Silicone is truly evil.

[mbd]

Yes, butyl from the tube is quite messy - but effective! No deadlight leaks to date...

[mbd]

I'll have lexan windows bolted on over butyl tape. It bends nicely around curves.

...but what about those beautiful powder coated frames of yours??

[ebb]

Mike, glued to the boat like that I don't see how you communicate with your pc.? They bring you food, right?

I'm slabbing on the lexan (doesn't sound very elegant) so the beautyful frames (I give them a 90% grade) won't be used.
That's the plan.

BUT just in case, I feel I have to hold on to them for a little while longer because an albergeze aesthetic embarrassment storm might hit me.
Those aluminum frames were altered before powder coating to take thrubolts (machine screws), so they have holes in them!!!!


[DANG! just took a look using your blueline. Haven't seen those in a long time, they're covered and stored in the garage shop. It looks like NOT ENOUGH HOLES, top and bottom should have two more fastners each! Might work with what they have because the cabin side is mildly curved and the frames are flat - even after 40 years attached to the boat!!!!]

[mbd]

Mike, glued to the boat like that I don't see how you communicate with your pc.? They bring you food, right?

I'm on the inside. That is my friend and sailing buddy who is glued to the portlights - and yes, I feed him every now and then.

[ebb]

Polyether is a 'next generation' silyl terminated urethane.
I am unable to find any web discussion on just what the difference is between silicon-urethane caulk viz LifeSeal and certain Bostik products
- and the newer polyether.
Compared to death grip adhesives like 5200 and Sikaflex 291, there are no free isocyanate molecules to outgas.
The claim is better adhesion to non porous surfaces, greater resistance to UV and weather.
If you absolutely must BOND polycarbonate windows to the cabin side or frames, this is the stuff to use when you never want to take it apart again.

I've used the bathroom sized tube of WM's polyether. And the gun tube. It has the quality of silicone in that it goes on glossy and makes a silicone-like rubbery seal. But it is easier to tool, much easier than polysulfide, or polyurethane tube sealants.

I have read that it bonds better to surfaces than LifeSeal. But this may be hearsay.
I have also read that it cannot be used under water. Like plain silicone can't.
Polyether does not outgas. You see it marketed for use around food.
On the other hand LifeSeal can be used underwater and on polycarbonate.
[check out ChemLink M-1 (it's a polyether) Structural Adhesive Sealant. Read the Technical Data Sheet at www.bestmaterials.com (Copperstate). Good for underwater - $5.95 / 10.1oz gun tube.]



Practical Sailer (August 2010)
tested ("Jack Tar's New Goop") some of the caulks/sealants available from the West Marine catalog. They tested only some that are available from the catalog. There is a 100% chance you won't find what you need at one of their stores. Call first.
One polyether is a toothpaste tube of West Marine brand that is packaged to look unmistakably like a child of BoatLife. A black and yellow motif separated with a red band.
BoatLife's LifeSeal (the silicone/polyurethane) is NOT included in this 7 product comparison test by Practical Sailor. A serious omission.
Probably because the West Marine packaging confused them as well.
Naturally you may think the BoatLife look alike was packaged for West Marine by BoatLife that now makes polyether calk. Nope. The stuff is made by StarBrite, your favorite boat wax company.
3M makes a polyether listed in the WMcatalog...
BUT it is not included in the Practical Sailor "test". Why wouldn't a polyether be tested against another manufacturer's polyether? For crying out loud.
It's the POLYETHER that is the real "NEW GOOP". Let's find out all we can about the new marine caulk.

Practical Sailor has a side bar in the article: "Does Marine Matter? Do You Get What You Pay For?" that talks about "bathroom" caulks available from non marine sources. They patronize by talking about latex and acrylic caulks that no subscriber would think of using on their boat, The article says that some home-improvement brands of silicone are still intact after five years in an ongoing test of 23 products. Five years on a Home Depot caulk is something I'd like to know about! Especially if it wasn't a damn silicone.

The polyether you can buy from West Marine online for $13/3oz, $19/10oz. $10 flat charge for shipping.
You can go to a roofing site (like CopperState) and find Novalink and Sonabond polyethers for $5 a 10oz tube. Polyethers are not new polymers, they have been around in the trades for 20 years.
Wouldn't it be nice to know which of these roofing goops would cross over to the boat?

Practical Sailor says that without their guidance in marine sealants you'll be sure to make a mistake and buy "an inadequate caulk that prematurely fails (negating) the value of all the labor in the project."
That said, if PS was on my side, they would test ALL brands and types of caulks.
Telling me my inability to choose and "saving a few dollars on bargain-priced materials is a foolish gamble" IS patronizing, insulting, and suspicious.

The article covers many aspects of caulking. Despite it's idiosyncrasy it's definitely "worth considering."
The PS tests focus on bond strengths, adhesion. There is no mention of butyl or other bedding compounds. Not all adhesive products are tested. Nor is longevity, weathering, addressed. The Sikaflex 291LOT, for instance, is recommended for stanchion bases. This despite polyether's promise for remaining bonded and flexible forever.
Polyurethanes shrink, harden and crack over time as they get older. And PS shows a photo of a pre-teen Sikaflex 291 that will delaminate your deck if you try to remove your stanchions).
The PS article ignores recording for us silicone's evil reputation amongst boaters for contaminating gelcoat surfaces. This omission is absolutely inexcusable.
There is obviously nothing inadequate about truly evil silicone.

Before bedding (not gluing) any wood for any length of time to the boat, do a search on the subject here.
On the hidden surface that is bedded there is imco no better prep than a couple coats of laminating epoxy, first coat thinned a bit with xylene.
I'm convinced the best way to protect exterior varnish is to seal and precoat all surfaces with epoxy. In fact I'm convinced the at least two or three coats will do the filling of pores and allow the first coats of varnish to be layed on without telegraphing surface imperfections into multiple coats of gloss. In other words use epoxy to create an ultra smooth surface, then coat with a UV finish of your choice.



__________________________________________________ __________________________________________________ ___________
(9/03/10)
Mike, who is at this moment in the throes of divesting himself of SeaGlass
was the last poster on this year old thread.
He will be sorely missed.

[ebb]

Got an email from P.S. (5/04/11) because they still think I'm a subscriber.
I may have resubscribed because they DO cover a lot of product I wouldn't know about and a lot of fancy gear I can't afford.

But for Practical Sailor, when it comes to goop there is nothing new under the sun.
"The trick is to choose the right one..." they begin.
But when we get to the bottom of the page we aren't much wiser at all.

On Butyls, for instance, they say they "cure fast" and "stick well". If this were so they'd have to elaborate, but they don't. The tape butyl I use DOES NOT CURE. In fact it works because it doesn't. If you are talking about TUBE butyl and want it for plastic we'd have to know what solvents are in what tube butyl. Don't know that PS can go there. West Marine doesn't have any.
Tape butyl is sticky - but mostly to itself - it does make a good seal under pressure, but not too much pressure,
But the attribrute of butyl IS that it doesn't CURE like silicones, polysulfides, polyurethanes or polyethers. "Cures to a supple rubber." is the last sentence. But in no way does butyl compare with the other rubbers they mention.
.."can be used on polypropylene where polysulfide cannot." [see footnote]

Practical Sailor's favorite marine supplier for tube goop testing is West Marine - who do not carry tube or tape butyl (altho I haven't been there in a long while). Since we are too stoopid to make our own choices outside the marine catalog we should be getting information from our WISDOM SOURCE.
It is obvious that Practical Sailor can't find it either!

In this "Stop That Leak" piece they don't mention that polysulfides attack many plastics - and some plastics attack polyurethanes,. It would be important to warn loyal subscribers just what plastics you can't stop that leak with what tube rubbers. Polyurethanes aren't for stopping leaks anyway - they are for permanent bonds. Both products have industry and testing techies ignoring long term problems with UV in exposed joints.
This may be old stuff. I'm not a testing facility. These rubbers may have been improved for weather exposure. I'm not betting on it.

Practical Sailor keeps flogging Silicone ...."Sticks to almost everthing including glass, electrical insulation, and most metals."
"Don't use with polypropylene...." again that's a new one on me. Something I didn't know.
Can't find it on the net. If true, thanks PS for that knowledge.*
But we boat owners know why we DON'T STOP THAT LEAK WITH SILICONE.
Every boat forum knows this.
As a matter of fact Practical Sailor might have informed themslves as to what their public thinks... if they had done a little internet research instead of continuing their silicone myth. A sickness that comes from reading labels too much.
What the hell, what do I know?
Any movement of a joint with silicone caulking in it breaks the seal and allows water in. I know that.
If you smear silicone into a joint with silicone caulk in it to stop leaking - it won't happen.
Silicone doesn't stick to silicone, nor to the oil left behind in surfaces after you've troubled to carefully remove it.
Do any of the testers at PS do maintenance on their own boats?

They mention 'bedding compounds' avoiding the most famous: Dolfinite, opting for the more poetic Interlux 214. It bugs me because Dolfinite has a long standing rep and recognition as THE bedding compound that the "such as" Interlux product does not. The Dolfinite name is synonyimous with bedding compound - almost generic. Putting Interlux 214 forward is fishy and inappropriate - unless it has comparison tested better than all others - which I'm positive PS has never done.
That's OK, Practical Sailor has a problem with methodology.
They are aware of that. They carefully tell us how they set up their testing. On some products it's good enough.
On others, it's not conclusive, or complete, or correct.
I must be missing something!
__________________________________________________ __________________________________________________ _________________
*It may be that Practical Sailor is trying to warn us off using silicone as a sealant for polypropylene because it is a "low surface energy" plastic.
Polyethylene is also a hard wax-like plastic. These plastics don't think epoxy is a glue.
And they may think likewise about some synthetic rubbers.
I would scuff non-conforming plastic surfaces and use tape butyl.
But you'll have to leave the fold and find it without Practical Sailort's guidance at a non-marine RV supplier.

If you insist on using silicone use NON-CORROSIVE silicone. It should say something like MANC or NC. Or neutral cure.

[c_amos]

Pure undefiled religion right there brother Ebb!

Keep preaching that!

If the owners of boats I never care to own should choose to use silicone to "stop that leak" it would be unfortunate.

For an A/C owner to do so is tragic.

[ebb]

Silicone is truly evil.
But can it be said that a vinyl polymer, POLYISOBUTYLENE is truly good?
It is, afterall, a synthetic rubber compound - with a petroleum ancestry.

Our other choices besides silicone: polyurethane, polysulfide, perhaps polyether -
all OXIDIZE in time and will stiffen and crack.

PRO:
Butyl rubber "under the influence of heat, vibration, oxygen and ultra-violet radianion"
(In one test butyl survived without degrading 9000 hours in a UV booth.*) will not harden, crack, loose adhesion, crack or flow out of a joint.
Essentially remains permanently elastic. Butyl tape is chemically INERT.
It adheres to polycarbonate, acrylic, abs, stainless steel, wood, concrete and nearly anything else on a boat. Haven't tried it with polypropylene or p.ethylene.
It's self amalgamating: butyl tape combines with itself - self healing. It's solvent free. doesn't outgas.
Resists acids, alkali's and salts. Weather and age resistant. Doesn't oxidize. 20 year life, retains its tack.
Stores indefinitely.
As a tape it absorbs vibration and sound. Moisture and water vapor and air doesn't penetrate butyl rubber. Doesn't get mildewed.
Working with the tape is generally a much cleaner experience than tube apps. The material doesn't smear. Squeeze out can be removed easily and cleaned away with mineral spirit or xylene dampened cloth or paper towel.

CON:
Not an adhesive.
Doesn't come in clear.
Petroleum solvents will attack butyl.
Because it is an ever-sticky seam it does get dirity** (maybe there's a clever way to fix this?)

GOOD isn't perfect.

__________________________________________________ __________________________________________________ ______________________
*the standard longevity (weathering/UV) test in the industry is placing a product to be tested
in a box with UV mercury bulbs. "20 year life" is a tech spec, not a track record.
If you chew gum, it's probably food grade butyl. [I don't want to know!]
__________________________________________________ __________________________________________________ ______________________
**The Surebond SB-140 Skylight & Window Butyl Sealant I have mentioned,
not used yet, but
suggest experimenting with....has all the attributes of the tape version. But has 15 to 30% aliphatic solvent (mineral spirit, paint thinner, white gas, are considered aliphatic or 'weak' solvents.) in the mix - with 1% toluene. We assume, given the product description, that it's OK to use with chemically sensitive plastics like acrylic and polycarbonate.
ALWAYS stays sticky - but skins over. This minimizes dirt but an exposed seam can attract it. Need confirmation.
www.bestmaterials.com
[Just looked at the open tube of Bostik Chem-Calk 300 on the boat. Must have got it locally. have a globby screw stuck in the applicator. When a little is needed,, pull the screw and squeeze. It gets more difficult, and the caulk gets thicker, but it's still usefull after 6 months - or has it been a year??? Label says the contents is polyisobutylene/isobutylene/isoprene copolymer with calcium carbonate filler. Mineral spirits is the ONLY solvent listed.]

__________________________________________________ __________________________________________________ ______________________
Vendor quote: "SB-140....withstands extreme outdoor environments with very long life. Usefull for sealing difficult surfaces and joints. SUPERB ADHESION TO DIFFICULT MATERIALS INCLUDING SILICONE RUBBER AND STAINLESS STEEL....." Best Materials, 10.3oz Tube $4.25
Let's hope West Marine never smartens up.