Trim Tab Install

Salmon Fisher · Posted: Tue Oct 13, 2009 11:12 pm Post subject: Trim Tab Install

My next project before hydraulic steering is installing Bennett M120 sport tabs. Roger, C Squirt, has been kind enough to walk me through process. He used West System epoxy. I will be removing core in pilot holes with a dremel and filling with epoxy. What is the best way to accomplish that in the transom that is vertical? Use of a syringe and then taping over until epoxy cures? I suspect I need to use a heat lamp/flood light arrangment to put some heat on it.

Am I on the right track? I will also need to fix bad screw job in cockpit on the existing fuel tank holding pieces as they have pulled out. Any suggestions on that would be appreciated, too. Just finished the cooler holder over splash well with Work Release Jim's help. Consulted True Story's photos, too. Sure is nice to get cooler off floor. Oh, am also building floor boards for cockpit. Sure is fun doing projects on the boat to make it better.

Thanks all!

Patrick

Yellowstone · Posted: Wed Oct 14, 2009 12:00 am Post subject:

Patrick - the balsa core under the fiberglass and gelcoat of both the transom and the sole is easily removed to a wider diameter than the hole you drill originally or find already in place. You can put in a hefty core of epoxy to surround your screw, but if you do, then it becomes difficult for a SS screw to get much purchase in the hole that you need to accommodate your SS screws. Instead of epoxy I use good old 3M 5200 to fill the voids and make sure that the mating surfaces are really clean (the plate which holds the tabs against the transom and the cleat which screws down to the sole are slathered with 5200) which helps create another barrier to moisture penetrating into the core via the screw. The correct diameter hole before you engage your screws may take some trial and error to get the right tension. After the 5200 sets up, things are tight and in my experience, waterproof. Others may have different strategies they use when they set screws in the transom and sole.
John

Robbi · Posted: Wed Oct 14, 2009 12:21 am Post subject:

I used a syringe and then taped over the holes. Mix your epoxy and fairing compound under a heat lamp so you can get as much mixed in and still pull into the syringe. Have your tape right next to the hole so that you can put on quickly. Put heat on the surface to speed the set up time. If you are going to redrill, I would use 5200 and not epoxy. That is how I remounted my trim tabs. I did epoxy the holes left from the screws that held the wood fuel tank pieces.(87 CD 16) I didn't redrill these holes, I used 5200 to hold the pieces in place. My trim tabs were mounted with 5200, (screws and tabs) and they came off with a little heat and a piano wire cutter behind the tabs. (04 CD 19)

Robbi

matt_unique · Posted: Wed Oct 14, 2009 7:58 am Post subject: Fill

Interesting idea with the epoxy in a syringe. I would have suggested mixing colloidal silica to form a paste consistency so that it will 'stay up there'. Let us know how it all works out with the tabs.

thataway · Posted: Wed Oct 14, 2009 6:51 pm Post subject:

I must not be envisioning how you are using the 5200 as a filler. It is not a filler, and not a good material to substitute for epoxy. The routing out of the core all around the hole--I usually make the hole about 3/8" or slightly more, and route out the core for another 1/4". Colloidal Sillica (Cabasol) is a good thickening agent, but I like to add about 50% Silica and 50% medium density filler. You can make a mixture which is as thick as peanut butter, and work it in with a stick (1000 popcycle sticks from a craft shop cost a couple of dollars--I have used less than 1/3 box over the last 6 years, and do lots of projects. l use an exact knife to cut the popcycle stick to the appropiate size. After the epoxy has set up--usually over night, you can drill the pilot hole, the same size as the shank of the self taping screw. Then put a small dab of 4200 or 5200 if you want it more permant over each screw hole before tightening up the screws. There is no problem with "purchase of the screws"--I have been doing this technique for over 35 years, and yet to have a failure.

thataway · Posted: Wed Oct 14, 2009 6:51 pm Post subject:

I must not be envisioning how you are using the 5200 as a filler. It is not a filler, and not a good material to substitute for epoxy. The routing out of the core all around the hole--I usually make the hole about 3/8" or slightly more, and route out the core for another 1/4". Colloidal Sillica (Cabasol) is a good thickening agent, but I like to add about 50% Silica and 50% medium density filler. You can make a mixture which is as thick as peanut butter, and work it in with a stick (1000 popcycle sticks from a craft shop cost a couple of dollars--I have used less than 1/3 box over the last 6 years, and do lots of projects. l use an exact knife to cut the popcycle stick to the appropiate size. After the epoxy has set up--usually over night, you can drill the pilot hole, the same size as the shank of the self taping screw. Then put a small dab of 4200 or 5200 if you want it more permant over each screw hole before tightening up the screws. There is no problem with "purchase of the screws"--I have been doing this technique for over 35 years, and yet to have a failure.

After you have the routed out hole filled, putting the tape on keeps the epoxy from sagging. But with a good stiff mixture, the sag is minimal.