Aside from it sticking real permanant like to hands, clothes . . . that one I seem to keep learning every time I work with it.
I had two scenarios recently where I turned to two part. One was stiffening up some column bases that, while dilapidated and unsightly, were primarily just suffering from age and a little dry rot. They did not seem to need a full blown replacement.
So on those, I drilled a series of holes at a downward angle around the bases, mixed the two part with a shot of epoxy reducer (which is very, very thin) and poured it in the holes with a paper dixie cup. And poured more. And more. And . . . ok you get the pic. That worked great. The thinner reduced the stuff so much the dried out wood just absorbed the heck out of it. Next day, rock solid. Sand, fill, prime.
The next go sounded like a good idea. Gluing some boards together face to face. Couldnt buy the thickness I wanted, so thought hey, epoxy oughta hold real good. And I’m gonna thin that down a touch to make it easier to brush. Even a little thinner reduced it so much that the faces just soaked it in. I took the clamps off the next day and could pull the boards apart with my hands. So I redid that without reducing, and put on plenty. It held on the 2nd attempt.
Real trucks dont have sparkplugs
Replies
You "thinned" the epoxy? That's not really possible without destroying it holding strength. Thinners such as acetone, toluene or MEK while they do thin the mix the also kill the catalytic reaction that is what takes place as epoxy cures. You can "cut" the epoxy with other materials to make it more thixotropic (and they sometimes in the case of carbon and glass fiber help strenghen it) but thining is a no no.
There are however specially designed thinner or less thixotropic epoxies that are used in various penetrating applications.
I guess you learned that lesson the hard way.
Been there, done that.
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I used the reducer made for the stuff. Not something like lacquer thinner. Its supposed to let it absorb into wood for fixes like example #1. Works.Real trucks dont have sparkplugs
A reducer? What brand of expoy is this? I've never heard of a reducer. And just what does it say on the bottle or can is in this reducer?
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Jerrald. You think I'm an idiot, just say it.
The epoxy is West. The reducer is Sherwin #54. It doesnt say on the can so I looked until I found a MSDS on it. Ethylbenzene, Xlyene, Ethanol, and Methyl Isobutyl Ketone are the main components of the reducer.Real trucks dont have sparkplugs
RW - "Jerrald. You think I'm an idiot, just say it."
Far from it Randal and I have no idea where that's coming from. In fact I've always thought you to be one of the sharper minds here and have on occasion printed out your posts and articles and given them to my guys. I don't post much here anymore here but given that respect I thought I thought I 'd post something to let a friend and peer know I've made the same error too. I'll say what I'm going to say right now and in the future I'll keep my mouth shut and avoid any Breaktime discussions with you in the future.
We do lots of epoxy and fiberglass work from sculptural to structurally to restoration and have used lots of different brands and systems of epoxies, fiberglass resins, and polyester fillers over the years. My late father was also a chemist who developed some of the patents on epoxy so while he was still alive he would always put in his 2¢ on what we were using and what it was actually doing chemically so I learned from him, reading all the manufacturers manuals, as well as several articles and books on boat building, theatrical scenery construction, and restoration regarding epoxy and fiberglass. I also learned a lot by playing around and trying things like thinning epoxy with various solvents just to see what they would do (ignoring my fathers cautions and advice) which is what I meant by "been there, done that".
Wile we use a lot of different brands of epoxy our brand of choice 90% of the time is West Systems (and we generally buy it in 5 to 55 gallon quantities) and right there in the West Systems Manual it says:
The truth of the matter is though there is a solvent you can use to thin epoxy that wont necessarily adversely effect it strength since it only thins the mix and doesn't effect or take part in the chemical reaction and it was called something like an 'ester glycol' or a 'glycol ester" but I don't really recall since it was pretty noxious and we felt it wasn't worth the trouble or risk to find and use.
And from what I understand from a discussion I once had with a boat building friend of mine (he works for a company that builds 12 meter America's Cup yachts among other luxury yachts) the 'ester glycol' only works effectively as a thinner if you can be assured it will evaporates before the epoxy catalytic reaction completes. If the reaction goes off before the 'thinner evaporates' you'll have a bad set up. Basically he said they never add thinners.
When we have wanted a penetrating epoxy we would either switch to the Slow West Systems Hardener and even sometimes chill it or switch to one of the penetrating epoxies from one of the other manufacturers.
If we wanted to spread a small amount of epoxy to laminate two boards together we'll spread it with a scraper rather than thin it.
"The epoxy is West. The reducer is Sherwin #54. It doesnt say on the can so I looked until I found a MSDS on it. Ethylbenzene, Xlyene, Ethanol, and Methyl Isobutyl Ketone are the main components of the reducer."
Like I said we primarily use the West Systems Epoxy and unless this thinner was a brand new thing I knew from my experience they don't provide or recommend a thinner so that's was why I asked. Along with that I have never heard of a thinner used in epoxy lamination work. On the other hand I do know that the paint manufacturers make a thinner for their epoxy paint coating but I unfamiliar with it use and what in it which is why I asked what is said on the can. I thought maybe you we using a coating thinner or possible one of the 'reducers' used to clean boat hulls which are really solvents that break down the curing reaction if you mix them into the epoxy.
I was looking to see if the reducer you had contained acetone, toluene or MEK. I'm not a chemist so outside of the Ethanol which I know isn't an ester I don't know for sure if any of those other chemical are although I suspect they aren't esters. I would however have no problems or reservation using Sherwin 54 for thinning Sherwin Epoxy paints since that's what it was engineered for but I would have reservations using it with West Systems or any other brands epoxy for lamination and gluing applications. Epoxies I have found are generally engineered systems and they generally don't work well mixed with components from other manufacturers.
Also from experience when I was still working in the theatre designing and building scenery when building flats we would always cut and dilute our white or yellow glue with water so that you could paint it onto a surface and use it to attach muslin or canvas that you would then use as the surface you would actually paint on. Since in addition to making the glue easier to spread one of the other reasons you diluted it was so that when muslin surface was worn out as a painting surface and needed replacing you could pull it off relatively easily. You would never be able to pull the fabric off if it was glued with un-cut full strength white or yellow glue. And conversely you would never use that cut glue to glue on the corner blocks (gussets) that joined the frame of the flat together since you knew it wouldn't hold. I would naturally think that that same kind of thinking would hold true for epoxies too although I often ignored what I knew and cheated trying things like cutting adhesives and paint and paid the price when it didn't work out like I hoped it would.
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Hatchet buried. I thought you were trying to jump on me.
I think the point I was aiming at originally wasnt so much epoxy but that, after having used it for so many things here and there over time, this was the first time I'd done anything to reduce it, and the results of those experiments.
Real trucks dont have sparkplugs
Okay hatchet is buried. Life is kool....
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Wow, you said a mouthful! I too was wondering about the "thinner" - although I have nowhere near the background with epoxy that you do. I used to repair surfboards, and several of my friends built and fiberglassed them, so I have some experience with resin and epoxies. Recently I have had my painters epoxying fiberglass tubs, and I've been able to utilize some of my surfboard repair experience.
And like you, the "idiot" comment caught me completely off-guard. But then again, I know how one's mood at the moment can slant a comment completely different than the spirit it was offered in. So I figured the poster was having a bad day, or maybe my bad day (it was a doozy) was causing me to over-react to his comment.
At any rate, thanks for the useful info, and the explanation of your background with the subject. Epoxy resin methods are not "intuitive", their requirements and reactions are specific
"I needed a drink, I needed a lot of life insurance, I needed a vacation, I needed a home in the country. What I had was a coat, a hat and a gun."
Raymond Chandler's Philip Marlowe
Edited 5/21/2007 10:18 pm by Huck
Huck - "Epoxy resin methods are not "intuitive", their requirements and reactions are specific" That's actually a very good observation in regard to working with epoxies. I wish I had thought of and said that.
I thought the topic was a little bit ironic in that just the other day I was in a topic over on the JLC site that evolved in talk about thinning bondo and I had just thrown my 2¢ in over there too. Bondo it turns out you can thin. What I wrote over there regarding bondo:
I was using epoxy and polyester resins and bondo in the theatre long before I ever even thought of using it in remodeling and many of the things we did with those materials to get certain artistic effects I wouldn't even mention here since those tricks run counter to common good practice and techniques you need in remodeling and restoration.
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Epoxy can be tinned as long as the thinner evaporates before the reaction is complete. Most two-part epoxy paints allow up to 25% thinner for lower viscosity when spraying with no reduction in their final strength.
TJK -
"Epoxy can be tinned as long as the thinner evaporates before the reaction is complete."
That's true if the thinner is a compound that doesn't chemically effect the catalytic reaction in the epoxy (as I just stated above).
"Most two-part epoxy paints allow up to 25% thinner for lower viscosity when spraying with no reduction in their final strength."
But I would think what you are describing is spraying for coating (painting) application and not for lamination or gluing purposes. I don't see how the thinner is going to evaporate from the interior of a lamination before the catalytic reaction goes off.
PS edit: When I say "I don't see how the thinner is going to evaporate from the interior of a lamination before the catalytic reaction goes off." I'm talking about solid material laminations and not fiberglass or carbon fiber.
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Edited 5/21/2007 8:51 pm ET by JerraldHayes
Of course the best way is to just buy low viscosity epoxy resin to begin with, but that is not always possible or convenient. Most of the readily available solvents like acetone, MEK, and denatured alcohol are OK for use with epoxies. I suppose someone might try an exotic solvent that could inhibit the reaction, but outside of a chemistry lab where would they buy it?Yes, the materials sandwiching the bond have to allow the solvent to evaporate, and that is the one big limitation. The solvent also rules out use on plastics and foams that otherwise are very happy with normal epoxy resin.
TJK - "
Of course the best way is to just buy low viscosity epoxy resin to begin with, but that is not always possible or convenient."
Well you're certainly right about that. Finding and getting the right epoxy is often the most difficult and time consuming part of the job.
"...Most of the readily available solvents like acetone, MEK, and denatured alcohol are OK for use with epoxies. I suppose someone might try an exotic solvent that could inhibit the reaction, but outside of a chemistry lab where would they buy it?"
Acetone will inhibit or shut down the catalityic reaction and that's why we use it to clean brushes and tools so even in a pinch I would never want to use it as a 'thinner'. And MEK while it may thin the epoxy it tends to hasten the reaction. We actually do use MEK in cold weather to get our mixes to go off faster. As for denatured alcohol I wouldn't know.
"....The solvent also rules out use on plastics and foams that otherwise are very happy with normal epoxy resin."
On of the threatical tricks I used in the past for sets I've built that's really simple was I created the look of weathered limestone (rottenstone) by spattering lightly Dow type styrofaom boards with acetone and then coating the boards with epoxy resin to give it a hard durable shell.
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Jerrald,WEST System 105/206 is runny enough for everything I've needed to saturate. Warming it up makes it runnier. Best is to warm the substrate so the epoxy soaks right in, then no bubbles as the substrate cools down.Thanks for the education on the chemical interference caused to cure times by acetone and MEK. That may come in handy one of these days. Is this forum cool, or what?BillPS My dad is a chemist, too.
Edited 5/26/2007 3:43 am by BillBrennen
>Acetone will inhibit or shut down the catalityic reaction and that's why we use it to clean brushes and tools so even in a pinch I would never want to use it as a 'thinner'. And MEK while it may thin the epoxy it tends to hasten the reaction. We actually do use MEK in cold weather to get our mixes to go off faster.
That surprises me, as they are such similar solvents -- MEK (methyl ethyl ketone) vs. acetone (methyl methyl ketone). I would expect them to behave similarly. Surprising what a difference a couple atoms can make.
Don
(not a chemist, just a tidbit I remember from chemistry class a looong time ago)
But the shelf-life and open times for the more exotic (very thin, very thick, coloured, high-strength, etc.) tend to be real short.
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