My first boat and a new project.

Hello all,
I got my first boat and am now starting the repairs. Its a 1978 15foot boston whaler. There are several delaminated spots in the deck that I am going to repair. I have started to fill all the screw holes and other smaller holes, but am nervous about injecting the delaminated spots. Seems like a simple task, but some of the spots that are delaminated are not that bad and I don't know if the gap will be big enough to allow the epoxy to flow freely to all the voids under the deck. Maybe bang it with a rubber mallet to create a bigger gap?
I got a gallon of 105 west systems epoxy and and the 206 slow hardener. I was told after I bought it I should use the 209 extra slow hardener to reduce the thermal expansion that could happen between the polyester shell and the polyurethane foam.
Anyway I have a few question about this stuff. The holes that I filled were done with the epoxy, and the 403 filler. I had to add a lot to get the epoxy thick enough to not sag off the boat since they are vertical holes. How much of this filler can I add before it seriously loses strenghth.
And the last question for now is the sanding. This stuff is tough to sand even with the filler added. When I start sanding it heats up and gets gummy and will not sand properly. Do I just let it cool for a few minutes and then jump back on it to sand again? Sorry for all the question I have a million more still. I tryed both whaler forums, but there does not seem to be a great deal of activity over there.
Thanks in advance.

 

I wouldn't worry about thermal expansion unless you have a void the size of your mixing cup.

Don't cause more damage to your boat with a mallet. Maybe try a syringe?

You will not weaken your epoxy with 403 filler.

If it's gummy, it's not cured. More time or the proper mix ratio will get you where you need to be.

 

Re the slow cure, and being runny enough to fill the voids:-

After you have injected the epoxy, warm the spot up with an airgun (heater) . It will make the epoxy super runny, and enhance its flow into awkward spots, and hasten its cure.

 

403 is milled fibers and typically needs a thixotropic additive to keep it from sagging or running. Silica is the obvious choice for this (West System 406) and just a little works wonders.

Epoxy will flow with capillary action into tight fitting voids, but often it can also just run right through the foam in a Whaler. You see, not only are there voids and delaminated areas within the foam filled space, between the deck cap and hull shell, but usually there are cracks too. This means when you inject or attempt to pour epoxy into them from above, it just runs right through to the lowest point, often just pooling on the bottom of the boat in a puddle, after finding it's way through cracks and fissures.

After years of attempting to repair these boats, I don't do them any more for this reason. You can pump gallons of goo into them, just to have it float the foam up to the deck cap, after it's pooled on the bottom of the hull shell. I will not touch another one, unless the owner lets me pull the cap and liner. This is a very rare thing for the owner of a 15', relatively cheap boat, so most just get beat down, until they're land fill food.

As to sanding cured resin, properly mixed will not gum, unless you're using too fine a paper at too high a speed. Yep, it's tough stuff, particularly with milled fibers and silica in the mix. Log onto westsystem.com and download their free user's guide, about how to do the various things you need to with epoxy. It'll cover mixing, fillers to use, etc. Using proper procedures and insuring proper mix ratios will yield success.

Lastly, to prevent ooze out on vertical holes, use a wooden plug, which can be mashed into the injection site hole, after you've done the deed. When the goo cures, drill out the wooden plug and mix up a new batch of filler to fix the shallow hole that remains. This way you don't have to over thicken the goo and you don't have streaks of epoxy all over the boat. Also supply a vent hole above the area where you're injecting, so the epoxy can flow as you're injecting. This will let the epoxy get into all the nooks and crannies and if you see epoxy coming out of a vent hole, you know you've filled that local area. Use the wooden plug thingie on these too.

 

Damn I have done well over half of the holes with 403 filler assuming it would be the best. I also have a can of the 406 filler that I should have used. I will use that for the rest of the holes I have to fill. As far as the expansion issue I am very nervous there is voids bigger then my measuring cup. I really don't know whats down there. For the injecting I think I am going to switch brands to o resin reasearch who has a hardener with 200 minute pot life. I think this will reduce the heat as it cures over a longer period of time. I would use west systems as I already have it, but the slowest hardener they make is the 209 extra slow whit a pot life of 60 minutes. Maybe a thickened epoxy won't flow as much and tent to stay where I want it, but the tricky thing again is I really want it everywhere there is a void. I want to let gravity take care of this, but as you guys said it may make its way to the bottom of the hull.

 

I use a caulking gun for these sort of things. You can purchase empty cartridges, fill them with thickened goo and just pump it right into the holes.

You'll want to use both milled fibers and silica in your mixture. Milled fibers have the best bond on 'glass, while silica will control viscosity, so it doesn't sag.

 

Thanks I will do a combo of 403 and 406 for the next set of holes.

 

Mostly 403 with enough 406 to control viscosity. You can add some talc (baby powder) to smooth out the mixture, so it flows a little better.

 

I filled some holes using this method and you guys are right the 406 controls the viscosity much better then a bunch of 403. Thanks for the tip. I am going to sand the hole tonight and see how it affects that task.