How To Rebuild a TeaK Overlay Hatch Cover

[RLewis]

Hi- I have a new boat with teak decks and teak in the cockpit. In the cockpit there is a hatch that is ~2ft x 3ft in size. The underside of the hatch lid is a base of marine plywood which is rotted. The top side of the hatch lid is overlayed with solid teak strips that measure about 2 inches wide. They are spaced evenly and about 3/16 caulking in between each row. The hatch lid has a "picture frame" outer border with 45 degree mitered corners. My question is how best to rebuild this. Would it make sense to keep the teak courses in tact and rely on the caulking to maintian its shape and remove the bungs and the screws and then route out or peel out the rotted plywood and once removed and cleaned of debris then cut and fit a new plywood piece? Then rescrew the teak overlay to the new plywood and once in place then strip out the caulking and recaulk. Trim down the new bungs and reinstall the hatch?

Does this make sense or should a person remove each teak strip and rebuild the hatch lid "from scratch"?

Thanks Randy

[Blue Stocking]

If the plywood base layer overlaps the hatch frame, you're gonna have to get that out.
Take it apart and start from scratch.

[atoll]

personally i would scrap the old hatch,recovering the teak if possible.

then build a female mould,and gelcoat and laminate with fiberglass a new hatch.

then with sikaflex glue the teak back on.

if the old hatch is rotted out it should be fairly easy to separate the caulked teak in one piece from the plywood,then once sanded back relay it in one piece on top of the new hatch.

[RLewis]

Thanks for the tips. To be clear the hatch lid comes to rest on a fiberglass surface which is the molded portion of the lazerett. The underside of the hatch lid has as recessed (simple dado cut) area around the entire border that houses rubber weatherstripping for sealing to the fiberglass cockpit opening. The teak overlay is mostly cosmetic and in line with the rest of the cockpit and decks. It will be easy to remove the plywood portion and keep the original shape of the teak outer surface. I think I will attempt the rebuild in this fashion as opposed to making a fiberglass mold. I guess at worse if I botch it I can start from scratch. But I really envision a removal of the plywood under structure and replace with a like size and thickness and of course accounting for the groove to place new weather stripping.
Certainly I am open to any additional thoughts you may have.

Thanks Randy

[casual]

I,have an exact sitituation,How do you build a fiberglass mold.It seem's to me laying mat up on the inside of theexisting hatch will make it too large.As I,said how do you do it.Thank's to all

[atoll]

Originally Posted by casual

I,have an exact sitituation,How do you build a fiberglass mold.It seem's to me laying mat up on the inside of theexisting hatch will make it too large.As I,said how do you do it.Thank's to all

making a female mold is increadibly easy for a hatch as described,
first buy a sheet of melamine faced mdf board,use 4 pieces of pine 2x 4 or larger as the outer edge,place mdf on work surface with shiny side up,screw 2x4 onto it to make outer border of the hatch,and tape wood off with masking tape.
apply release wax to interiour of mold then 2-3 coats of gel coat,then 5-6 layers of chopped strand mat depending on the thickness required.
laminate in battons if an interiour lip is required and additional stiffening.

dismantle 2x4 and lift off from mdf,trim outer lip....voila! one laminated hatch cover,about 3 hours work!

if you look on my avatar under my images there are quite a few photos of this process of stuff i have fabricated in the past.

[casual]

Originally Posted by atoll

making a female mold is increadibly easy for a hatch as described,
first buy a sheet of melamine faced mdf board,use 4 pieces of pine 2x 4 or larger as the outer edge,place mdf on work surface with shiny side up,screw 2x4 onto it to make outer border of the hatch,and tape wood off with masking tape.
apply release wax to interiour of mold then 2-3 coats of gel coat,then 5-6 layers of chopped strand mat depending on the thickness required.
laminate in battons if an interiour lip is required and additional stiffening.

dismantle 2x4 and lift off from mdf,trim outer lip....voila! one laminated hatch cover,about 3 hours work!

if you look on my avatar under my images there are quite a few photos of this process of stuff i have fabricated in the past.

OK I,think I,have it remove old hatch turn upside down surround with board use 2x4 as forms secure with screws apply mold release lay in mat to desired thickness let dry and clean up mess.Sound's doable.One question using battens for stiffening .Do you lay these in the lay up and what do you use?
Many Thanks Dave

[minaret]

Originally Posted by atoll

making a female mold is increadibly easy for a hatch as described,
first buy a sheet of melamine faced mdf board,use 4 pieces of pine 2x 4 or larger as the outer edge,place mdf on work surface with shiny side up,screw 2x4 onto it to make outer border of the hatch,and tape wood off with masking tape.
apply release wax to interiour of mold then 2-3 coats of gel coat,then 5-6 layers of chopped strand mat depending on the thickness required.
laminate in battons if an interiour lip is required and additional stiffening.

dismantle 2x4 and lift off from mdf,trim outer lip....voila! one laminated hatch cover,about 3 hours work!

if you look on my avatar under my images there are quite a few photos of this process of stuff i have fabricated in the past.

Why not use melamine for the side boards as well? And what are you using for a fillet? Without a fillet in the mold you will end up with a part with a 90 degree corner full of voids. Also, if you make the side walls the correct finished height you can green trim the part in the mold and save yourself some work after it's cured. Why only CSM and no WR or DB? How are you determining and achieving the correct camber? Just questions relevant to the problem for the sake of posterity...

[motion30]

the fillets can easily be made with modeling clay

[atoll]

Originally Posted by casual

OK I,think I,have it remove old hatch turn upside down surround with board use 2x4 as forms secure with screws apply mold release lay in mat to desired thickness let dry and clean up mess.Sound's doable.One question using battens for stiffening .Do you lay these in the lay up and what do you use?
Many Thanks Dave

for the battens i normally wait untill the first lot of laminate has cured,then give a quick grind and use gorilla glue to stick in place if it is nessacary for more exact positioning.

as mineret suggested use melamine for the sides as well,and add a fillet.

using woven rovings after a layer of csm also speeds up the lamminating process if you have it(i'm working my way through a 60 kg roll of csm,so buying rovings is out of the question for me)

making an exact mold and trimming whilst curing is also time saving,but you need to watch the cure time(i generally am on cf with a cup of tea ,or on the boat once i have finished the lay up doing other stuff and trim with a grinder once cured)

using the old cover as a template will ensure a correct fit.

happy thanks giving,cheers alex

[minaret]

Originally Posted by motion30

the fillets can easily be made with modeling clay

I like hot wax fillets, but clay is just fine for most users. If you wet it down a little you can make a pretty nice fillet.

[minaret]

Originally Posted by atoll

for the battens i normally wait untill the first lot of laminate has cured,then give a quick grind and use gorilla glue to stick in place if it is nessacary for more exact positioning.

as mineret suggested use melamine for the sides as well,and add a fillet.

using woven rovings after a layer of csm also speeds up the lamminating process if you have it(i'm working my way through a 60 kg roll of csm,so buying rovings is out of the question for me)

making an exact mold and trimming whilst curing is also time saving,but you need to watch the cure time(i generally am on cf with a cup of tea ,or on the boat once i have finished the lay up doing other stuff and trim with a grinder once cured)

using the old cover as a template will ensure a correct fit.

happy thanks giving,cheers alex

Happy Thanksgiving! Do you guys celebrate Turkey Day at all in your neck of the woods?

[atoll]

Originally Posted by minaret

Happy Thanksgiving! Do you guys celebrate Turkey Day at all in your neck of the woods?

no ,the turkey's are safe,happily gobbbling away till just before xmas

[minaret]

Originally Posted by atoll

no ,the turkey's are safe,happily gobbbling away till just before xmas

I'll enjoy some extra for ya!