re-coring questions

[stephen]

I had a delamination around the mast and cut it open this morning. I have two questions:

1. I removed all of the wet balsa and now have a 3 in. lip around the mast hole. I need the 3 in. lip to feather in the repair. Any hints on how to slide the balsa in and make sure there are no voids, while avoiding any overheated epoxy issues?
2. Aft of the mast is a hatch. I would like to pull the hinges and re-bed them while I am doing all of this. Does anyone know if Morgan bedded threaded plates or nuts under the deck (nothing visible down below)? Haven't gotten up the nerve yet to pull the screws to see what happens.

Thanks

 

[terry_thatcher]

most of us that have not replaced them have old aluminum Bomar hatches. The frame is screwed to a plywood core, not through bolted. You have a hatch I do not recognize. My mast also is surrounded by plywood core, not balsa, but I have a 1979 382.

 

[stnick]

From what i know the balsa comes in small squares mounted to a backing of netting. So it can conform to a bending deck . A West slow drying epoxy should do the trick . I would ask Jeff he is the expert .

 

[svpilgrim]

What model / year Morgan 38?

I recommend the use of Plascore rather than balsa when you recore the decks.

Per controlling the cure time & heat generation. Cool, cloudy weather is best time to do this type of repair. If that is not possible, then I suggest...

• Use slow cure or tropical cure catalyst
• Create a shade tarp over area you will be working
• Use bottles of cold water or ice atop project area where possible
• Cool the cabin with air conditioning or fan blowing across ice block.

#1: Do the small diameter holes around the mast partners pass through the entire deck or just extend into the core material? My guess is just into the core.... If yes, then...

• Carefully drill out holes around mast partner to the largest size possible w/out boring into the side wall of the partners or thru the deck below.
• Cut and dry test fitting your core material so that you can slide as much new core material as possible in under the flange around the partners.
• Ok now have all your epoxy, thickeners, syringes, spreaders, cleaners, etc. ready to go. You will likely need to work quickly once you begin.
• Use syringe and brush to push epoxy thickened to honey consistency (or a bit thicker) under flange.
• Slide pieces of core into position. Hopefully you will get some squeeze out from holes. Squeeze out is a good sign.
• Hopefully you kept the top skin from the deck and can epoxy it back down using thickened epoxy at this point. Do not worry about scarfing the deck joint this will be done later.
• Now back to the small holes... using a syringe fill any voids with epoxy thickened with a mixture of cabosil & microfibers. Keep filling until you see epoxy beginning to come out of adjacent holes. Then go onto next hole. Keep going until you visit all the holes at least once. This process may take several rounds if large voids still exist.
• Monitor for overheating.
• Once assembly has fully cured (24 hours) then use a grinder to create a 4" to 6" scarf around joints on deck.
• Fill scarf joint with fiberglass cloth until even with original deck.
• Allow to cure (24 hours) grind down scarf joint.
• Cosmetically fair area.

#2: I would guess, if no hardware is visible from below, that the center hatch screws are simply threaded into the balsa core. Remove them and replace them with machine screws that pass thru the entire thickness of the deck. Use a hole saw at least 1'2" larger that the OD of the fasteners you intend to use (i.e. 1/4" fasteners will require a 3/4" hole) to drill out the existing hole. This will serve to remove any nuts that may be embedded in the deck. Used duck tape to seal the underside of the hole. Now fill the hole with epoxy thickened with a combination of micro-fibers and cabosil. Once cured... redrill the holes for the thru deck fasteners. This system will prevent future issues with wet core.

Hope this is helpful...

Lots of info. Let me know if you have questions...

 

[stephen]

Jeff,

She is a Morgan 35.


The partner bolts pass completely thru. I was going to repair then drill out and create epoxy plugs for partner bolts and hatch bolts. The approach of doing this along with re-coring makes sense. Should help in making sure all the old core is gone as well as prevent gaps in new core.

Thanks

 

[svpilgrim]

Jeff,

She is a Morgan 35.


The partner bolts pass completely thru. I was going to repair then drill out and create epoxy plugs for partner bolts and hatch bolts. The approach of doing this along with re-coring makes sense. Should help in making sure all the old core is gone as well as prevent gaps in new core.

Thanks

Agree that thru bolting with epoxy plugs is the best method. Use duct tape (epoxy will not bond to either face of duct tape) to seal the under deck holes at the mast collar. Should be able to squirt enough epoxy through enlarged top holes to avoid the need to go back and drill / refill a second time.

Thought a more about drilling out the holes for the hatches, and need to add a bit (pun intended) of instruction... If you do discover a nut buried in the deck core, then using a hole saw is a good method for removal. Use a hole saw with a short arbor bit (drill bit in center that serves as a guide). Hoefully you can find an arbor bit that extends 1/4" beyond the hole saw. Place the arbor bit in the hole for the existing fastener. Slowly start drilling. Once hole saw bit has created a 1/8" deep cut in the outer fiberglass skin, then remove the arbor bit. Carefully restart the cutting in the 1/8" deep kerf . The hole will guide the saw through the remaining material and around the buried nut.

Jeff

 

[stephen]

Jeff - thanks for help. Almost implemented it this weekend but got derailed by weather and business travel this weekend. Will let u know how I make out when I can get the time/weather to uncover it again.