Epoxy Questions

[Forkliftt]

I am finishing a teak project where the microwave opening needed to be enlarged. I had my trim teak provided by a marine woodworking shop in Kemah and was told to use West System for strength when I put my mitered corners together.*I did some reading on the advantages of epoxy and see the value of being able to thicken the mix depending on your need.
Short of time and money this weekend- this is what I did. I had a 2 part Ace epoxy mix I had recently purchased for a project and did not use. I would mix up a batch and then add teak sawdust slowly and thicken it up. Wiped some on, put pieces together, screwed together, wiped excess with Acetone, let harden and sand. Wonderful stuff!! I am sure I read somewhere about adding the sawdust.
So what other applications are there on a boat for epoxy?

 

[Fotoman]

Forkliftt wrote:

So what other applications are there on a boat for epoxy?

Just about anything you can imagine. Its 100% waterthight properties make it great for under water use, repairs, building, etc. But you can also do a lot of projects with regular and much cheaper polyester resin.

*

 

[Delfin]

Next to penicillin, Epoxy may well be mankind's greatest discovery.* I use epoxy wherever I wanted to make absolutely sure wood parts will never come apart, but there are cautions and limitations.* First, when the pieces are put together, they really shouldn't be tightly clamped unless you use a biscuit joint or equivalent.* Epoxy depends on itself for integrity and strength, and when you clamp it, most of the epoxy exits the joint, leaving it weaker than if you used another glue, like a polyurethane.* If you get carried away with the thickener, you can reduce the epoxy's ability to soak into wood and end up with a weaker joint.* All thickeners should be no coarser than fine sanding dust.* Color matching to the wood being glued can be kind of sort of achieved by using sanding dust from the wood itself.* Don't add more thickener than necessary to achieve the desired reduction in 'runniness', unless you are using the epoxy as a fairing compound.*

I have used epoxy to fix a threaded vent fitting into a bilge tank that would weep diesel when the tank was filled.* I sprayed it clean with carburetor cleaner, then dripped MEK thinned epoxy into the joint.* Once that kicked, I finished it off with silica thickened epoxy.* No leaks.

I am also a strong believer in using thinned epoxy as a pre-varnish base.* It has to be sanded carefully because it tends roll up rather than sand, but with varnish providing UV protection, you have a very durable finish.

Finally, Ace epoxy is the bottom of the barrel, quality wise.* West is good, as is Systems Three.* The West thickeners are outstanding.

I could go on, but I have to re-epoxy my wife's feet to the floor in front of the stove.* She pulled up the tiles.

 

[Marin]

Forkliftt wrote:

So what other applications are there on a boat for epoxy?

*

If you have a wood boat, or a boat with wood trim, one of the best products on the planet is CPES (clear penetrating epoxy sealer).* While our boat is fiberglass it has a rainforest of teak on it, from the exterior trim, handrails, and caprails, to all the interior trim and cabinetry.* The boat's interior sidewalls and bulkheads are painted mahogany, the window frames are mahogany, mast and boom are wood, etc..*

Any repairs we do to just about anything made of wood other than the deck get several applications of CPES (a two-part expoxy with the consistency of diesel fuel) before the application of a bright finish (we use Bristol) or paint.* The CPES soaks into the wood farther than heavier epoxies and seals the wood cells against moisture intrusion.* No moisture intrusion, no rot.* CPES applied prior to a varnish, Bristol, etc application makes the finish adhere much better and makes it more resistant to lifting over time from moisture intrusion.*

CPES, like most epoxies, has no UV resistance so it must be covered with finishing coats that do, either brightwork finish or paint.* And while it is a two-part epoxy it is not intended to act as an adhesive.* In other words, it's not something you'd use to fasten two pieces of wood (or anything else) together.* It is a wood sealer, but probably the most effective sealer around.* Fabulous stuff.

*


-- Edited by Marin on Tuesday 27th of April 2010 01:38:57 AM

 

[RT Firefly]

Hiya,
Don't forget 5 minute epoxy. The kind you get in the double tube applicator. Thickened with talcum powder, it can be used to fill those nasty nicks and gouges that occasionally occur. Had small "oopsie" from dock rash. Fixed in about 10 min. Ya, ya, it's "on the list" for a permanent repair.

 

[albin43]

Delfin wrote:

I could go on, but I have to re-epoxy my wife's feet to the floor in front of the stove.* She pulled up the tiles.

*Great!

 

[albin43]

I use west system for everything. my whole deck project, bedding down anything and everything to insure a watertight seal. ive gone through two 105c kits (5gal each) on my boat. nothing leaks

here are a few examples.

- deck work, recored almost half my decks using douglas fir endgrain bedded with 105/205/406

- glassed my entire decks with 15oz biaxial fabric using 105/205

- glassed my boiler stack in using the same 15oz biaxial fabric and the 105/205

- teak handrail repair using 105/205/405

- fixed leaking windows using a razorblade to remove old caullk and plunge between the wood and cabin and filled with 105/205/406

-rebuild hatches

- glassed over old throughhulls when the boat was last out.

-filled in abunch of crazing and stress cracks and holes from old hardware using 105/205/410

the list goes on and on and on... there isnt any project I dont use it for

west system has a GREAT tech service line and a wonderful epoxyworks magazine. i vote it as the best thing ever invented.

also its folds better then polyester resin, thats for another subject. google polester vs epoxy......

 

[albin43]

http://www.c-cyachts.com/images/com...91-785DC064755F/16cf4_Adv_of_Epoxy_v_Poly.pdf

 

[C lectric]

When doing wood glueing useing epoxy you should paint the raw wood with unthickened epoxy first so it soaks in a bit. Other wise you may end up with a dry or weaker than expected joint.

Use good gloves, not those crappy latex things which tear easily and defeat the whole purpose of gloves.

I also use a respirator and suggest you do too. I've made myself sick twice from failure to protect properly. The last time I was working in an open at both ends garage with a breeze. What I failed to realize was that because I was working with my face very close I still got a heck of a dose.

The filters need to be able to absorb fumes, not block dust although they will do that.* If you can smell laquer thinner through the elements you have the wrong type.** Activated charcoal is part of it.** You will need several.* They are generally good only for a days use, then a new one.** Keeping them in a tightly sealed plastic ziplock* bag will help but the best is usually two days.

Yeah, some can get away with it for a while but who knows who will get nailed. So protect yourself.

-- Edited by C lectric on Tuesday 27th of April 2010 10:09:11 PM

 

[skipperdude]

Delfin wrote:

*


I am also a strong believer in using thinned epoxy as a pre-varnish base.* It has to be sanded carefully because it tends roll up rather than sand, but with varnish providing UV protection, you have a very durable finish.


.

Would not the addition of a surfacing agent or wax prevent this from happening?
*


-- Edited by skipperdude on Wednesday 28th of April 2010 10:33:47 AM

 

[Marin]

skipperdude wrote:Delfin wrote:I am also a strong believer in using thinned epoxy as a pre-varnish base.* It has to be sanded carefully because it tends roll up rather than sand, but with varnish providing UV protection, you have a very durable finish.

Would not the addition of a surfacing agent or wax prevent this from happening?This is what CPES was created for.* Soaks farther into the wood than even thinned epoxy and after application the wood can be finish sanded perfectly.* No roll-up problems or anything.* For sealing wood permanently against moisture intrusion, it's the best stuff on the planet.* We've been using it now for some eleven years and if one has to deal with wood on a boat it makes life WAY easier and the repairs or finish prep we do are as permanent as it's possible to get on a boat.

*


-- Edited by Marin on Wednesday 28th of April 2010 11:35:24 AM

 

[albin43]

west system 105/207 special clear coat is great stuff aswell, ive never used CPES but have used the 105/207. 2 coats of that and then 2 coats of cetol looks like 12 coats of cetol. when refinishing is needed you sand down to the epoxy and recoat. it really is great stuff. i cant afford to do that to all my teak right now or i would. looks like only cetol for me.

 

[Delfin]

I have used Smith's penetrating epoxy which is the same stuff as CPES, but found it was only regular epoxy mixed with MEK, so it is cheaper to make your own.* The other advantage of mixing your own is that you can pick your consistency.

 

[Forkliftt]

Great info!

 

[Delfin]

skipperdude wrote:

Would not the addition of a surfacing agent or wax prevent this from happening?
Maybe, although it might then affect the adhesion of the varnish.* It's not really a problem - you just have to avoid a lot of pressure since it is friction heat that makes the epoxy gummy.

*

 

[Marin]

Delfin wrote:

I have used Smith's penetrating epoxy which is the same stuff as CPES, but found it was only regular epoxy mixed with MEK....

Not true, actually.* What CPES isn't is regular epoxy mixed with MEK.* If you do this, you end up with a very brittle filling since the MEK flashes off and you're left with the hard, brittle cured epoxy.* Also, since the MEK flashes off so fast it doesn't carry the epoxy very deep into the wood.** All standard epoxies, including WEST, are petroleum based, and thus cure very hard and brittle.* The resins in CPES are derived mostly from wood and when cured have a toughness and flexibility very*similar to wood.

There is also alchohol and other organic additives in CPES*to help it displace moisture and so penetrate deeper into wood because these "carriers" evaporate over a long period of time.

This info is all on the Rot Doctor website.

I know a few*people in our marina*who tried the "thinned epoxy" route and they told me that while*it worked to a degree it didn't do as good a job as CPES, and they went back to CPES.*

I learned about CPES on the GB owners forum where it is one of the most important repair and restoration tools, particularly for the woody owners.* Many of them have stated they*tried the thinned epoxy route and subsequently went back to CPES for its superior penetration qualities and ability to maintain the attributes of the wood it's applied to.

 

[Delfin]

Marin wrote:

*
Delfin wrote:

I have used Smith's penetrating epoxy which is the same stuff as CPES, but found it was only regular epoxy mixed with MEK....

Not true, actually.* What CPES isn't is regular epoxy mixed with MEK.* If you do this, you end up with a very brittle filling since the MEK flashes off and you're left with the hard, brittle cured epoxy.* Also, since the MEK flashes off so fast it doesn't carry the epoxy very deep into the wood.** All standard epoxies, including WEST, are petroleum based, and thus cure very hard and brittle.* The resins in CPES are derived mostly from wood and when cured have a toughness and flexibility very*similar to wood.

I'm not sure how many gallons of MEK thinned epoxy I have squirted into rotten window sashing, footings, or painted on teak, spruce, port orchard cedar, but it would be a few.* The MEK does not 'flash', but carries the epoxy as far as reasonable into the wood.* If you use Balsa wood, like the manufacturers advertising their products do to demonstrate their products, or punky wood like I do in real life, you get great penetration.* The "organic" solvents in CPES that you say go over over a "longer period of time" have a name.* It is MEK.* Take a whiff of CPES, then take a whiff of MEK.* Besides losing 2% of your brain cells, your sniffer will tell you what the solvent in CPES is.* MEK is not acetone and goes off fairly slowly, which is why they use it for this purpose.*

Marin, you're quoting from the CPES advertisement when you say "epoxy dries hard and brittle."* Compared to thinned epoxy like CPES, which don't actually harden much, that might be true but it depends on the thickener you use.* Want 'wood like' epoxy?* Thicken with wood dust and plane it like wood.


-- Edited by Delfin on Friday 30th of April 2010 05:21:35 PM

 

[Marin]

Delfin wrote:

*The "organic" solvents in CPES that you say go over over a "longer period of time" have a name.* It is MEK.*

I guess that's something you'll have to take up with the CPES folks, since the owner of Rot Doctor here in Seattle**has told me that they DON'T use MEK in their product which he says say is why the product he carries*works better as a penetrating epoxy sealer than simply mixing regular epoxy with MEK.

I'm not a chemist, so it's not something I know about nor have any interest in learning about.* All I care about is what people who have tried both have told me--- CPES does a better job and penetrates farther than standard epoxy cut with MEK.

Given the credentials and experience*of people like Bob Lowe and Mike Negley on the GB Owners forums, I'm going to follow their recommendation and advice reagrding CPES vs. any other type of penetrating epoxy, home-made or otherwise.

Not saying you're wrong, just that I have no reason to believe you're right

*

 

[FF]

"Would not the addition of a surfacing agent or wax prevent this from happening?"

A wax or surfectant is required on the last coat of polly resin , as the stuff is air inhibited, (the surface doesn't cure) so the next layers can be put on ,,,with out sanding (secondary bonding).

We have always alcohol to create our own "Git Rot" from OTS (usually West) epoxy.


Extra hardener is required after about 5% thinning.

 

[RickB]

Marin is right, CPES is not epoxy thinned with MEK. It is epoxy thinned with naptha, xylene, and toluene in decreasing proportions. About 70 percent of the stuff is solvent.

Look at the MSDS if you want to see what is in it. The primary ingredient, listed first just like the contents label on a can of soft drink, shows a mysterious "aromatic hydrocarbon" which if you look up the CAS# 64742-95-6 will tell you it is naptha, the same stuff used to fill a Zippo lighter.

Just like the mouse milk folks, these guys depend on establishing a cult following based on ignorance of the process and the blend of ingredients. The only way to get rid of rot is to replace the rotten wood. All you get with magic wood restoration products is a volume of plastic surrounded by rotten wood.



-- Edited by RickB on Saturday 1st of May 2010 06:10:41 AM

 

[Delfin]

Marin wrote:I guess that's something you'll have to take up with the CPES folks, since the owner of Rot Doctor here in Seattle**has told me that they DON'T use MEK in their product which he says say is why the product he carries*works better as a penetrating epoxy sealer than simply mixing regular epoxy with MEK.

Marin, if you look at the MSDS sheet for CPES, you'll see that it contains Xylene, Tuolol, Isopropyl alcohol, 2-Butanone, 4-Methyl 2-Pentanone, etc.* These are not Tofu based ingredients, and when a chemist says 'organic' solvents he means something rather different from your local juice bar.* 2-Butanone is the chemical name for MEK, so Dr. Rot probably needs to take a chemistry class or read his own MSDS.* By the way, this is a great product, it is just a lot more expensive than regular epoxy thinned out, and to sell their product, Smith's tends to, shall we say, obfuscate what they are actually selling?* Otherwise, how could they convince you, as their web site says, that "This Stuff is True Magic!" so you'll pay through the nose for the product?

*

 

[Delfin]

RickB wrote:

Marin is right, CPES is not epoxy thinned with MEK. It is epoxy thinned with naptha, xylene, and toluene in decreasing proportions. About 70 percent of the stuff is solvent.

Look at the MSDS if you want to see what is in it.

*

From that MSDS for CPES, you see that 2-Butanone is one of the ingredients.* From Wikipedia:* Butanone, also known as methyl ethyl ketone or MEK, is an organic compound with the formula CH₃C(O)CH₂CH₃.

They don't spell out MEK on an MSDS because the chemical name for it is 2-Butanone.
Incidentally, if you look at a can of MEK, you'll see that one of its listed primary uses is as a thinner for epoxies.





-- Edited by Delfin on Saturday 1st of May 2010 04:33:10 PM

 

[RickB]

Delfin wrote:
From that MSDS for CPES, you see that 2-Butanone is one of the ingredients.*

Good catch, thanks ... I didn't bother to look it up as beyond about the 3rd ingredient the percentages usually get pretty small. I'll know better next time.

 

[Marin]

RickB wrote:

Just like the mouse milk folks, these guys depend on establishing a cult following based on ignorance of the process and the blend of ingredients. The only way to get rid of rot is to replace the rotten wood. All you get with magic wood restoration products is a volume of plastic surrounded by rotten wood.

If you believe CPES (or thinned epoxy if that's what you prefer to use) will get rid of rot, you are absolutely correct, it won't and it's silly to think it will.* What CPES does extremely effectively is prevent the start of rot if wood is treated with it beforehand.* This is how its use is advocated by the shipwrights and restoration and maintenance experts on the Grand Banks forums.* If wood is rotted, no question, cutting out the rotten portions and replacing with new wood, or replacing the entire structure with new wood, are the only cures.

But if new wood-- or undamaged old wood that is being refinished-- is first saturated with CPES, this permanently seals the outer layer of wood cells against moisture intrusion and also helps maintain the integrity of whatever finish you put on top of it, paint, varnish, etc.* (You have to put something over CPES because it is not UV resistant).

Smiths/Rot Doctor do carry a product that can be used to replace rotted wood in small areas.* It's called "Fill It" (I think) and it's a putty-like two-part epoxy similar in concept to Bondo but made for a marine environment, which Bondo is not.* Where it's very useful is on window frames, for example, that might have a rotten section in part of a frame section.* The rotten wood is cut or carved away and replaced by Fill It which, once cured, can be sanded to blend with the rest of the frame.* This makes for a permanent repair which in many cases is far easier and less expensive than replacing the entire frame section.* But there's a point at which it becomes more effective to replace the whole section.

CPES is not a magic bullet but there are instances where it can "fix" a rot problem.** I have used it very effectively to solidify and protect the failing plywood underdecks of our three lazarette hatches which had sections of soft and crumbling wood where they simply never dried out.* After letting the hatches dry out thoroughly (which took the better part of a month inside our house) and sanding away the punky wood, repeated saturations with CPES turned the plywood hard as a rock and they have held up beautifully for the ten years since we did this.

*

 

[Delfin]

Marin, you identified one of the critical factors in successfully dealing with punky wood, and that is drying it out completely first.* Rot Dr. makes it sound like their product can be applied with some moisture in the wood, but that is not my experience.* If there is any, no epoxy, including theirs, will dry correctly.* The best method is as you describe - dry it out completely, remove the rot, soak the wood around the rot with epoxy, then fill or replace.* I soak all plywood edges with thinned epoxy before building anything that will be subjected to moisture to avoid this problem in the first place.* For very moist areas, like an ice box, I have painted a couple of coats of thinned epoxy on before laminating with epoxy glass.

 

[Marin]

Delfin wrote:

Rot Dr. makes it sound like their product can be applied with some moisture in the wood, but that is not my experience.

Yes, I know they imply or say that CPES can penetrate wood and "displace" moisture, but that claim is one I do not*practice.* CPES might*so this to a degree, but why compromise the project if you're going for a*permanent fix?*

To me, having the wood--- new, stripped old wood in good shape, or having rot problems--- completely dry is the correct way to start off with CPES.* And from our hatch project, it's amazing how long it can take water-soaked wood to completely dry out.* We set the hatches up vertically in one of our bathrooms during the winter so there was heat on in the house most of the day (we built a temporary plywood cover for the big open hole in the aft deck of the boat).* And it took weeks for those three hatches to dry out completely.* They literally dripped water from the lower edges for a good portion of that time.