Silicone, again

If you've been reading this blog for a while, you might remember my declaring my absolute hatred for silicone rubber.  Our Previous Owner loved the stuff - he slathered it everywhere.  He even used it to glue stuff to Eolian's vinyl headliner.  I removed the various things, but try as I might, I was unable to remove the silicone from the vinyl without damaging it, creating a bigger problem than I was solving.

Years went by.

And then Drew reviewed a product: Re.Mov.It, aka DSR-5.  (Sorry Drew, I can't find the reference in your blog)...

I ordered some:

Holy cow!  This stuff actually works!

OK, it doesn't actually dissolve the silicone (I don't think anything would do that). But what it does do is soften it and swell it, making it easy to scrape off.

I applied it using the end of a paper napkin, wiping it on the silicone over and over.  And then I lowered my thumbnail and continued to wipe back and forth, scraping the silicone as well as wetting it.  The silicone came right off!

I need to mention again that previously I had actually reached the point of damage to the naugahyde headliner in trying to remove the silicone...  and now it's gone!

If you have a Previous Owner like ours, you need this stuff!

Silicone, again

Ratty Port Replacement

One of two failing ratty fixed ports

Last summer while doing gelcoat repair, I mentioned that the ratty fixed ports on Eolian's aft-facing cabin house were long overdue for replacement. Well, now is that time.

Even Plexiglas eventually falls prey to the relentless UV from the sun, tho it lasts far, far longer than Lexan - this port is 38 years old.  If it had been polycarbonate, it would have looked much worse after only 5 years.

Tho there are no leaks (yet!), the bedding is overdue for replacement, as well as the port.

Removing the port was easy.  Back out the screws on the inside, and then push it out.  No, that bedding was definitely NOT firmly holding the port in place.  Tho it was clearly not leaking, there appeared to be no reason for that except for habit.

The next problem was that the new port is a little larger than the old one (well, I guess that's better than the reverse...).  First I taped over the entire area with some white duct tape I had on board to protect it from the vibrating sabersaw table.  Then I used the outer trim ring of the new port as a stencil, and marked a cut line.  My trusty (but crummy - I gotta get a better one) saber saw with a grit-edge blade cut thru the 1" thick sandwich of fiberglass, foam, fiberglass with relative ease.  To constrain the mess, Jane was  inside with a shop vac positioned to catch the dust and chips.

(Note to self:  Next time, just tape some plastic over the inside and clean up afterwards - that will be more effective and easier.)

The new opening port is a little larger than the old one.

Before the final installation, one more step was necessary.  Because we often sit on the back deck and lean against the bulkhead that has this port (and a second one, which will also get replaced), it was necessary to trim the spigot to a minimum projection - for comfort.  So I installed the port, held the trim ring in place, and traced around the projecting spigot with a ballpoint pen.

Then I removed the port and laboriously cut off the extra spigot length with a hand hacksaw (the same one I used to cut the exhaust hose...).  I preferred to use a hand tool for this job because, tho it cut slowly...  it cut at a speed that permitted me to maintain a uniform 1/8" from the pen marking.  After cutting, I used a fine file to smooth off the saw cut markings, and break the resulting sharp edges slightly.

Trimmed and ready for final caulking

Before final installation, I carefully sealed the exposed foam core in the opening with the same silicone that Beckson requires for bedding the port*.  If there was any leakage in the future, I didn't want it to get into the core.  Then I injected silicone into the gap between the port and the deckhouse, and smeared a little on the back side of the trim ring.  Press the trim ring into place, some clean up, and it is done!

Now, one more to go, and then all the fixed and opening ports on the boat will have been replaced, giving us a total of 11 opening ports.

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* I hate the use of silicone on a boat, but this is one of the few places that I will use it.  In this case, it is because Beckson specifies it.

Ratty Port Replacement

PO Recursiveness

In the past I have repeatedly referenced the Previous Owner with some disdain.  In fact I have attributed most of the problems we have dealt with aboard Eolian to the Previous Owner. 

However, astute readers of my previous post will have noticed something:

• I whined about the use of silicone rubber as caulking under the caprail
• I last exposed the caprail to daylite in 1998.

Yes, embarrassingly,  it is true.  That was me - I put that silicone rubber there.  I have become my own Previous Owner.  If you own your boat long enough, this is inevitable.  You will eventually have to face your own repairs, made by a younger, less experienced version of yourself.

In the 16 years we have been responsible for Eolian's care, I have learned some things.  No, that's inadequate.  I have learned A LOT.  And the inappropriateness of silicone rubber is one of those things.  While I may have whined about our Previous Owner using silicone rubber for simply everything (liquid duct tape?), I was guilty of bringing this nasty stuff aboard too.

But that is one of the purposes of this blog - to keep others from making the mistakes I have made.

Learnings:

• Leave the silicone rubber ashore (except where explicitly required - by Beckson for installation of their ports for example).
• Hubris can result in embarrassment

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Years ago when I was a kid, I used to read Flying magazine. I particularly enjoyed a long-running series of articles entitled "I Learned About Flying From That." Each article was written by a pilot, who humbly admitted to having made a mistake, and then having lived, told about it in the hopes that others would not have to make the same mistake. I thought then that it was a good format, and I still think that now. This series of postings is my attempt to recreate that article series with a new subject and new technology.

(If you would like to help others to learn from your mistakes, please send your article to: WindborneInPugetSound at gmail dot com)

PO Recursiveness

Tip tip

Have trouble with polysulphide, silicone or 5200 curing in the tube tip between uses?  

Here's a tip: wipe the tip clean before you snap the cap back on. See that thin ridge that goes around the tip?  That is supposed to seal with a mating groove inside the cap, making a *snap* when you push it on. 

None of the compounds I listed above "dry" - instead they harden by reacting with water vapor present in the air.  And the reaction is designed to propagate over significant distances of the material, so that thick layers will cure all the way thru. Therefore if there is a continuous layer of material reaching from outside the sealing ring and past it into the tip interior, the reaction will proceed into the tip and then eventually into the tube itself. 

Thinking of this as if the tube were filled with polyester resin, and the air was saturated with MEK peroxide catalyst will give you a clearer picture perhaps. 

Just before the final capping, extrude some of the contents, flushing the end bit which has been exposed to moisture. Then thoroughly wipe off the tip and install the cap. You'll be surprised at how little in-tip curing there has been the next time you need to use the material.  

Tip tip

Silicone rubber - Just Say NO

I despise this stuff.

No, that's not a strong enough word - I HATE silicone* rubber.  There, now I feel better.

It's a weak adhesive.

It cannot be sanded.  Or painted.

Nothing sticks to it - not even silicone rubber.  Except dirt.

If you have ever used it on a surface, that surface is almost irretrievably contaminated.  The only certain way to decontaminate a silicone fouled surface is to remove that surface, by sanding, sand blasting, etc.

Eolian's previous owner loved the stuff. 

I can think of only three places on a boat where silicone rubber is called for:

• There are some plastics that cannot tolerate contact with polysulphide, polyether or polyurethane adhesives or sealants.  Where the manufacturer (notably Beckson, for their ports) requires it, you should use silicone rubber.
• Lubricating/sealing head hose during assembly.  Apply a coating to the inside of the hose end, carefully heat it with your heat gun until both the main body of the hose and also the stiffening spiral have become soft, and assemble.  Get the hose clamp on while the hose is still soft if you can.
• Making non-skid rings on the bottom of dishes, serving bowls, etc.  Put down a piece of wax paper, run a bead around the bottom of the dish or bowl and set it on the wax paper.  When the silicone is cured, peel off the wax paper and voilà! - a nonskid dish.

Anywhere else on the boat that you think you might use silicone rubber, polysulphide is probably the correct choice.  You might possibly know polysulphide by its other name: BoatLife Life Calk (yeah, that's how they spell it).  Another choice could be a toned down polyurethane, like 3M-4200  (but stay away from the full-blown stuff - 3M-5200, unless you intend for the installation to be permanent).

Now put down that caulking gun and step away from the boat!

* A little definition is in order.  Silicon (note the absence of the trailing 'e') is a silvery metallic substance - here's a picture of a piece I have on my desk right now:

I should know - I used to work in a manufacturing facility that made the stuff, starting with quartz.  Silicon is the basis for most semiconductors made today, albeit in a more purified form than that chunk on my desk.  It is also dissolved in copper along with other stuff to make silicon bronze.

Silicone is a term that is used to refer to a whole series of compounds based on silicon, in much the same way as the term carbohydrate or hydrocarbon are used to refer to a whole series of compounds based on carbon.  Silicone rubber, silicone grease, silicone oil (in silicone breast implants - not silicon, Heaven forbid!) are silicon compounds.

Sadly, the press seems to use the terms more or less interchangeably, indicating that they have no idea what they are talking about.  But then I repeat myself.

Silicone rubber - Just Say NO