Butyl Tape with Acrylic

[witzgall]

Hi,


Does Butyl Rubber tape have any adverse reaction with cast Acrylic?

We are 1/2 way through rebedding our portlights, and I hate tube goo!....

Our portlights are three pieces, designed to work with a flange built into the boat. On the outside, is an aluminum trim ring with holes. Next is the acrylic, also drilled with holes. The acrylic sits inside a flange built into the cabin sides, and the outside trim ring covers up the edge of this flange and the acrylic.

Inside is another trim ring. Barrel, or "Sex" bolts, are used to compress the stack together. I was using Down 795 to put these all together, but I have some of Mainesail's Butyl Rubber tape, and thought it would be a better solution, with tape used between the acrylic and the cabin side flange, and then also on each bolt head, to keep out water. Also some between the outer trim ring and the acrylic.

Good idea? Did I say I hate tube caulk?

Chris

[sailr69]

works good, different types of butyl though, some is very messy(like auto winshield type of a few years ago). you would want low squeeze out.

[rolandgilbert99]

The real Butyl has no effect and it is black, the only inconvenience is the fact that it never dries and will continue to expend for years! Don't use the grey type of caulk in rolls, it will mess up your acrylic when the water drips over it and on your windows.

[GordMay]

Yes, Butyl Glazing Tapes are compatible for use with smaller* Cast Acrylic Portlights.

* Ie:
"... Tremco butyl tape sealants are considered compatible and acceptable for glazing acrylic and polycarbonate sheet.
However, the severe thermal movement that is characteristic of such applications can cause permanent deformation and squeeze-out of the tape.
Glazing plastic sheet with tape sealants should be restricted to small lites, with a maximum dimension of approximately 36 inches (914mm)..."

➥ http://www.tremcosealants.com/filesh...utyltapeai.pdf

[witzgall]

Rolland,

It is the grey stuff in rolls I wish to use. I do not understand the issue you raise with using this, assuming that the frame is held in compression.

[rolandgilbert99]

When the rain runs over the window, some of the water washes up the grey stuff between the frame and the fiberglass (only if the gray caulk is slightly visible, which may not be your case) and this leaves a trace of milky stains on the acrylic, which can be removed but are a pain in the neck.

[SVTatia]

Originally Posted by rolandgilbert99

When the rain runs over the window, some of the water washes up the grey stuff between the frame and the fiberglass (only if the gray caulk is slightly visible, which may not be your case) and this leaves a trace of milky stains on the acrylic, which can be removed but are a pain in the neck.

Rolland, the grey butyl you are talking about, did you buy it from Maine Sail?

[casual]

Been useing Gray Butyl on ports windows deck hatches ect for 20 plus years,Now using it to rebed ports with real glass never experienced the streaks referred too.

[Maine Sail]

Originally Posted by rolandgilbert99

When the rain runs over the window, some of the water washes up the grey stuff between the frame and the fiberglass (only if the gray caulk is slightly visible, which may not be your case) and this leaves a trace of milky stains on the acrylic, which can be removed but are a pain in the neck.

You've used a poor quality butyl tape if this is happening.. There are vast differences in the quality of butyl tape. Not all butyl is the same.

[rolandgilbert99]

Originally Posted by Maine Sail

You've used a poor quality butyl tape if this is happening.. There are vast differences in the quality of butyl tape. Not all butyl is the same.

Here in my area the only "real" Butyl is black. Other makes are grey or even white (I heard but never found), some are sold in RV stores, like the one I purchased once and was not satisfied with it. The black one I purchased at a hardware store will last forever and works fine, as I said earlier, the only problem is that it expends also forever and around some fix portholes I have to clean once in a while. And if you change your mind and replace the part, cleaning it requires a lot of paint thinner!

[Blue Stocking]

Ask at any commercial glass shop.
I was a partner in a Business that installed Curtain Wall building systems.
I have installed MILES of tape, which reqire 10 year warranties.
TremCo (Canada) was my supplier.