Fixed window replacement - Dow 795 still the sealant of choice?

[bstreep]

Originally Posted by zeehag

i use nothing by dow corning. i remember agent orange and i use any other corporate stuff not dow.
i use sikaflex and i use 3m 4200. neither are dow corning.
3m does good gooo...

Don't blame Dow, blame your Congress. Dow was REQUIRED by law to produce Agent Orange, along with a whole bunch of other companies.

Agent Orange

[zeehag]

Originally Posted by bstreep

Don't blame Dow, blame your Congress. Dow was REQUIRED by law to produce Agent Orange, along with a whole bunch of other companies.

Agent Orange

i was advised otherwise by folks with high security clearances, and also relatives who worked for dow. .....only dow made agent orange and then there was the disinformation from there.
i buy nothing dow.

[sailvayu]

Jedi I have had some real problems with Sikaflex 295UV on a few hatches I did. It cracked and I ended up having to remove it all and went with boatlife silicone which lasted years without a problem. Which is a good point for those who do not like Dow. Use the Boatlife silicone it is a very good product as well.

[clockwork orange]

Originally Posted by zeehag

i was advised otherwise by folks with high security clearances, and also relatives who worked for dow. .....only dow made agent orange and then there was the disinformation from there.
i buy nothing dow.

Zeehag, do you use West epoxy?

[clockwork orange]

Originally Posted by motion30

I am having trouble finding the Dow 795 what would be equivalent in another brand. I'm setting glass windows into an aluminum frame

GE Silpruf 2000 is a good substitute for Dow 795.

Steve.

[bstreep]

Originally Posted by zeehag

i was advised otherwise by folks with high security clearances, and also relatives who worked for dow. .....only dow made agent orange and then there was the disinformation from there.
i buy nothing dow.

Right... So Monsanto, Diamond Shamrock (now Valero), Uniroyal, Thompson Chemical and T-H Agriculture all OPENLY ADMIT that they made Agent Orange - under FEDERAL LAW requiring them to do so (Defense Production Act of 1950), that gave the President the authority to require companies to supply specified product to the US Government. This is an absolute fact - and they paid into a settlement fund to pay veterans.

It makes no sense that a company would settle a lawsuit for a product that they never made. Nor does it make sense for a government cover up that Dow was the only maker of the product.

Dow 795 is a great product. You can certainly choose not to use it, but spreading unfounded rumors about a company that aren't true, isn't fair to Dow. If you want to say "I don't buy anything from Dow, Monsanto, Valero... etc. because they made Agent Orange", that's another story.

There is/was a whole lot of blame to go around on Agent Orange - it's just not fair to dump it on a single company. A LOT of people knew there were problems with Agent Orange. Including our military.

[Cpt Pat]

Originally Posted by bstreep

Right... So Monsanto, Diamond Shamrock (now Valero), Uniroyal, Thompson Chemical and T-H Agriculture all OPENLY ADMIT that they made Agent Orange - under FEDERAL LAW requiring them to do so (Defense Production Act of 1950), that gave the President the authority to require companies to supply specified product to the US Government. This is an absolute fact - and they paid into a settlement fund to pay veterans.

It makes no sense that a company would settle a lawsuit for a product that they never made. Nor does it make sense for a government cover up that Dow was the only maker of the product.

Dow 795 is a great product. You can certainly choose not to use it, but spreading unfounded rumors about a company that aren't true, isn't fair to Dow. If you want to say "I don't buy anything from Dow, Monsanto, Valero... etc. because they made Agent Orange", that's another story.

There is/was a whole lot of blame to go around on Agent Orange - it's just not fair to dump it on a single company. A LOT of people knew there were problems with Agent Orange. Including our military.

And who manufactured Napalm B? In my mind, one of Dow's major revenue streams has been the manufacture of chemical weapons.

More here: Napalm - Wikipedia, the free encyclopedia

"From 1965 to 1969, the Dow Chemical Company manufactured napalm B for the American armed forces. After news reports of napalm B's deadly and disfiguring effects were published, Dow Chemical experienced some boycotts of all its products, and its recruiters for new chemists, chemical engineers, etc., graduating from college were subject to campus boycotts. The management of the Dow Chemical Company decided that "its first obligation was the government." Meanwhile, napalm B became a symbol for the Vietnam War."

"In 1980, the United Nations 'declared the gel's use on concentrations of civilians a war crime'."

[SVTatia]

Wow.

Acrylic windows, aluminum frames, Dow 795, Sikaflex, Agent Orange and Napalm.
All in the same thread.

[Cpt Pat]

I used 3M VHB tape, which provided a sufficiently tenacious watertight bond to install 1/2 inch thick acrylic on a cambered cabin surface without frames.

Details and photos are here: http://www.pearsonariel.org/discussion/showthread.php?2520-Portlight-replacement.

[bstreep]

Originally Posted by Cpt Pat

I used 3M VHB tape, which provided a sufficiently tenacious watertight bond to install 1/2 inch thick acrylic on a cambered cabin surface without frames.

Details and photos are here: http://www.pearsonariel.org/discussion/showthread.php?2520-Portlight-replacement.

Nice project. I did notice that your screws appear to be tight. They should only be used to keep th window in place while the adhesive cures. Otherwise you may find the holes cracking as acrylic expands with heat.

[Cpt Pat]

You are absolutely right! The holes in the acrylic are twice the diameter of the screw shanks, and allow for 1/8th inch expansion and contraction. The screws are #10 size (3/16th inch diameter) and the mounting holes are 3/8th inch diameter.

During initial mounting, I used 3/8th inch diameter screws to center up the holes, and I then allowed 24 hours for the VHB tape to bond. After that, I removed the 3/8 inch screws and substituted #10 (3/16th inch) screws that are torqued only to a snug fit. With the VHB tape, I could remove the screws entirely and the acrylic would still cleave to the cabin surface. The acrylic floats on the surface with the screws only providing alignment in sheer (sideways movement).

Looking at the panels from the outside, you can see finish washers under the screw heads. But concealed under the finish washers are 316 SS flat washers that are slightly larger in diameter. The finish washers look good cosmetically, but the surface area that would be in contact with the acrylic is too small, not smooth, and would concentrate stresses on the acrylic surface. The sharp edges of the finish washers could also dig into the acrylic surface when the panels expand and contract, preventing thermal movement. So I got the best of both worlds by using flat washers under finish washers.

For a water-tight seal at the screw-head-to-washer interface, I used Loctite.

[Beersmith]

I just finished installing some large acrylic windows using only Dow 795, no tape or fasteners:



full write up of the project here: Making and Installing Large Cabin Windows | The Quest for Wind and Waves

[neilpride]

I do lots of windows using SIKA with the sika primer and the uv tape shield, so far no problems, but as you guys mention a lot Dow 795 i guess is worth the try, i put hig in my list this product , we see.....

[s/v Jedi]

Originally Posted by neilpride

I do lots of windows using SIKA with the sika primer and the uv tape shield, so far no problems, but as you guys mention a lot Dow 795 i guess is worth the try, i put hig in my list this product , we see.....

Dow 795 is just a non-sagging silicone sealant.

[duckpond49]

I used Dow 795 to refurb my Lewmar deck hatches w/acrylic. No problems. The specs on the stuff are terrific. Dow: "The cured sealant is durable and flexible enough to
accommodate ± 50 percent movement of original joint dimension when installed in a
properly designed weather seal joint."
The only downside I've run across is that it does not store in tube well. 1 year old 795 won't cure. Good news. It's cheap! About $8 a tube.