thinning epoxy with metho

[ford]

is this feasible? :confused:

[thechemist]

If you mean methyl alcohol, no, I would not advise it. It may look good at first blush, but microscopically, when soaking into wood it dissolves the water and the epoxide side precipitates out, separating resin and curing agent, leaving the wood with epoxy on the surface and goo internally. I actually did some experiments on this a year or more ago when someone else offered this idea.

Negative outcome.

Not good.

[swingking]

WEST SYSTEM likes fast evaporating lacquer thinner to thin epoxy.

See:

http://westsystem.com/webpages/epoxyworks/14/ThinningEpoxy.html

Kern Hendricks of System Three Resins (Google rec.boats.building):

"We see no problem with thinning epoxy with isopropyl or denatured ethyl(solvent or shellac) alcohol up to about ten percent IF extra time is allowed for the solvents to evaporate AND additional unthinned coats will be applied."
2000/12/03

"We use anhydrous isopropyl alcohol. It disolves both the epoxy and amine curing agents well." 1996/06/12

Mat

[gaffman]

I tried MAS epoxy instead of West System. It is thinner and you may find it doesn't need to be thinned at all. I used it with Dynel on my decks.

[Bruce Hooke]

Last I knew West System said in no uncertain terms that their epoxy should not be thinned.

Why are you trying to thin epoxy? In a glue joint I certainly wouldn't recommend using thinned epoxy because you would probably end up with a glue-starved joint. If you are planning to use it for coating then thinning it will just mean that you will need to apply more coats...

If you want something that will soak deep into the wood then CPES would probably be a better way to go (if you can get it 'down under').

[ 10-18-2002, 04:58 PM: Message edited by: Bruce Hooke ]

[John B]

They have a product called Everdure out here. This stuff used to be a very thin ( I assume epoxy) with a veritable agent orange cocktail of bug killers in it.Hell, even boatbuilders used to say to be careful with the stuff. A few years ago they removed all the poisons but still sell it under the same name.
I clean epoxy up with meths.

[thechemist]

Lacquer thinner will do a much better job, dissolving the resin and hardener more efficiently and leaving less of a sticky residue.

[mhoffman]

So Chemist...
is there an effective thinning agent for epoxy to get better surface penetration, without haveing to buy two different products (CPES and "regular" epoxy)? My garage already looks like a HAZMAT storage facility...
BTW, I would like to add a sincere thanks for all of the techincal insight and knowledge that you impart to the forum, especially considering your steadfast refusal to support or promote any product line, which you clearly are in an excellent position to do. Refreshing to find someone (or something?) willing (or programmed?) to share information for altruistic reasons. BZ!
Matt

[thechemist]

Originally posted by mhoffman:
So Chemist...
is there an effective thinning agent for epoxy to get better surface penetration, without having to buy two different products (CPES and "regular" epoxy)? My garage already looks like a HAZMAT storage facility...
BTW, I would like to add a sincere thanks for all of the techincal insight and knowledge that you impart to the forum, especially considering your steadfast refusal to support or promote any product line, which you clearly are in an excellent position to do. Refreshing to find someone (or something?) willing (or programmed?) to share information for altruistic reasons. BZ!
MattMy programmers thank you for your appreciation of their algorithms.

There is actually no "regular" epoxy.

When everything becomes the same then one cannot understand any differences, and one becomes less able to think in that area.

There are groups of similar products. Some people may make near-exact copies of the products of others. The epoxy-wood-rot-treatments sold in Canada by the Sys. 3 folks, and the other stuff sold in Austraila [made by the International licensee or agent, I think] use the same xylene/butyl alcohol solvent system, near as I can tell, and fairly similar resin systems at about the same solvent content. Are they identical? I dunno........probably close to it. Is that different from CPES? Do a search of Building/Repair for CPES in the title and read what is there, and I think you will conclude they are much more different, both in their solvent systems and their resin systems.

The word "epoxy" means a three-membered ring of two carbon atoms and an oxygen atom, also known as an oxirane ring.

There is one common epoxy "resin", diglycidyl ether of bisphenol-A, molecular weight around four hundred, and a few higher-molecular-weight versions used in coatings and such. There are dozens of other epoxy-functional resins and modifiers that formulators use in various amounts, in conjunction with the above or even entirely themselves. Most of these are petrochemical in origin but some are derived from wood or other natural vegetable sources, and those generally tend to be larger molecules and to impart more flexibility to the cured system.

There are literally hundreds of amine-terminated chemicals that are used as "curing agents" for the above epoxy-functional chemicals. These, too, may be large or small molecules from a variety of sources.

Formulators also use "additives", which do things that affect curing characteristics, wetting of a substrate, air release from glass cloth, bubble-breaking, adhesion to different things, and other [secret] things.

If one is making a paint or filler, there are many different kinds of particles that have a lot to do with cured properties, as well as how the stuff handles before it cures.

Some of these products cure faster or slower, are more-or-less critical in their mixing ratios, and some will not cure reliably on acidic wood while others do [or don't] glue teak and other oily wood.

The ones that do better for fiberglass layup would be optimized for that, and would not be expected to do the best job of gluing hardwoods, by the way. The mechanical properties should be different, and fiberglass has a different surface-tension-characteristic from an oily hardwood surface.

The entire issue of surface-tension of some solvent or resin blend has a lot to do with why CPES wets selectively the surfaces it does. You can learn more about that at www.woodrestoration.com. (http://www.woodrestoration.com.) You can do your own tests with whatever you can come up with and see how your results compare, but I can't give you formulas that will do what that stuff does.

Fairly sophisticated formulations are required to do specific things. CPES is one of those. Some specialized glues or fillers are, also. If you are gluing dry wood with negligible oil in it......CDX fir plywood or even meranti, you will find that most of the epoxy products out there easily do that sort of job. Layup of glass cloth is not difficult if the glass is bone-dry. If it accumulates a little water vapor adsorbed on the fiber surface, then some commercial products may not wet it well, while those more robust formulations will still perform in that less user-friendly environment.

Sometimes the difference between apparently-equivalent products is not obvious, as one works all the time and another works most of the time.

[gaffman]

Bravo Chemist! Signed, a social scientist.

[mhoffman]

Not wanting to sound ignorant (though I am), how does one determine which product performs which functions best for a particular set of circumstances? Given that most folks here (if not most, at least myself anyhow)is/are using epoxy products for all of the functions you mentioned above at some point or another in their various projects, can one product provide "adaquate" performance for that entire range?
Moreover, I feel certain that if I were to call a particular supplier and question their formulation's design performance wrt my applications, I would get something akin to their's is the best product for my purpose. (The never ending battle between engineering and marketing I suppose.) In other words, how do I, the end use, relatively low volume, consumer, find out what product would best suit my application, because the supplier is going to tell me that his product line is best.
I suppose though, based on your information, I am better prepared to ask the right questions, which is far better position to in in than not...

Thanks for sharing your stored data...

[NormMessinger]

You can't. That is my conclusion, Matt. All the theory in the world won't help. Ya gotta have faith. Perhaps, maybe, probably, okay, I hope if one stays with "regular epoxy", that is the mainstream goops advertised to the boating community, WEST, System Three, MAS one might get one of the more robust formulations chemist mentions. If one goes with one of the inexpensive (everything is relative, right?) brands one get goop that works okay in the mid optimum range but if one works in a wider range of temps, materials, humidity, etc., one has less chance of failure with "regular epoxy".

Now some will argue that the difference between say, RAKA and WEST is advertising. Perhaps. Ya pays yer money and ya take yer chances.

That's my superstition re epoxy and I'm stickin' to it. Praise the Goop.

--Norm

[mhoffman]

Norm-

I agree about going by faith- that applies with pretty much every facet of boat building (and life) I suppose, especially for first time. I know I will have at least some trepidation the first time I cast off all lines. I am counting on application of the building principals I learned from others, quality materials and equipment. To be certain, every aspect of the construction process (and operating process too, for that matter) is a series of comprimises; I just like to know what comprimises I am making, or even if they are required in that circumstance. I am sure I could have built my project with lots more (or less) money and lots more (or less) time- I made comprimises though. However, when I made those decisions, I did so based on what I felt was a good understanding of the variables involved and the consequences of those decisions. Operational risk management. How much design margin have I built into my project? No idea.

Am I asking for external reassurance that my decisions are/were sound? maybe to a degree. More than that though, I'd like to continue to develop my skills and knowledge so future projects (or repairs...) can utilize the materials effectively and appropriately. If I could, for example, convert the epoxy I have sitting on my workbench into a less viscous form for greater penetration for an application, or improve its adhesive qualities for a particular type of wood, I become more efficient, right?

Walking by faith though, is still a good thing.
Matt

[Wild Wassa]

Method 1, When I want to 'thin' epoxy, I just warn up the resin slightly, then add the hardener.

Method 2, When I want to really reduce the viscosity of the epoxy, I'll add BoatCraft Pacific's TPRDA. Which is designed to enhance penetration into timber surfaces. I'll add 1 part TPRDA to 3 or 4 parts by volume.

Warren.

[ 10-25-2002, 01:41 AM: Message edited by: Wild Wassa ]

[thechemist]

Originally posted by Wild Wassa:
Method 1, When I want to 'thin' epoxy, I just warn up the resin slightly, then add the hardener.

Method 2, When I want to really reduce the viscosity of the epoxy, I'll add BoatCraft Pacific's TPRDA. Which is designed to enhance penetration into timber surfaces. I'll add 1 part TPRDA to 3 or 4 parts by volume.

Warren.Maybe you mean their "Timber Preservative Additive"? I looked on the site and could not find its MSDS, but as they seem to use cycloaliphatic curing agents, which require some benzyl alcohol as a molecular lubricant and plasticizer so they will cure at room temperature, I suspect that they are selling more benzyl alcohol.

They say that their TPA is not a solvent, but benzyl alcohol really is a solvent, and really does evaporate with time. It produces crazing of epoxy surface coatings. One sees this occasionally with WEST coatings.....they use benzyl alcohol as a plasticier and it migrates out with time. the polymer gets more brittle with age, and that's why a cracking or crazing occasionally shows up with age.

They might also using benzyl buytyl phthalate, a low-viscosity plasticizer that finds its way into some epoxy formualtions.

Either *Does* degrade cured properties, so if that is what they have I would avoid it.

[ford]

Bote Cote to the best of my knowledge use benzyl etc with resin, that's all. Apparently it somehow breaks the surface tension thereby wetting out the timber better than straight epoxy, it can only be used as a wetting agent. I have used this for years and have never noticed any crazing.

[Nicholas Carey]

Originally posted by John B:
They have a product called Everdure out here. This stuff used to be a very thin ( I assume epoxy) with a veritable agent orange cocktail of bug killers in it.Hell, even boatbuilders used to say to be careful with the stuff. A few years ago they removed all the poisons but still sell it under the same name.
I clean epoxy up with meths.Everdure...an epoxy? Everdure is a trademark for a particular silicon bronze alloy.