Electriceddie

Hi Guys,

I have an issue with the Great Planes Epoxy portion of the 30 min epoxy set. I buy things I need from tower and I will buy building supplies like Glue etc. Sometimes I may buy things I may not use for 8-12 months. Every time I seem to buy epoxy, the epoxy (Not the Hardener) seems to get hard on me in the un-opened bottle. Any reasons why? I keep it in the shop which is cool and fairly dry. Any solutions?

Thanks

Ed

scale only 4 me

My Feedback: (158)

This is a well reported problem with GP epoxy, crystallizing in the bottle,, some guys put in in warm water to get it back in a fluid state

speedracerntrixie

My Feedback: (29)

Crystallization is a result of the epoxy resin evaporating some of the solvents out and attracting moisture. There is no way to know how old the epoxy was prior to being bottled and no way to know how long it sat on the shelf prior to even getting shipped to the end user. The result is an epoxy that will never completely crosslink correctly. Bottom line is that it will not be as strong as fresh epoxy. Impossible to say if that will create you issues or not. I gave up on hobby grade 1:1 epoxy systems long ago. I keep a quart kit of laminating epoxy resin around at all times with several different hardeners that allow me to choose the cure time that works best for the job at hand. In order to make up a paste adhesive, just add milled fiber and Cabosil until you get the consistency desired. The end result is much stronger then hobby grade epoxy.

j.duncker

My Feedback: (2)

I prefer West System over the model brands. I have resin and hardner that are 8 years old and still set hard when mixed.

NB West seems more sensitive than most to being mixed in exactly the right proportions. Use syringes or weigh the stuff remember the ratio is different by weight from by volume.

ibuild

As suggested above to revitalize the epoxy have the bottles in hot water for 15-20 minutes, usually it will be good as new. Epoxy should (opposite to CA glue) be stored at room temperature - not too cold.

Pylonracr

Shawn beat me to it here. I gave up on hobby shop minute epoxy years ago. The quality is too poor and inconsistent, and the resin is thickened with some form of filler I can not identify. I use laminating resin, and will thicken it with silica, microballoons, carbon nanotubes or milled fiber as the application requires. The initial cost is higher than tubes of minute epoxy, but you will never look back. My go to resin is US Composites 635, but there are plenty of quality resin systems available. I will caution against the use of West Systems resins for aircraft use. They are a very high quality resin made for marine use and therefore remain quite flexible when cured.

Scott

Propworn

My Feedback: (3)

West Systems from Aircraft Spruce

West Systems Epoxy System On Wicks Aircraft Supply

Funny good enough for full size but not for our absurdly light loaded models LOL. Someone needs to get a grip.

Pylonracr

West system resin was developed for marine use. It remains one of the premiere marine resins, but for the builder that understands the difference, it is completely unsuitable for aircraft use, See their website for more information. Gougeon Brothers, Inc.manufactures marine grade WEST SYSTEM Epoxy Read it in their own words. Any Questions??

j.duncker

My Feedback: (2)

Well West System have a section devoted to the use their epoxy in aircraft construction.

Bert Rutan used West on at least one of his builds.

I helped out with a Cozy 4 again with West.

Pylonracr

Yes he did, but that does not change the facts. Read the data sheet. Tensile strength 7900psi, Flexural strength 14,100psi.....This is a flexible resin made for boat building. It is one of the best for what it is designed for; there is a reason Reggie Fountain builds all of his boat hulls with it, his boats are the best, Nothing against West resins, they are made for a specific application. There are many resins that are much better suited for aircraft use. If you wish to use West, go ahead, There are many resins that are better suited for this application.
Scott

Propworn

My Feedback: (3)

If you think your getting anywhere near the failure point of any brand name epoxy with our models then you are standing to close to the mixing pot. Go get yourself some fresh air and give your head a shake.

Guys build jets, pattern planes, pylon racers even dynamic soaring airframes with nothing more than off the shelf hobby adhesives AND THEY WORK!!!!!!!!

So if you feel you need some out in left field epoxy then by all means knock yourself out. For the rest of us who realise we are not building full size man carrying airframes and any brand name epoxy will more than suit our needs, pick one you feel comfortable using, is easy to come by and fits your budget.

Think about what we are doing here. I wouldn't think to use house paint on a full size build yet there are plenty of how to's that accomplish award winning finishes.

I have to wonder about those who drag facts and figures from real world situations then try and justify why we all should be using them in our miniature recreations when none of the real world (full size) dynamics apply.

Almost like a master race complex if you ask me.

The reason a lot use the West System is it more than meets any structural or dynamic force we could put on these miniature airframes, it has one of the widest working temperatures to accommodate the amateur builder who may have difficulty controlling humidity and temperature, One resin two hardeners one fast one slow, easy to work with (sand/form) and they carry a extensive line of fillers and any extras you could possibly need. Cost is reasonable, storage life is great and for the most part the brand is readily available.

Dennis

Rodney

That slight flexibility is a furtunate ( very good) thing. Too ridged a bonding surface contributes to failure. Ideally, you want the bond to be at the same flexibility as the base material with the same thermal expansion capabilities. You do NOT want a rigid bond.

Hydro Junkie

I use West Systems for two basic reasons:
1) It's not brittle like the hobby shop epoxies I've used have been, regardless of brand
2) IT WORKS EVERY TIME
Do I need I say more?

speedracerntrixie

My Feedback: (29)

Like everything else it all boils down to your expectations. If you are happy with crap epoxy then who am I or anyone else to tell you otherwise? Some of us do have higher expectations, as someone who has been doing composites in the aerospace industry for a while and has been exposed to very high quality resin systems has driven me to seek out better solutions for my models as well. Yes I was once happy with hobby grade epoxies, once I was happy with West Systems. Since then I have gained a few years of experience and have sat through countless hours of training seminars. Those products no longer meet my expectations. When using higher quality materials I am able to design models with less structure for the same strength. In other words.....lighter.

Electriceddie

Hi Guys,

I thought flexibility would be good. Maybe the wing halves could flex like a bird in flight............ Then I would not use so much fuel up....LOL.....

Propworn

My Feedback: (3)

Horse Pucky!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!LOL

Watched 2 jets built last year both used west system both added minimum weight. Both flew this year very fast hard turns and pull ups no problems. They used time tested methods to remove any access resin and very light cloth. Doubt any of your methods could result in a lighter application. Sounds to me like the old My swartz is bigger than yours again. LOL. I'm better because my epoxy is what they use on the space shuttle LOL. I'm better because my radio equipment is the latest and greatest. I'm better because I can tell you how I invented epoxy. LOL.

In my many years in the hobby I think I've listened to hundreds of self proclaimed experts all to willing to put others down when they don't subscribe or follow the latest prophet of rc modelling yet------yet there have to be hundreds of thousands world wide having great success with old tried and true methods including hobby epoxies, or the west system or any other name brand be it hobby or commercial. Get over yourself don't think the op is going to run out and buy your recommended product for his application. After all the original topic asked about premature thickening of a product. Sounds like to me your looking for a big ATTA BOY am I impressed (NOT!!!!!!!)

Why not help the op out with a reasonable suggestion rather than confuse him with horse puckey he will never make use of. Unless the object of your response is to hear yourself tell us how great you are LOL. If it will make your day ATTA BOY AND WE ARE NOT WORTHY (everyone large sweeping bow)

Dennis

speedracerntrixie

My Feedback: (29)

So Dennis.....just what are YOUR qualifications to make such a statement?

Pylonracr

Dennis
Do you believe everything you read? You obviously have no experience in the composite industry, yet you choose to attempt to discredit those of us who do. We are here to assist the OP and anyone with the willingness and ability to learn. I guess that counts you out. Fine, do what you do and leave us alone. For those that are interested in quality, there are many laminating resin systems that are much more suited to our aircraft use for about the same money as West. Do a little research and choose one you like. Or settle for ninth or tenth best and be happy. I don't care, but I obviously have much higher standards than you.

speedracerntrixie

My Feedback: (29)

Did I reccomend ANY product here? Did I say what he has won't work? I simply stated that there are better products out there. If you can't beleive that then you are as stupid as you are loud.

Pylonracr

Shawn,
The problem here is that you don't endorse the use of an epoxy that was developed to fiberglass wooden canoes as a structural laminating resin. That makes you a bad guy like me. The irony is that the makers of West systems resins actually make a laminating resin. Go figure.

speedracerntrixie

My Feedback: (29)

Scott, it's a real shame that this scenario plays out way too often. A legitimate question is asked and of course there are multiple correct answers and the OP gets the benifit of being able to choose what he feels is the best fit for him and we get to share some knowledge/experience that benefits a few of our R/C brothers. All too often someone will come in an derail the thread with a strong opposing opinion. Nothing wrong with different opinions but it's obvious some guys do not have enough emotional stability to be trusted with a keyboard.

Pylonracr

How true,
The part I am still laughing about is that when I pointed out that West resin is too flexible for structural applications, a couple of "Experts" chimed in and stated that flexible is what you want. Much better than a rigid structural bond....HUH. Maybe they should be using rubber cement for their structural bonds. Never mind that the heat deflection temp is 118 and the onset of Tg is 129. Can you say bubble gum in the sun?

Propworn

My Feedback: (3)

Not trying to discredit anyone and is not about me. The op asked about a problem he had with a 30 min epoxy he purchased from Great Planes.

To me it’s obvious by his post he’s not designing competitive pylon racers. Like thousands of others the hobby epoxy is going to do a fine job for him.

You could have said that he should not take a chance and get a fresh product.

Better yet you could suggest that just about any commercial brand would be better than the hobby brands.

Remember he probably builds one or two models a year he mentions stuff sometimes stays on the shelf months at a time. That being a consideration his purchases will probably be no more than set of 4 oz bottles every couple of years.

Of all the commercial brands available that sell small lots the West System seems to be the easiest to lay hands on. Maybe you would choose not to use it but many do with great success. I believe it can be had in pints and half pints. It is a great deal better than the hobby epoxies.

If there is a different brand available in small quantities that to is a viable choice.

Are there better products? No doubt. For the use the op intends will he notice a difference in performance? He probably at this time wouldn’t be able to tell the difference between the hobby epoxy and a commercial brand.

So it comes down to cost and availability. Last I looked an 8 oz pack of 30 min Z-poxy was under 15 bucks. The smallest West System was about 35 bucks but was near 3 times the volume. It might take him 5 or 6 years to make use of that much epoxy. If he’s like most of the guys I know he’s using it to join wing halves, join firewalls and maybe fuel proof. If he’s into electrics that may last him 10 years or more.

So what are the smallest quantity, cost and availability of your choice? Shelf life?

Instead of attempting to help the op you want to make everything an argument. At this stage the op isn’t going to run out and buy your recommendation to fasten some wings together and fuel proof the firewall. I didn’t see this topic have anything to do with discussing composites you are the only one trying to hijack the topic in that direction.

speedracerntrixie

My Feedback: (29)

I hear you Scott but realize this is a no win situation for us. most times guys don't want real answers. They are looking for confirmation. Some obviously come looking for conflict. Notice I have not made any mention of what I currently build at work. This is a catch 22. A guy who once watched jets being built and flown is laying claim that he is more knowledgeable then I and when I mention what I build and work then come the labels such as " arrogant " " braggart " and the like. It's best we just put the info out there and hopefully someone will benifit from it.

1QwkSport2.5r

Shawn and Scott - not to be a ninny here... BUT!! Why not list the brand, price, size of container, source, and/or any other useful information about the product you use and rely on that meets your standards, so the rest can have the chance to benefit from such products. We're missing the nitty gritty details, fellas. We can't use the help if we don't know what specifically you're talking about.