Monday, June 26, 2017

Reclaiming The View

If your boat has Beckson ports, or any ports which feature polycarbonate (Lexan) lenses, then if those ports are more than a couple years old, they are turning brown and hazy.  Lexan does not do well with UV exposure, but it is used for port light applications because it is easy to injection mold.

For years, I have been removing the affected port lenses (That's what Beckson calls the transparent part) and laboriously rubbing them out with Meguires compounds (#17 and #10).  It helped, but it was a losing battle - the brown coloration was going deeper and deeper into the outside surface of the lenses.

Well, it turns out that that auto manufacturers like that easy injection molding too, and so on all modern cars, those clear headlight covers are also Lexan.  And they too turn brown and hazy.  Now, a product to address boat ports is a lot less likely than one aimed at auto owners trying to refurbish their headlights, and, no surprise,  several companies have met that need.  I trust 3M:

So I bought one of their kits.  It has a velcro disk that is to be chucked in your electric drill and a number of abrasive disks.  It also has a rippled sponge (it's the orange thing in the package picture) and some fine rubbing compound in a pouch.  There is also a wax, but I didn't use it - see below.

So here's what I started with.  You can see how the UV has attacked the plastic, except where the gasket had protected it around the edges.  It's brown, and it's hazy.  The kit first has you go after the surface with a 500 grit disk.  They suggest doing it dry, but the disk materials are all waterproof, so I did it wet - this has the advantage of keeping the dust generated by removing the surface layer suspended in water and keeps it from clogging the sanding disk.  Just sprinkle on s few drops of water.  And boy, did it make a terrible-looking brown slurry out of that decayed Lexan.

After 500 grit
I wiped off the slurry and changed to the next finer disk:  800 grit; I also did this one wet.  And the slurry this time was white - I got all the brown off with the 500 grit!  Now, the purpose of each successively finer grit used is to remove the scratches made by the previous grit, so after the 800 grit treatment, all the 500 grit scratches should be gone.  After wiping off the slurry, I found that I had been a little too impatient and needed to go over the surface again.

After 800 grit
Next on the agenda is 3200 grit.  This time the kit wanted it to be used wet, so, not breaking stride, I used water again.  Same drill - remove the 800 grit scratches.  It's starting to look clear!

After 3200 grit
Finally, after wiping down the lens again, I put on the sponge disk and applied a little rubbing compound to the lens.  Then, scrubbing it around a little so that it wouldn't spray all over the place when I keyed the drill, I turned on the drill and went over the surface a fourth time.

After compounding
Wow!  It's good, but...  So I got out the Meguires and used the #17 and the #10 on it.  This was way easier than in years past because all the hard work had already been done by the drill.

Much better!
Well, it's not quite like new, but this port is much, MUCH clearer than it has been for years.  I suspect that the remaining haziness may be in depth in the plastic.

The whole process took a couple of hours to do four ports, including the time to unmount and remount the lenses...  that's less time than I would have spent doing one port by hand, with more mediocre results.  And a tired arm.

The directions want you to have a medium speed drill, and I would second that.  You definitely want to use a variable speed drill, running at a moderate speed.  One of those single speed drills will turn so fast that heat generation will be a problem (especially if you follow the directions and do it dry...  don't do that).  It is also important to tightly control the drill so that less than half of the disk is in contact with the surface.  If you try to hold it flat, it will inevitably spiral out of control, and then you will likely gouge the surface with the edge of the abrasive disk.

Would I recommend the 3M kit?  Absolutely.  Even for your car.



Anonymous said...

Hi Bob,

I used the exact same kit on a large Bomar hatch and got similar results. Unfortunately, it only bought me about a year before noticeably degrading again. It's not as bad as before but I think the accumulated damage in the bulk of the material greatly accelerates the decline of the surface.

Good tips on technique. I didn't sand wet in the initial steps and I didn't follow up with the plastic polish. I'll try it again with your improved technique.

Kyle said...

Did the 3M kit come with a UV protectant or sealant? Sounds like you didn't use the wax, did you protect them with something else? Just curious, thanks!

Robert Salnick said...

Anon -
I don't have any Bomar hatches, but I thought the glazing They used was acrylic... well, I learn something new every day.

Robert Salnick said...

Kyle -
Yes I did follow up with a final coat: Meguires #10 is a sealer/wax/polish

Drew Frye said...

The first time I tackled the Bomars, it was as you describe. Now, I give them a light compound (just a few minutes each) and wax each spring to maintain. I bought a cheap Harbor Freight 6-inch buffer just for hatches, and it has been well worth it. If I were going to buff the whole boat it would probably burn up, but for windows it's fine.

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