Replacing Windows & Hatches – Glued Windows

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Since we presented a 'recipe' for gluing windows back into later Mark III's, IV's and V's using methacrylate (the original material), Sikkens has introduced a bonding agent ('glue' doesn't seem quite the right word) specifically intended to fix hatches, Sikaflex 295 UV and associated cleaners and primers, and it seems an obvious candidate for fixing our portlights. As noted on the first page of this section, a hatch-fix in 2007 and a small and large-portlight-fix in 2008 indicate it's a durable solution – not yet up there with the 20+ years of methacrylate, but encouraging. Moreover, it's inexpensive in dollars and hassle. True, the preparatory work is time-consuming but no special applicator is needed, Sikaflex is widely available and the material costs are quite reasonable.

This page provides photos taken by Josh Hynes of Betty Boop when he did his windows in August, 2009.

Portlight with lens out
Cleaning up the surface
Lens ready for insertion
Initial fit
Secured in place
Inside – initial fit
The goal – outside
The goal – inside


"No tricks here – just elbow grease and money. Persistence was key as the old adhesive will come off. The right tools help, too.


  • Windows – plexiglass bronze. All 4 windows plus labour and tax, C$192. Source was Plastic World (see Links & Contacts) with 24 hr. turnaround!
  • Sikaflex – $20/tube (2 required), primer sticks $3/tube (3-4 required depending on efficiency) from Noah's (see Links & Contacts).
  • Framing – approx. $20 at Home Depot.
  • Cleanup –  an X-acto knife and a window paint-remover blade are very helpful when removing excess exterior Sikaflex from the window frames.


  • A Dremel tool with the handheld attachment and a grinding disc was invaluable. 80-grit on a hand detail sander helped too. Two discs and ten sheets of 80-grit were consumed.
  • Framing – I'm not entirely convinced it was necessary as the Sikaflex begins to set the windows within 10 minutes. Pushing the windows into the frames with your fist and squeezing out excess works best and the windows don't move. Frames tended to push the window down slightly.


  • Windows (remove and grind out) –  6 hrs.
  • Set-up (taping windows, frame) – 4 hrs
  • Gluing windows – 1 hr.
  • Cleanup (removing excess Sikaflex) - 1 hr.

An easy 2-day job!"

– Josh Hynes,
Betty Boop, #942
Etobicoke Yacht Club, Toronto

Postscript: Seven years later, the windows are still watertight and "holding up perfectly:".