Repair of Unused Fastener Holes in Transom

Repair or modification of Boston Whaler boats, their engines, trailers, and gear
otter
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Repair of Unused Fastener Holes in Transom

Postby otter » Wed May 31, 2023 8:09 am

Q1: how should old fastener holes in the lower transom be filled?

Q2: would the best way to fill old fastener holes in the lower transom be to use the LOCTITE Marine Epoxy?

Q3: if LOCTITE Marine Epoxy is used to fill old fastener holes in the transom, is any other repair work needed?

Q4: beyond using LOCTITE Marine Epoxy, should holes in a hull be repaired [in some additional but unspecified manner]?

BACKSTORY: I plan to remove two fasteners from the transom of a 1998 OUTRAGE 17 boat transom which may have been used to hold a SONAR transducer.

jimh
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Re: Repair of Unused Fastener Holes in Transom

Postby jimh » Wed May 31, 2023 9:54 am

otter wrote:Q1: how should old fastener holes in the lower transom be filled?
Old fastener holes in the transom which are going to be always below the water line, as likely to be in the case of old holes used to retain a SONAR transducer, should be filled with epoxy resin thickened with a filler. It may also be advisable to fill the hole with a soft wood plug in the deeper section of the fastener hole which reached the embedded wood in the transom.

A good epoxy resin to use is WEST Systems epoxy. WEST Systems sells small epoxy repair kits which include resin, hardeners, fillers, and fiberglass cloth, along with instructions for their use. The resin and hardener are provided in pre-measured foil sealed packets. The shelf life of the resin and hardener will be excellent due to the complete sealing in packets until use. One WEST System repair kit can be used to make many repairs over a span of years. The WEST System epoxy repair kit is available from many sources.

The WEST Systems 105-K FIberglass Boat Repair Kit retails for about $50. It includes eight sets of resin and hardener packets, brushes, syringe, scraper, gloves, high-density filler, low-density filler, gloves, and fiberglass cloth.

The ubiquitous marine retailer WEST MARINE (which is not related at all to WEST Systems) sells the WEST Systems 105-K Fiberglass Boat Repair Kit. See

https://www.westmarine.com/west-system- ... 54095.html

jimh
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Re: Repair of Unused Fastener Holes in Transom Below Waterlinefastener holes in transom

Postby jimh » Wed May 31, 2023 9:55 am

otter wrote:Q2: would the best way to fill old fastener holes in the lower transom be to use the LOCTITE Marine Epoxy?
That is one way to fill unused fastener holes, but your inference that it will be best is unjustified.

jimh
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Re: Repair of Unused Fastener Holes in Transom Below Waterlinefastener holes in transom

Postby jimh » Wed May 31, 2023 10:00 am

otter wrote:Q3: if LOCKTITE Marine Epoxy is used to fill old fastener holes in the transom, is any other repair work needed?
Again, your limitation in your question to use of only one brand of epoxy imposes restrictions on the answer to your question. Instead, I will answer your question without regard to mandatory use of LOCTITE Marine Epoxy.

A good marine epoxy will make a water-proof repair. If the repair is in an area that is not particularly highly visible, such as a hole on the lower portion of a boat transom, there is really no need for further repairs.

A drawback of using only an epoxy resin for repair is the general nature of epoxy resins to exhibit a color change due to exposure to ultraviolet radiation from the sun. Because the lower portion of a boat transom is generally submerged in water, there will be very little exposure to sunlight. And, even if there is a color shift in the epoxy over time due to some UV-exposure, a small repair on the lower part of a boat transom is not in a particularly high-visibility area where there will be great concern about color matching to the original surrounding gel coat resin area.

For repairs made with epoxy resin in areas of high-visibility, the best outcome will occur if some relief is left in the epoxy repair and a color-matching gel coat resin is applied as a top coat. This will produce the best long-term color match to the surrounding original gel coat resin area. However, in the case of small fastener holes that are not below the water line and are in high visibility areas, a very simple method to repair is just to insert a new screw fastener with oval head and use a dress washer. This results in a rather innocuous extra screw fastener appearing in the hull or deck, which is usually unobtrusive and blends with the many other screw fastener already in sight.

jimh
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Re: Repair of Unused Fastener Holes in Transom Below Waterlinefastener holes in transom

Postby jimh » Wed May 31, 2023 10:02 am

For general advice on making repairs to the Unibond hull of a Boston Whaler boat, see the answer prepared in the FAQ:

Q5: how is damage to a Unibond hull repaired?
https://continuouswave.com/whaler/reference/FAQ/#Q5

msteinkampf
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Re: Repair of Unused Fastener Holes in Transom

Postby msteinkampf » Thu Jun 08, 2023 3:52 pm

There are several ways to repair fastener holes in a transom, and they each have their advantages and disadvantages. They all share a [two initial steps]:
  • use a drill to remove any rotted wood, and
  • chamfer the gel coat with a chamfering bit
A large drill bit for to chamber the holse, perhaps if you ran it in reverse, but I always use an inexpensive chamfering bit. After that, you have some choices--and I’ve done all of these:

Option 1
Put some masking tape around the hole and squirt some epoxy (whatever you have on hand) into the hole. Use a matchstick or something similar to get the epoxy down into the hole itself. Wipe off the excess with a rag, and remove the masking tape after the epoxy dries. This is easy and cheap, but it’s the least cosmetically appealing. Expect the epoxy to yellow over time. If the hole is larger than one made by a mounting screw, you could add some thickener to keep the epoxy from sagging, or you can cover the hole with clear packing tape, or do both.

Option 2Squirt Loctite Marine Epoxy into the hole to overfill slightly, cover with clear masking tape to prevent sagging, and remove the tape the next day. This leaves a shiny spot whose color is close to that of my 1990 17-foot hull. I’ve added thickener before, but for small screw holes it didn’t seem to matter. For larger and deeper holes, I’ve loaded the epoxy into a plastic syringe and injected it into the hole, which limits the mess a bit. This option is easy, and I’ve got a few holes repaired like this on my transom currently. This option is my first choice if I’m going to cover the hole repair with another transducer bracket.

Option 3
Perform wither option 1 or 2, then the next day (or the next year--it doesn’t matter), sand down the epoxy down until there is a very slight depression, then apply a coat of gel coat repair paste, allow to set, and sand it down until it’s flush with the hull. I’ve done this repair several times on my transom, and the repair is almost invisible. It’s also by far the most tedious and expensive option.

If you are considering this, I recommend watching this YouTube video: “How to Repair Screw Holes in a Fiberglass Boat” (https://www.youtube.com/watch?v=b3ea4Lr ... ormanGooch)

The presentation includes the source for the Spectrum repair paste. This gel coat repair paste can also be used (without the epoxy) to repair superficial dings in your hull. It’s pricey stuff and the color match may not be 100%, but I think it’s the best method for fastener hole repair if you are looking for the best cosmetic appearance.
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