Drilling Pilot House Roof

[FlowThru1]

I think I remember a thread about treating the wood when drilling through the roof. I think it was referred to as "wetting the wood" ? I've been searching but can't seem to find it.

Based on recommendations here, I will be installing a Battlewagon radar mount soon. I have a question regarding the cure time for the epoxy. How long do you usually wait between treating the wood and installing the mount ? I also plan to use 3M 4200 to seal the bolt holes.

I have Raka thin epoxy resin(127) and fast cure hardener(610). I have been experimenting with a test piece. It seems 1st coat is tacky enough after 2 hours to apply a second coat. Second coat seems to cure after about 5 hours.

If anyone can point me to the thread or has experience they would like to share, it would be greatly appreciated.

Thanks,
John

 

[TimC2520]

One bit of advice real quickly, start with the smallest drill bit you can find. Once you know where the larger hole will fall in the cabin ceiling, then use a utility knife or something to cut some of the carpet away cleanly. When I mounted my Battlewagon, I mistakenly started with the larger bit and when it broke through into the cabin, it grabbed the "carpet" and twisted the hell out of it and knotted it up in a 3-4" area surrounding the bolt. I never could get it to lay flat again.

 

[GoodChance]

Unless you have an older Parker, most likely the core is not wood. I had a 1986 25 Pilothouse and the core on the cabin roof was a structural foam (divinyicell). It is a closed-cell green-colored foam material. Very hard. I'm not sure if Parker reverted to a wood core in later years or not.

Regarding the RAKA epoxy (same as I use), if you find wood in the cabin, you can "hot-coat" with successive coats in the matter of 15-20 minutes. You'll be able to see the epoxy being sucked into the wood. Once pulled-in, apply another coat. The last coat, you may consider adding a small amount of cabosil to the resin to thicken it up

 

[sydngoose]

Regarding the RAKA epoxy (same as I use), if you find wood in the cabin, you can "hot-coat" with successive coats in the matter of 15-20 minutes. You'll be able to see the epoxy being sucked into the wood. Once pulled-in, apply another coat. The last coat, you may consider adding a small amount of cabosil to the resin to thicken it up

concur. This is the proper way... don’t forget the last coat thickened w cabosil ....just enough so it doesn’t sag.
Also, painters tape on the bottom of the hole to catch your drips....

 

[pelagic2530]

Unless you have an older Parker, most likely the core is not wood. I had a 1986 25 Pilothouse and the core on the cabin roof was a structural foam (divinyicell). It is a closed-cell green-colored foam material. Very hard. I'm not sure if Parker reverted to a wood core in later years or not.

Interesting. My '95 definitely has a balsa core in the pilothouse overhead. There have been a lot of threads on here from mid-'90s to '00s boats with balsa as well, so I'd say it's a safe bet that it's pretty common. Strange that they'd switch back to wood after using a composite.

 

[FlowThru1]

One bit of advice real quickly, start with the smallest drill bit you can find. Once you know where the larger hole will fall in the cabin ceiling, then use a utility knife or something to cut some of the carpet away cleanly. When I mounted my Battlewagon, I mistakenly started with the larger bit and when it broke through into the cabin, it grabbed the "carpet" and twisted the hell out of it and knotted it up in a 3-4" area surrounding the bolt. I never could get it to lay flat again.

Great advice. Thank you for sharing.

 

[FlowThru1]

Unless you have an older Parker, most likely the core is not wood. I had a 1986 25 Pilothouse and the core on the cabin roof was a structural foam (divinyicell). It is a closed-cell green-colored foam material. Very hard. I'm not sure if Parker reverted to a wood core in later years or not.

Regarding the RAKA epoxy (same as I use), if you find wood in the cabin, you can "hot-coat" with successive coats in the matter of 15-20 minutes. You'll be able to see the epoxy being sucked into the wood. Once pulled-in, apply another coat. The last coat, you may consider adding a small amount of cabosil to the resin to thicken it up

I have a 2002 2520 (so I guess a new fuel tank may be in my future as well, lol. Plenty of great info on this site regarding that.)

Thanks for the cabosil tip. I will have to look into that. Wondering if using cabosil to thicken will shrink the hole diameter drastically ? I guess a may need to start with a larger diameter hole.

 

[FlowThru1]

concur. This is the proper way... don’t forget the last coat thickened w cabosil ....just enough so it doesn’t sag.
Also, painters tape on the bottom of the hole to catch your drips....

Was thinking if I put painters tape flat across the bottom that any drips would pool there and close the hole too much. But rethinking it now the carpet thickness would move the drips away from the roof hole. Thanks for that info.

 

[FlowThru1]

Interesting. My '95 definitely has a balsa core in the pilothouse overhead. There have been a lot of threads on here from mid-'90s to '00s boats with balsa as well, so I'd say it's a safe bet that it's pretty common. Strange that they'd switch back to wood after using a composite.

I have been using the terms "balsa" and "wood" interchangeably. I guess they are Not the same things ? Would the Raka epoxy be used for both ? My boat is from 2002.

Appreciate all the info

 

[pelagic2530]

I have been using the terms "balsa" and "wood" interchangeably. I guess they are Not the same things ? Would the Raka epoxy be used for both ? My boat is from 2002.

Appreciate all the info

Balsa is a type of lightweight wood. It's used for the pilothouse roof because it's lighter than ply, so it keeps weight up high to a minimum, and the roof is also less likely to experience heavy loading.

When using the epoxy to seal the hole, drill the hole just a bit bigger than you need it to be. The epoxy and cabosil, if done correctly, will reduce the diameter just a hair. I would put the tape as close to the bottom of the hole through the glass as possible; otherwise the epoxy could soak into the carpet and cause discoloration. If the accumulated drips cause extra thickness buildup at the bottom, just file it away or take it off with a Dremel sanding wheel, being careful not to break through the epoxy coating and to just take off the excess.

 

[DanLovingood]

I agree with pelagic2530 above. My process for sealing holes like this is to drill it on location, but slightly oversize. Seal the bottom of the hole with tape to prevent leakage of epoxy through the hole. Wet out with unthickened epoxy, then completely fill the hole with epoxy thickened with cabosil. Once that has cured, drill out the new hole to the required size. If done properly, you will now have a hole that is completely sealed around the outside with epoxy.

Cap'n Dan

 

[FlowThru1]

Balsa is a type of lightweight wood. It's used for the pilothouse roof because it's lighter than ply, so it keeps weight up high to a minimum, and the roof is also less likely to experience heavy loading.

When using the epoxy to seal the hole, drill the hole just a bit bigger than you need it to be. The epoxy and cabosil, if done correctly, will reduce the diameter just a hair. I would put the tape as close to the bottom of the hole through the glass as possible; otherwise the epoxy could soak into the carpet and cause discoloration. If the accumulated drips cause extra thickness buildup at the bottom, just file it away or take it off with a Dremel sanding wheel, being careful not to break through the epoxy coating and to just take off the excess.

Nice explanation and info. Thank you

 

[sailmaster]

Balsa is a type of lightweight wood. It's used for the pilothouse roof because it's lighter than ply, so it keeps weight up high to a minimum, and the roof is also less likely to experience heavy loading.

When using the epoxy to seal the hole, drill the hole just a bit bigger than you need it to be. The epoxy and cabosil, if done correctly, will reduce the diameter just a hair. I would put the tape as close to the bottom of the hole through the glass as possible; otherwise the epoxy could soak into the carpet and cause discoloration. If the accumulated drips cause extra thickness buildup at the bottom, just file it away or take it off with a Dremel sanding wheel, being careful not to break through the epoxy coating and to just take off the excess.

 

[sailmaster]

Balsa is a type of lightweight wood. It's used for the pilothouse roof because it's lighter than ply, so it keeps weight up high to a minimum, and the roof is also less likely to experience heavy loading.

When using the epoxy to seal the hole, drill the hole just a bit bigger than you need it to be. The epoxy and cabosil, if done correctly, will reduce the diameter just a hair. I would put the tape as close to the bottom of the hole through the glass as possible; otherwise the epoxy could soak into the carpet and cause discoloration. If the accumulated drips cause extra thickness buildup at the bottom, just file it away or take it off with a Dremel sanding wheel, being careful not to break through the epoxy coating and to just take off the excess.

Balsa is about 6 lbs per cubic foot while common plywood is about 32 lbs for cubic foot Plywood exposes a lot of end grain in a hole drilled through it while the balsa is end stacked to stop this. Bonding an epoxy or other resin to the balsa will not be as potent as it would be with plywood but neither are recommended. Professional Boatbuilder has a "tear out" article this month with best practices. Removing the core after drilling out for the fastner or piece of equipment. replacing the core with an impermeable composite - redrilling with attention paid to preferred bedding and end use. torqueing fastners before bedding cures to stop shear or crushing or cured bedding or just forgetting to come back or just missing it

 

[FlowThru1]

Balsa is about 6 lbs per cubic foot while common plywood is about 32 lbs for cubic foot Plywood exposes a lot of end grain in a hole drilled through it while the balsa is end stacked to stop this. Bonding an epoxy or other resin to the balsa will not be as potent as it would be with plywood but neither are recommended. Professional Boatbuilder has a "tear out" article this month with best practices. Removing the core after drilling out for the fastner or piece of equipment. replacing the core with an impermeable composite - redrilling with attention paid to preferred bedding and end use. torqueing fastners before bedding cures to stop shear or crushing or cured bedding or just forgetting to come back or just missing it

Sailmaster, thank you for pointing out the magazine and article. Looks like a great resource. I just subscribed.

 

[pelagic2530]

Balsa is about 6 lbs per cubic foot while common plywood is about 32 lbs for cubic foot Plywood exposes a lot of end grain in a hole drilled through it while the balsa is end stacked to stop this. Bonding an epoxy or other resin to the balsa will not be as potent as it would be with plywood but neither are recommended. Professional Boatbuilder has a "tear out" article this month with best practices. Removing the core after drilling out for the fastner or piece of equipment. replacing the core with an impermeable composite - redrilling with attention paid to preferred bedding and end use. torqueing fastners before bedding cures to stop shear or crushing or cured bedding or just forgetting to come back or just missing it

For the VAST majority of cases, this realistically is overkill. Soaking the core with epoxy, then coating with thickened epoxy, then applying a sealant to the overall installation, is going to prevent water intrusion into the core with far less complication than the process described.

If it's a small hole, you could overdrill the hole, completely fill it with epoxy creating a "plug" and then redrill the hole through the epoxy plug, effectively creating an impermeable barrier between the hole and the core material. This is the recommended practice for installing screw-in hardware into a cored surface. For a larger hole, this is pretty much just going to waste epoxy, as you're going to pour a lot of it in, and then drill it right back out. Coating it with several coats of brushed-on epoxy, finishing with a thickened coat at the end, will be more than sufficient.

Where core removal and replacement becomes important is in soft composites where the fastener will be under load. In those cases, replacement of the core with something that will not be crushed when load is applied is recommended. Depending on how high the load is, doing this in a balsa core could also be a good idea; but for the vast majority of hardware installation epoxy is going to be fine.

There's perfection, as described in Professional Boatbuilder, and then there's the practical solution. In the end, you have to be the judge of what your application requires.

 

[GotChrist?]

Several ways to handle the core.

 

[GotChrist?]

After digging out the foam core, and packing it with thickened west system, I redrilled the holes.
Another method which Dan suggested and I included a diagram of in my post above, is to make the hole bigger, fill it with thickened epoxy, then drill the smaller, correct sized hole. No wet core to worry over.

 

[sailmaster]

I think I remember a thread about treating the wood when drilling through the roof. I think it was referred to as "wetting the wood" ? I've been searching but can't seem to find it.

Based on recommendations here, I will be installing a Battlewagon radar mount soon. I have a question regarding the cure time for the epoxy. How long do you usually wait between treating the wood and installing the mount ? I also plan to use 3M 4200 to seal the bolt holes.

I have Raka thin epoxy resin(127) and fast cure hardener(610). I have been experimenting with a test piece. It seems 1st coat is tacky enough after 2 hours to apply a second coat. Second coat seems to cure after about 5 hours.

If anyone can point me to the thread or has experience they would like to share, it would be greatly appreciated.

Thanks,
John

not familiar with raka BUT some epoxies develop something called 'polyamine blush' they do not take subsequent bonds with same materials or with different materials. Best practice is to follow MFG advice on cure time. Also recognize that many epoxies have huge variations in viscosity with differences in temperature, and this will affect how you work with it. Same thing with cure times.

 

[DanLovingood]

not familiar with raka BUT some epoxies develop something called 'polyamine blush' they do not take subsequent bonds with same materials or with different materials. Best practice is to follow MFG advice on cure time. Also recognize that many epoxies have huge variations in viscosity with differences in temperature, and this will affect how you work with it. Same thing with cure times.

Amine blush is a byproduct of cure that occurs on the surface of cured epoxy. It can be removed with a fresh water rinse and sanding to create an anchor tooth profile (for mechanical bond) so that subsequent coats can bond to previous cured coats. There is usually a window of time during cure that you can recoat without the sand/wash cycle, as stated above refer to manufacturer's directions. The way I do this, it is all one operation. Wet out the ID of the oversize hole with unthickened epoxy, add thickener and fill hole while wet out is still wet.

Cap'n Dan