Generic Spartite equivalent

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Back to Home ... s/v Stella Blue home ... New Rig Page ... Projects

January 2009 --

Back when we rebuilt the rig, I had wanted to put Spartite in.
I never got around to it, and made a dozen custom fit wood chocks instead, then wrapped everything with tape.
It never budged or leaked in seven years, so I didn't mess with it.

Spartite is expensive. After looking at the technical specs for Spartite,
I found a close match at McMaster-Carr,
part number 8644K18. I sat on the idea for years,
but mentioned it to other folks on internet sailing lists.
A few of them have used it, and have reported good results.

We had to pull the rig during my 2008 haul out,
so it's a good time to do this.

I used three cans of it, total cost of $100. Each can is 25 cubic inches.

Technical specs:

Spartite has a hardness of 55-60 Shore D, and this is 94 Shore A.
( Here's a link to a comparison table between Shore A and Shore D.)
Spartite has tensile strength of 4000 PSI, this is 3120.
Spartite shrinks .001 in/in, this shrinks .0005 in/in.

So, Spartite is a litle bit harder, but shrinks more.
I really believe this stuff works just as well.

Back in 2002, after we put the rig back together and had the mast perfectly aligned in the boat, I made this
teak wood trim with LED lights.

It made it really easy to get the spar lined up again, when we restepped it in 2008.

That might sound simple, but my collar isn't perfectly centered in the boat.

Aw, shucks.

I had a few leaks, and just kept
wiping them up with denatured alchohol and
slapping strips of butyl tape over them.

There were no cleanup instructions with the cans of product, so I tried denatured alchohol.
That cleans the stuff off nicely.

I always start with the weakest solvent first,
for health reasons.
Why break out the acetone if you don't have to?

We'll see how bad I screwed up,
and how ugly my mistakes are,
and then can decide how to make it pretty again.

Here's what the collar looks like from the inside.
I replaced it in 2001.

Fortunately, it is a nice metal collar,
about four inches wide top to bottom.
It tapers like a funnel, and is wider at the top than at the bottom. That's perfect for this job.

I smeared petroleum jelly all over it,
and made it thick enough to
fill any stratches or dimples in the metal.

Note the stainless steel tangs, bolted to the mast.

They go up and hook over the top of the collar, and are very important. They keep the deck from moving. There's a lot of stess on the deck at the the bottom of the mast, from the running rig, and when the standing rig gets stressed.
That junction must be rock solid.

The tangs can be part of the plug, no problem. But they'll make this project tricky.

I added one can, and waited for it
to kick off and get thick before adding the other two.

The idea was to try and have a good seal around the bottom before moving forward with the total volume of liquid urethane. The stuff doesn't mass much,
but I have a healthy respect for gravity.

Here's a view from the top, after adding the third can.

Note that I didn't try to fill the collar.
I don't consider this to be a watertight, leakproof solution. This is just to hold the spar in the perfect position.

Don't do this unless you are sure that your mast
is positioned correctly. The rig can be pulled and replaced, but don't expect a watertight seal after that.

So I have a plug that's about three inches thick.

The temperature is about 55F,
and this stuff took about 45 minutes to kick.

Note, I don't care how it looks,
since I'm going to cover it.

We used lines and winches to get the spar lined up in exactly the same place.

This isn't pretty.

Hopefully, having some petroleum jelly contaminating the tape isn't going to make it leak.

It's clamped down hard,
at the top and at the bottom,
with big hose clamps.

(Note: Two weeks later, it rained hard and this leaked.
I should have cleaned off all the
vaseline before installation.
Oh, well.. do it over.)

It's really important to build a good dam around the bottom of the collar. Like, really imporant.
Big time important.

Modeling clay is normally used, but I had a bunch of butyl tape sitting around, so I used it. What the heck. It was either use it, or throw it away, since I'm moving onto the boat and cleaning out the garage.

I tried to make a good seal between the stainless ears and the mast, but for extra insurance I sealed down along the stainless tangs. It won't really matter if they get
glued to the mast.
I should have spent some time
with a good solvent to
remove excess vaseline.

I've never believed that
Spartite is a good way to keep water out.

I believe that the plug replaces chocks,
and should still have a watertight boot on top.

I used this stuff before, and it
worked without a leak for seven years.
You just wrap it around and around, and it seems to weld to itself and create a solid rubber boot.

Of course, that's assuming
you don't have petroleum jelly all over the place.
I should have cleaned up better before applying it, but the sun was going down and it's going to start raining in a few hours, and I'm rushing.

The slot in the mast is plugged up with Lifeseal.

Marine Silicone works just as well,
but I had an open tube of Lifeseal.

The old plug was fine, so I scuffed it up
and spewed on it.

I made this Sunbrella thing, years back.

It fit a bit better before I added the rigid vang.

I wanted the vang bracket as low as possible on the mast, and figured that a few wrinkles in the Sunbrella cover wouldn't really bother me.
I was right.

As I recall, the last time this bothered me was the last time I thought about it, six years ago. I'm sure it will be fine in the future.

I resewed it while the rig was apart,
adding Goretex thread just for the heck of it.

The next day,
it's time to take a good look
and see how big of a mess I made.

This picture has contrast and brightness
turned up high, so that detail is visible.

Butyl was not easy to get off, and I want to emphasize that I only used it because I had it sitting around and was about to throw it out. Modeling Clay is the traditional tool for the job, and would probably have been easier to deal with. However, the butyl did a great job
of sealing up leaks in progress.

Some of the butyl is permanently
bonded to the urethane compound.
I'll bet that happens with modeling clay, too.

Note how the urethane leaked down the stainless steel tang. I'm glad I covered everything with butyl. It all came off easily with a putty knife, although you can see the urethane bonding the tang to the mast.
That's no big deal. I can still pull the rig.

Cool. Now I can start putting this rig back together.

So, in a few days, it will be painted up pretty and I'll have the teak trim reinstalled.
Maybe I'll add a picture, later, if I think of it.

The other side was really ugly, because I had big time leaks around the tang.

So, it looks like I'll have to do a little sanding and repainting.

No big deal.

Butyl cleans up easily with mineral spirits,
so I'll melt away the excess,
rough it up, and paint.

One thing of note: Where the urethane hit the mast, it seriously bonded, and removing it lifted the paint. However, the paint only lifted from the Zinc Chromate primer, not down to the aluminum. That's great.
I am very glad that I primed my entire rig with a thin layer of sprayed Zinc Chromate.
Zinc Chromate primer is soft, and gives way.
All over my rig, every ding and scratch only fails down to the primer, not to aluminum.