Replacing acrylic in top side ports

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richie30's picture
richie30
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Replacing acrylic in top side ports

I have somebody in town that can cut new Acrylic for our top side ports. Has anybody ever replaced their own? They said if I bring in the old ports they will take out the old and replace it with acrylic but they do not do the caulking around the edge. Not sure if anyone has tried it and if they met with success. Thanks, Rich

Rich

Richard & Joan Bain
PAZZO Hull#1670
1997 Catalina 36 MK11
Bayfield, Ontario

My Day Job Below
www.richardbain.com
www.bineapress.com

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dlincoln3
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Are you talking about the large deadlight fixed ports, the fixed ports in the sides of the hull, or the opening hatches on deck?  I have replaced all but the fixed hull ports.  The method is basically the same for the deadlights and the opening hatch lenses. 
(1) Use a spray compound like "Debond Marine Formula" and spray it around the old caulk/sealant to break the adhesion. Let it soak for 15 minutes or so. 
(2) Pry the old lens out with a putty knife and screwdriver. 
(3) Clean all of the old sealant off of the from with the Debond spray and a razor blade. 
(4) Wipe off the clean frame with acetone to remove all of the Debond spray. 
(5) Lay down 3M VHB double-sided foam tape in the frame.  This is what will hold the new lens permanently in place.  There are different widths and thicknesses of this tape.  I recommend VHB 5952 in black. 
(6) Remove the paper from the "inside" surface of the new lens.
(7) Put masking tape all around the outside of the frame.  The purpose is to make sure there is only 3/8" wide bead of caulk, so the tape keeps you from gooping excess sealant all over the frame.
(8) Peel the backing off of the top surface of the VHB tape to expose the adhesive.  This can be difficult because it doesn't want to peel off easily.
(9) Carefully place the new lens into the frame and onto the VHB tape.  You only get one shot at this so be precise.  The VHB is tenacious.
(10)  With a caulk gun, lay a very heavy bead of Dowsil 795 black sealant into the groove between the lens and the frame.  Lay it on heavy and smoosh it deep into the joint with your finger.  I usually make a couple of passes around the joint with the caulk gun just to make sure there's plenty of sealant in there. When the whole joint is covered, run your finger around the joint to smooth it over and flatten any excess sealant.
(11)  Carefully peel off the paper backing from the new lens.  I suggest starting a corner of it somewhere before you caulk, because it can be hard to get a corner started once the caulk is on.  Also pull off the masking tape.  I do this when the adhesive is still wet so you don't damage the adhesive seal by trying to rip off cured sealant.

I have attached a PDF with some photos of my salon hatch replacement that may help.  I replaced that lens about 3 years ago or so, and it has been leak free.

Thanks,
Don Lincoln

Don Lincoln
"Nancy Lynn"
1993 Catalina MK1.5, Hull 1238
LaSalle, MI (Lake Erie)
Universal M-35AC

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richie30's picture
richie30
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Thanks Don for this detailed post which will help me very much. Also, thanks to all the others who added good information to the post. Don I'm just across the river from you in Sarnia. Take care, Rich.

Rich

Richard & Joan Bain
PAZZO Hull#1670
1997 Catalina 36 MK11
Bayfield, Ontario

My Day Job Below
www.richardbain.com
www.bineapress.com

rstonge
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Posts: 67

Don,

​​​​​How did you cut the lexan? Did you use a router?
 

Ron St. Onge

1995 Catalina 36 MKII Hull 1384

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dlincoln3
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I used a jigsaw with a plastics blade in it. No issues. 

Don Lincoln
"Nancy Lynn"
1993 Catalina MK1.5, Hull 1238
LaSalle, MI (Lake Erie)
Universal M-35AC

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Peter Taylor
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Posts: 107

Great information Don.
Thanks very much.
Can you tell me how thick was the Lexan sheet you used

Peter Taylor Melbourne Australia. Altair  #2227 2005 C36 Mk11

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dlincoln3
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If we're talking about the deck hatches, I ordered 3/8" thick acrylic in "Gray 2064" from eStreetPlastics.com.  The Gray 2064 color was recommended to me by Catalina Yachts as being the tint that they used in all of their ports and hatches.  The large deadlights are 1/4" thick, but I ordered those pre-cut directly from the parts dept at Catalina Yachts in Florida rather than cutting those myself.  They have a bevel around the perimeter of them that needs to seat precisely into a mating bevel in the cabin side openings, and I felt that it was a little too difficult for me to try to cut accurately with a jigsaw.

Don Lincoln
"Nancy Lynn"
1993 Catalina MK1.5, Hull 1238
LaSalle, MI (Lake Erie)
Universal M-35AC

rstonge
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Does anyone have an opinion on using lexan (polycarbonate) vs. acrylic (plexiglass)?

Here is a source for polycarbonate:
https://www.ebay.com/itm/174064270120

 

Ron St. Onge

1995 Catalina 36 MKII Hull 1384

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dlincoln3
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I used to be in the commercial lighting business, and light fixtures were typically available with both types of plastic material.  Polycarbonate was stronger (impact resistant), but was very sensitive to UV exposure from sunlight.  After a couple of years of exposure to sunlight, the lenses would start to turn yellow and become brittle.  Acrylic was not as tough, but was basically impervious to UV exposure if it remained below 80°C (176°F), which on a boat is obviously not a problem.

Don Lincoln
"Nancy Lynn"
1993 Catalina MK1.5, Hull 1238
LaSalle, MI (Lake Erie)
Universal M-35AC

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Sojourn
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Posts: 171

Here's link to a comparison for the two materials.  UV resistance favors acrylic.

Lexan vs. Acrylic - Discover the Difference Between Lexan & Acrylic | A&C Plastics (acplasticsinc.com)

Lou Bruska
Sojourn
1985 C-36 Mk-I TR #495
Eldean Shipyard
Lake Macatawa (Holland, MI) Lake Michigan
Rallyback@comcast.net

rstonge
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Posts: 67

Looks like Acrylic is the way to go.  Thanks for the help.  Much appreciated!

Ron St. Onge

1995 Catalina 36 MKII Hull 1384

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KevinLenard
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Posts: 215

Not sure how relevant this still is, but when I did this replacement on my old Mirage 26 I was told that there is only one version of Sikaflex caulking in black that will bond to BOTH acrylic and fiberglass.  More expensive, but did the trick.  From Sika: "Used as a system, Sikaflex® 295UV and SikaPrimer® 209 provides very durable adhesion to plastic (acrylic or polycarbonate) windows."

Kevin Lenard
"Firefly"
'91 C-36 Mk. "1.5" Tall Rig, Fin Keel, Hull #1120, Universal M-35 original (not "A" or "B")
CBYC, Scarborough, Lake Ontario, Canada

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