Putty for acrylic

[thinwater]

Originally Posted by Emmalina

Thanks all will wait and see. Anybody know the expansion rate of acrylic ? Sika 295 UV is bloody useless

Did it debond from the glazing after a years or so?


Did you use the primer?


Explain, because it is very widely used.

[thinwater]

Originally Posted by john61ct

Top quality butyl tape

Bolted fittings, yes, but it has zero bond strength for many glazing bonding applications. It will also cause polycarbonate to craze.

[Emmalina]

Originally Posted by thinwater

Did it debond from the glazing after a years or so?


Did you use the primer?


Explain, because it is very widely used.

Used the primer but after 4-5 years not bonded to the ss anymore.

[hellosailor]

Sikaflex 295, or any of the highly technical products on the market these days, comes with very specific conditions and restrictions. If the product was past the shelf life and was hard to apply? Yes, you can expect it to fail. If it was applied without the proper cleaner and primer both being used properly? Yes, it will fail. If it was applied over a surface that had previously been contaminated with silicone seal or polishes? Again, it could fail.

Butyl tape has some advantage over all the modern adhesive caulks, in that you just slap it in and trim it off with no fine print about the application. Then then again, it will never actually bond two surfaces.

The "architectural" sealants that are using to secure glazing in "glass" roofs and other inaccessible areas somehow manage to work. The devil, as usual, being in the details.

[john61ct]

Sealant and adhesive are often separate product categories.

Sometimes one product will include both functions well.

Yes the better-performing modern ones have very specific environmental specs, and the better your surface prep the more likely they will do their job properly for many years.

[KRMS]

I’m not sure I’d use putty but I do have a suggestion that may get you past the annoyance of 70% left in the Sikaflex tube going hard. There’s a product that is new to me in past couple of years called CT1. Similar price to Sikaflex. It is much better at remaining usable. I haven’t had to throw any away. There is also an associated cleaning spray (quite expensive (£7 for a small spray can) but really good for cleaning hands and places where you didn’t want the sealant to go). Videos of all this are on YouTube.

[zboss]

Originally Posted by Emmalina

Thanks all will wait and see. Anybody know the expansion rate of acrylic ? Sika 295 UV is bloody useless

"approximately .00984″ per foot length for each 20 degrees of temperature change"

[john61ct]

Sikaflex is not a product.

Sika is a company with thousands of excellent products.

Like saying "that 3M stuff".

Better to be specific in our discussions.

[KRMS]

Originally Posted by john61ct

Sikaflex is not a product.

Sika is a company with thousands of excellent products.

Like saying "that 3M stuff".

Better to be specific in our discussions.

I think we all know this. The question was about 295. Is there a Sika sealant product that you’d recommend with a longer usable life once opened?

[john61ct]

My point was best to specify the product.

Thanks for clarifying that you were talking about 295 specifically.

[Emmalina]

Originally Posted by john61ct

Sikaflex is not a product.

Sika is a company with thousands of excellent products.

Like saying "that 3M stuff".

Better to be specific in our discussions.

As I specified 295 to start with mmm Did you read the thread ?

[thinwater]

A specific weakness of polyurethanes is that the bond area is very UV sensitive. If light passes through the glazing, within a few years the bond is gone. The primer helps. This is better with the UV versions, but only a little.


Polyurethanes also have trouble with SS. Sika 291 and Locktite PL S-40 bond better. Sheer testing I did for a magazine, and long term rack samples.



Many tests latter, I've become convinced that Dow 795 is the best answer. Easy to work with, long life, not hard to remove with Re-Mov.

[john61ct]

Specifically for acrylic, or other use cases as well?

[lifeofreilly57]

Uhm, I think someone mentioned butyl tape.
I had a boat 30 years ago that had aluminum frames with a mix of tempered glass and acrylic frames. I had the frames and windows out every season for 4 seasons trying to get something that would seal for at least part of one full season (in New England), tried every high tech solution on the market, I even did half with one product, half with another to compare and go through more products in one season. Yeah, they all leaked.
Next season I went to good quality butyl rubber tape, they never leaked again. I ran into the third owner of the boat since I sold it several years ago, he asked me what I used, seeing that no one since had re-sealed the frames or theglass/acrylic (the acrylic is opaque now) and the windows had been leaking a little recently.
Most miracle sealants set up, or harden over time, boats continue to flex and work their joints, any sealant that "sets up" will eventually lose it's bond, as the sealant forms to a fixed state and the boat continues to be in a transient state.
This year I pulled every single piece of deck hardware and ports from my current boat during a refit, including the chain plates, every piece was re-installed with butyl rubber tape. Even though this boat is built lie a brick solid waste depository, it too will flex at some time or another. Maybe go to the low tech solution?

[er9]

Originally Posted by lifeofreilly57

Uhm, I think someone mentioned butyl tape.
I had a boat 30 years ago that had aluminum frames with a mix of tempered glass and acrylic frames. I had the frames and windows out every season for 4 seasons trying to get something that would seal for at least part of one full season (in New England), tried every high tech solution on the market, I even did half with one product, half with another to compare and go through more products in one season. Yeah, they all leaked.
Next season I went to good quality butyl rubber tape, they never leaked again. I ran into the third owner of the boat since I sold it several years ago, he asked me what I used, seeing that no one since had re-sealed the frames or theglass/acrylic (the acrylic is opaque now) and the windows had been leaking a little recently.
Most miracle sealants set up, or harden over time, boats continue to flex and work their joints, any sealant that "sets up" will eventually lose it's bond, as the sealant forms to a fixed state and the boat continues to be in a transient state.
This year I pulled every single piece of deck hardware and ports from my current boat during a refit, including the chain plates, every piece was re-installed with butyl rubber tape. Even though this boat is built lie a brick solid waste depository, it too will flex at some time or another. Maybe go to the low tech solution?

interesting. on my 1980 boat they used butyl between the hull and deck and between the keel and hull. im really curious what the bond between the keel and stub looks like when i eventually drop the keel. so far no signs of water intrusion in either yet. i wonder does butyl come in a semi liquid form?