Embedded Files
This step involves removal of the old rotten wood, which was mainly done previously during the damage assessment phase, and then replacing the supporting wood. The supporting wood is affixed or adhered to the inner part of the transom by using fiberglass and a lot of resin. The fiberglass outer shell is left intact. There are some minor stress cracks in the outer shell that will be fixed later, but otherwise it's good to go. Here we will only be replacing the supporting wood which is on the inner side of that shell.
Creating a template prior to cutting the boards.
On the left we're cutting the first draft of the transom template out of 4x8 sheet of cardboard. We were able to get this from the lumber yard for free. Well we did buy a lot of plywood, so I guess it wasn't free. On the right, you can see how beautiful the transom will look, nice to not see rotten wood there anymore. On the right we finally have the template cut just right, the dry fit is nice and snug.
Cutting the Wood
Here is the result of the pieces cut. If you plan it just right, you should be able to cut the transom pieces and have enough left over for other parts. We're using 3/4" MDO plywood which isn't cheap. So we used the remaining wood to carve out some other pieces we wanted to replace. Also, I decided to put a bevel on the edges that will have fiberglass laid over. Take peek at the bevel and how we anticipate the transom boards fitting together.
Preparation of the transom support boards.
Here we want to rough up the surface on the boards to encourage the wood to absorb the resin, as well as give the resin something to hang on to. You may ask, why did we get plywood with the overlay (paper surface)? Well, I was really after the core wood here, and the paper served as a marker to see the locations on the board that I needed to grind more. Looking back on the wood purchase, I think we could have done without the overlay, but I am completely impressed with the quality of the wood. The image on the right shows the roughed up surface, which will absorb the resin rather well.
Glassing in the transom boards.
We plan to do this on May 9th, and May 10th. This will be a learning experience for sure as the first hands-on experience with wetting out fresh fiberglass. I've heard this is more enjoyable than grinding fiberglass, I hope it's true.
Materials
Here is a few summary shots of the materials bought to do the fiberglassing work. The left photo consists of the initial shipment and shows the epoxy resin and hardener. We also got some 6" tabbing, a box of cheap brushes, and some milled powder material we plan on mixing for a fillet (anxious to see how that goes).
The middle picture shows the roll of 1708 biaxial fiberglass we used for backing the transom boards. We would have preferred to use regular Chopped Strand Mat (CSM) to save money but this will work just fine. We realized the less expensive substrate would have worked just as well after ordering the biaxial. This info was gathered after viewing the posts at http://forums.iboats.com.
Finally the rightmost photo shows a tool that we gained much appreciation for. This mixer-bit attached to a cordless drill proved very valuable. We got this tool from Home Depot and found it was very useful for thoroughly mixing the resin with hardener. Also note the glass cup below the red end of the mixer. We found that filling a glass with acetone, and then dunking the end of the mixer in the glass cleaned it instantaneously. The point here is that the mixer and the cleaning method proved to save a lot of time and basically saved energy otherwise.
Cutting Fiberglass
Cutting the fiberglass was not easy with normal scissors. Although it's hard to see, we found that placing the fiberglass matting (or cloth) against a board and then running a razor blade along the line to be cut was very easy. Keep those scissors near by for the random strand of fiberglass you'll run into when dry fitting your application.
CRITICAL STEPS!
The next step involved everyone within earshot. Hell if we had a small children around, we probably could have used their help too. I would suggest AT LEAST 3 people to do the next step. Luckily my younger brother came by on short notice to assist. Jena and Nick (boat owners) were in the boat and Alex (bro with a free ride pass) was in the shop mixing new batches of epoxy resin. Here's how it went.
We first dry fit everything, and ran through a few rehearsals on how things were anticipated. We then put the transom board in the boat where Jena and Nick applied a solid coat of epoxy resin directly to the board. We then placed the fiberglass on top of the board and wet out that layer with a few batches of epoxy resin. Meanwhile Alex was making new batches of epoxy resin. Finally, when the board was wet out we carefully placed the board, with the resin and fiberglass applied to it, against the stern of the boat. After pulling the flaps of fiberglass mat that was left to hang off of the perimeter of the board we quickly clamped the board against the stern. Take a peek at the result below.
Transom Core Installed (Part 1 of 2)
Those are 4x4's that don't flex at all on either side of the transom, we used 1/2 carriage bolts and fender washers to hold the 4x4's and transom boards against the boat. The smaller bolts were inserted through pre-existing holes (like the 1/2" bolts) to get more "glue and screw" action to hold the board against the hull/fiberglass. Those supplementary bolts are 1/4" carriage bolts, you can get these for cheap from Lowes or Home Depot (we got ours from Lowes). Also worth taking note on is the hand hold cut out with a small hole saw (see right photo). This hand hold made placing the board against the stern much easier. In the end, carefully placing the board against the boat's transom has been the most difficult to do so far on this project (and it wasn't that bad with the hand hold and assistance of others).
Tabbing the First Transom Board
After a short break, we were mixing more batches of epoxy resin and hardener and weting out the tabbing. What is misleading in the right photo above, is that the flaps of fiberglass are really not shown. I trimmed them back before taking the picture. If you look on the right photo shown below, you can get a better look at how the fiberglass is wet out against the hull. I'll make a better attempt at taking photos of the flaps left over immediately after the (second) board is clamped against the stern.
Coating Various Other Parts
With some remaining epoxy resin and time left over we decided too put some initial coats on various other boards that were cut earlier. This will potentially save us some time later on in the project. At this point we feel like we're slightly ahead of schedule, but any chance to save time later is being exercised. We actually do intend on taking this boat out for a lengthy vacation in the first week of July.
COME ON BOAT GODS, KEEP US ROLLING ON SCHEDULE PLEASE!!!
Broken Bolts
Remember the 1/4" carriage bolts mentioned earlier? Well those broke off when we were removing them out of the 2nd transom board. Yup, everyone of them. The bigger 1/2" bolts came out fine. We are very happy with the results of the adhesion, it was apparently clamped a little too good. Anyway, I'll need to grind those out of the holes while at the same time being careful not to damage the new transom boards or even worse, the hull. A slight delay on progress, so we'll need to pick up the pace a bit to catch up.
Thankfully the bolts were easily removed by simply heating up the bolt shaft which then caused the resin to release its strangle hold. We first used a propane torch to heat up the only bolt with a bolt head still attached (the other bolts were broken on both sides). The other bolts could not be heated up via a torch because it would have burned the gelcoat or fiberglass, so a different method of heating the remaining bolts had to be used. A grinder was used on the bolt shaft stubs that were sticking out, careful not to actually grind the bolts we just wanted to heat them up. For the bolt shafts that broke at a point inside the fiberglass transom, I used a Dremel rotary tool with a small bit to carve a slot in the bolt shaft. I was then able to use a flat-tip screwdriver to unscrew those bolts.
Anyway, all six bolts were taken out in some fashion or another... To make this possible, we basically had to heat up each bolt shaft. I used a propane flame for one bolt, and otherwise used heat from friction for the rest. Once each bolt was hot enough to make the resin soft, I was able to unthread the bolt shafts with either a screwdriver or a pair of vice grips. This may sound dull, but it was very exciting because we saved many hours of time (much easier and faster than doing a root-canal on each bolt shaft). Here are some photos of the whole process.
Ok, now that we're done fixing what I broke, it's time to move on to the fill the gap on the sides of the new transom boards and otherwise make a nice smooth curve for the fiberglass to be laid up against.
The fillet mixture turned out to be:
4 oz of epoxy
9.5 tablespoons of wheat flour
2 tablespoons of milled fiber powder (for strength)
After lots of experimentation we found these proportions were optimal in making a peanut butter consistency fillet or putty-like substance that was resistant to sagging and was very workable.
More recently we have been cutting the hole for the outdrive to go through the hull. To do this we used a router with some cool bits on the end. We didn't take a shot of the router bits but they gouge a channel through the wood. The bits also have a bearing on them to guide the bit, making an exact replica of the fiberglass shell. Here you can see a sequence of the results:
The lower right most photo shows the clearance we need for the steering rod to clear the wood. There is an installation manual that talks about the specs needed but you basically need a 1 3/4" hole saw drilled in the transom at a 60 degree angle. We may need to do some minor grinding but when we put the inner transom plate up against the resulting hole, it looked spot on. We'll see when we have time to get the entire assembly on for a test fit. In the lower middle and right photo you can see how solid the MDO plywood is, and that we made a good wood--fiberglass/epoxy--wood sandwich.
Not yet done with this phase, this is the primary reason we are "rebuilding" this boat. Once the transom is replaced, we will move forward to replace a stringer near the driver's seat. Check back soon.
For now check out the repair work being done on the stringers and decking by clicking here.
You can also, check out the work being done simultaneously on the outdrive here.
Back to the main page:
Page updated
Google Sites
Report abuse