This sounds like a crazy idea but since I have the mast step torn apart this would be a good opportunity. Other parts of the cabin top have rot as well even though you cant feel it when stepped on. I was thinking about getting some semi flexible tubing such as a brake line or copper tubing to use like a syringe to inject epoxy. The tubing can be fed through the open area of the fiberglass (mast step) to areas normally unreachable without tearing everything apart. Thoughts?
Must keep the mast from coming down (fiberglass)
- Thread starter Project_Mayhem
- Start date
I'm thinking you are going to need a high pressure pump to geta semi liquid very far. Perhaps a grease
gun
gun
I was thinking about pressurizing a soda bottle with an air compressor. That should have more than enough power to push it through and if it starts to gel it's a pretty cheap loss. Below is roughly what I'm talking about. It would of course have a cap with metal tubing going through it. I've used this method in the past for liquids
Im guessing it's probably a lot of rotten wood. I really should sell it but I digress. It'll add some strength to the cabin top but of course it'll never be perfect and it's not worth ripping everything apart, at least not on this boat. My idea is to put a fiberglass fish tape in there as far as I can, move it around a bit, insert the tubing as far as possible into the new void and inject while slowly pulling it out. Or inject until I see epoxy coming out from the top and then pull out the tubing
I'd be inclined to dig out as much rotten wood as I could as deep as I could. Vacuum it out and let it dry out as much as I could. Then, using pieces of G10 slathered in thickened epoxy I would stuff the G10 into the void. That is the rough description, it will take a bit more finessing to actually do this to account for the uneven edges of the buried rotted core material.
G10 has some advantages over wood products in that it is impervious to water, unlike plywood, among others.
G10 has some advantages over wood products in that it is impervious to water, unlike plywood, among others.
There's slightly less than a half inch between the two skins. I was thinking about doing a 2ft radius around the mast step so it probably wouldnt be possible to put any new material in there that deep. Some of the stuff I pulled out was like wet sawdust
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,250
Doing that might be accomplished with one of the Thixo products. I'd contact Jamestown and ask them about the project and your considered solution.
Mast support has been torn apart and reglassed. I had to do some sanding because some masking tape was embedded in in the epoxy. How even does the surface need to be before applying gelcoat? There's at least an 1/8" difference between various areas. Im assuming gelcoat is too brittle to be used in thick amounts under the mast?
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jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,250
Gelcoat is pretty but not able to sustain the weight of a mast. You would need a step (it would have a flat surface) and then put a bedding caulk like 4000 to further cushion the gelcoat.
Apply a thick coat of was on a hard surface, The wax is a release agent. Then slather the area of the surface with a final layer of thickened epoxy with fiberglass fibers. Press the waxed hard surface on to the final layer of epoxy. Gently level the surface against your hard waxed board. The board serves too give you a level surface. Some epoxy will squirt out from under the board, but you should get a level surface. You might even put a small level on the hard board to assure near level. If you have applied wax, when the epoxy hardens you should be able to remove the leveling board. Let the epoxy cure hard a couple of days. When cured, sand any over shoot. You may put gel coat on top after cleaning the wax off. If you are putting a mast on ttop of gel coat it is possible that it will break. Since the epoxy is not exposed to UV light You can leave it alone.
At least that is what I would consider.
Thanks for the fast response. Your approach is reasonable and logical. Why do you suggest 4000 instead of butyl?
So far, looking good. You're correct a thick layer of gelcoat will likely crack. Not a big structural issue, however you just put all this work in to it and you would like it to look decent. Fair the surface with an epoxy based fairing compound, like TotalBoat TotalFair or Interlux Watertite, or your own fairing compound with West System. Slather it on like you are doing drywall and sand it smooth. Then apply the gelcoat. You'll want the gelcoat to be a little proud of the surrounding area because it will need to be sanded smooth and polished.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 23,250
I like butyl when I have fixtures with fasteners to adhere the parts together. When dealing with a water environment I prefer a product that serves as a caulk and bit adhesive. Flexible and cures with a smooth surface. I’ve used the 4000 UV in the past. Practical Sailor gave it a bad rating in their reviews of Caulk sealant. The preferred the Sika 291 and 295. The 295 is similar to the 4000 product but with a recommended usage by PS.
I'm doing gelcoat on this repair mainly for educational purposes for future projects. After a bit of thought I am leaning more towards 4000/4200. I'm guessing butyl will just keep getting thinner and thinner as the mast sways/compresses whereas the caulk will retain it's shape after there's no longer a higher load exerted by the mast
I assume the fairing compound should be a hair shallower than the surrounding deck?
Gelcoat
How many coats of gelcoat are recommended? Just enough to make it look pretty? My gelcoat has waxed added to it. I assume I need to wipe it down with solvent to get rid of the wax that came to the surface after it cures? Can I apply more on top of a partially cured (tacky) layer? I would assume no since some of the wax is on the surface
On a side note, I bought some E-Bond epoxy since the name brands are close to $200/gallon. This is the first project I used it on. I found a LOT of amine blush (visible in first pic) on the uncovered repair after curing. It felt like rubber but of course disappeared within a minute of sanding. Other than that, I'm pretty happy with it's performance. Blush aside, West and TotalBoat only performed a hair better. Estimated temp during the day was about 50F. I can feel the temp drop lower in the building when the sun goes down. Not sure if temp has anything to do with amine blush.
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Yes.
As much as needed. This is why I use gelcoat without wax. If the gelcoat hasn't fully set up, then it is easy to add more. And since no wax gelcoat won't set up until it is cut off from air, it is possible to just keep adding coats. When is it time get it to cure, spray some liquid car wax on it. It will set up in minutes. Spraying PVA will also work, it is just more expensive than spray wax but it is easier to clean up.
With wax gelcoat it will be necessary to clean the wax off before adding more, thus it is better go thicker and sand it off than use multiple thin layers. Do not sand it off and do use a solvent designed for removing wax. Sanding will embed the wax deeper into the gelcoat.
Amine blush is water soluble, no need to sand it off. Clean it with warm water and a scotch brite pad. Sanding will grind the amine blush into the surface.
The gelcoat I applied yesterday never cured. I'm guessing ambient temp was around 55F. The can was warmed up with a heating pad and we also tried a space heater on the the repair for a couple of hours. I added roughly 1.75% MEK to it. Can stated around 1.5%. I suspect they forgot to add the wax to this batch. If I cover it up today, will it work or does MEK evaporate?
Get some spray auto wax something that has real wax not a lot of other stuff. Spray the gel coat with the wax. The gel coat will set up in minutes.
I applied some liquid wax to a piece of sheet metal and placed it over the gelcoat (too thick to spray it) and it hardened most of the way! I'm definitely picking up some spray wax. Thanks Dave!
Gelcoat won't fully cure if it is exposed to air, that's why some gelcoat has added wax. The wax floats to the surface and seals the gelcoat from air. The spray wax simply seals the surface from air and the wax hardens. Of course there is a "proper" way to do this with PolyVinylAlcohol (PVA) which is water soluble, so it is easier to clean off, but it is also about $30 a quart. It makes sense if you do a lot of gelcoat work, but for an odd job or two in a small area, go for the TurtleWax.