Making a console

[Grant Holdsworth]

Firstly I'm going to apologize in advance if this is the wrong place to post this. I've been scouring countless forums trying to answer my own questions.

I want to build a center console for my flat bottom jon boat. 30"w X 30"L x 42" h. I've designed the top to be large enough to stand on for sight casting, so it will need to be strong enough to support 200lbs. This is common practice in Texas bay boats. I have absolutely 0 experience with fiberglass so would like to avoid using it, but i don't know if thats possible. Bear in mind my non-existent knowledge and experience of fiberglass, I am not overly concerned with weight and can afford for it to be roughly 100 pounds (ideally less but not mandatory), and i want to get this thing on the water as quickly as possible.
Here is what I am thinking, please tell me if this is a terrible idea or if it will work.
3/4" plywood construction, cleats for support on inside corners, glue joints together with loctite PL3 (will screw together as well as long as they won't hinder epoxy setup), epoxy coat inside console with 1 coat. Then for the exterior, Epoxy + silica thickener + glass microballoons laid on thick maybe 3 coats. Idea behind it being thick is for strength as well as nice finish. Then hit with topside paint and primer. This would be my ideal method of construction due to my extremely limited knowledge of fiberglass, and really i just want to get this thing on the water already. Main concerns with this method is strength, but that's why i want to use 3/4" plywood. Is the thickened epoxy coats on the exterior a good idea or would i be better off with multiple coats of JUST epoxy? I would also add bracing on the part of the console i intend to stand up on.

Would 3/4" with proper internal supports/bracing and just 1 coat of penetrating epoxy interior and exterior, and then topside paint and primer work? Or would this not hold up? Again i have no knowledge or experience in this field but i am looking to get my feet wet. I appreciate any and all advice, even if you're just here to call me an idiot!

 

[fallguy]

The sides don't need to be 3/4" plywood.

Never seal plywood with thickened resin.

If you want to stand on the top, 1/2" plus fiberglass is good, but 30x30 is pretty large.

There are a couple ways to go about it. The big issues are the sun and water getting into the bottom or endgrains on tbe top and or under the attachments. For this reason, at a minimum, fiberglass ought to be used to close all end grains. You don't need great finishing, but if you don't glass the ends; they will blow open.

If you spend a bit more money; you can build it out of coosa.

 

[wet feet]

I agree about avoiding thickened epoxy for sealing wood,you are aiming for good penetration.You are heading in the right direction with your scheme but there are a couple of pitfalls to avoid.I would recommend screwing the cleats to the plywood panels from the inside to avoid the situation where the filler over the screw heads is pulled away from the plywood and water can gain entry.It takes careful drilling of pilot holes and equal care to avoid spinning the screws too tight,but it can be done.After all,the glue will be stronger than the wood and the screws are simply holding things together while the glue cures.You could avoid the need for 3/4 ply if you used the 1/2 inch recommended earlier and if you add battens say 1 1/2 X 3/4 to reduce the unsupported span of the top,obviously on edge.On the outside there is a case for brushing a coat of slightly thickened epoxy over the exposed edge grain of the ply,but only after at least one sealing coat has been applied all over.To avoid chipping on the edges,they should have a radius of perhaps 3/8 applied.Your paint scheme isn't bad and too little is easier to remedy than too much.Too much will be brittle.Just remember to seal the edges of any holes you have to cut for instruments or controls too.

 

[fallguy]

Here is a camper shell with glass tapes. They only protect the ply from thermal and moisture.

 

[voodoochile]

https://www.boatbuildercentral.com/product/console-and-pilothouse-plans/

im sure you can modify from these plans to suit your needs. its cheap considering someone did the design heavylifting for you.
if you know where to reinforce you dont need to be nowhere near 3/4 inch.
fibreglassing is easy to do, easy to redo and start again if need be