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mic
03-24-2003, 07:21 PM
Hi every one, i've been having a look in the search thingy at the top of the page and cannot find an answer to how my planking boards will react when put back in the water. My boat is a 46' carvel style hull with jarrah planking this is going to be my first antifoul so i plan to use the opportunity to pull the boat out and get it back to bare timber, i was hoping to give it a good coat of CPES then redlead and then put on the color and the antifoul, but i was told that i should not use the CPES because it will stop my hull from swelling back to the correct size. Will CPES realy do this? And if it does will this create any problems, will i have to recaulk my boat? :eek:

mic
03-24-2003, 08:20 PM
Ok. http://www.imagestation.com/picture/sraid43/p4b9e52d99c8c0acdc3e2af1ad1882424/fce27ac2.jpg http://www.imagestation.com/picture/sraid44/p239ebc21fc26212c1caec7e2cdbcfd42/fcdd9d3c.jpg

mic
03-24-2003, 08:30 PM
yup! it sure is

WFK
03-24-2003, 08:40 PM
mic;
My question is why use cpes below the waterline? It simply isn't nessesary and in my opinion a waste of money. Use it where it helps most, Above the waterline, as a sealer, on bare wood, prior to painting.
As I say, this is my opinion, based on experience I have working in the marine industry, may be other people will see it differently.

Bill

mic
03-24-2003, 08:59 PM
Ok, name "SOUTHERN MIST" loa.48' beam 14'6" draft 6' POWER 6 LX Gardner diesel age 1961 apparently one of the last of old man cayzer's boats that he actually built himself. Hey donn i've finished painting that wheelhouse now i'll have to show you some more photos. When i take some!

Dave Carnell
03-25-2003, 06:58 AM
CPES is over 50% solvent. Hellishly expensive solvent. Check this site:

<http://www.epoxyproducts.com/>

thechemist
03-25-2003, 05:19 PM
The site to which Dave refers you offers one world-view of reality. Strangely, reality sometimes seems to be a matter of opinion as well as of science. See, for example, www.woodrestoration.com (http://www.woodrestoration.com) .

Actually, reality is a matter of agreement; but, I digress.

As to your original question, which has not hitherto been answered, I can give you a very accurate answer which is that it depends.

Whether or not a plank will swell upon immersion depends in the change in its moisture content. You can learn more about how wood behaves with regard to its moisture content from The Wood Handbook produced by the Forest Products Laboratory of the U. S. Department of Agriculture. You can read it or order your own [which I highly recommend] from http://www.fpl.fs.fed.us/documnts/FPLGTR/fplgtr113/fplgtr113.htm .

Getting back to moisture content, the equilibrium moisture content of a piece of wood depends on the rate at which water may come in and at which water may escape, as well as the humidity of the air and the temperature of the wood.

If you put one side of the wood in water and have no ventilation on the other side, the wood will get pretty soggy, well above the fiber-saturation point. It will swell, unless it is alrady that damp, in which case it will not swell.

If you put a decent moisture-diffusion-barrier on the side of the wood that is in water [as your antifouling paint may well be] and have excellent ventilation on the other side, so the small amount of water that DOES diffuse through the outer barrier and into the wood, can escape easily, then it should be obvious that the equilibrium moisture content of the wood will tend to the equilibrium of wood with the humidity of the air. It won't swell. It may shrink, if it started off really soggy.

For situations intermediate to those two above, it will swell some, as its moisture content rises........or shrink some, as its moisture-content falls.

Knowing what the moisture-content is [get a good capacitance-type moisture-meter] you may have some idea if it will swell or not. If it is already close to the fiber-saturation-point, It may not swell much if at all.

CPES has been discussed in other threads. See, for example,

http://media5.hypernet.com/cgi-bin/UBB/ultimatebb.cgi?ubb=get_topic&f=1&t=004731&p=

http://media5.hypernet.com/cgi-bin/UBB/ultimatebb.cgi?ubb=get_topic&f=1&t=004574&p=

http://media5.hypernet.com/cgi-bin/UBB/ultimatebb.cgi?ubb=get_topic&f=1&t=002553&p=

http://media5.hypernet.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=001155

What does it all mean? It means you need to know the moisture-content of your wood when the boat is on the hard, and you need to know what degree of ventilation you have inside the boat, in the area below the waterline. It does not appear, from the foregoing and other discussions, that CPES on your hull will affect plank swelling as much as those other factors.

mic
03-26-2003, 12:00 AM
Hey thanks for your help again guys, Bill the only reason i thought to do my hull with CPES is in order to give it as much protection as possible because once the outside's done i'm doing the inside.
Chemist i do understand your answer about keeping equilibrium of moisture in the timber, but am still a little confused about how this moisture meter will work. Just so i understand, what your saying is if i paint my planking with CPES while it's close to saturation point it wont swell very much i.e. doing it quickly befor the timber drys out to much. IF the timber is reasonably dry when i paint the CPES on the plank will swell, will that affect the bonding of CPES to the timber or will it just expand like paint?

warwick
03-26-2003, 12:16 AM
MIC, the simple answer to your CPES question is DON'T!!
CPES as you know is an epoxy, albeit only 30%, it is pointless putting it below the waterline, to protect the timber from what?, it will only interfere with the timbers natural ability to swell and keep the seams watertight.
"if it aint broke, don't fix it."

thechemist
03-26-2003, 12:21 PM
Originally posted by mic:
Hey thanks for your help again guys, Bill the only reason i thought to do my hull with CPES is in order to give it as much protection as possible because once the outside's done i'm doing the inside.
Chemist i do understand your answer about keeping equilibrium of moisture in the timber, but am still a little confused about how this moisture meter will work. Just so i understand, what your saying is if i paint my planking with CPES while it's close to saturation point it wont swell very much i.e. doing it quickly befor the timber drys out to much. IF the timber is reasonably dry when i paint the CPES on the plank will swell, will that affect the bonding of CPES to the timber or will it just expand like paint?The data at www.woodrestoration.com (http://www.woodrestoration.com) indicates that CPES will stretch at least as much as the wood. Go to section 4 and look at the bending tests of treated and untreated wood.

Moisture-meters of the radio-wave kind work like stud-finders. They send out radio waves and measure how much water is in the wood within an inch or two of the surface. That kind [no pins that stick in the wood] are not affected by salt in the wood and are accurate. The ones with pins are not.

The CPES threads I referenced [a SMALL selection of what seems to be available by searching....I used the words CPES and breathe to find those] seem to indicate that CPES is different from other kinds of epoxy products, and mainly promotes adhesion of other things to wood, better than those other things themselves. Read them and see what you think.

You need to evaluate those anecdotal data in light of your own experience, and perhaps talk to the manufacturer, and perhaps even do a test or two yourself and form some opinion based on personal experience instead of listening to everyone else and then attempting to form a decision with certainty.

The highest certainty comes from personal observation and personal knowingness......although I do have to admit that the endorsement of that youth boat-building group in the "Sanding and CPES" thread is pretty convincing.

Bob Cleek
03-26-2003, 11:04 PM
Been there, done that. Fact is, CPES is moisture permeable, so, while it will SLOW the absorption rate of "real" water into the immediate surface of the plank, and will to a lesser degree slow, but not ultimately limit, the amount of moisture absorbed by the plank overall, it will have no effect on the actual swelling and shrinking of the wood.

Whether it is worth the cost and labor is another question entirely. While it isn't cheap, a little bit goes a surprisingly long way. I am not familiar first hand with jarrah. I have used it below the waterline on bare teak, however, which may have somewhat the same parameters. In such an instance, I used it because I wanted to ensure that the antifouling adhered as well as possible, which is a problem to begin with on teak. In an application other than teak, where marine borers are a consideration, I also would strongly favor CPES'ing a bare bottom because the CPES coating, albeit as thin as it is, should logically deter marine borers, who are looking to eat wood, not dull their teeth on epoxy. (Imagine soaking your next Big Mac in the stuff... you'll see what I mean.) There is also, with any wood, the significant advantage that it makes the paint stick so much better.

Again, as has been observed here so many times before, laying red lead over CPES may be a "belt and suspenders" approach, but, heck, the more deadly stuff you can lay on your bottom, the better! I'd say go for the red lead over the CPES if you really want to go first class. Besides, red lead is a lot cheaper than bottom paint if you need to put a couple of coats of an oil based coating down on a bare bottom and only the top layer of the coating, the anti-fouling is going to be doing the work. Not much sense in paying for bottom paint if you are using it as primer.

As for bottom paints, I'd caution you to check around and make sure that the anti-fouling paint is compatible with CPES. I don't know of any that isn't, but you sure don't want to be wrong. Of all the marine coatings on the market, bottom paints are about the most tricky. You can't put vinyl based anti-fouling on top of a prior base ofablative stuff, for instance. It won't stick. Check with the bottom paint's manufacturer, or somebody who's tried it, before you put any bottom paint on top of CPES'd wood cold... just to be sure. I don't think red lead is a problem with any bottom paint, and it's fine on top of CPES, so maybe that's another reason to do the "belt and suspenders" thing as well.

mic
03-28-2003, 04:43 AM
well, i now have my answer. As usual there's always a few differing opinions but thats to be expected, thanks everybody i realy appreciate your experienced advice and input, any other coments are welcome.

paul oman
03-28-2003, 09:33 AM
We usually never recommend coating a wooden boat with a layer of epoxy unless absolutely necessary - Like to keep it from sinking. I think it is a short term fix, but a bad for the hull in the long term and could shorten its total life. (Just my opinion).

Instead of CPES (70%) solvent - I might consider using 100% solvent or something like that to kill any fungus etc that might be in the wood (this is probably what a coat of CPES would do for you too). Again, just my opinion, I probably wouldn't bother to do this myself.

Over the years I have also followed threads etc on the net suggesting that carvel style hulls should not be glassed, epoxied in the seams, etc. Thus, I would be even less inclined to put anything like epoxy on the wood.

paul oman
progressive epoxy polymers
www.epoxyproducts.com (http://www.epoxyproducts.com)

Art Read
03-28-2003, 01:12 PM
Paul... From your previous discusions on the relationship between Smith's CPES and regular, but diluted epoxy, I understand that you've done considerable experimentation on the characteristics/usefullness of solvent thinned, "penetrating" epoxy. But reading what you wrote above about "epoxy coating" carvel built hulls, etc. , I'm really curious. Have you ever actually BOUGHT a can of "real" CPES and used it? I can't see how anybody who was familiar with Mr. Smith's product could mistake it for a product one would, or even COULD, use to "encapsulate" wood. If you do have first hand experience with it, what exactly leads you to believe it represents a potential cause for "long term harm" to the boat?