Butyl Tape, Silicone and sealing

[V'sGlassSleeper]

We bought Flexible Seal (by AC Products) at our local RV store. This is the final caulking that Per used in his tutorial on sealants which started this thread.

Jeanne

Thank you, Jeanne, I will look for that specific product here.

Val

[Per Walthinsen]

Jeanne and Steve, Val and Kayla, et. al.:

It is possible that I have made a major mistake in recommending FlexibleSeal. It was certainly recommended to me, and it works well, etc. but I have found that over time it yellows a bit, probably from UV exposure. Not appetizing.

So I went to my local West Marine store, thinking they might know something about this. The local store seems to have several employees who give the impression that they have been personally and intimately involved in the ins and outs of fiberglass and gelcoat. I described the problem and they recommended 3M Marine Adhesive Sealant - Fast Cure 4000UV.

Their reasoning also included the idea that this is meant to be a sealant with great "cosmetic" qualities, i.e. it stays white over time, and since the butyl putty tape is the "real" sealant for our cute little vents and windows this would be what I really wanted.

The description says: "Premium cosmetic sealant, stays flexible. Exceptional protection against harsh marine environment. Superior UV resistance. <1% VOCs, low odor."

I'm going to try this product soon, and if I find it lives up to the hype I will report on it (probably after 1-3 years) along with a huge apology if it lives up to expectations.

On edit. A caution: on the 3M 4000, found both on the tube and from the sales people: The stuff, once opened, supposedly starts curing throughout the tube (meant for a caulking gun), so until I have checked it out I will plan to have enough sealing to do to make it worth the tube. I'm also unable as of now to find a screw cap for it of the right size so far, so I'm holding off until I can determine what its shelf life is once it is opened and resealed with a good cap.

[Greg A]

This is the stuff I have used on my redo. It is available at Wally for about $6.50 a tube in the tiny marine section.
Very good sealant to use with fiberglass. It does stay flexible and seals well.

[V'sGlassSleeper]

Well, that's excellent information, thank you. The guys at Home Depot swore by the 3M Marine adhesive sealant that they had (the 5200), however it seemed intended for places that one would never, ever, ever take it off, which may not be the case if, for example, a vent needs some maintenance and needs to be temporarily removed. I figured there had to be one that was a little less permanent, and it sounds as though Per and Greg have found just the thing in the3M Marine Adhesive Sealant - Fast Cure 4000UV and with low VOC to boot (the 5200 VOC was off the charts). We can only try these things out for ourselves and, as Per indicated, share with each other how well they perform over time. It's still the trial and error method, but sharing info and resources does reduce the errors in the long run.

Thank you!

[John Perry]

I am in the process of removing and resealing resealing the windows in my 1977 Scamp. I noticed that they were installed using a foam tape. I took a peice to the local glass shop and asked if he had any.
He said no but that it was called glazing tape.
Technology LK in the links section has double sided glazing tape which I have used to reseal 3 windows so far. It is a closed cell foam with glue on both sides. It is neat and easy and I really doubt that it will leak.
Not paying attention I put the first window in upside down and had a terrible time getting it out because the tape was so strong.
I figuered that since the windowns had been installed with the same basic tape and were not leaking after 30 years I would try it.
I was wondering if anyone else has used glazing tape to reseal their windows?

John

[DanPatWork]

On edit. [b]A caution: [b] on the 3M 4000, found both on the tube and from the sales people: The stuff, once opened, supposedly starts curing throughout the tube (meant for a caulking gun), so until I have checked it out I will plan to have enough sealing to do to make it worth the tube. I'm also unable as of now to find a screw cap for it of the right size so far, so I'm holding off until I can determine what its shelf life is once it is opened and resealed with a good cap.

Caution is right!! I don't suggest you open a tube of this stuff unless your going to use it within a day or 2 at the most. I was using it to re-glue some cabinet components, left the tube with the customary 1/4 - 1/2 inch "sacrifice plug" on the end. When I came back to finnish it off the next day it was hard all the way down the nozzle, and required a 6 inch screwdriver to open up a path for the remainder to come out.


Seems like good stuff tho. Sets up fast, and is tougher than snot! I had to cut, scrape, and sand some that got dropped on the floor. Just don't wipe your fingers on your jeans.

[V'sGlassSleeper]

Update on using 3M Marine Grade 4000 UV: To prevent it from curing in the tube if you don't use it all in one go, wrap a piece of saran wrap around the nozzle and stick the tube in the fridge... it lasts a long time in there, and just needs to be brought back to room temperature before using it again (so it flows decently).

[Per Walthinsen]

Val and Kayla:
If that is true you have saved my sealin' life. I may even do a test seal and test out your advice too. The stuff is too expensive to throw out half-used (I'm cheap). Thanks!

[V'sGlassSleeper]

You betcha! If it sits a long time, you may have to use a long nail to remove the "plug" of dried caulk that forms in the nozzle, but once you get that out and bring it to room temp, the stuff in the tube will flow just fine. This stuff really is expensive...$13 for a small tube and $20 for the caulk gun size... Youch!

Now if you find an easy way to spread the oily, sticky stuff... let us know! It took me forever to caulk a nice clean line with it because it's harder to spread than regular caulk and it doesn't clean up as well (of course, I didn't use anything toxic to clean it up with... what I finally found worked best was wetting the surface with water before smoothing it with my bare finger, and cleaning off excess with just a dry paper towel).

But I could just cry now, because it appears that I may have to razor blade through some of the caulk I just put around the belly band... it seems I may have hit some interior wires when I replaced the old rusty screws...waaahhh! I didn't think to plug the trailer in after replacing all the screws and before doing all the caulking, so my final advice is don't caulk until everything else has been checked over. Sigh.

Val

[FredericL]

WOW!!!!!!...Thanks to all who provided such amazing and great information on this thread...Per, Donna D., Con, etc. etc....

Removing and replacing windows in our little '86 Bigfoot needs to be done for resealing, appearance and other purposes and this thread is going to be a lifesaver.

[Jason, M]

Can i get thoughts on using a band of butyl caulk under the windows (instead of butyl tape)? And having it squish out when tightening the screws down? Am I playing with fire if I don't use tape?

[Roy in TO]

Jason,
My thoughts are that butyl caulk will "set" and make it more difficult to work around if you have to do anything later on.

[Tim D.]

A local rv person recommended Vulkem for sealing around windows and vents. He swears by the stuff and it is cheap--less that $5/caulk-gun-tube at Jerry's, our local home improvement center in Eugene.

http://www.tremcosealants.com/commercial/p...mp;product_id=4

Vulkem 921

Product Description:
Vulkem 921 is a one-part moisture curing, gun grade polyurethane sealant. Vulkem 921 is low modulus, durable, flexible, and offers excellent performance in moving joints. Vulkem 921 does not require a primer on most construction materials.

Basic Uses:
Vulkem 921 is an excellent general purpose sealant designed for use in precast, masonry, window and door frame perimeters and similar types of construction joints. Vulkem 921 is also suitable for continual immersion in water with the use of appropriate Vulkem primer. Vulkem 921 is designed for exterior and interior use.

Does anyone have experience with it? I plan to test it around a vent on the roof before sealing around the windows of my 1986 Bigfoot.

[Donna D.]

Vulkem
Does anyone have experience with it? I plan to test it around a vent on the roof before sealing around the windows of my 1986 Bigfoot.

I've used it on my home. It's still very pliable after 8 years. I'd sure want to read the cautions, etc. carefully. It MAY not be designed to be used on fiberglass. The RV person could be using it on aluminum skinned trailers?

[Tim D.]

According to what I have read it will adhere to fiberglass. The problem seems to be removing it if the time comes. Xylene works according to some, but there seems to be a difference of opinion on its safety for use on fiberglass.

[Patrick J]

Originally Posted by Con

I have said it in my thread and on the my pictures on Webshots. Thin rubber gaskets made from bicicle inner tubes make wonderfeul gaskets.

Forgive my stupid question here. How exactly do you punch out the tube to get the correct size gasket? Do you put the gasket under the SS washer? So from the outside in it goes - outside - Machine Screw Head, SS Washer, Gasket - inside - SS Washer, Hex Nut, Acorn Nut?

[Raya]

I'm not Con, but yes, that is the order it would go in if you were using a gasket. You want a large surface (washer) to compress the gasket evenly. Of course on something with a large base, you would put the gasket under the base.

Also, I would choose one or the other: gasket or sealant, but not both.

If you can get gasket material with UV inhibitors, that would be a plus. I would look in the McMaster Carr online catalog for gasket material, as they sell small amounts to the public, deliver amazingly quickly, and give a lot of information about the properties of their products.

Raya

[Joe Z]

Originally Posted by Per Walthinsen

Beth:

The method I use for vents, grilles, etc. is butyl putty tape followed by a non-silicone sealant like FlexiSeal. Here are a few pictures to illustrate the process:

The putty tape is somewhat sticky, so you press it on to cover the area to be sealed and attach the cover (screwed on in this case. This is a very small cover, so it is quite magnified):

Your post is from 2006 and i have been using your method with great success and it does a great job....butyl tape is good stuff.
Joe

[Raya]

Originally Posted by Jason, M

Can i get thoughts on using a band of butyl caulk under the windows (instead of butyl tape)? And having it squish out when tightening the screws down? Am I playing with fire if I don't use tape?

Hi Jason,

People do use butyl caulk (i.e. from a tube) on boat portlights (windows) without issue. The butyl kind of separates like gooey pizza cheese when you later go to remove the window, and then you can fairly easily clean up with solvent (nothing like how it would be to clean up more "difficult" caulks).

There are two schools of thought in terms of cleaning up squeeze-out. In one, you tape neatly all around the edge of the flange, and then any squeeze-out goes onto the tape, which you later remove. In the other, you let the squeeze-out squeeze out, and then clean it up with something like a popsicle stick and then solvent.

Raya

[Joe Z]

Originally Posted by Raya L.

Hi Jason,


There are two schools of thought in terms of cleaning up squeeze-out. In one, you tape neatly all around the edge of the flange, and then any squeeze-out goes onto the tape, which you later remove. In the other, you let the squeeze-out squeeze out, and then clean it up with something like a popsicle stick and then solvent.

Raya

I like your idea better ....sometimes a simple solution flies right over my head and will give that a try next time.
Joe