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PostPosted: October 8th, 2017, 8:41 am 
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Location: 1999 Concourse
Butyl tape is a bedding compound. That means that you place it between two items you want to seal (that are also held with clamping pressure from something else). Examples:

1) Roof vent flange and roof surface
2) Window flanges and outside wall surface
3) Compartment door flanges and outside wall surface

You get the idea. Why do I like butyl?

a) It works really, really well.
b) If you get the good stuff, it'll last for a very long time.
c) When you do want to remove it, it removes easily and leaves no contaminating residue (ahem: silicone :evil: ). Easy cleanup with mineral spirits.
d) Easy to store, super long shelf life. Opened vs. non-opened makes no difference.
e) Compatible with many materials (but not fuel, so don't use to be fuel fills).
f) Easy to work with.

Note that cr*ppy butyl won't have all of the above properties. It's more like a breakable putty.

Downsides: Will continue to ooze out for awhile (although easy to peel away). Not super adhesive; items need to be mechanically fastened as well, typically. Never fully hardens (although this is also why it lasts so long as a bedding compound). Can't just run to the corner store for the good stuff.

What are some other options?

1) Polysulfide (hard to find, short shelf life so may be bad in tube when you buy it, leaches plasticizers from plastic components).

2) Polyurethane (3M 4200, 5200, and others). Pretty darned- to ridiculously adhesive. Not a picnic to remove if ever needed (may break item, damage gelcoat). Super adhesive not needed if item is fastened with screws, etc. A bit hard to work with, difficult to remove. Opened tube needs careful storage, may harden. White will yellow in UV. A fine option if you *need* an adhesive.

3) Polyether (3M 4000). I haven't used this for very many years, but it seems like a decent choice when you need something that will "cure," you will see it (it's white). Not sure how hard to remove - certainly not as easy as butyl, maybe easier than polyurethane? Doesn't yellow in UV (they say). However, I'm not as familiar with it and the oldest thing I've used it on is only four years old, kept out of the weather and hasn't had to be replaced.

4) Huh, my fingers suddenly just don't want to type ;) But if someone forced me to, I'd put silicone here. In my opinion, there is ALWAYS a better option. Why don't I like it? Well, it's not really that great a bedding compound, but mainly because IT IS FOREVER :o But NOT forever in the sense that it will keep on working forever. Oh no. No, no no. Rather, in the sense that you'll just about never get the darned stuff off. And even if you do succeed in "removing" it, there will be an invisible, contaminating "oil" left behind that will keep anything from sticking ever again. Even more silicone (although who would even do that?). Paint? Ha ha ha (unless you love fish eyes). Okay, maybe I have a strong opinion on this, but that stuff is EVIL :twisted:

As long as I'm already sounding like a total curmudgeon, a pet peeve: I don't know why this is, but on RV's there seems to be this tradition of putting bedding compound ON TOP OF the item you are sealing. To me this is like putting Neosporin on the outside of the band-aid. In boating this is never done, all bedding goes under the flange where it will do some good. It gushes up under the screw heads (where there is preferably a chamfer) (or you can put a worm of butyl under the screw head) and that's that. Any time you see bedding compound or caulk on the outside of something on a boat, you know that person had a leak, and rather than re-bed properly (remove the item, bed under the flange), they globbed some on top. Probably worked great.... for a week. And boats take "green" water (meaning not just spray but solid water) over the decks often, and they may be flexing and working at the same time. If they don't put bedding on top of the item, I can't see it on an RV. It also looks ugly, traps dirt, and disguises issues. Okay, got that out of my system :mrgreen:

On the LED lighting, you'll see that they express "color" in degrees Kelvin. For a warmish light that is pleasant (to me), I like something around 3600K or even a bit less (warmer). 4000K and over is getting whiter, and 6000K and over is really white almost blue looking, to my eye. One caveat is that some of the cheapie LED strips (which can be super useful) seem to be more "yellow" than warm (bleah).

Brightness can be expressed in lumens. I can't remember the figure now, but I was able to look up the lumens of one of our original fluorescent tubes, and I used that as a guide to how many lumens I wanted in my LEDs.

I have bought quite a few bulbs and fixtures from Marine Beam (for boats and RV's) and they are good quality and give good information on the product pages. Even if you don't choose to buy from them (they're not the cheapest), they have a good "bulb finder" page that shows the different types of bulb shapes and bases.

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PostPosted: October 8th, 2017, 9:31 am 
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Great info again, appreciate that, I'll get back to you with reply later...........

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PostPosted: October 23rd, 2017, 8:13 pm 
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BG-

Ok, so having owned (2) less than top of the line travel trailers, you have to remember that you have many different types of construction other than a complete fiberglass shell such as the Chinook. Some bottom of the line RV's use wood framing in the walls and roof. As you move up in quality, you transition to aluminum framing, but still wood sheeting below a membrane roof covering. IMO there is a lot more movement of the overall structure in general while traveling down the road as compared to the Chinook one piece construction.

So, some type of sealant is applied to those things that penetrate that membrane roof. That sealant is applied between and on top of the mounting surface because of the movement of the structure. Also, as the saying goes, out of sight and out of mind. You can't see the roof of an RV unless you climb up there. So, the manufactures don't really care what the roof looks like as long as it doesn't leak. Some RV roofs look a lot better than others as new, I've seen it. Now the front, rear and sides usually look very good for appearance.

But, in the situation of a boat where fit and finish can be seen everywhere, you are not going to see excess sealant oozing all around.

So, I have three areas on my Chinook roof that need attention. The base mounting of the TV antenna, the Refer vent and the vent pipe for the bathroom. Do you think this butyl material is best for those spots? I have used Eternabond in place of Dicor on my trailers.

Thanks

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PostPosted: October 24th, 2017, 8:28 am 
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Location: 1999 Concourse
I guess I still don't see how having sealant on top of two moving pieces helps. Wooden boats don't do that, and wood moves a lot. And most all boats "shift" quite a bit when pounding through waves. What I don't like is that the "on top of the band aid" caulk can make little dams, and dirt trapping swirls and stuff, and then that dirt can hold water, mildew, etc. Bleah. Not that I'm out to change RV manufacturers (as if I could).

If one has a core to protect (say wooden framing just under the roof hole, then coating it with neat epoxy can be a good move.

Anyway...

reddingnative wrote:
So, I have three areas on my Chinook roof that need attention. The base mounting of the TV antenna, the Refer vent and the vent pipe for the bathroom. Do you think this butyl material is best for those spots? I have used Eternabond in place of Dicor on my trailers.


Here is what I would do:

1) TV Antenna
If yours is like mine (was), the base is cast aluminum. It's held on by many screws, so you have plenty of clamping pressure. I would start by removing the base and cleaning up the fiberglass surface (mineral spirits, acetone, or alcohol [but no alcohol if you are going to use a polyurethane sealant as it retards the cure]).

Then, if you want to be really "proper," you could overdrill/fill the holes with thickened epoxy (boat style). That guards (more) against any water penetrating the roof core, which is plywood in the way of the antenna. But you may not elect to go that far. That's cool. But I *would* most definitely chamfer the holes in the fiberglass. You will see that Chinook did not, and therefore you may have spider cracks, "ruffled up" fiberglass edges, or chips. I use a chamfer bit in a drill and drill down making a nice bevel. This accomplishes two things: Keeps the fiberglass from cracking (and in this case hopefully eclipses the original damage due to no chamfering), and makes a little "well" for an "o-ring" of sealant. This is preferable to just two flat faying surfaces and you screw the thing down and crush the bedding compound out (that can work too, but the chamfer is better).

Since I would use good butyl (which at this point is only the Bed-It brand based on my ordering a bunch), no need to tape off anything. If using a tube type sealant, you may want to lay the antenna base down again and tape around it (or make a pencil line around it and tape to that). Then clean again. I also clean the screws and the base of the item with solvent.

Oh, one other thing to check: Basically, "pointy" screws into fiberglass is not really the best. The fiberglass is so hard (as compared to wood or etc.) that you either drill a regular sized pilot hole and then break the fiberglass that is in the threads, or you drill a larger sized pilot hole and have little grip. It does work, after a fashion but just isn't the best. However if your screws have good grip, then they can be re-used as is. If they don't have good grip, to keep this part simpler, how about just come back to the thread and we'll talk about options in another reply.

Now if using butyl, you can apply the butyl to the base of the antenna. I also take a small "worm" and put it around the screw just beneath the head, kind of working it into a little "volcano" and pressing it to attach to the screw shank. Then plonk the item in place (in the right place!), and start screwing it down, working around like you would with tire lugs. You can just try to pull it all the way tight (if you have to), but a better way with butyl is to get it like 80% tight then leave it for a bit (day to a week depending on how hot it is). The clamping pressure will slowly compress it and then you will retighten it a few times until it's 100% down. This is also a benefit if you are using pointy screws into fiberglass, as you are less likely to strip the fiberglass "threads" by trying to pull everything together all at once against the butyl (especially if it's not really warm out). You can use warmed up butyl if it's cold out, to help (like put it inside in a sunny spot - you don't want it TOO mooshy). Once you are happy with things you can pretty easily remove the excess butyl that has oozed out (for stubborn spots you can dab at it with a ball of waste butyl). I don't like to leave the ooze, because just like with caulk it makes a little ramp to funnel water right at the joint. You will also see that a ring of butyl appears around each screw head (squeeze out from the volcanos you put on the fasteners), and that can just be pulled off. The rest is in the chamfer, doing its job.

One nice thing about butyl is if you mess up you can just remove, clean with mineral spirits, and have another go. Same thing when it comes time to re-bed (or the item breaks, or you want to upgrade). That's when butyl starts to seem really nice (again).

If you are using something out of a caulk tube (polyurethane, polyether, etc.) then you may want to tape off around the base (or you can just clean with solvent, just not alcohol with polyurethane). Put in LOTS of caulk and go for heavy squeeze out (don't think about trying not to waste any). If it cures and you have some tiny gap that allows a leak, it will be a real pain to re-do it. Tighten it 100% right away. Again, I don't go for the whipped-cream-on-top effect, but instead clean off all excess.

2) Refrigerator vent (in context, I'm guessing you mean the roof vent not the wall one).
This has a flange, so I'd treat it very much like the TV antenna. One thing to watch out for is since the flange is likely either thin aluminum or plastic (I forget which plus yours might not be the same as mine), you have to guard against getting so much butyl or caulk that the flange bulges up between fasteners. With butyl, warm butyl, warm surface, and warm day can all help. Even with all that when I replaced my roof vent (the Fantastic vent, not the fridge one), I ended up using aluminum bar stock on top of the flange. The plastic was so soft/weak that it was basically impossible not to make "puckers" of plastic on the flange - annoying. You can also put some pressure on the flange before tightening the screws which can help (say you set a strip of plywood on the flange then step on it to apply even pressure - then you aren't using the screws to press only on certain spots).

3) Sewer pipe vent.
As I remember it, this also has a flange, so same basic idea. If you use any caulk tube type product, make sure not to have a bunch go to the inside of the hole (butyl will stay put).

I'd use good butyl (Bed-It) for all three, myself.

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PostPosted: October 24th, 2017, 11:25 am 
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BG-

Your exactly right about the sealant collecting dirt and whatever when it's applied on top of the flanges and mounting screws. But, the dealers always want to offer a free roof inspection and then tell you how dirty it is and that the calking is cracked and should be cleaned and re-applied. IMO, I think the roof membrane has a lot to do with the sealant being applied under and over a flange and on top of fasteners. RV membrane roof maintenance is a booming business.

Sometime go to an RV dealer and ask to look at a new RV. If there is access to the roof, you should take a look the sides where the membrane wraps over the edge and meets the walls. You can feel the edge of the plywood under the membrane and, in some cases, feel a rough edge with splinters. No wonder they caulk the heck out of them. I have a relative that works at a RV repair facility. He tells me about $400,000 Class A coaches with a membrane roof covering a patch work of sub grade plywood as roof surface.

Anyway, I'll get the butyl, they have some great install pics on their website as you described.

Thanks

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PostPosted: November 4th, 2017, 8:44 am 
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Where is the LED lighting thread?

Also, I was down in Napa, Ca helping my Uncle who lost his home in the fires. We are co-owners of this Chinook. Ironically, the Chinook was being stored at a friends of his property before we moved it to my house where I could work on it. His friends house also burned and the Chinook would have been consumed as well.

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PostPosted: December 7th, 2017, 6:46 pm 
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Can I use the good butyl tape to seal around the Suburban Furnace vent/intake cap on the fiberglass exterior. I have a email into Bed-It but says over 140 degrees may sag. Can't find any temp specs new furnace.

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