The past 3 years I have been restoring a 1983 Class C. I am about ready to re-install the aluminum windows and I am looking for advice on the proper sealant to use. Silicone based, Pliable rubber goop? Give me some advice. By the way, first post. I wish that I had found this forum sooner, might have saved me a lot of headaches! Thanks Robert
I've replaced a couple of windows on travel trailers using black butyl rubber tape, with good results. RV supply stores sell it. They also sell a putty-like tape, but I prefer the butyl. If your coach has the older style "corrugated" aluminum siding, you might want to use a double thickness to get a good seal all around.
I'm not a fan of silicone caulks. It's too hard to get any other kind of sealant ever to stick where it's been.
Caseydon, Thanks for the reply. It has fiberglass siding. I have several rolls of the butyl rubber so I will give it a try. Thanks ( rebuilding this thing has been a nightmare)
I have posted a number of times in the past about resealing windows, but as you mentioned, first post! OK, welcome to the forum!!
There is a huge amount of valuable information here.
I have been known to fix the occasional RV here and there. I've done lots of windows. Here is what I recommend:
First of all, it is critically important that the window mounting flanges have been thoroughly cleaned of all residue from previous sealants. Mechanically removing most of it can be done with a stiff plastic scraper knife. A metal knife will scratch the painted surface.
Then a solvent such as paint thinners can be used to breakdown the residue after scraping. Scrubbing with a toothbrush or similar will help you get into the small crevices.
Then the residue from the paint thinners needs to be removed. Acetone or lacquer thinners will take this off. Apply a liberal amount to a cotton rag and wipe the flange surface down. USE CAUTION ! ! These 2 chemicals will remove the paint if you rub too hard. The idea is to have all the old sealant gone and use this only as a final cleaning of the metal.
Now the same cleaning concept applies to the siding on the motorhome. You did not specify what it was but I will assume aluminum. It must be perfectly clean and dry! Please remember my caution about the final cleaning. A quick wipedown is OK with the lacquer thinner or acetone, but do not rub with it or you will see the paint go away!!
Now, the sealing material:
First and foremost - Do not let anyone tell you to use silicone! Silicone has absolutely no place in the exterior sealing of anything that is out to the weather, especially a vehicle that flexes and twists as it goes down the road. NO SILICONE! Now I have been criticized a lot for saying that here, I'm not going to start it again, but I have over 30 years experience in the exterior home renovation business and I have personally scrapped many hundreds of thousands of dollars of product that had been destroyed by silicone failing to keep a seal. Nuff said!
Having said that, there are a number of things that will work, but I believe that the best thing is a good quality butyl tape. I'll detail more:
There are basically 3 types of tape available:
1) The first is the ultra crummy el cheapo putty tape that a lot of RV manufacturers seem to love to use for sealing everything. It is cheap, it is garbage and it does a very poor job of sealing anything long term. It's OK at first but very soon dries out, leaving a substance that is prone to cracking, crumbling and losing its adhesion.
2) The second is much better than the first, and is widely used for sealing windows and doors. It is a putty/butyl mix and has much better qualities than the putty tape. It will do a reasonable job, but there is a better product available.
3) The best one of these tapes to use is a butyl rubber only tape. There is no cheap putty in it. This product will cost you a bit more than number two, but it is well worth the few extra bucks a roll. In the scheme of things, an extra 20 or 30 bucks for all your windows is a small price to pay for a good seal. The tape will likely be gray in color, although some of the stuff used in residential glazing is black. I find the black butyl is generally a bit stiffer than the RV counterpart. Try to use the RV stuff, it is a bit softer and really sticks good.
When you go to your local RV dealer, they will likely have all 3 kinds - most of the ones I have seen do. Ask the counter parts man to show you the best quality butyl tape and don't be afraid to ask him if this is the good stuff. If he only stocks the cheaper stuff, shop elsewhere or ask him to order it in.
The actual application will differ depending on the surface it is being applied against. If your siding profile has large hills and valleys, it may be necessary to fill the valleys with a layer of the tape. Apply the tape to the window flange, making sure there is enough on there to completely cover most of the flange at the point where it will contact the siding. Depending on how much play there is in the window opening, you may have to double up on the tape. You want lots of it in there.
Once you place your window in the opening, try to get it centered evenly as you set it into the hole. An assistant on the inside will help here. When you put the retainer ring on the inside and start running the screws in, be sure to tighten them evenly a bit at a time. You will be making several passes around the window to get the flange drawn in tight.
The butyl tape will ooze out all around the window on the outside! Don't get excited about this - you want it to ooze out. When the window is in place as tight as it is going to be, go around the outside with a PLASTIC knife and cut the excess flush with the window to the siding. It will probably ooze a bit more as the window gradually "settles" into its opening. If more comes out, simply trim it with the plastic knife.
If you do this process very carefully, your windows will never leak!
Good luck!
Bob
PS, Check out my rebuild site - link in my sig.
On edit, I notice that you mentioned fiberglass siding. No valleys to fill, a good bead of the tape will do.
* This post was
edited 11/17/07 11:29pm by BobsYourUncle *
2007 GMC 3500 dually ext. cab 4X4 LBZ
Duramax / Allison Fire Red
Bob, after viewing your web page (WOW) I will be following your advice. I thought that I had a big project but nothing compared to yours. I really appreciate the information. Thanks, Robert
Remember the best seal requires totally removing the window and resetting it in fresh sealant. Applyin a bead of sealer around the window perimeter is useless.
Dave
Live every day as though it were your last; someday you'll be right.
cjhauler wrote: Bob, after viewing your web page (WOW) I will be following your advice. I thought that I had a big project but nothing compared to yours. I really appreciate the information. Thanks, Robert
Hey, we are all here to help! (well, most of us . . . )
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