need to install a cable gland

[paulga]

I need install a Seaview cable seal (CG30PG2) purchased from WM during Thanksgiving.
It requires to drill one hole and four pilot screw holes.

For the hole, several tools came up in my search:

1. regular Bi-metal hole saw (toothed)
2. grit edge hole saw
3. Sheet Metal Hole Cutters purported this can cut 7/16 - 1/2" thick material
4. Holepro

Later, I might also need cut a 2 1/8" hole on the topside hull of the salon for an exhaust throughput. I want to seek some input from you guys, what tool best suits hole cutting purpose?

 

[Comodave]

I just use regular hole saws from HD or Lowes. They have always worked fine for me. For the small screw holes make sure you use a countersink on the holes so you don’t chip out the gel coat. Good article on bedding things at marinehowto.com.

 

[STB]

What are you drilling into? How thick?

Answer might be different for glass on skin, aluminum, steel, hardwood, glass on soft core, etc, and depending upon thickness. My answer would be, at least.

 

[paulga]

What are you drilling into? How thick?

Answer might be different for glass on skin, aluminum, steel, hardwood, glass on soft core, etc, and depending upon thickness. My answer would be, at least.

It's to route Ethernet cable through salon wall. I don't know how to measure the thickness



Inside look:

 

[Shrew]

Hole Saw!! GOODENESS NO!!!

Here is how that cable gland should be installed.

1) Locate where you want to install the cable gland.

2) Mark and drill the first hole.

3) I use either a counter sink or a large drill bit and hand spin the large bit to bevel the hole slightly (like a partial countersink). This reduces gelcoat cracking.

4) Install he glands base and lightly install the screw for the first hole.

5) Now using the gland as a template drill the second hole.

6) With the gland loose on one screw you can actually spin the gland out of the way and counter sink the second hole.

7) Lightly screw in both hole one and two.

8) now use the gland base to drill out the last two holes.

9) remove the gland base and bevel the last two holes.

The reason I bevel the holes is because the threads of the screw will likely blow apart the gelcoat. I drill the hole large enough for the screw and bevel out the gel coat to be wider than the threads.

10) Install the gland base and screw in all four screws.

11) Drill a hole in the center large enough to pass your cable. (Here is why I'm saying HOLE SAW WTF!! The hole only needs to be big enough for the cable.

12) Drill out the rubber gland

13) run the cable through the rubber gland and into the hole in the hull/bulkhead/deck.

14) Assemble the cable gland and screw down the cap.

 

[Bmarler]

I like regular hole saws too. Look for fine tooth, I like them best. Use blue tape to cover the area, run the hole saw backwards to score the line, switch to forward. Drill till the center drill pops out the other side. Move to the other side with the hole saw, tape, score, drill through.
I get my fine tooth hole saws here: Missouri Precision Tools, Inc.: Rockhard HSS BiMetal Fine Tooth Hole Saws
No relation to seller.

 

[Shrew]

Later, I might also need cut a 2 1/8" hole on the topside hull of the salon for an exhaust throughput. I want to seek some input from you guys, what tool best suits hole cutting purpose?

So I re-read this. No offense, but you've presented a solution, for which you're asking advise. However, you haven't presented the problem.

A cable gland would not be used for a 2 1/8" hole. It is used to pass a cable like a radar or VHF wire, or a power cable through a deck, hull, or bulkhead.

Can we take a step back and talk about what you're doing? Because a cable gland would not be used for any application that is calling for a 2 1/8".

 

[CharlieO.]

So I re-read this. No offense, but you've presented a solution, for which you're asking advise. However, you haven't presented the problem.

A cable gland would not be used for a 2 1/8" hole. It is used to pass a cable like a radar or VHF wire, or a power cable through a deck, hull, or bulkhead.

Can we take a step back and talk about what you're doing? Because a cable gland would not be used for any application that is calling for a 2 1/8".

He is talking about two different holes for two different installations.

 

[TJM]

As Comodave states, a hole saw from a hardware store will be fine. Make sure the arbor shank fits into your drill chuck. Some are 3/8 and some are 1/2 dia. After you drill the hole, keep the plug for reference of what your wall is made of in the future.
Make sure the arbor style you purchase has the capacity for your next project at 2 1/8 dia.
Fiberglas (gelcoat skin) is very brittle and will fracture if threaded into. On the pilot holes, I like to use a center drill to make the the starter hole first, go deep enough to make the chamfer or edge break larger than the outside diameter of the screw. Then drill the thru hole for the pilot holes. Getting the gelcoat out of the way first is much easier.

 

[Bmarler]

I guess everyone has their opinions. I don’t like twist drills for gel coat. Small holes sure, just not bigger ones like you need to pass an Ethernet cable end through.
Don’t forget to seal the core whatever method you choose.

 

[Bmarler]

I use these sometimes for the screw holes. Drill and countersink in one operation.
https://www.amazon.com/FTG-Maximum-...HzsLXOpAx-ob5oAz9X2O7PLUbKhoCSLYQAvD_BwE&th=1

 

[jgwinks]

A regular bimetal hole saw will work fine but it will dull quickly in fiberglass. The diamond grit kind costs more but will last longer. So it depends on how many times you think you'll use it.

 

[paulga]

A regular bimetal hole saw will work fine but it will dull quickly in fiberglass. The diamond grit kind costs more but will last longer. So it depends on how many times you think you'll use it.

is the diamond grit edge hole saw easier to drill through fiberglass and less likely to make the drill snag during the drilling?

 

[paulga]

Thanks for the details.

when do you know the gelcoat is already worked through so you flip the control button to forward?

should the drill be set at lowest torque and lowest speed? I'm using dewalt 996b

I like regular hole saws too. Look for fine tooth, I like them best. Use blue tape to cover the area, run the hole saw backwards to score the line, switch to forward. Drill till the center drill pops out the other side. Move to the other side with the hole saw, tape, score, drill through.
I get my fine tooth hole saws here: Missouri Precision Tools, Inc.: Rockhard HSS BiMetal Fine Tooth Hole Saws
No relation to seller.

 

[paulga]

Thanks for the list.
I heard of hole saw from Seaview installation video

Hole Saw!! GOODENESS NO!!!

Here is how that cable gland should be installed.

1) Locate where you want to install the cable gland.

2) Mark and drill the first hole.

3) I use either a counter sink or a large drill bit and hand spin the large bit to bevel the hole slightly (like a partial countersink). This reduces gelcoat cracking.

4) Install he glands base and lightly install the screw for the first hole.

5) Now using the gland as a template drill the second hole.

6) With the gland loose on one screw you can actually spin the gland out of the way and counter sink the second hole.

7) Lightly screw in both hole one and two.

8) now use the gland base to drill out the last two holes.

9) remove the gland base and bevel the last two holes.

The reason I bevel the holes is because the threads of the screw will likely blow apart the gelcoat. I drill the hole large enough for the screw and bevel out the gel coat to be wider than the threads.

10) Install the gland base and screw in all four screws.

11) Drill a hole in the center large enough to pass your cable. (Here is why I'm saying HOLE SAW WTF!! The hole only needs to be big enough for the cable.

12) Drill out the rubber gland

13) run the cable through the rubber gland and into the hole in the hull/bulkhead/deck.

14) Assemble the cable gland and screw down the cap.

 

[paulga]

The screws are 634SMS316. I remember the fiberglass is brittle, not like wood. what # of drill bit should be used?

does brad point drill bit mentioned in the drilling fiberglass section of this article make drilling screw holes easier?

 

[DDW]

A grit hole saw will be slower, but easier to control in fiberglass and has less chance of chipping gel coat around the hole or catching. In soft materials (like fiberglass) both types of saws will quickly load the cutting teeth (or grit) with dust and swarf, so you have to withdraw very frequently to clear that out before you continue. In any hole larger enough to use a hole saw, I'd vastly prefer it over a twist drill. Twist drills - at least the variety you find at the hardware store - self-feed badly in fiberglass making them difficult to control and can damage the gel coat and surrounding laminate.

Whenever you drill or saw in fiberglass, it is a good idea to cover the area with masking tape, it helps reduce and damage surrounding the hole.

 

[paulga]

Thanks. I also heard people recommend

"Finish off by sanding the edges of the hole smooth before removing the painters tape"

Do you sand the edges using some sand paper? Or is there a tool for this?

A grit hole saw will be slower, but easier to control in fiberglass and has less chance of chipping gel coat around the hole or catching. In soft materials (like fiberglass) both types of saws will quickly load the cutting teeth (or grit) with dust and swarf, so you have to withdraw very frequently to clear that out before you continue. In any hole larger enough to use a hole saw, I'd vastly prefer it over a twist drill. Twist drills - at least the variety you find at the hardware store - self-feed badly in fiberglass making them difficult to control and can damage the gel coat and surrounding laminate.

Whenever you drill or saw in fiberglass, it is a good idea to cover the area with masking tape, it helps reduce and damage surrounding the hole.

 

[TJM]

The larger the hole saw or cutting diameter the slower the drill speed used. Assumption is within the same material. I like hole saws because they can be used on any material. Grit saws are slow, but easily controllable and load up quickly on soft materials like wood.
As mentioned, larger twist drill can bite into fiberglass and self feed there way in. I have a few straight flute drills (no twist) that work fantastic.

 

[paulga]

I guess everyone has their opinions. I don’t like twist drills for gel coat. Small holes sure, just not bigger ones like you need to pass an Ethernet cable end through.
Don’t forget to seal the core whatever method you choose.

do you mean using BedIt butyl tape under the gland, around the cable and around the screws?

 

[C lectric]

I'll chime in.
NO. Use epoxy to paint the ID of the hole you just made so the core is sealed from any water ingress. Let it sit overnight to harden.

THen yes, use Bed It Tape to seal the fitting to the deck. I use a pair of scissors to cut the BIT narrower , about square since

 

[Bmarler]

do you mean using BedIt butyl tape under the gland, around the cable and around the screws?

no, i meant that you should use some un-thickened epoxy on the exposed area, especially if it's wood cored. mix a tiny amount and paint it on. (only on the inside of the hole)
you might think about getting a set of forstner bits too. don't get expensive ones, the cheaper sets will do ok. they cut cleaner holes than twist drills do. i run them high speed low pressure at first to score the gelcoat, then go low speed and vary the pressure to cut. fiberglass will dull drill bits pretty quickly so i don't use my best drill bits on it. the little taper drills with the countersink built in is a good way to go for the screw holes.
if the cable gland is going to be in a rain exposed area, you'll want to bed it with something unless there's a really nice built-in rubber gasket.
i will use a screw the same size as what's used for mounting, and run it in every hole to establish the threads. then throw it away and use new ones for the mounting.
like everything on this forum, there will be a different opinion from each person. use the best bits of info to make a procedure that works best for you. as time goes by you'll get more comfortable with these projects.
as a side note, crimpers for doing ethernet cables aren't too expensive. if you only have to drill for the cable size the hole will be smaller and you can crimp the end on after it's strung through.

 

[paulga]

forstner bits are interesting. I initially thought it's a typo.

from previous posts, I remember the principle is to remove some core to create a pocket, and seal with thickened epoxy (un-thickened? west system 610 or?), redrill pilot holes without waiting for cure. For small screw holes, it’s easier just to overdrill the screw holes by 3/32 more than outside diameter of fasteners, fill with thickened epoxy, then redrill pilot holes (credit to Flatswing).

Do you mean the above bedding process should be followed if the installation is exposed to weather? now that the installation is in the sundeck, so there is no need to remove some peripheral core. Just adding a token amount of epoxy into the screw holes is sufficient for sealing. is my understanding correct?

no, i meant that you should use some un-thickened epoxy on the exposed area, especially if it's wood cored. mix a tiny amount and paint it on. (only on the inside of the hole)
you might think about getting a set of forstner bits too. don't get expensive ones, the cheaper sets will do ok. they cut cleaner holes than twist drills do. i run them high speed low pressure at first to score the gelcoat, then go low speed and vary the pressure to cut. fiberglass will dull drill bits pretty quickly so i don't use my best drill bits on it. the little taper drills with the countersink built in is a good way to go for the screw holes.
if the cable gland is going to be in a rain exposed area, you'll want to bed it with something unless there's a really nice built-in rubber gasket.
i will use a screw the same size as what's used for mounting, and run it in every hole to establish the threads. then throw it away and use new ones for the mounting.
like everything on this forum, there will be a different opinion from each person. use the best bits of info to make a procedure that works best for you. as time goes by you'll get more comfortable with these projects.
as a side note, crimpers for doing ethernet cables aren't too expensive. if you only have to drill for the cable size the hole will be smaller and you can crimp the end on after it's strung through.

 

[Bmarler]

forstner bits are interesting. I initially thought it's a typo.

from previous posts, I remember the principle is to remove some core to create a pocket, and seal with thickened epoxy (un-thickened? west system 610 or?), redrill pilot holes without waiting for cure. For small screw holes, it’s easier just to overdrill the screw holes by 3/32 more than outside diameter of fasteners, fill with thickened epoxy, then redrill pilot holes (credit to Flatswing).

Do you mean the above bedding process should be followed if the installation is exposed to weather? now that the installation is in the sundeck, so there is no need to remove some peripheral core. Just adding a token amount of epoxy into the screw holes is sufficient for sealing. is my understanding correct?

yes, sealing this in a protected location is different than an exposed deck fitting. just drilling the pass through hole on size and painting with epoxy is fine. same for the screw holes. just drill and dab in some epoxy with a q tip or similar. always wait for epoxy to cure. the un-thickened epoxy will wick into the core . re-drill the screw holes, then fit the gland.

 

[paulga]

yes, sealing this in a protected location is different than an exposed deck fitting. just drilling the pass through hole on size and painting with epoxy is fine. same for the screw holes. just drill and dab in some epoxy with a q tip or similar. always wait for epoxy to cure. the un-thickened epoxy will wick into the core . re-drill the screw holes, then fit the gland.

is epoxy available in small size tubes?
sealant in a tube has a very short shelf life once the seal is punctured. Buying west systems 105/205 for this job is overkill. I also do not expect a lot of glass projects within two years.

 

[Bmarler]

is epoxy available in small size tubes?
sealant in a tube has a very short shelf life once the seal is punctured. Buying west systems 105/205 for this job is overkill. I also do not expect a lot of glass projects within two years.

sure, something like this maybe? https://www.amazon.com/dp/B08DZH7V9...p_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM

 

[paulga]

Thanks for your quick response Bmarler
I should pay you for the consultation service

sure, something like this maybe? https://www.amazon.com/dp/B08DZH7V9...p_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWxfdGhlbWF0aWM

 

[DDW]

Thanks. I also heard people recommend

"Finish off by sanding the edges of the hole smooth before removing the painters tape"

Do you sand the edges using some sand paper? Or is there a tool for this?

Just some sandpaper is good. Seal the edges with something if it is cored, a good idea even if not. If cored, the usual method is to dig out the core for 1/4 - 1/2" at the edge of the hole, then fill with thickened epoxy (West Six10 works well right out of the tube). On a large hole you can work various tools around to dig out the core, on a small hole one fairly easy way for soft cores is to chuck a small Allen key wrench in the drill, small enough that the short leg fits across the hole. Then starting slowly (because the drill will kick back initially), use the short leg of the Allen key to pulverize the core. The reason for this is that water can easily enter and migrate into the core if the wet seal fails, and wet core is a bad idea. Filling a donut around the hole with epoxy seals the edge.

 

[garyj4101]

Drill size

View attachment 144739

View attachment 144740The screws are 634SMS316. I remember the fiberglass is brittle, not like wood. what # of drill bit should be used?

does brad point drill bit mentioned in the drilling fiberglass section of this article make drilling screw holes easier?

Using a caliper (must have tool imho) measure the root diameter of the screw you need to install, that is the size of hole you should be drilling.

 

[Bmarler]

Thanks for your quick response Bmarler
I should pay you for the consultation service

we are all here for a common purpose. helping each other is the key to a successful forum interaction.
there are many members here with decades of experience that are more than happy to pass on what they've learned over the years.
plus, with the weather outside being less than ideal for doing my own projects, the conversation is nice, and kills some time.