Treated wood ok?

rcl700

Petty Officer 2nd Class
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Jul 8, 2008
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161
Is pressure treated 3/4 ply doubled up ok to make a new transom board out of ? Mine is still ok but I'd like to make one so it will be ready when I need it.

My boat makes about 15 trips a year to the lake.
8hr max each time.
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: Treated wood ok?

Most people advise against it. Exterior grade coated in epoxy resin.
Myself i went composite and have no regrets....it was pricey but will never rot again.
Is this fiberglass or aluminum boat?
 

ezmobee

Supreme Mariner
Joined
Mar 26, 2007
Messages
23,767
Re: Treated wood ok?

The new PT will eat aluminum.
 

papaz

Cadet
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Feb 26, 2010
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15
Re: Treated wood ok?

Mine had pressure treated (the previous owner had redecked with) on it. The top of the plywood will buckle and it will eat fasteners up. I replaced mine with 3/4 marine and have never regretted it.
 

northernmerc

Chief Petty Officer
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Apr 6, 2009
Messages
401
Re: Treated wood ok?

Are you referring to the plywood board that fastens over the top part of a transom that is made of fiberglass or aluminum, or of replacing the complete transom?

If your PT wood is anything like what we get here, it delaminates easily. It also has a rough surface and easily gives off slivers. A good exterior grade fir plywood or marine plywood should be fine. That is especially true if the wood will not be immersed much and will have a good opportunity to dry after use.
 

rcl700

Petty Officer 2nd Class
Joined
Jul 8, 2008
Messages
161
Re: Treated wood ok?

Are you referring to the plywood board that fastens over the top part of a transom that is made of fiberglass or aluminum, or of replacing the complete transom?

If your PT wood is anything like what we get here, it delaminates easily. It also has a rough surface and easily gives off slivers. A good exterior grade fir plywood or marine plywood should be fine. That is especially true if the wood will not be immersed much and will have a good opportunity to dry after use.

I mean the transom. I thought exterior grade was PT (same) shows what I know. The one on the boat now has no epoxy or fiberglass coat on it. Will it be ok to make one without these coating or is that a bad idea?
 

ezmobee

Supreme Mariner
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Mar 26, 2007
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Re: Treated wood ok?

Yeah exterior grade mainly means it's got waterproof glue in it.
 

northernmerc

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Apr 6, 2009
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401
Re: Treated wood ok?

Coating it with epoxy or fiberglass would be fine if the wood is dry and stays that way. Any cracks or holes in the coating could let moisture in and may actually cause the wood to rot more rapidly as it never will dry properly because of the coating. If you don't want to spend much time or money on this, just use a good suitable exterior or marine grade plywood.

I don't know about your area, but where we live fir exterior grade plywood is relatively inexpensive. Usually, fir plywood is an excellent product. Look for G1S or G2S fir plywood (knot free and sanded), and try to find a piece without patches. Many pieces will have patches where they cut knots out. Stay away from Spruce exterior plywood; it's not nearly as durable as fir plywood.
 

northernmerc

Chief Petty Officer
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Apr 6, 2009
Messages
401
Re: Treated wood ok?

Another thing - how thick is the transom on your boat? Will you have to laminate two pieces of 3/4" plywood together? Or can you find thicker plywood at your local lumber yard? Thicker plywood is available, but not every lumber yard will stock it.

If laminating, use a top quality glue (Weldbond) and also screw (or bolt) the pieces together using non-rusting fasteners.
 

rolmops

Vice Admiral
Joined
Feb 24, 2002
Messages
5,299
Re: Treated wood ok?

It is very important to use marine grade plywood.This plywood is much denser than any other.
A good transom is one and a half inches thick,so a good way to make one is by gluing two pieces together with waterproof glue (gorilla glue-water proof).After having glued it,drive a good number of wood screws through to keep it together while the glue sets(and expands).
After it is al hard and dry,cut the shape of the transom out of your double thick marine ply.Now use resin epoxy on all the cut edges to makes them water proof.The rest you can just paint with a good quality wood paint,but paint it twice.
When you drill through your new transom,always daub the inside of the drill hole with epoxy to make sure water will not penetrate into the wood.
Good Luck
 
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