Using West System with Aluminum channel

[Jackman]

Working on rehabbing the hatch to the bilge we walk on to get in the salon on my 1985 32ft FB. It flexes a lot when we walk on it because the core was waterlogged. I want to encapsulate birch plywood with west system to reinforce it but instead of putting the hinge bolts through the wood I want to set some narrow aluminum channel in west system and drill through the channel for the bolts. I think the water intrusion came from the bolts leaking rainwater into the core. Any thoughts on Aluminum and the West System?

 

[Boatsb]

No plywood. That's just the wrong way to fix it.

If your using epoxy you can use 1/2 PVC foam core. Put the bolts through the foam core and glass. No need for aluminium.

I would tear out the old messy core, fair and add a layer of 1708 in thickened epoxy and lay the core in it. Then 2 layers of 1708 over the top and its stronger than the original and cant rot.

 

[Cricket]

Are you cutting the underside of the hatch open and removing the current wet core or just trying to add plywood to the underside of the hatch?

 

[Jackman]

Core is already out and everything is already sanded and cleaned up. Will PVC be stiff enough for the larger beer bellies that frequent my boat? I don’t like flex if I can avoid it

I’ll try to locate some. Have not seen pvc local to me

 

[SKYCHENEY]

I have bonded aluminum to fiberglass with West and it worked fine. I'm not sure that its your best option, but I don't think you'd have a problem with it.

 

[Cricket]

Pretty sure Scott is referring to cores like Divinycell or Corecell, or Coosa, etc.
The other posters are correct, forget about using plywood.
As far as inserting something to attach to we always use G10 fiberglass strips and then tap for machine screws instead of using sheet metal screws.
Post a photo if you can, you will get some really good advice from the gang here.

 

[Boatsb]

No actual PVC sign board. It's a common foam core. DO NOT USE IT WITH POLYESTER.

Rough up the sides and epoxy away. Its available all over at reasonable cost. Coosa, divincel and the other core materials referred to work well with both epoxy and polyester and are usually more expensive and harder to find if you dont have wholesale supplier in the area.

 

[racclarkson@gmail.com]

Core is already out and everything is already sanded and cleaned up. Will PVC be stiff enough for the larger beer bellies that frequent my boat? I don’t like flex if I can avoid it

I’ll try to locate some. Have not seen pvc local to me

I wondered about the rigidity and came across this plywood/PVC foam board comparison.

http://www.bertram31.com/proj/tips/pvc.htm

Not sure if this the same stuff being talked about. If it is, the rigidity comparison is striking.

 

[Jackman]

So I found a commercial source for 1” pvc sheets in 4ft by 10ft sheets. Might try this stuff. I also have to rebuild my battery box that sits underneath the hatch I’m fixing. Have 2 8D batteries sitting on the old plywood platform that’s shot. Not sure pvc is such a good idea for this

 

[Boatsb]

3/4 is the largest I'd use. Its the right stuff.

Based on real world experience.

1 an increase in rigidity when laminated with 2 x 1708 bias each side makes it lighter and stronger than expected.

2 you can bend it into shapes and laminate to curved surfaces that plywood wont contour to.

3 it wont rot. Ever.

Just rough it up with 40 grit on a pad sander. Use good epoxy and enjoy years of trouble free use.

 

[SEVEN]

Find a plastic water tank with similar Dimensions. Cut the top off and add a few pieces of trim so the top fits over the batteries. It’s an easy and yet great way to protect your batteries and your bilge

 

[Jackman]

So you convinced me to go PVC for my combing pads as well. Going to use silicone bronze hardware with closed cell foam. Which closed cell have you folks used for combing pads? The pool noodle type or the black type?

While I’m at it might go pvc with battery boxes and west system it to the hull in between the motors