Ross M
10-26-2002, 02:23 AM
Author Topic: Red Oak vs. White oak
Jim Dowling
posted 01-17-2000 10:13 AM
--------------------------------------------------------------------------------
I am building a 13' rowboat, using okoume plywood for the sides and bottom, and it was suggested that I use white oak for the skeg, chines etc. I know how tough white oak is, but are there any other reasons why white oak is preferable to red oak? I can get longer lengths of the red oak at a good price. I will be bonding and also encapsulating with epoxy.
Scott Rosen
posted 01-17-2000 10:28 AM
--------------------------------------------------------------------------------
Warning: Red Oak has poor decay resistance and is unsuitable as a boat building wood. You really must use white oak. Moisture has been known to penetrate encapsulated wood, so I wouldn't rely on encapsulation as a substitute for the right wood.
If you want more information on oaks, check out the Wood Handbood published by the U.S. Forestry Service. If you do a search in this forum under "Wood Handbook" you will find the url for the entire book, online, in Adobe Acrobat format.
[This message has been edited by Scott Rosen (edited 01-17-2000).]
NormMessinger
posted 01-17-2000 12:25 PM
--------------------------------------------------------------------------------
Ummmm.... Scott?
It's a 13' rowboat encapsulated in epoxy--a boat-of-wood, not a wooden boat.
I guess I'd be more concerned about glueing white oak with epoxy, from what I've read, than about rot resistance. Okoume is not all that rot resistant either but is commonly use due to offsetting attributes.
Ash would be my choice.
--Norm
[This message has been edited by NormMessinger (edited 01-17-2000).]
Scott Rosen
posted 01-17-2000 01:11 PM
--------------------------------------------------------------------------------
Norm, you have a point. But if the epoxy coating is going to eliminate every possible problem with using an inferior wood, why would you use ash? And why bother with oak at all? You could go down to the local lumber yard or Home Despot, buy a couple of 12 foot Doug Fir 2X4s, and use those. Why even worry about drying or seasoning?--Doug Fir is relatively stable, and anyway, the expoxy will stabilize it even more.
I'm singing the same old tune. Use the stuff you know is good. Compromise is unavoidable, but it's false economy to give up a known advantage for the sake of a small convenience or saving a couple of bucks. Boats are unforgiving. Every time I've taken a shortcut, or used something I knew wasn't right for the job, or ignored a potential problem, I've paid for it in spades.
Remember, failures occur when the boat is under stress. And when the boat is in conditions that cause it to be under stress, you can't afford the failure.
Sort of reminds me of a political saying: Better dead than Red (oak, that is).
Mark Jenson
posted 01-17-2000 03:00 PM
--------------------------------------------------------------------------------
I'm sure this thread will generate a lot of opinion-trading.
Jim, here's a summary of what I've been able to glean from various readings and experiences. A lot has already been said about this subject in this forum - try searching on "white oak" and you'll see.
White oak has been preferred to red oak as a boatbuilding wood because it has a closed cell structure which prevents moisture from penetrating, which supports the fungi which cause rot. This may contribute to gluing difficulties with epoxy, but a bigger problem seems to be the high tannic acid content. No less an authority than Dr. Jaegels suggests washing oak with a 10% caustic solution and redrying to overcome this disadvantage (see WB 145). Others suggest leaving the surfaces rough cut, although still others scoff at that idea.
Red oak has an open cell structure, kind of like a bundle of straws, which allows water to wick deeply into the wood, supporting the fungi which cause rot. However, this very feature allows preservatives to also soak deeply into the wood - Clear Penetrating Epoxy Sealer (CPES) would probably be the best choice, followed within 3 days if possible by regular epoxy for encapsulation. One needs to consider the extra cost in so treating the red oak and then compare it to the cost of white oak, which does not require the treatment.
As far as toughness, weight, and the capacity to hold fasteners, the woods are comparable with white oak being heavier.
One thing I seldom hear in connection with rot is that oxygen is required as well as moisture to support the rot-causing fungi. Encapsulation and preservatives, if properly applied and maintained, can keep both the oxygen level and the moisture level too low to support fungi.
Since the longevity of your boat will only be as good as the job you do encapsulating the okoume, which is very rot-prone, it sounds to me like you should go for the red oak and use CPES if possible, followed by encapsulation.
Now I will brace myself for being told I have it all wrong by other participants in the forum.
Bob Cleek
posted 01-17-2000 03:10 PM
--------------------------------------------------------------------------------
Oh my, such a lot of navel-lint picking going on here! Nothing wrong about all the insights offered so far, but, hey! When am I ever going to convince you guys that YOU CAN'T POLISH A TURD!
Numero Uno: we're talking about a cheap plywood skiff here... basically a short lived "throw away" boat (in the grand scheme of things... It may last your lifetime, though.) It is going to be "en-crap-sulated" in plastic snot. It isn't dependent upon anything to hold it together but a lot of plasic goodge. We're talking a "fibreglass" boat with wood instead of glass in the laminate.
Now, having already made your bed with okume ply and epoxy... which is okay for what you are trying to accomplish, why pick nits over red or white oak? IF you had a hunk laying in the woodpile, fine. On the other hand, Doug fir from Home Despot (good one, Scott!) is every bit as servicable as the rest of the materials in this boat and compatible as well. No point in spending the extra money for a skeg that will last ten times longer than the boat, is there?
Get real, use Doug fir or any other similar plank stock and sheath it along with the rest of the boat. The sheathing will actually provide far more abrasion resistance on the skeg, where you really need it, than plain oak, red or white, ever will. No sense building a Ford with Rolls Royce parts!
Mark Jenson
posted 01-17-2000 03:53 PM
--------------------------------------------------------------------------------
Jim, you didn't say in your original posting that you planned on sheathing the boat with fiberglass. If you don't, I'd say one of the oaks is still probably your best choice. If you do plan to sheath in fiberglass, you can get away with almost anything. But you have to consider the cost of sheathing using a softer wood against the cost of a more durable wood. In other words, if you weren't planning on sheathing in fiberglass to begin with, I wouldn't change the plan just because you could use Doug Fir.
Besides, maybe you like to work with oak - it's your time and money, after all.
Allen Foote
posted 01-17-2000 04:33 PM
--------------------------------------------------------------------------------
LOL...Bob! Scott, ditto to you. Jim, buy the white oak and give yourself the oppertunity to learn how to work with a superior boat building material...that experience may be put to good use on your next venture as well.
NormMessinger
posted 01-17-2000 06:10 PM
--------------------------------------------------------------------------------
Doug. Fir from Home Depot? Not a chance. Can you spell knotty SPF? or Hemfir?
--Norm
Greg H.
posted 01-17-2000 06:32 PM
--------------------------------------------------------------------------------
Where would you rate yellow pine in this list?
If you build it well and take care of it, it will last....if you don't, well a boat made of oak and mahogony will decompose more slowely than one made of plywood (or plastic for that matter) laying out in the weather.
Norm, I lucked out once at hd and found a whole pallet of Dougfir 2x4's...but it's rare...
Bob Cleek
posted 01-17-2000 08:11 PM
--------------------------------------------------------------------------------
I'd think yellow pine would be excellent!
Ah, yes, Hemfir... LOL... what else do those guys call that stuff? "White wood?" We are a little better off here in the west, where the Home Despots sell more local stuff. I guess they are okay for pressure treated fence posts and so on, but somehow, I can't bring myself to build anything handcrafted out of wood that's advertised as "premium" because it has "less shakes, less splits, less bark and less knots!" Oh, wow... I should hope so! Then there's their magnamous offer: "No extra charge for selecting your own!" ROTFLMAO! They KNOW they aren't losing a dime on letting you hand select the stuff because they only sell one grade!
Don Danenberg
posted 01-17-2000 10:26 PM
--------------------------------------------------------------------------------
Long-leaf Yellow Pine has been, for centuries, considered an excellant replacement choice for White Oak (Quercus Alba) as framestock. 'Quercus Rubra' is waaaay below that on the list. Don
TomRobb
posted 01-18-2000 08:22 AM
--------------------------------------------------------------------------------
I suppose we all imagine we're building for the ages, that someday some yet to be born archeologist will dig up a boat of ours and put it in a museaum - The Sausalito Ship. Obviously there's no point in consciously making crap that we'd be embarassed about later in life. But a question: Is one of the virtues of wood (biodegradable)that it won't likely be around forever? Isn't there a certain poignancy to the idea that our work is only temporary - like we are? Do the best you can and move on, and make way for the next generation? A counter example might be the glut of ugly fibrglass boats that will eventually have to be landfilled or maybe sunk as artificial reefs? (Could they be ground up for furnace fuel?) At the Center for Wooden Boats in Seattle we're more or less constantly repairing the fleet. It may seem to some to be treadmill work. It really is keeping the old skills alive. It maintains the waterfront/boat/seafaring culture that is the real point of that museum. If Jim Dowlings skiff doesn't last forever he, or his grandchildren, can make a new one. It's the skills, the culture that need to be passed on. It seems to me that's what WB, this forum, the Bobs-n-Scott, Ian, et.al. are doing here.
Eb
posted 01-18-2000 12:08 PM
--------------------------------------------------------------------------------
I don't want my boat to last forever, just longer than me.
Scott Rosen
posted 01-18-2000 02:49 PM
--------------------------------------------------------------------------------
No offense, but if your goal is to have your boat outlive you, the easiest way to do that is to build the cheapest, easiest boat you can, and then kill yourself when you see the boat starting to fall apart. The cost of a cheap boat and one bullet, in both time and money, is significantly less than the cost of a well built boat and a long life, in time and money.
[This message has been edited by Scott Rosen (edited 01-18-2000).]
Bob Cleek
posted 01-19-2000 01:05 AM
--------------------------------------------------------------------------------
Truer words were never spoken, Scott! AND, I understand that Glock makes a nice 9mm out of epoxy and kevlar!
Jim Dowling
posted 01-19-2000 04:34 PM
--------------------------------------------------------------------------------
Thanks for the many and often passionate answers. I don't know how clear it made my choices, but at least I have some advice from experts. Actually, the idea of encapsulation came from this forum. The plans came with instructions to paint the boat, while bonding with epoxy and bronze silicon screws. I think I will use white oak, and encapsulate at least the okoume. Thanks again
Keith Wilson
posted 01-19-2000 05:08 PM
--------------------------------------------------------------------------------
Oy, I thought you guys had calmed down! So somebody posts a reasonable question; he's building his own boat, out of wood, no less, and our professional curmudgeons sneer at his choice of materials and tell him YOU CAN'T POLISH A TURD. Not very encouraging, but we have to keep the True Faith pure, don't we? The Unworthy should go buy Jetskis.
(end of rant) ;)
One point to consider when selecting materials for any small boat is how much time it will actually spend in the water. Most small boats 100 years ago stayed afloat or sat in the mud almost all the time. Most small boats today are kept on a trailer, completely out of the water when they're not actually being used. Different conditions, different criteria for material selection. For example, on a boat built using epoxy that will live out of the water, gluing characteristics may be more important than rot resistance, and is certainly more important than fastener-holding ability, which is where oak really shines. Douglas fir (which you can buy at Home Despot around here, anyway) was often used on the west coast in place of white oak, but with somewhat heavier scantlings - I think it would work very well for chine logs unless you have to steam-bend them. The skeg needs a lot of abrasion resistance, so it might not work so well there. On the other hand, how much can a piece of white oak the size of a skeg for a 13' boat cost? Or even black locust, for that matter?
[This message has been edited by Keith Wilson (edited 01-19-2000).]
Scott Rosen
posted 01-19-2000 06:01 PM
--------------------------------------------------------------------------------
Do you really need to encapsulate it? Good plywood, properly finished and maintained will last a very long time. The encapsulation will add wight and cost, and you may not need it for your intended use (whatever that is). Some folks say that glass and epoxy adds abrasion resistance. That may be so, but if you're beaching the boat on a rocky beach, you'd be better off with painted ply. Scratched and gouged 'glass/epoxy is harder to fix than scratched and gouged ply--which you can just putty and paint.
Don't make it any harder or more complicated than you need to.
redjim777
posted 01-19-2000 07:02 PM
--------------------------------------------------------------------------------
Jim, If you can get it Purpleheart is an excellent substitute for White Oak. I have used white oak for hatches on my father's boat, it glues poorly and cups quickly the high humidity here can begin to cup the wood in your garage! I used the Encyclopedia of Wood, printed by the Forest Service and now out of print - but still availble if you look, to find substitutes suitable for boat building. They listed Purpleheart as superior to White Oak in all catagories with the exception of strength, there they are equal. I just laminated the stem for "Firefly" with Purpleheart with excellent results. This wood also takes an excellent finish, I originally used it for handles on kitchen knives. The only concern I have heard is that it dulls cutting edges quickly. To compare the cost, in Houston Purpleheart, 4 qtr rough is $3.75b/ft, White Oak is $2.65, but!!! the majority of the Purpleheart has no grain runout, whereas the majority of the White Oak is from very young trees and has alot of runout. One of my clients is from Trinidad and they use Purpleheart for boat building, it has an excellent reputation and high cost. I know I sound like the leader of a Purpleheart support group, but if you are concerned with the finished product I would consider alternatives.
Good Luck,
Jim
Bob Cleek
posted 01-20-2000 02:40 AM
--------------------------------------------------------------------------------
Ditto on the purpleheart! Add me to the list of fans. BTW, on polishing turds... the point was that if you are building a plywood boat and are going to epoxy coat it, although it is always possible it IDENTIFY the theoretical best material for this or that... it is just as important to keep all the materials in harmony. No point in making yourself crazy trying to find clear straight grained air dried white oak like the books say (blah, blah, blah) if you are building an epoxied ply boat... you don't need any link in the chain that much stronger than the weakest one, do you?
Jim Dowling
posted 01-17-2000 10:13 AM
--------------------------------------------------------------------------------
I am building a 13' rowboat, using okoume plywood for the sides and bottom, and it was suggested that I use white oak for the skeg, chines etc. I know how tough white oak is, but are there any other reasons why white oak is preferable to red oak? I can get longer lengths of the red oak at a good price. I will be bonding and also encapsulating with epoxy.
Scott Rosen
posted 01-17-2000 10:28 AM
--------------------------------------------------------------------------------
Warning: Red Oak has poor decay resistance and is unsuitable as a boat building wood. You really must use white oak. Moisture has been known to penetrate encapsulated wood, so I wouldn't rely on encapsulation as a substitute for the right wood.
If you want more information on oaks, check out the Wood Handbood published by the U.S. Forestry Service. If you do a search in this forum under "Wood Handbook" you will find the url for the entire book, online, in Adobe Acrobat format.
[This message has been edited by Scott Rosen (edited 01-17-2000).]
NormMessinger
posted 01-17-2000 12:25 PM
--------------------------------------------------------------------------------
Ummmm.... Scott?
It's a 13' rowboat encapsulated in epoxy--a boat-of-wood, not a wooden boat.
I guess I'd be more concerned about glueing white oak with epoxy, from what I've read, than about rot resistance. Okoume is not all that rot resistant either but is commonly use due to offsetting attributes.
Ash would be my choice.
--Norm
[This message has been edited by NormMessinger (edited 01-17-2000).]
Scott Rosen
posted 01-17-2000 01:11 PM
--------------------------------------------------------------------------------
Norm, you have a point. But if the epoxy coating is going to eliminate every possible problem with using an inferior wood, why would you use ash? And why bother with oak at all? You could go down to the local lumber yard or Home Despot, buy a couple of 12 foot Doug Fir 2X4s, and use those. Why even worry about drying or seasoning?--Doug Fir is relatively stable, and anyway, the expoxy will stabilize it even more.
I'm singing the same old tune. Use the stuff you know is good. Compromise is unavoidable, but it's false economy to give up a known advantage for the sake of a small convenience or saving a couple of bucks. Boats are unforgiving. Every time I've taken a shortcut, or used something I knew wasn't right for the job, or ignored a potential problem, I've paid for it in spades.
Remember, failures occur when the boat is under stress. And when the boat is in conditions that cause it to be under stress, you can't afford the failure.
Sort of reminds me of a political saying: Better dead than Red (oak, that is).
Mark Jenson
posted 01-17-2000 03:00 PM
--------------------------------------------------------------------------------
I'm sure this thread will generate a lot of opinion-trading.
Jim, here's a summary of what I've been able to glean from various readings and experiences. A lot has already been said about this subject in this forum - try searching on "white oak" and you'll see.
White oak has been preferred to red oak as a boatbuilding wood because it has a closed cell structure which prevents moisture from penetrating, which supports the fungi which cause rot. This may contribute to gluing difficulties with epoxy, but a bigger problem seems to be the high tannic acid content. No less an authority than Dr. Jaegels suggests washing oak with a 10% caustic solution and redrying to overcome this disadvantage (see WB 145). Others suggest leaving the surfaces rough cut, although still others scoff at that idea.
Red oak has an open cell structure, kind of like a bundle of straws, which allows water to wick deeply into the wood, supporting the fungi which cause rot. However, this very feature allows preservatives to also soak deeply into the wood - Clear Penetrating Epoxy Sealer (CPES) would probably be the best choice, followed within 3 days if possible by regular epoxy for encapsulation. One needs to consider the extra cost in so treating the red oak and then compare it to the cost of white oak, which does not require the treatment.
As far as toughness, weight, and the capacity to hold fasteners, the woods are comparable with white oak being heavier.
One thing I seldom hear in connection with rot is that oxygen is required as well as moisture to support the rot-causing fungi. Encapsulation and preservatives, if properly applied and maintained, can keep both the oxygen level and the moisture level too low to support fungi.
Since the longevity of your boat will only be as good as the job you do encapsulating the okoume, which is very rot-prone, it sounds to me like you should go for the red oak and use CPES if possible, followed by encapsulation.
Now I will brace myself for being told I have it all wrong by other participants in the forum.
Bob Cleek
posted 01-17-2000 03:10 PM
--------------------------------------------------------------------------------
Oh my, such a lot of navel-lint picking going on here! Nothing wrong about all the insights offered so far, but, hey! When am I ever going to convince you guys that YOU CAN'T POLISH A TURD!
Numero Uno: we're talking about a cheap plywood skiff here... basically a short lived "throw away" boat (in the grand scheme of things... It may last your lifetime, though.) It is going to be "en-crap-sulated" in plastic snot. It isn't dependent upon anything to hold it together but a lot of plasic goodge. We're talking a "fibreglass" boat with wood instead of glass in the laminate.
Now, having already made your bed with okume ply and epoxy... which is okay for what you are trying to accomplish, why pick nits over red or white oak? IF you had a hunk laying in the woodpile, fine. On the other hand, Doug fir from Home Despot (good one, Scott!) is every bit as servicable as the rest of the materials in this boat and compatible as well. No point in spending the extra money for a skeg that will last ten times longer than the boat, is there?
Get real, use Doug fir or any other similar plank stock and sheath it along with the rest of the boat. The sheathing will actually provide far more abrasion resistance on the skeg, where you really need it, than plain oak, red or white, ever will. No sense building a Ford with Rolls Royce parts!
Mark Jenson
posted 01-17-2000 03:53 PM
--------------------------------------------------------------------------------
Jim, you didn't say in your original posting that you planned on sheathing the boat with fiberglass. If you don't, I'd say one of the oaks is still probably your best choice. If you do plan to sheath in fiberglass, you can get away with almost anything. But you have to consider the cost of sheathing using a softer wood against the cost of a more durable wood. In other words, if you weren't planning on sheathing in fiberglass to begin with, I wouldn't change the plan just because you could use Doug Fir.
Besides, maybe you like to work with oak - it's your time and money, after all.
Allen Foote
posted 01-17-2000 04:33 PM
--------------------------------------------------------------------------------
LOL...Bob! Scott, ditto to you. Jim, buy the white oak and give yourself the oppertunity to learn how to work with a superior boat building material...that experience may be put to good use on your next venture as well.
NormMessinger
posted 01-17-2000 06:10 PM
--------------------------------------------------------------------------------
Doug. Fir from Home Depot? Not a chance. Can you spell knotty SPF? or Hemfir?
--Norm
Greg H.
posted 01-17-2000 06:32 PM
--------------------------------------------------------------------------------
Where would you rate yellow pine in this list?
If you build it well and take care of it, it will last....if you don't, well a boat made of oak and mahogony will decompose more slowely than one made of plywood (or plastic for that matter) laying out in the weather.
Norm, I lucked out once at hd and found a whole pallet of Dougfir 2x4's...but it's rare...
Bob Cleek
posted 01-17-2000 08:11 PM
--------------------------------------------------------------------------------
I'd think yellow pine would be excellent!
Ah, yes, Hemfir... LOL... what else do those guys call that stuff? "White wood?" We are a little better off here in the west, where the Home Despots sell more local stuff. I guess they are okay for pressure treated fence posts and so on, but somehow, I can't bring myself to build anything handcrafted out of wood that's advertised as "premium" because it has "less shakes, less splits, less bark and less knots!" Oh, wow... I should hope so! Then there's their magnamous offer: "No extra charge for selecting your own!" ROTFLMAO! They KNOW they aren't losing a dime on letting you hand select the stuff because they only sell one grade!
Don Danenberg
posted 01-17-2000 10:26 PM
--------------------------------------------------------------------------------
Long-leaf Yellow Pine has been, for centuries, considered an excellant replacement choice for White Oak (Quercus Alba) as framestock. 'Quercus Rubra' is waaaay below that on the list. Don
TomRobb
posted 01-18-2000 08:22 AM
--------------------------------------------------------------------------------
I suppose we all imagine we're building for the ages, that someday some yet to be born archeologist will dig up a boat of ours and put it in a museaum - The Sausalito Ship. Obviously there's no point in consciously making crap that we'd be embarassed about later in life. But a question: Is one of the virtues of wood (biodegradable)that it won't likely be around forever? Isn't there a certain poignancy to the idea that our work is only temporary - like we are? Do the best you can and move on, and make way for the next generation? A counter example might be the glut of ugly fibrglass boats that will eventually have to be landfilled or maybe sunk as artificial reefs? (Could they be ground up for furnace fuel?) At the Center for Wooden Boats in Seattle we're more or less constantly repairing the fleet. It may seem to some to be treadmill work. It really is keeping the old skills alive. It maintains the waterfront/boat/seafaring culture that is the real point of that museum. If Jim Dowlings skiff doesn't last forever he, or his grandchildren, can make a new one. It's the skills, the culture that need to be passed on. It seems to me that's what WB, this forum, the Bobs-n-Scott, Ian, et.al. are doing here.
Eb
posted 01-18-2000 12:08 PM
--------------------------------------------------------------------------------
I don't want my boat to last forever, just longer than me.
Scott Rosen
posted 01-18-2000 02:49 PM
--------------------------------------------------------------------------------
No offense, but if your goal is to have your boat outlive you, the easiest way to do that is to build the cheapest, easiest boat you can, and then kill yourself when you see the boat starting to fall apart. The cost of a cheap boat and one bullet, in both time and money, is significantly less than the cost of a well built boat and a long life, in time and money.
[This message has been edited by Scott Rosen (edited 01-18-2000).]
Bob Cleek
posted 01-19-2000 01:05 AM
--------------------------------------------------------------------------------
Truer words were never spoken, Scott! AND, I understand that Glock makes a nice 9mm out of epoxy and kevlar!
Jim Dowling
posted 01-19-2000 04:34 PM
--------------------------------------------------------------------------------
Thanks for the many and often passionate answers. I don't know how clear it made my choices, but at least I have some advice from experts. Actually, the idea of encapsulation came from this forum. The plans came with instructions to paint the boat, while bonding with epoxy and bronze silicon screws. I think I will use white oak, and encapsulate at least the okoume. Thanks again
Keith Wilson
posted 01-19-2000 05:08 PM
--------------------------------------------------------------------------------
Oy, I thought you guys had calmed down! So somebody posts a reasonable question; he's building his own boat, out of wood, no less, and our professional curmudgeons sneer at his choice of materials and tell him YOU CAN'T POLISH A TURD. Not very encouraging, but we have to keep the True Faith pure, don't we? The Unworthy should go buy Jetskis.
(end of rant) ;)
One point to consider when selecting materials for any small boat is how much time it will actually spend in the water. Most small boats 100 years ago stayed afloat or sat in the mud almost all the time. Most small boats today are kept on a trailer, completely out of the water when they're not actually being used. Different conditions, different criteria for material selection. For example, on a boat built using epoxy that will live out of the water, gluing characteristics may be more important than rot resistance, and is certainly more important than fastener-holding ability, which is where oak really shines. Douglas fir (which you can buy at Home Despot around here, anyway) was often used on the west coast in place of white oak, but with somewhat heavier scantlings - I think it would work very well for chine logs unless you have to steam-bend them. The skeg needs a lot of abrasion resistance, so it might not work so well there. On the other hand, how much can a piece of white oak the size of a skeg for a 13' boat cost? Or even black locust, for that matter?
[This message has been edited by Keith Wilson (edited 01-19-2000).]
Scott Rosen
posted 01-19-2000 06:01 PM
--------------------------------------------------------------------------------
Do you really need to encapsulate it? Good plywood, properly finished and maintained will last a very long time. The encapsulation will add wight and cost, and you may not need it for your intended use (whatever that is). Some folks say that glass and epoxy adds abrasion resistance. That may be so, but if you're beaching the boat on a rocky beach, you'd be better off with painted ply. Scratched and gouged 'glass/epoxy is harder to fix than scratched and gouged ply--which you can just putty and paint.
Don't make it any harder or more complicated than you need to.
redjim777
posted 01-19-2000 07:02 PM
--------------------------------------------------------------------------------
Jim, If you can get it Purpleheart is an excellent substitute for White Oak. I have used white oak for hatches on my father's boat, it glues poorly and cups quickly the high humidity here can begin to cup the wood in your garage! I used the Encyclopedia of Wood, printed by the Forest Service and now out of print - but still availble if you look, to find substitutes suitable for boat building. They listed Purpleheart as superior to White Oak in all catagories with the exception of strength, there they are equal. I just laminated the stem for "Firefly" with Purpleheart with excellent results. This wood also takes an excellent finish, I originally used it for handles on kitchen knives. The only concern I have heard is that it dulls cutting edges quickly. To compare the cost, in Houston Purpleheart, 4 qtr rough is $3.75b/ft, White Oak is $2.65, but!!! the majority of the Purpleheart has no grain runout, whereas the majority of the White Oak is from very young trees and has alot of runout. One of my clients is from Trinidad and they use Purpleheart for boat building, it has an excellent reputation and high cost. I know I sound like the leader of a Purpleheart support group, but if you are concerned with the finished product I would consider alternatives.
Good Luck,
Jim
Bob Cleek
posted 01-20-2000 02:40 AM
--------------------------------------------------------------------------------
Ditto on the purpleheart! Add me to the list of fans. BTW, on polishing turds... the point was that if you are building a plywood boat and are going to epoxy coat it, although it is always possible it IDENTIFY the theoretical best material for this or that... it is just as important to keep all the materials in harmony. No point in making yourself crazy trying to find clear straight grained air dried white oak like the books say (blah, blah, blah) if you are building an epoxied ply boat... you don't need any link in the chain that much stronger than the weakest one, do you?