Mac 26X front window replacement

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Andysigrist
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Mac 26X front window replacement

Post by Andysigrist »

We purchased replacement windows from Blue Water Yachts for our MacGregor 26X. They came with installation instructions that specified to install the new windows with lots of black silicone. While we installed the windows as per instructions, working with silicone was messy and we still had leaks afterwards.

In the end we found a better, simpler and cleaner way to install them is with Butyl tape from an RV store. We laid a 1" wide strip of butyl tape on the window flange, then placed the window on top of the butyl tape and installed the screws (not tight, just snug). No leaks, no mess, and the ability to remove the windows relatively easy again if and when needed.
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kmclemore
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Re: Mac 26X front window replacement

Post by kmclemore »

Yes, I'd imagine that would work quite well. That's what we used to use at Lotus Cars to install windscreens, which in that car were a structural element as well.
macowneril2015
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Re: Mac 26X front window replacement

Post by macowneril2015 »

Andysigrist wrote: Sun May 12, 2019 7:13 pm We purchased replacement windows from Blue Water Yachts for our MacGregor 26X. They came with installation instructions that specified to install the new windows with lots of black silicone. While we installed the windows as per instructions, working with silicone was messy and we still had leaks afterwards.

In the end we found a better, simpler and cleaner way to install them is with Butyl tape from an RV store. We laid a 1" wide strip of butyl tape on the window flange, then placed the window on top of the butyl tape and installed the screws (not tight, just snug). No leaks, no mess, and the ability to remove the windows relatively easy again if and when needed.
I just discovered that same problem but I am going to just seal around the edge with a bead of silicone but I wish i thought of this the other weekend would have saved a lot of headaches.
donraynerjr
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Re: Mac 26X front window replacement

Post by donraynerjr »

Did you happen to take any pictures of how you applied the tape? Also, did you not need silicone at all and no leaks?
I'm wanting to replace my windows, as well. Thanks!
svscott
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Re: Mac 26X front window replacement

Post by svscott »

Although i know it's the old standard, I haven't had great luck with butyl tape (sealing flat glass windows in houses and buildings). It tends to dry out and lose it's seal after baking in the sun.
I highly recommend using Dow Corning 795 instead of just a regular black silicone. The 795 bonds WAY better than most sealants to acrylic or polycarbonate and remains quite stretchy and flexible for many years. Plus it is slow cure so working time is longer and it smells (and tastes) much better than the vinegar smelling regular silicone.
*I don't eat silicone but have many years experience of weather sealing glass and aluminum framing and saliva works well to aid in tooling the finished bead.
When resealing windows with silicone, prep is 90% of the project. Properly clean and degrease with acetone for fiberglass and denatured alcohol for acrylic then dry fit and pre-tape everything (window and frame, inside and out) with 2" painters tape prior to even touching the sealant.
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Re: Mac 26X front window replacement

Post by Inquisitor »

kmclemore wrote: Sun May 12, 2019 8:42 pm Yes, I'd imagine that would work quite well. That's what we used to use at Lotus Cars to install windscreens, which in that car were a structural element as well.
The worked with Lotus part.
Cool!!!! 8)
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kmclemore
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Re: Mac 26X front window replacement

Post by kmclemore »

Inquisitor wrote: Tue Jan 26, 2021 2:49 am The worked with Lotus part.
Cool!!!! 8)
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Re: Mac 26X front window replacement

Post by NiceAft »

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Namideev
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Re: Mac 26X front window replacement

Post by Namideev »

Butyl tape is more expensive than silicone, and its effectiveness depends greatly on the quality. I have always installed windows using silicone and have never encountered leak problems. Maybe you don't have much experience using silicone, or you missed some steps, for example, degreasing glass. I sometimes have to work with car windows as well. At the beginning of summer, I installed a car shade for baby on the rear window so my son could sleep peacefully even on sunny days. Now I'm thinking about getting the same for my sailing boat.
Last edited by Namideev on Tue Aug 23, 2022 5:36 am, edited 1 time in total.
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Highlander
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Re: Mac 26X front window replacement

Post by Highlander »

Namideev wrote: Sat Aug 20, 2022 1:50 am Butyl tape is more expensive than silicone, and its effectiveness depends greatly on the quality. I have always installed windows using silicone and have never encountered leak problems. Maybe you don't have much experience using silicone, or you missed some steps, for example, degreasing glass.
when I had to reseal a front window on my :macm: I deglazed both the fiberglass & plexiglass edges & for ur Info silicone comes in diff grades of use & adhesive strengths for this job u need the highest quality which will b the strongest adhesive strength & will absorb vibration & still flex with boat hull flexing movement without breaking it's seal so do ur homework by checking out each manufacture's spec. sheets , may not b avail in ur local auto or hardware store or marina u may have to go to a commercial establishment & hope u do,nt have to buy by the caseload ! :D :D :D
Butyl tape is usually cheaper to buy at RV stores :wink:

J 8)
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