WHAT TOOL DO I USE?

[zengirl]

I am going to replace windows in the next few weeks. I don't want to use screws like in the picture. Can I just use a good sealant and what brand do you suggest? (not 3m5200). Also, I want to get rid of that blue gelcoat and the crazing. I read somewhere there is a planing tool to strip it with. Do you know the name of one that will do the job? Thanks for all your input.

[Muaddib1116]

I think some people have had good results with 3m VHB tape, or a combination of VHB tape and sikaflex. I'm not sure the recommendation is to not have any mechanical fasteners though. As far as the blue gelcoat, the planing tool I've heard about is designed to take the gel coat off entirely, down to the fiberglass. If that blue is just a surface layer on top of the white gelcoat, I think you'll have better results sanding it.

[JPA Cate]

@zengirl,

There is Sikaflex that is used for glazing huge window panels on skyscrapers. You can probably get it at a place like Home Depot. However, with your port lights (windows), I would anchor them with screws as needed while the goop sets up.... Drill the holes way oversize. If you're replacing with acrylic panels, their expansion is 25%, which is why you need serious clearance holes. It is the too small size of the clearance holes which has led to the cracking. You might also consider making shade cloth covers for the acrylic and never use ammonia based cleaning products on it. Pressure snaps for attachment.

Your gelcoat cracks and especially the chip out of it makes me think there has been a lot of flexing there, and I am not knowledgeable enough to say what the best way to deal with it is. You need to address first the flexing, then the cosmetic issues. I would talk to someone friendly who does fiberglass repairs. Don't be surprised if you do have to plane off the gelcoat and repair with epoxy and fiberglass to stiffen up the area.

Ann

[Don C L]

I have even older gelcoat crazing and what I did was first blast it with a high pressure sprayer, that took off the loose pieces, then I filled it all back in with MarineTex epoxy putty. There are similar epoxy putties that are less expensive, like West Marine's. Then I sand and fair it for priming. There is a local guy here who does it that way for gelcoat repairs. I have also heard of giving the larger areas of deep crazing a coat of epoxy, but that wouldn't really work for vertical surfaces. This all assumes you will be painting, perhaps you'd prefer not to.
Removing the gelcoat and then replacing it seems like a huge job to me if not necessary. I saw a boat where they did that to the house and all I could think was, why? It was a big job. Now the hull when there are concerns about blisters, ok, but up on top I didn't see the logic, but maybe I'm missing something.
There are some threads dealing with bonding windows with butyl rubber without screws and other techniques but I don't have time to find them right now.

[coopec43]

My understanding is that butyl tape is just a sealant?.

When I installed the windows in my yacht I used toughened glass glued in with the same sort of adhesive that they use to secure automotive windscreens in place.

I held the window in place overnight with cloth adhesive tape then in the morning I masked 10mm out from the edge of the window and used my thumb as a tool to put a bevelled edge on the adhesive

Anne says to hold the window in place with screws. That should be OK too as the screw holes would be covered by the bevel edge of the sealant

[Benz]

Use a sander and 40-grit to get rid of the blue. Once you've sanded the crazing out, just fair, prime, and paint.
I wouldn't trust an acrylic panel just surface-glued to the rim to hold; better to use screws with oversized holes like Ann suggested. I'd also use a big-ish washer to spread the load.
Also don't be afraid to use 5200: it's what I would use in that place.
As long as you're grinding and doing glasswork, you could take the old windows and use them as a mold to make a fiberglass rim that would screw to the cabin side and hold in the new panels. That way the new windows would have a positive clamp holding them on. It would require someone who knows a little about glasswork, but it wouldn't be difficult or require too much material, nor even take as long as it will to get that blue crazing out.

[marcjsmith]

Zen, I used the 3m VHB tape on my moody. I just replaced the windows this past season.


here are a couple pics. and a few talking points.



https://www.cruisersforum.com/forums...se-248978.html post 15

[LittleWing77]

Hey Zen,

Here's a great resource if you don't already know it:

Marine How-To
Installing New Port Lights
https://marinehowto.com/installing-n...ls-portlights/

While it's not your specific project, I'm sure Rod will have useful tips, as he always does.

I would stay away from 5200...you don't need to create more long-term problems for your boat. As the discussion indicates here, and also in the thread Marc Smith posted above (Post #7), "it [the sealant] needs to seal and be flexible."

Good luck!
LittleWing77

[deblen]

https://www.youtube.com/watch?v=MQyjxVUskd8

[George DuBose]

I am using 3M VHB to bond 1/2" Lexan on the exterior frames and the butyl rubber tape to fix the exterior frame to the cabin top. I will run a bead of Sikaflex between the Lexan and the cabin top.

After battling portlight leaks for a decade, I am hoping that this new to me technique will work.

I am aware of the fluxuation in the Lexan due to heat and I am pretty sure that the VHB can keep hold of the Lexan, I am not worried about the butyl rubber tape holding, I just hope that the Sikaflex stays stuck.

Originally, I wanted to make storm shutters out of the Lexan. I just removed the 3/16" safety glass that was cracking and the vinyl layer was fogging.

[sinnerman]

Try using a 3m rubbing wheel on a drill to remove the stripe.

Maybe also try heavy duty oven cleaner (wear gloves).

https://www.amazon.com/Stripe-Wheel-...21021261&psc=1

[zengirl]

Originally Posted by sinnerman

Try using a 3m rubbing wheel on a drill to remove the stripe.

Maybe also try heavy duty oven cleaner (wear gloves).

https://www.amazon.com/Stripe-Wheel-...21021261&psc=1

haha I tried easy off! Didn't do a thing to it. I tried 40grit sanding, didn't touch it. I'll look into the wheel, thanks.

[zengirl]

Thank you all for such good advice. Have a lot to think about, but am very excited to get started!

[Don C L]

Remember you don't have to remove the blue gelcoat to prepare it for painting. Once divots are filled and faired and it is sanded, a good primer will work wonders. I'm using a polyurethane enamel so I am using Pre-Kote, a one part primer and even that is very good at filling and covering. The two part primers are even better.

[Clivevon]

"Also, I want to get rid of that blue gelcoat and the crazing. I read somewhere there is a planing tool to strip it with. Do you know the name of one that will do the job? Thanks for all your input."

You do not strip crazed gelcoat. You paint it - after proper preparation & priming of course.