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Recently purchased a 1998 boat. It has several small holes in the lower transom from previously mounted transducers that I thought about filling correctly and permanently. They currently have what appears to be 4200 and/or silicone - something soft at least. The boat hasn't been sitting in the water for any period of time at all, and there does not appear to be any damage from the "fillings," just figured I'd see if anyone has any advice on proper way to fill those holes permanently. I went to the two local marine supply stores and got two very different answers, so figured I'd ask here.
I do not know how small, your small holes are, but when I replaced the transducers, the holes I had were about 3mm in diameter.
I drilled them slightly larger to remove the thread pattern then tapped in tight fitting pieces of wood dowel to about 1/4 inch of the surface. I filled the remaining part of the hole (over-fill it) with resin. Once it cured, I sanded it flush with the transom and gave a nice even coat of gel-coat with an airbrush (for model boats and cars).
Remove screws
Drill out to about 1/2", but not all the way through
Chamfer hole
Scrape some deep ridges on the inside of the hole
Fill with thickened epoxy
Drill out for new mounting screws in center of epoxy plugs
Finish with colored gel coat
Install transducer.
Epoxy resin thickened with cabosil. Mix it up and put it in a syringe and back fill the holes... pulling the syringe out as you fill from the back of the hole forward. Fill until almost level with the transom surface (within 1mm). Then let cure. Now sand/grind smooth and out from the hole about 1/2" or so. Now you can do the gel coat touch up.
Where is a good place to get those syringes without going to the boat stores and paying tooo much? I've asked around at the pharmacies and the employees look at me like I'm a junkie
Where is a good place to get those syringes without going to the boat stores and paying tooo much? I've asked around at the pharmacies and the employees look at me like I'm a junkie
If you know a diabetic or "allergy person" (like myself), they could hook you up with small 1cc syringes cheap. All they have to do is renew their prescrip.....there's no set amount that an allergy person would use...sometimes I am religious about doing my shots, many times I procrastinate lol/.
__________________ 1974 Formula F-233-C
Original Mercruiser Ford 302/TR Outdrive
for syringes, check out Tractor Supply Company or any local feed and seed store. Most of the Southern States and Purina Stores have them. Should have various sizes. You may also check out the grocery store for one used to inject turkeys with marinade. Epoxy Resin won't go through a needle however, you gotta remove it.
I can squirt most consistencies of thickened epoxy through the tip on the syringe I posted. For the really thick consistencies, I cut about 2-4 mm off the end. Been using them since I discovered them 7 years ago.
Feed and livestock should have something of this nature as well.
Those curved ones will definitely handle epoxy, does bring back bad memories of having my wisdom teeth taken out (all 4 were impacted, hurt like a SOB). Spring break of my senior year of college none the less, while all my friends were in the keys sailing......bastards. Had to do it then while the parents insurance would cover it.
West System sells a kit available at (shudder) every West Marine and Boat US. Small packs of Epoxy resin, filler, mixing cups, mixing sticks, syringe, instructions. Like $18.00. Great for what your doing. Bigger jobs justify bigger cans, but for just a few holes....
Had a balsa cored boat once. Used them every time a new hole got drilled. Way better than wood fillers.
Remove screws
Drill out to about 1/2", but not all the way through
Chamfer hole
Scrape some deep ridges on the inside of the hole
Fill with thickened epoxy
Drill out for new mounting screws in center of epoxy plugs
Finish with colored gel coat
Install transducer.
RingLeader - 2/1/2005 1:20 PM
Epoxy resin thickened with cabosil. Mix it up and put it in a syringe and back fill the holes... pulling the syringe out as you fill from the back of the hole forward. Fill until almost level with the transom surface (within 1mm). Then let cure. Now sand/grind smooth and out from the hole about 1/2" or so. Now you can do the gel coat touch up.
Ollie: between my over view and your detail I think by george we've got a perfect job.
If you are going to make a permanent repair and not mount again in the same spot, here is what I would do.
Supplies needed...A few dixie cups, a few popsicle sticks or similar, a razor blade, blue masking tape, 100, 200 & 360 grit paper, lacquer thinner or acetone.
Your local auto paint supply store should sell a product called "kitty hair". It is fiberglass resin & chopped fiberglass hair. Also buy a small can of Evercoat polyester glazing putty. It should come with a small tube of hardener. The kitty hair and the putty use the same hardener. Ask for a color hardener. A color hardener makes it easy for you to see it is properly mixed. Take some of the blue painter masking tape and tape around the hole, leaving about an inch of gelcoat showing. The tape will protect the gelcoat you are not messing with.
Lightly sand and rough the area around the hole and then wipe clean with lacquer thinner. Take a spoonful of kitty hair and a pencil eraser size drop of hardener in dixie cup and mix with popsicle stick. When all of the kitty hair is the same color, you can stop mixing. Fill hole with kitty hair. Overlap the holes and leave a raised surface.
Gently heat the kitty hair with a heat gun or blowdryer and it cures quickly.
Take 100 grit and knock it down level with the surface. Remove the blue tape.
Now take 220 grit and smooth it out nice and level.
Now mix a spoonful dab of putty and pencil eraser size drop of hardener in the dixie cup. You have about 3 minutes to work with it. Spread a small amount of the putty on one side of the razor blade and spread a light coat over your work. Gently heat to cure. Repeat procedure.
Now work the 220 and 360 until you have the smooth finish you desire. Use your fingertips to find any problems. Just repeat the putty if you have a spot that needs a little more attention. If your hole is the size of a quarter, the full repair area to be sanded and painted will be about the size of the bottom of a beer can. It is now ready for paint, but that's another thread. If you decide on this method, just PM me and I will walk you through it. I have fixed boats and a ton of bathtubs with this method.
Filling Holes 
