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View Full Version : Oak vs. Mahogany Frame Repair



PRIMEAUX
08-29-2010, 09:55 AM
My 12' Concordia Sloop has 2 rotted pieces of oak framing, the last and lowest piece on each side that is right up against the transom. The blueprints specify oak, but a friend mentioned replacing it with mahogany. Said I would never have to worry about it rotting again. Is oak that much stronger? Why would I not use mahogany? Have both woods in stock, nor are they very big pieces, so it is not a cost issue.
Thanks.

Ian McColgin
08-29-2010, 10:00 AM
Mahogany rots just fine. But in that size boat, either will work as a frame. I'd go with oak just for continuity. Pour some antifreeze into the endgrain and red lead the ends or seal with CPES and it will outlast your grand children.

G'luck

beachgeek
08-29-2010, 04:58 PM
What does the antifreeze do? Does the red lead keep out mold & mildew?
Thanks

skipper68
08-29-2010, 06:46 PM
Antifreeze absorbes water out of the air.Theres a chemist on the site did tests,as he preserves museum drydocked boats with it.As far as red lead,we use it for smoothing,otherwise,I'm hoping to learn another lesson here. The only things I know,is oak is stronger,but theirs a fungus that attacks it down south,so it must be encapsulated.

sdowney717
08-29-2010, 07:01 PM
The green antifreeze is poisonous to all life.
The wood absorbs it like water
It takes a long time to dry out
When it dries out Ethylene Glycol is still in the wood just more concentrated or crystallized
I do think in humid air the wood will keep a more stable balance if EG treated.

beachgeek
08-29-2010, 07:03 PM
Wow, I live in Florida and have some boards to replace, I'm not sure what they are though. So you just put it at the ends where it butts to the next piece?

I am an EE and trying to fix my wood boat, which I know nothing about wood working.

gavinpascoe
08-29-2010, 07:19 PM
So is it best to add antifreeze before or after steaming frames? In my case am bending them in-situ to replace some old rotten ones.

thanks

Peter Malcolm Jardine
08-29-2010, 07:29 PM
Antifreeze absorbes water out of the air.Theres a chemist on the site did tests,as he preserves museum drydocked boats with it.As far as red lead,we use it for smoothing,otherwise,I'm hoping to learn another lesson here. The only things I know,is oak is stronger,but theirs a fungus that attacks it down south,so it must be encapsulated.


Nope, antifreeze is an antifungal in this case. Nope, red lead is not for smoothing, it contains lead tretraoxide, which is poisonous to everything, including people. It is a very effective killer of rot and bacteria spores. Nope, Oak should not be encapsulated. White Oak is one of the top five wooden boat building woods ever, and is very rot resistant. It does turn black if exposed to fresh water, but it lasts longer as framing than almost any other wood.

If you paint everything with red lead thoroughly before you assemble pieces, and then paint it again, lots of rot resistance happening. Copper napthenate (Pentox) is another wood treatment. The copper kills rot spores. Antifreeze is something I have never used, but heard lots of people talk about it. On smaller boats, we are talking a lonnnnnnng time between replacements woods with any of these treatments.

Breakaway
08-29-2010, 09:20 PM
Does anyone know if the treating wood with antifreeze affects its ability to be coated; painted or varnished?

Kevin

skipper68
08-29-2010, 10:01 PM
:)See! Knew I'd learn more!Didn't know about anti rot on the EG tho, or red lead. Heres the post to find;Resources/product search..AntiFreeze to swell checks,by Dave Carnel. 6/18/10. It's Fascinating! I liked the part where he let it set and weighed it,watching the volume increase with the water in the air. Hope this help.

hanleyclifford
09-05-2010, 07:59 PM
I have used both of these woods to laminate and scarf in new frame heels and found them to be equally satisfactory.