have to ask about hole filling I have been reading

J

Jake B

New member
so I have read numerous times about drilling holes into boat to over drill and epoxy in, then drill into the epoxy.

to be honest I have never read this or seen this on any previous boat holes in my past and current c-dory.

all we have ever done is use a liberal amount of 4200 and have never had a water penetration or failure with this method. I guess at this point I am just curious if people out there Have had 4200 fail on them and cause water damage?

or is the epoxy method just a more thorough method? I am just wondering what peoples experience were. as I am going to be rigging transducers and trim tabs here in the near future. I will say the previous owner did just the same as I have in the past with 4200 and no failure although the boat has 319 hours on it the electronics were from the early 90's
 
I've had the fun of a few re-core jobs (not on C-Dorys but on other boats with similar sandwich construction), so I favor the overdrill/thickened-epoxy fill/re-drill method on any penetrations into cored areas (after which I still bed fittings with caulk or other bedding). In non-cored areas, then just bedding.

In addition to helping protect the core, the thickened epoxy fill also gives a solid annulus to tighten fasteners/fittings against (vs. potentially compressing the core and creating a crack or a low area).
 
A number of years ago I took a professional boat builders' repair course at Gougeon Brothers in Bay City, MI. They are the folks who make West Systems epoxy.

The technique described works extraordinarily well. One variation of this method that they taught is to drill an oversize hole and then insert the screw into the wet, thickened epoxy, rather than wait until it is dry and then drilling and inserting the screw. When using this method it is necessary to spray the screw with Pam, the spray cooking product. This acts as a release agent in case the screw has to be removed in the future. If Pam is not used, it is also possible to remove the screw by putting the tip of a hot soldering iron on the screw head, which softens the epoxy enough for the screw to be backed out.

The drilling of an oversized hole gives a larger contact area, which really strengthens the grab of the screw, in addition to sealing the wood that is being drilled to prevent water intrusion.

Hope this helps someone out there.

Best,

Nick
"Valkyrie"
 
Ray,
Nice write up and web site.

Will 4200/5200 prevent core problems? Possibly; but not 100% warrantee.

Do I drill out every hole in the boat and re fill with epoxy--no. But those which are subject to being under water (think transducer and trim tabs). But every time I pull a citing (for example the hand rails on the 22), I do the epoxy treatment--same for the transducer mount, and a few other misc screws. If the deck hardware leaks or needs better backing, then again, the epoxy treatment before a backing plate and re-assembly.

Why do I do the epoxy prevention? Because I have both built boats and repaired/restored boats which had some serious core problems (mostly deck) and this will prevent the issues. (Ask the owner of the 2005 22 who spent $7,000 to have the cored repaired, if it is worth sealing the core?)

The reasons for using a high density plastic block for the transducer is that you need to get it positioned just right, and may have to redrill holes, or you may want to change transducers--thus put in another set...or two of holes. Each set of holes is a risk.
 
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