What's the best way to seal the deck core for the little self tapping screws used for the dodger snaps? The installer put a bit of caulk on the screw but I'm skeptical that this will last - although I pulled a screw and there was no sign of moisture. To fix it, I could drill a larger hole, fill with epoxy, and screw into that. Or, would it be "good enough" to take out the screws and wrap them with a bit of Bed-it butyl tape before screwing them back in? Or should I just leave it as is?
Wet core from dodger snaps?
- Thread starter CarlN
- Start date
I've also wondered if one could "screw" into an epoxy plug without shattering it regardless of how carefully you sized the pilot hole in the epoxy. Anyone had any experience with this earthshaker ?
I've used both butyl tape and 4200 sealant and so far, no obvious signs of soft cores. Mind you, it's the less obvious ones that get you.
I've used both butyl tape and 4200 sealant and so far, no obvious signs of soft cores. Mind you, it's the less obvious ones that get you.
While I have never had an issue with water infiltration on my dodger snap screws I get your concern. See post #2 in this thread for a solution Deck hardware screw sealer ? | Boat Design Net.
The original poster in Deck hardware screw sealer ? may be due for a checkup when he says:
"When I wash my deck or even just morning dew, the water will; even if only slightly, drip into the cabin."
I think he's exceeded a wet core by just a little bit at that point.
"When I wash my deck or even just morning dew, the water will; even if only slightly, drip into the cabin."
I think he's exceeded a wet core by just a little bit at that point.
Thanks for the idea @CarlN . I've got to get to work on some epoxy plugs and see what they behave like when screwed into and what size pilot hole is required. Looks like all male portions are a #8 screw if I recall. Didn't have anything lined up for the winter/fall anyway.
To prevent cracking of the epoxy plugs, push in a few snippets of fiberglass cloth (1/2" x 1 1/2" strips of 6 oz. cloth work well) after adding about 1/2 of the epoxy. Then finish filling. This also greatly improves thread holding.
Also, some people think it’s good to leave room for the screw to be further tightened to allow for another half turn of compression on the sealant after its cured, and you might read about this online. I think that’s a very bad practice, as it breaks the bond between the screw and sealant.
Once the screw is in place it should be left as-is. If you ever need to turn it, it should be removed and resealed.
Once the screw is in place it should be left as-is. If you ever need to turn it, it should be removed and resealed.
@Maine Sail covered this on his Marine How To site in some detail, with detailed explanations as to why each step was needed and pictures: Sealing Deck Penetrations To Prevent Core Rot - Marine How To
BTW: If this works for you, throw a couple bucks at Rod's recovery fund (SailboatOwners.com) or the Marine How To funding (DONATE - Marine How To) by way of thanks. I did.
BTW: If this works for you, throw a couple bucks at Rod's recovery fund (SailboatOwners.com) or the Marine How To funding (DONATE - Marine How To) by way of thanks. I did.
You are correct that the buttons will eventually leak and wet your core. The dodger installer will be long gone by then. I have used 5/16" diameter drilled holes, filled with gflex epoxy, followed by 1/8" pilot holes and No.8 sheet metal screws successfully on deck chainplates. I did gouge out some of the damaged core after drilling the 5/16 hole through the outer skin. I do not think you have to worry about splitting the epoxy plug if you drill a pilot hole for the screw. Done in this manner, you can remove and replace the screws anytime.
Agreed. One of the dumbest ideas I have ever seen.
This idea has appeared on SBO several times over the years and needs to be identified as "false news" every time it appears.
One of the reasons @Don S/V ILLusion penned this
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I apologize in advance if this offends anyone. Its ungracious, impolite and ignorant to not respond when someone takes the time to answer your questions. This is particularly irritating when someone asks very basic questions like “where is my water heater” or “do I have a diesel engine” which...
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This is good but I think only addresses where you are through drilling the hole for a bolt and nut and not really screwing into the epoxy.
I have read about a method of drilling an oversize hole partially through the work surface then filling the hole with epoxy and putting in the screw before the epoxy is cured. Before inserting, the screw is coated with a mold release agent so the epoxy doesn't stick to the screw. The result is you have essentially molded in the female threads. This from a Gougeon Brothers technical advisor may explain it better than I can:
Fasteners and Hardware
When you want to install a threaded bolt or screw and be able to later remove the fastener, there are a couple of easy options. In our boat building class with the Saginaw Bay Community Sailing Association, we keep a wax toilet ring for on the workbench and stick a bunch of screws in it. We just pull these out as we need them. The wax gets in the threads and we can back the screw out easily after the epoxy has cured. You can also put automotive paste wax on a piece of cheesecloth, grab the threads firmly below the head, and back it out with a cordless drill in reverse. This applies a nice thin coat of wax evenly over the entire thread pattern.
Pam® Cooking Spray is a quick and convenient adhesion preventer. Simply place the fastener on a paper towel and spray the threads, butter the threads with a bit of thickened epoxy so air isn’t trapped, push the fastener into the oversized, partially filled hole and let the epoxy cure. Back it out after the epoxy hardens and now you’ve cast threads in the epoxy.
Polyvinyl alcohol or PVA is a green liquid available at hobby shops and craft shops. Dip the fastener in or brush it on the threads, let it air dry, and install the fastener like I just described for Pam.
There are a number of aerosol mold release sprays on the market. A couple we’ve used around the tech shop are Stoner® E-497 and E-499 Thermoset Mold Release. They work well for all thermoset resin systems used in most boats – epoxy, polyester, and vinyl ester. They do not contain any silicone, which you want to avoid in any mold release, especially a spray. Silicone aerosol sprays can contaminate the entire shop if you’re not careful.
Another common household product that makes a decent mold release is Aqua Net® Regular Hold hair spray. It is nearly all PVA and works well.
The above is an excerpt from :
What you can do if you don't want epoxy to stick
What do you do when don’t want epoxy to stick. This is where mold release agents come in very handy. Learn what to use and when.
Anybody ever done this?
I'm going to experiment with both thickened Gflex epoxy and Bed-It Butyl after using a countersink bit to give the butyl more surface area. With these little self tapping screws I fear the epoxy is going to be messy and difficult. To clear up one matter - as Rod said - when using Butyl instead of a sealant like 4200 it's important to go back the next day and tighten again. This forces the butyl into the crevices and makes the seal tighter.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 22,886
In my experience using Bed-it butyl over the past 6 years, it works great as a sealant when you have fasteners holding the object in place. I have found you can over tighten it and too much can squeeze out from between the objects and the deck, thus value to the counter sink reservoir of butyl. Thickened epoxy works well as a plug to stop the water from entering your core.
I prefer to use through bolts than screws into the deck.
The adhesive, yet flexible properties of Bed-it Butyl surprised me.
I prefer to use through bolts than screws into the deck.
The adhesive, yet flexible properties of Bed-it Butyl surprised me.
