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CPES alternatives?

PostPosted: Thu Nov 19, 2009 3:12 pm
by synaps3
Has anyone tried anything like this: http://www.campingworld.com/shopping/it ... llon/32151

or any other alternative to CPES? The cost of CPES is crazy! I'm planning on building a standie on a budget, so the 2 gal kit might not even cut it. I hate the thought of spending almost all of my remaining budget on sealant :cry:

If not, how do you CPES? How many layers, what do you put on afterwards (for UV protection), etc?

- Dave

PostPosted: Thu Nov 19, 2009 3:35 pm
by Arne
you are talking apples and oranges..... I'm not even sure that stuff will stick to wood very well..

PostPosted: Thu Nov 19, 2009 6:21 pm
by madjack
Dave, this no place to skimp...all of your investment will be for naught if you don't take the time and money to protect it properly...you would need 3 coats CPES(I would prefer regular epoxy like from www.raka.com )minimum with 2-3 coats of a urethane based marine topside paint for proper protection(see Interlux Brightsides, Petit Easyrpoxy or similar)...if not, you might as well use house paint and use it till it falls apart...not trying to be harsh, just trying to keep it real and help you protect your investment.........
madjack 8)
http://www.discountmarinesupplies.com/c ... hild=99470 ...for reference only.............mj

PostPosted: Thu Nov 19, 2009 6:42 pm
by synaps3
Jack --

Okay, then. No skimping. :lol: There goes my budget... :?

So you reccommend Raka over CPES? Why is this?


Let me make sure I have the process right here...

Raka Epoxy (3 coats). Let dry fully (maybe wait a day or two)
Urethane-based Marine Paint topcoat (3 coats)

I'm guessing I only wait an hour or two between the epoxy layers, for a good chemical bond. How about for the marine paint topcoat? Do I let dry or sand between coats?

Thanks for all your help. :)

- Dave

PostPosted: Thu Nov 19, 2009 7:07 pm
by madjack
...this is strictly my opinion on the CPES vs Epoxy thing...
CPES was/is designed to be injected into rotten wood to stabilize it...to this end CPES is thin, contain a LOT of volatiles that must gas off, leaving microscopic holes which must be sealed with additional coats of CPES and paint...any other use is incidental
Epoxy is much heavier bodied and may not soak as deeply(note I said may). However, this heavier body will leave a thicker more impervious coat on the surface...there is a night and day difference in the finished look of CPES and epoxy because of this...CPES will look like wood with a sealer on it and the Epoxy will leave it looking ENCAPSULATED...also, you won't find boat builders using CPES to protect their investment
You will probably havvta wait longer than an hour or so for additional coats or you may induce sag into the epoxy...if you wait less than 24 hours, you can apply without sanding...over 24 hours and you will havvta sand...also you will want to wait, especially on the first two coats for any captured air to escape which will leave an entrance into and through the finish(whether CPES or Epoxy).
I CANNOT EMPHASIZE ENOUGH TO GET THE USER MANUALS FROM THE MANUFACTURER READ AND FOLLOW RELIGIOUSLY FOR PROPER PERFORMANCE OF THE PRODUCT ...this applies to CPES/Epoxy/Paint
For the paint, I would recommend a light sanding between each coat for best performance and look
madjack 8)

p.s. I have never used CPES and probably never will for these purposes...as I stated, these are just my opinions and others may vary greatly............mj

PostPosted: Thu Nov 19, 2009 8:10 pm
by synaps3
Aye, capp'n. Thanks for the words of wisdom. A smooth finish sounds much more appealing to me than wood grain anyways...

How many gallons of epoxy do you generally use for a tear?

PostPosted: Thu Nov 19, 2009 8:37 pm
by Lou Park
I agree, not the same at all, but it does look like a cool product.

PostPosted: Thu Nov 19, 2009 8:43 pm
by Ageless
I've always used an epoxy sealer: System 3. You can thin it with acetone and it will penetrate very well.

PostPosted: Thu Nov 19, 2009 10:52 pm
by madjack
s3, I am a fan of the products from www.raka.com ...I especially like their non-blushing epoxy hardner system and would recommend a 3gal kit...it is not cheap but should give you enough to do your trailer and since it basically has no shelf life limit, you can keep it around near forever and use for any other projects you come up with........
madjack 8)

PostPosted: Thu Nov 19, 2009 11:42 pm
by Corwin C
My personal experience (building canoes) is that epoxy alone doesn't penetrate deep enough into the wood to prevent delamination if bumped hard enough to dent the wood. :o The thin layer of wood that the epoxy bonds to seems to pull away from the rest of the wood. Not a failure of the epoxy, but a failure of the wood. I have been using cedar which is quite soft.

A friend of mine used CPES as a deep penetrating "bonding layer" before the fiberglass/epoxy and despite really hard use in rocks he has had absolutely no delamination on similar wood.

Due to this experience, my future build will be a generous coat of CPES followed by fiberglass/epoxy, enough to completely fill the weave (usually 3 - 4) applications. Like MadJack, I also tend to use RAKA epoxy most of the time, and recommend it. The hardener yellows a little with age, but I still have some that is 7-8 years old (stored in less than ideal conditions) that still works very well.

Corwin

PostPosted: Thu Nov 19, 2009 11:55 pm
by madjack
Corwin, that is sound advice based on experience...the best teacher of all but if I get to bumping my TD on rocks, I probably have more problems than delamination...nowattimean ;)
madjack 8)

PostPosted: Fri Nov 20, 2009 12:07 am
by High Desert
madjack wrote:Corwin, that is sound advice based on experience...the best teacher of all but if I get to bumping my TD on rocks, I probably have more problems than delamination...nowattimean ;)
madjack 8)

would that fall under the "Operator Error" catagory Jack? ;)

I had been wondering about the differences in results between CPES and Epoxy. And whatayaknow, here's the info. :thumbsup:

are you laying cloth with the epoxy or just applying it directly on the wood?

PostPosted: Fri Nov 20, 2009 12:16 am
by madjack
...operator error or not it would sure be an error...on my present tear, I embedded camo cloth directly into the epoxy, cause I wanted a camo tear...if you look at Doug Hodder's stuff, he applies epoxy directly to the wood and then uses automotive finishes...no fiberglass cloth used at all...on the other hand, look at Steve Frederick's stuff, he uses fiberglass cloth...both do wonderful work using similar materials with different techniques...I personally don't believe the fg cloth is needed unless you are using inferior plywood(non exterior rated) or expect extreme usage........
madjack 8)

Image

PostPosted: Fri Nov 20, 2009 12:28 am
by High Desert
Thanks Jack. Those are three great examples of superior results :thumbsup:

PostPosted: Fri Nov 20, 2009 12:37 am
by Ageless
Madjack is right. You only need glass cloth for strength. While I was in the Navy; training. We used cotton to reinforce the resin; held 150 psi water pressure. The glass reinforce patch will hold 250+

With wood, the resin is a 'sealer'