Trimming plywood thickness

[Berrimilla]

Hi there,

This is not house related but rather boat related. However with a bit of luck the question is generic enough that it might find an answer here.

I am currently re-bedding the deck hatches of my boat, as they are all leaking. The hatches consist of a square aluminium frame on which the hinges and then the hatch panel are mounted. The alu frame is then mounted on the deck on top of a wooden frame. The frame is epoxy-glued to the deck. The whole assembly (alu frame, wood frame, deck) is then thru-bolted.

The leak happens to be between the wooden frame and the deck. So I am rebuilding new frames using plywood (2x12mm) glued with epoxy.

The problem is, the deck is not flat (of course). I need to trim the thickness of the frame so it sits flush on the deck. I made a template in MDF of the curvature of the deck. I need to remove about 12-15mm of thickness in the center of the frame.

How would you approach that? Sanding? Planing? using a router? a jig-saw?

Many thanks in advance for any advice!

Antoine - Berrimilla 2

[Kermit]

What gear have you got at your disposal @Berrimilla? I'd probably just start with a sander and see how I go.  

[Jason]

Hi @Berrimilla,

Welcome to Workshop. This looks like a great project. Let me tag some of the other members that have shared boating projects on the site such as @happy and @PeterT to see if they might have some suggestions for you. But as you say, your question might also be able to be answered by other community members, too. We have loads of members sharing helpful advice and inspiration every day. 

Great to have you on board! (pardon the pun) We are looking forward to seeing how your project progresses. 

Jason

[Berrimilla]

Hi @Kermit 

I've got:

- An orbital sander

- A Jigsaw

- An angle grinder with sanding flapdiscs and a sanding disc pad (I'm still waiting for the discs themselves)

- A router

[PeterT]

Hi
Does sound like an interesting yet challenging task that lies ahead. My boating project was completely different, as I had to replace the carpeted plywood flooring in my runabout boat. Incidentally the project was a little more involved then I first thought, but got there in the end.The two big tips I got from the workshop were both relating to the waterproofing of the plywood, to add to lifespan . The former floor was marine ply, but found that it was completely rotten in places, once I removed the carpet. I found the tip of using formply, instead of ordinary marine plywood to be an excellent tip, because the surface area was presealed on both sides, so no need to apply any waterproofing ...I used 17mm ply. What is relevant to this project though ( I think), is the need to ensure that the end grain part of the cut ply is water proofed. Bunnings @ Belrose advised that the best product was "Ecoseal", aerospray can (300grams)...made by Tanalised....problem was that most Bunnings stores were out of stock...hard to get...finally found plenty of stock at the Narrabeen Bunnings store. The active constituents of the product were Copper Naphthenate, Perethrin, liquid hydrocarbons...there may be other product brands more easily accessible, with the same ingredients..Not much help I know with the main problem facing you, but for what it is worth..good luck..Peter T

[Berrimilla]

Thanks for the advise @PeterT . I was actually planning to encase the whole assembly (the wooden frame once glued on deck) in fiberglass. Which is gonna be an interesting task in itself So it should be completely water-proofed and leak free for a long while.

Cheers,

Antoine