Techniques to rebed dead lights (windows)

[CSY Man]

Good timing for this subject:

I just started tearing into a portlight on "Rhapsody" 1979 CSY 33.

Not Lexan or Plexiglass, but a huge bronze frame around a small glass window facing forward in the V-berth. (Small shelter-deck in front)

Can not get the main bronze frame out, it was sealed by the factory with 3M 5200, some 27 years ago.
I can only use a dentist tool and pick out the caulk I can get to, then acetone clean, squeeze caulk in the cracks, let it half dry, then tighten down with new SS screws. (The old bronze screws were corroded and pink, and replacement screws and bolts, nuts in bronze, would be too expensive)

As for plastic windows:
I have storm-shutters all around the "pilot house": 3/8" smoked plexiglass outboard of the regualr windows. Keeps it dark and cool in the cabin and gives an extra level of safety in case of mad seas and/or loose whisker poles or somebody's bowsprit.

Have re-beeded those plexiglass shutters in the past and have had good luck with black silicone caulk. Let it "almost cure" then clamp down good on the 38 SS screws around the windows.

No leaks, no nothing.

Considered Lexan, but my plastic supplier said it is not as resintant to UV rays...That and the cheaper price for Plexi, uh, sealed the deal...

Now taking a beer and air-condition break before I go back on the boat again and wrestle with the bronze port....Them CSY's are built like tanks, not even a bigger hammer will budge it..

[Sunspot Baby]

OK, so I have decided to use Sikaflex. Did you know that there is no distributer in North Carolina? As active as the boating business is here, Hatteras, Parker, Fountane, Tiara, etc. No distributer? I did find Merrit Marine (spelling?) in Florida who will me less than case lots.

Any recommendation on how much I will need? I have 8 dead lights averaging ~50 inches long and 30 high for about 1280 linear inches. A can of the 209 primer is $31.50 for a small can (she says less than a pint). That would seem to be enough though. Its how many tubes of adhesive (295 UV) I will need.

Sika tech support is supposed to call me back. It was close to 1700 their time when I called.

George

[Alan Wheeler]

Arrrr, I see. Yep that's why I try and call the stuff Polycarbonate. Not just because I like to impress others with big words.:-)

From a lot of talking with A Marine Glazing specialist, he sold me on Acrylic. It lasts longer, it retains a higher strength over a far greater time and as long as you can go up a size, it is just as strong as the polycarbonate. Polycarbonate loses a considerable amount of its strength in a relativly short time. After a year of UV, it will be weaker than acrylic.

[hellosailor]

Dunno, Wheels. "it retains a higher strength over a far greater time and as long as you can go up a size, it is just as strong as the polycarbonate. "
There are probably over a hundred different makes and grades of each of those products, and while there's a lot of overlap polycarbonate tends to run 10x-100x stronger than acrylic, so going "up a size" doesn't sound strong enough to me. Take a deck hatch which might have to withstand a ton of green water dropping on it. What do you call "going up a size" ?<G>

CSYMan-
There is indeed at 5200 SOLVENT on the market now, even 3M has heard about it. If you can get some onto that frame, you might be able to break it out easier. And although I hate to say "use a torch"...5200 also lets go of hot metal much faster. A little judicious work with a *small* torch, by a careful worker, if the solvent didn't do enough of the trick?

[CSY Man]

There is indeed at 5200 SOLVENT on the market now,

Aye mate. Proplem solved:
I was able to get a sharp razor-blade knife in the crack and after working that for 10 minuttes cutting the 5200, the whole thing came out good.

Now the project is all cleaned up and ready to go in, just waiting for a fresh coat of varnish to dry as the bronse frame had thick teak frame around it......Sure makes for a sturdy and salty look, but all that stuff must have cost oodles of money, even back then and probably the reason CSY went out of business with a bang.
Legend says they lost $10,000 on every boat they sold...

I plan to caulk the whole thing with Life Seal, a product that is a combo of silicone and poly-something..Got the tube from the manufactor at a boat show a couple of years ago...Not a real critical installation so the stuff should be plenty good enough.

http://www.defender.com/product.jsp?...11448&id=15189

[Sunspot Baby]

In trying to estimate how much of the Sikaflex 295 to buy, Sika tech support told me one tube would lay about 20 feet of 1/4 bead. 1/8 bead would of course be more. He said 3 times as much, but since volume is a function of cross sectional area, it should be closer to 4 times.

OK guys, if my windows are about 50" by 25" and are supported with screws, how large a bead would you apply?

George

[GordMay]

I expect that you won’t be applying a round external “caulking” bead, so much as a flattened internal bond-line “connection & gasket”. The adhesive-sealant will cover the entire width of the bearing surface between window & cabin.

I’d calculate usage based upon a 1/16" thick application times whatever the bearing surface width (window overlap on coach-house) is. This will allow for the extruded sealant “wastage”.

Ie: A 1/4" diameter x quarter-round external bead would approximate a 1/6" thick x 0.7854" wide flat connection.

A 50 x 25" rectangular window will have 12-1/2 linear feet (150") of frame, suggesting something on the order of 1.6 (or more) cartridges per window (assuming about 3/4" bearing overlap, and 20' coverage @ 1/4" bead).

[alanperry]

I just re-bedded my hatches with Sikaflex 295 and it works really well. I have a plastic called " Chemcast - cell cast acrylic sheet".

My hatches had about 30 screws holding down the "glass" which firstly was overkill and secondly was a primary source for leaks as each screw hole had to be oversized to allow for the differing rates of thermal expansion. It was my goal to get rid of these screws.

I did not use the primer. I read all the info on both packages and it seems to me that the primer is primarily (is that a pun?) there to enhance the UV properties. I may use it on the next hatch as an experiment to see if it is really worth the $40.

After applying the Sikaflex I weighed down the "glass" with everything in my garage and it came out great and stuck down mightily. It looks really good too especially without all those screws.

One thing I would say about the sikaflex is, use plenty, more than you think it needs. It can be trimmed easily with an Xacto knife after it sets. You will avoid gaps. It is heavy and doesn't flow as easily as some other similar adhesives.

Alan Perry
S/V Oceanus
Seattle, WA

[Sunspot Baby]

Alan’s post got me to thinking more about this project.

I have ordered the Sikaflex but won’t start work until I have everything on hand.

What about a small O’ring between the pane and the screw head? It could act as a seal to keep water from entering around the screw or the screw hole and be a cushion to reduce the likelihood of over tightening the screws.

Just a thought. Anyone have comments?

I continue to think I will stay with the screws. The pane seems to fit outside the deck house, not sit in a well of any sort. I am not sure I could get good alignment otherwise. It might look sexier without the screws, but since I am planning to reuse the panes, not replace them, I would end up with a bunch or holes to fill somehow.

Alan, according to the tech info in Sika’s site, the primer facilitates a chemical bond between the sealant and the substrate. Without it, one may get only a mechanical bond. They call it Force Locking and Form Locking. It’s $31+ for a small can, but hoping that this project won’t need to be redone for another 10 years, I’m going not going to sweat the $$.

I am not planning to use the “Sika Aktivator”. I think proper cleaning with solvent and sanding will provide a sufficiently reactive surface.

George

[alanperry]

In your case I think I would stay with the screws unless you were going to replace the "glass". Also they are on the vertical so not as likely to leak I think, as the Hatch ones are.

As for that primer, yes I saw that on their site and it is probably a good idea to use it. I made the decision not to on the first hatch in case I had to take it apart again for some reason (like I screwed it up in assembly) because I have never used the Sikaflex 295 and did not know what to expect from it.

I think I will use the primer on the next hatch now that I know what I am doing more.

Although I have to question Sikaflex's pricing when the actual "adhesive" sealant is $12.95 a tube and the bloody "primer" is $30-$40 for a small can? Seems odd to me that price differential. Without being able to quatify the difference in holoding power with and without the primer it's a crap shoot on whether your $35 is well spent.

Alan

[Alan Wheeler]

OK so while on the topic of Sikaflex. How do you determin the date of this stuff??? On the bottom edge of the tube, is a small symbol kinda like a compass/old traditional steering wheel type shape and a four digit number. In this case, I think the number was 06 05. Is this the date stamp?? If it is, is that the "use by date"? "date of manufacture"?
Reason I am asking is, the literature states the product has a shelf life of 12months. But from when??? Now I do realise that often the product can last longer than that, but I have also come across product that didn't. My main concern is, if there was ever a failure in it's use, assuming all was done correctly and I went back to Sika and asked why, would or could they then say, "oh well the product was older than we recomend it should be, we won't cover a failure."???

[hellosailor]

AlanP-
"the actual "adhesive" sealant is $12.95 a tube and the bloody "primer" is $30-$40 for a small can? Seems odd to me that price differential. "
The difference between "goo" and SPECIAL GOO.<G> I wonder if the ratio used is one can of primer to three cans of sealer, so the dollars balance out.<G> No, really...stuff like CrazyGlue or Loctite products, or Stabilant22, can run a fast $50/ounce. You're buying the "advanced" chemistry on all of these things, apparently some of the ingredients aren't found at the 7-11.<G>

Wheels-
"06 05. Is this the date stamp" What I just went through on my PFD activator.<G> For something made in the USA, it would mean expires on June 2005. Anyplace else in the world, probably means expires on May 2006. Either way, it needs a call/email to the maker and a chiding to them for being so cryptic with that information.

[Alan Wheeler]

Well heres the thing. Firstly, this is definitly Sikaflex in a tube. Several different product type numbers. They all have these older numbers on them. The problem is that they are presently being sold by a friend in his shop. Actually I will rephrase that. He is selling an opposition product because Sika NZ will not tell him the date of them. They state that there is no date. He argues that if there is no date, then why does all the literature state a 12month self life. So he is about to throw all his Sika product back at them because he does not want to be in the middle of a dispute if a product fails. We both had a look on the tubes and came across this stamp and thought, hmmmm, wonder if that is a date stamp. If that is the case, then he is being sent new stock that is already over 12months old before it even sits on his shelf. Sika maybe good stuff, but it ranges for some of there products from NZ$25.00/tube upto $40 odd a tube depending on what.

[hellosailor]

Wheels-
"Sika NZ will not tell him the date of them." Sounds like time to contact Sika HQ and ask them about dating. And, perhaps, to let them know their NZ agents are not playing nicely.
Unless Sika NZ is locally making the goo, the tubes & date codes may come from somewhere else and HQ might know.
Do you have any product liability or consumer warranty laws in NZ that might help out some screws on Sika NZ? If the product says it must be used within 12 months shelf life for the warranty to be in effect, and they won't tell you the shelf date...that could be a material breach of warranty allowing all the product to be removed from sales channels. (Ran of out carrots, just have big sticks today.<G>)

[Alan Wheeler]

We have a consumers gauranttee act, but it protects the consumer, not the seller. So if a product fails, and it can be proven it is the product, the the retailer has to fix the problem. If the supplier is worth their salt, then they would come to the party of the retailer. The issue in this case is, Would the supplier do so. The fear is that the supplier may already be "pulling the wool over the retailers eyes" so you would have to wonder about backup wouldn't you. Hence the retailer friend of mine not wanting to sell the product and get into the middle of an argument and possible large sum of money to solve a customers problem.
OK, so that is on a extreme outcome. Having a product failure due to age is hardly likely. The main outcome would be a customer that has a tube that the product inside is already starting to cure and the product is hard to get out. BUT!!! where I see a possible issue is that the whole situation could all come "unglued" is if there is a failure of bond on a large expensive job and the supplier has an out of an argument becuase the product was older than a specified shelf time.

Now at present, this is all summising. I may be wrong and Sika may come to the party and back there product. I don't believe they should be selling a old time limited product in the first place, but maybe they aren't. so the fisrt thing that needs to be confirmed is, IS that symbol at the bottme skirt of the tubes the time stamp, IF it is, what does the date represent?? Use by or manufacture date???
Sika NZ wont say as far as I understand. Does anyone have any contacts in other countries to get this question answered??