Is it possible to loosen the feet and get some sealant under them? Share this post Link to post Share on other sites
jleamont Report post Posted April 23, 2018 I used these products on the last coach, everything except the roof, which had the tape and Dicor. Side windows and seams were all redone by me with these products; https://usa.sika.com/industry/en/industry-markets/transportation/bus-coach/01a601/01a601sa02/01a601sa0202.html By poor design of the exterior trim if traveling in the rain it would wick its way under the seam trim and lighting (especially the bunk area) and delaminate. All I have to say is I feel bad for the next guy that has to remove anything on that coaches body, that stuff was so strong you could remove screws after it set up and it wasn't budging. Share this post Link to post Share on other sites
wildebill308 Report post Posted April 23, 2018 Joe those sealants will keep someone busy trying to get them apart. There are other "better quality" sealants out there but most don't want to spend the money. Prep is the key and using the right promoter. Bill Share this post Link to post Share on other sites
five Report post Posted April 24, 2018 Recently I had friend with a roof leak and his tech said they use Geocel 2300 in the factory. https://www.geocelusa.com/product/2300-construction-tripolymer-sealant/ Share this post Link to post Share on other sites
kaypsmith Report post Posted April 24, 2018 Sikaflex is what I used to hold the aluminum skins that I used to cover the old window holes while converting the bus, I one rivet every 12 inches just to hold in place while the sikaflex cured. No water penetration in that area. The aircraft industry has used it for years to apply skins on their craft, also Great Dane trailers here in B'ham uses it to apply the aluminum skin on their box style trailers, and they sure do not leak. But as stated by Bill, prep is the most important part of doing anything well. I installed and climbed radio towers for many years, and someone suggested that I use a dab of silicone on the bolts that hold the legs of the tower, two years later, those galvanized bolts were so rusty that we had to break each one to replace them, so silicone caulk is also highly corrosive to metal. Share this post Link to post Share on other sites
OldBeaver Report post Posted October 31, 2019 I will add my upvote for Sika as well. It is industrial sealant. Silicone is horrible for RV (or boat) use. The previous owners used silicone on my RV and it is peeling all over the place and what they used above the windshield is leeching out when wet and leaving streaks on the windshield. Re-doing all the seams with a real sealant is on my list. Was going to do it this summer but the RV spent the entire summer waiting for the mechanic to get to it. I made the mistake of telling him that there is no rush. He is the best in the area so always extremely busy. Share this post Link to post Share on other sites
wildebill308 Report post Posted October 31, 2019 You just need to use the right RTV Silicone sealant/adhesive. Do your prep right and it will outlast the RV. Bill Share this post Link to post Share on other sites
rayin Report post Posted November 1, 2019 I agree, avoid using silicone caulk/sealant. Sure many RV mfgrs use it at the factory, they do not have to deal with the after-effects 5 -20 years later. It is the cheapest in price of all sealants/caulk for a good reason. Spend an additional $3-7 a tube and buy the best. I'm lazy, I'd rather to do the work required to get results that may outlast me. Remember the old addage, "do it right the first time". Share this post Link to post Share on other sites
wildebill308 Report post Posted November 2, 2019 2 hours ago, RayIN said: Spend an additional $3-7 a tube and buy the best. I'm lazy, I'd rather to do the work required to get results that may outlast me. Remember the old addage, "do it right the first time". This is my go to RTV silicone based adhesive sealant, yes it is more expensive than the Home Depot stuff 3oz for $41.85. https://www.aircraftspruce.com/catalog/cmpages/dowCorningRTV3145.php?gclid=Cj0KCQjwr-_tBRCMARIsAN413WRKuDhNTc5_IFssQSN1ORWIRqjKWPFfCDyfU6KXK0CDo5RMhWkTcZEaAs_-EALw_wcB Might as well add my favorit epoxy to the list. 3M Scotch-Weld Epoxy Adhesive 1751, Gray, Part B/A, 2 fl oz Kit $54.70. https://www.amazon.com/s?k=3M™+Scotch-Weld™+Epoxy+Adhesive+1751&ref=nb_sb_noss I have used both extensively working on little airplane projects. Bill Share this post Link to post Share on other sites
rayin Report post Posted November 2, 2019 Bill, I like to use the best, but I can't afford to use that much best on our MH. 😲 Share this post Link to post Share on other sites
rls7201 Report post Posted November 4, 2019 I use Sikaflex for my EPDM needs. Sikaflex 715 is self leveling for EPDM roofing. It's pricey but you can us it and forget it. It's a vast improvement over Dicor sealant. Share this post Link to post Share on other sites
wildebill308 Report post Posted November 4, 2019 Ray, wait till we get to the good stuff. I was certified on sealing aircraft / fuel tanks and the most important thing is prep. Bill Share this post Link to post Share on other sites
