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EPOXY - resin:hardener ratios ?
I see that vendors of epoxy sell resin:hardener combinations of 1:2,
1:3, 1:4, etc.... What's going on here ? Thank you, Courtney |
EPOXY - resin:hardener ratios ?
They are different formulations. Follow mfgr. ratio data exactly. This is
not a place for experiments! Dave |
EPOXY concerns ?
Dave W wrote:
They are different formulations. Follow mfgr. ratio data exactly. This is not a place for experiments! Dave Thank you. I can see I failed to adequately state my concern :-) Chemically, what is the difference in the resins when using the different formulations that require different amounts of hardener ? If only the viscosities are different, how are these different formulations attained ? Also, what is the difference in the hardeners, if any ? Is there a known website that fully delves into this without bias ? Thank you, Courtney |
EPOXY concerns ?
Go to http://www.systemthree.com/index_2.asp -- register -- download "The
Epoxy Book" in pdf -- read the introduction and Basic Chemistry. Unless you're an organic chemist, this is all you'll be able to digest. (I can almost understand it while I'm reading it, but it's been fifty years since I took P-Chem.) Note that only a very foolish company would give you the exact details of their formulations. They've spent many year$$$ coming up with these. I believe they all start with the same basic resins from DuPont or whoever. The magic is in the additives and there are huge differences between brands. Contrast the glasslike stuff from the hardware store for mending china with the resilient bond formed for building boats. As far as ratios go, the 5:1 used by the Gougeon brothers is harder for the user to measure accurately than the 2:1 used by System Three, but it apparently is closer to the basic resin as brought in by tank car. The appendices of "The Epoxy Book" give mechanical properties and usage; e.g. coverage, curing times, etc. Roger http://home.earthlink.net/~derbyrm "Courtney Thomas" wrote in message nk.net... Dave W wrote: They are different formulations. Follow mfgr. ratio data exactly. This is not a place for experiments! Dave Thank you. I can see I failed to adequately state my concern :-) Chemically, what is the difference in the resins when using the different formulations that require different amounts of hardener ? If only the viscosities are different, how are these different formulations attained ? Also, what is the difference in the hardeners, if any ? Is there a known website that fully delves into this without bias ? Thank you, Courtney |
EPOXY concerns ?
Roger Derby wrote:
Go to http://www.systemthree.com/index_2.asp -- register -- download "The Epoxy Book" in pdf Good resource, thanks! -- dadiOH ____________________________ dadiOH's dandies v3.06... ....a help file of info about MP3s, recording from LP/cassette and tips & tricks on this and that. Get it at http://mysite.verizon.net/xico |
EPOXY concerns ?
Epoxide resin is a commodity. They all buy it in bulk from the same chemical company. Then they try to make theirs look different to the consumer and advertise heavily. I doubt any will tell you what actually makes their brand different chemically. Generally the 1:1 is considered easier to measure and mix. I use very small quantities and can measure equal amounts by eye down to one drop of each to fill a couple of screw holes. -- ------------------------------------------------------------------------------ William R Watt National Capital FreeNet Ottawa's free community network homepage: www.ncf.ca/~ag384/top.htm warning: non-FreeNet email must have "notspam" in subject or it's returned |
EPOXY concerns ?
Courtney Thomas wrote:
Dave W wrote: They are different formulations. Follow mfgr. ratio data exactly. This is not a place for experiments! Dave Thank you. I can see I failed to adequately state my concern :-) Chemically, what is the difference in the resins when using the different formulations that require different amounts of hardener ? If only the viscosities are different, how are these different formulations attained ? Also, what is the difference in the hardeners, if any ? Is there a known website that fully delves into this without bias ? Thank you, Courtney ---------------- Hi Courtney There are about three different epoxy resins (bis A, F, and novolac). Just about everyone uses Bis A.... There are about 60 different curing agents that can be used. So.... most epoxies are, or can be, a blend of different curing agents. On top of that there are thinks like nonyl ... that can be added to part A or B to even out the mix ratios, lower the price, change visc. etc. The curing agents are a lot more expensive than the resins so forumulating an epoxy with with a 4 to 1 or so mix ratio (instead of a 1 to 1 or 2 to 1 ratio) saves the formulator $$ (or increases their profits) paul oman - progressive epoxy polymers, Inc. --------------------------------------------------------------- -- "Living on Earth is expensive, but it does include a free trip around the Sun every year." ============================================ PAUL OMAN Progressive Epoxy Polymers, Inc. Frog Pond Hollow - 48 Wildwood Drive Pittsfield NH 03263 10:30-3:30 Monday-Thur EST 603-435-7199 VISA/MC/Discover/Paypal http://www.epoxyproducts.com ============================================ |
EPOXY concerns ?
Paul Oman wrote:
Courtney Thomas wrote: Dave W wrote: They are different formulations. Follow mfgr. ratio data exactly. This is not a place for experiments! Dave Thank you. I can see I failed to adequately state my concern :-) Chemically, what is the difference in the resins when using the different formulations that require different amounts of hardener ? If only the viscosities are different, how are these different formulations attained ? Also, what is the difference in the hardeners, if any ? Is there a known website that fully delves into this without bias ? Thank you, Courtney ---------------- Hi Courtney There are about three different epoxy resins (bis A, F, and novolac). Just about everyone uses Bis A.... There are about 60 different curing agents that can be used. So.... most epoxies are, or can be, a blend of different curing agents. On top of that there are thinks like nonyl ... that can be added to part A or B to even out the mix ratios, lower the price, change visc. etc. The curing agents are a lot more expensive than the resins so forumulating an epoxy with with a 4 to 1 or so mix ratio (instead of a 1 to 1 or 2 to 1 ratio) saves the formulator $$ (or increases their profits) paul oman - progressive epoxy polymers, Inc. --------------------------------------------------------------- Thank you Paul. What's the difference between bis, A, F and novolac ? What do the 'curing agents' actually do ? Catalyze the polymerization ? Is the reason that everyone doesn't use the same 'hardener', because different ones lend a different character to the curing process, otherwise, the same end product... results ? So, is the bottom line that....if you can find a 1:1 or 2:1 mix that will satisfy your needs, that's the best way to go and the more exotic formulations are also more circumscribed in terms of usage hence more likely to be inappropriately applied, such as low temp applications, etc., that ultimately don't properly cure due to a flawed application process, hence fail ? Would this be just one more example of vendors bamboozling customers with attempts at masking a generic product with proprietary 'technology', witness the auto manufacturers and their glomming onto electronics, or do some actually have worthwhile differences and related costs and PERFORMANCE, that justify their claims and charges ? Any online references that address this ? Appreciatively, Courtney |
EPOXY concerns ?
OPINION!
One size does not fit all. One design is not satisfying to all people. I've gotten used to System Three which uses a 2:1 mix. West System (Gougeon Brothers) uses a 5:1 mix. Both are vendors who have satisfied customers for decades. Neither is bamboozling the customers. They use their own products and document the results. IMHO, the lower the ratio, the less you compromise the final product, but "acceptable" is a compromise and there is a range of "good enough." The stuff we used on the F-16, F-22, and A-12 was quite different from what I use in the barn for my boat, and the difference didn't happen in the user's shop. Are you prepared to use an oven and follow a careful post-cure time/temperature schedule to achieve the results you want? Caution, it may take several tries to get it right. On A-12, several LARGE center wing assemblies were unusable because the thermostat wasn't accurate. The stuff from Dow is not suitable for use in boat building. We typically use a "room temperature" cure and want a bond which is compatible with a wooden structure. Check out http://epoxy.dow.com/products/p-liquid.htm Building an aircraft structure, repairing a china cup, patching an engine block ... all require different additives. Boat builders are not a stupid, uneducated group. Don't think you are the first to wonder about "contributed value." Roger (BSE-Physics, Univ. of Illinois) http://home.earthlink.net/~derbyrm "Courtney Thomas" wrote in message ink.net... Paul Oman wrote: snip So, is the bottom line that....if you can find a 1:1 or 2:1 mix that will satisfy your needs, that's the best way to go and the more exotic formulations are also more circumscribed in terms of usage hence more likely to be inappropriately applied, such as low temp applications, etc., that ultimately don't properly cure due to a flawed application process, hence fail ? Would this be just one more example of vendors bamboozling customers with attempts at masking a generic product with proprietary 'technology', witness the auto manufacturers and their glomming onto electronics, or do some actually have worthwhile differences and related costs and PERFORMANCE, that justify their claims and charges ? |
EPOXY concerns ?
Roger Derby wrote:
The stuff from Dow is not suitable for use in boat building. Not quite. There are only 3-4 basic resin suppliers in the world. Dow, Ciba-Geigy and Shell come to mind. There may be another one or two. Each of the major formulators works with typically only one resin supplier. That's enough. I know my suppliers are a Dow house. They supply material to build more than one boat builder including me. Lew |
EPOXY concerns ?
With the resources available in your VERY large home city and your skills at
purchasing, I'm not surprised. If I'm not mistaken, you're buying the resin in 55 gallon drums. Where do you get your hardeners and who supplied the formulae? Roger http://home.earthlink.net/~derbyrm "Lew Hodgett" wrote in message k.net... Roger Derby wrote: The stuff from Dow is not suitable for use in boat building. Not quite. There are only 3-4 basic resin suppliers in the world. Dow, Ciba-Geigy and Shell come to mind. There may be another one or two. Each of the major formulators works with typically only one resin supplier. That's enough. I know my suppliers are a Dow house. They supply material to build more than one boat builder including me. Lew |
EPOXY - resin:hardener ratios ?
Visit: http://69.239.32.181/Jeffco/Hardener...ustomers2_html
and you'll see that each hardener is formulated for a specific use and nominal cure time. You'll also notice the chemistry of hardeners is not uniform, noting for example the various "main ingredients" that comprise these many selections: Amidoamine Aliphatic mannich Modified polyamine Modified aliphatic amine Novel modified cycloaliphatic Modified polyamide/polyamine etc... 'What's going on' is apparently an extensive ammount of research to find a combination of chemistry that perform specific tasks. BTW, I've used the Jeffco products (almost) exclusively in hand laminating my project (their 1310-L6 / 3138) in either 50 or 5 gallon increments and am happy with the performance / price. Yes, I do live in a BIG city, but they do sell direct to "non-annoying'' novices. (By this I mean they are *not* West or System 3 with a big "customer care" department willing to guide the uninitiated through the process). MW Los Angeles |
EPOXY concerns ?
Roger Derby wrote:
Where do you get your hardeners and who supplied the formulae? I use Diversified Materials Corp in San Diego. The formulator supplies the chemistry. Lew |
EPOXY concerns ?
Courtney Thomas wrote:
Paul Oman wrote: Courtney Thomas wrote: Dave W wrote: They are different formulations. Follow mfgr. ratio data exactly. This is not a place for experiments! Dave Thank you. I can see I failed to adequately state my concern :-) Chemically, what is the difference in the resins when using the different formulations that require different amounts of hardener ? If only the viscosities are different, how are these different formulations attained ? Also, what is the difference in the hardeners, if any ? Is there a known website that fully delves into this without bias ? Thank you, Courtney ---------------- Hi Courtney There are about three different epoxy resins (bis A, F, and novolac). Just about everyone uses Bis A.... There are about 60 different curing agents that can be used. So.... most epoxies are, or can be, a blend of different curing agents. On top of that there are thinks like nonyl ... that can be added to part A or B to even out the mix ratios, lower the price, change visc. etc. The curing agents are a lot more expensive than the resins so forumulating an epoxy with with a 4 to 1 or so mix ratio (instead of a 1 to 1 or 2 to 1 ratio) saves the formulator $$ (or increases their profits) paul oman - progressive epoxy polymers, Inc. --------------------------------------------------------------- Thank you Paul. What's the difference between bis, A, F and novolac ? ********* Bis A resins are the most common. Bis F and especially novolac provide much better chemical (an a bit more chemical resistance. What do the 'curing agents' actually do ? Catalyze the polymerization ? ******** they are the other half the the equation needed for the reaction to happen the forms the complete epoxy Is the reason that everyone doesn't use the same 'hardener', because different ones lend a different character to the curing process, otherwise, the same end product... results ? ******* yes pretty much the same end result, but yes different ones do have dif properties (cure rates, times, blushing properties, etc. Suspect $$$ is the controlling factor for some epoxy manufacturers. So, is the bottom line that....if you can find a 1:1 or 2:1 mix that will satisfy your needs, that's the best way to go and the more exotic formulations are also more circumscribed in terms of usage hence more likely to be inappropriately applied, such as low temp applications, etc., that ultimately don't properly cure due to a flawed application process, hence fail ? ******* in a marine setting they pretty much all will work. Boatbuilding, marine applications, etc. are not very demanding for epoxies, hence there are lots of them out their (we think ours in one of the best!) Would this be just one more example of vendors bamboozling customers with attempts at masking a generic product with proprietary 'technology', witness the auto manufacturers and their glomming onto electronics, or do some actually have worthwhile differences and related costs and PERFORMANCE, that justify their claims and charges ? ****** lots of ways to make an apple pie. It's all apple pie but we all have favorites (and some like it with raisins). Yes, most if it is very overpriced. Any online references that address this ? ****** yes, but afraid they are all written and posted by me! paul oman - progressive epoxy polymers Appreciatively, Courtney -- "Living on Earth is expensive, but it does include a free trip around the Sun every year." ============================================ PAUL OMAN Progressive Epoxy Polymers, Inc. Frog Pond Hollow - 48 Wildwood Drive Pittsfield NH 03263 10:30-3:30 Monday-Thur EST 603-435-7199 VISA/MC/Discover/Paypal http://www.epoxyproducts.com ============================================ |
EPOXY - resin:hardener ratios ?
Howdy Evan:
As with all epoxies, the pot life varies dramatically with temperature... But, during a nice 80 degree day, it's about 50- 60 minutes. I chose this combination due to the fairly low mixed viscosity of about 450 cps, which gives a nice wet-out to all of the glass / kevlar I've used to date. Note that the elongation % of concern is that of the 'system', as opposed to just the hardner. See for example: http://69.239.32.181/Jeffco/Systems/...y=1314with3138 which is Jeffco's 1314 resin with the same 3138 hardner. The elongation of the 'system' with a moderate post-cure is 5.5%, which compares most favorably to Gougeon's Pro-Set 125/229 at 4.5%. There used to be a similar 'system' page for the 1310-L6 / 3138 combination, but it looks like they've moved on. MW |
EPOXY concerns ?
On Thu, 10 Nov 2005 04:27:41 +0000, Lew Hodgett wrote:
Roger Derby wrote: The stuff from Dow is not suitable for use in boat building. Not quite. There are only 3-4 basic resin suppliers in the world. Dow, Ciba-Geigy and Shell come to mind. [snip] I think Shell sold their epoxy works to Resolution Performance Products. There is a lot of information about various formulations at www.resins.com, the Resolution website. --Mac |
EPOXY concerns ?
Hey, nobody says you can't reinvent the wheel. What irritates me is that
the people who have spent years developing the proper formulations and techniques are expected to work for free. Sort of like saying "Hey. There's nothing in this book except the letters I learned in kindergarten. Why should I pay the author?" If enough people adopt that attitude, no one will bother publishing anything. Maybe the rest of you find boatbuilding so easy that you can devote your energies to doing the tasks that come bundled with a purchase from System Three or West Systems; product support, trouble shooting, documentation, storage, shipping and handling. I'd rather buy small quantities of ready-to-use stuff in order to spread the cost over time and profit from their mistakes. A recurring theme in the criticism of technical reports is that they never discuss the blind alleys, fires, explosions and other events that ran the project cost up to two or three times what was expected. To read the report or listen to the presentation one would think that it was just a matter of doing X, then Y, and then Z; of course. At GD it was common to see a gallon can of epoxy blazing away on the apron -- thermal runaway. Another recurring problem was quality control -- how do you know that the "wet out" was complete when the exterior looks fine. Ultrasound scanning of every square inch is messy and expensive. (To couple the transducer to the skin being examined, one uses a gel.) It also requires operator skills that take time to develop. ... Ah, well. Sorry. Rant over. Roger http://home.earthlink.net/~derbyrm "Mac" wrote in message ... On Thu, 10 Nov 2005 04:27:41 +0000, Lew Hodgett wrote: Roger Derby wrote: The stuff from Dow is not suitable for use in boat building. Not quite. There are only 3-4 basic resin suppliers in the world. Dow, Ciba-Geigy and Shell come to mind. [snip] I think Shell sold their epoxy works to Resolution Performance Products. There is a lot of information about various formulations at www.resins.com, the Resolution website. --Mac |
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