Thanks Rodney, I appreciate the feedback. The OP simply stated if he needs to follow the directions on his packaging and we tried to give him the answer and reasoning behind it. Unfortunately RCU is famous for guys with limited experience wanting to argue points without fully understanding the situation. West epoxies are formulated for cold cures because they are intended for boats that may still be in the water or not able to get to a warm environment. Hobbyists like it because it is user friendly and it does the job. My last race airplane would not be the same if it was not built with materials and knowledge that go beyond common hobby. It has 520 sq in of wing, weighs 6.25 lbs and is powered with a YS 115. First off the weight would be almost impossible, the engine weight is 1/3 total aircraft weight. Figure in radio gear, retracts, 16 oz fuel tank, full paint job and you can see what I mean. The fuse is laid up using a surface layer of 2.4 ox cloth followed by a layer of 6 oz cloth with 3K CF tow between the layers in the nose and wing TE. Thats not a lot of material there yet the airplane does an honest 160 mph and will do a 180 degree turn in 50' dia. That is right around 20 G's. The fuse also has no formers, not even a firewall. What makes it work is that I used Hysol 9396 resin and then post cured the fuse at 180 degrees for 2 hours following an ambient cure of 48 hours. Once you have the knowledge of composites you will find areas to use the knowledge.

All I disagreed with were the two points I listed. The rest of the post is direct from the West System web site I cannot take credit for that. As far as knowing what they are talking about I think their expertise far outstrips anything you have to offer. By the way I still disagree with those two points. His remarks were inclusive of all epoxies and that is not true as some are designed to work in less than ideal environments. It wasn’t a criticism or rebuke but an observation from my experience using the West System. Hobby epoxies tend to be similar in that they work in less than ideal conditions. Most problems occur because modelers mix improperly or use epoxy that has been sitting around for years or has been contaminated. The OP is using it for a barrier coat against fuel penetration I don’t see any reference to using it for bond or adding strength. The cure he would get in less than ideal temps would be sufficient.

As to the West System web site the manuals, videos and general information is much more informative than the self posturing and poor attempt at putting down any who would dare to offer an opinion that might run contrary to the grand Wazoo and his elf.

Dennis

The advice from a few of the other non experts like using a heat gun or putting it in a heated area is enough to address the OP’s concern. Simple but effective. Going on about how big an expert you are adds nothing as far as I am concerned of value. It seems every time someone asks what should be a simple question there are those who feel the need to convince everyone they are the true messiah of what ever is being discussed. If there are several so called experts then look out the next 30 pages of posts are spent all of them trying to out do each other with their knowledge on the subject. Meanwhile the OP has fixed his problem, moved on and most likely is out flying never to bother to return to the topic again.

What ever happened to answering a simple question with a simple answer without all the chest pounding? It’s like a clip from the movie Spaceballs “I see your Swartz is as big as mine.”

http://www.youtube.com/watch?v=RI0i_tL-8aU

Now Dennis, you seem to be getting a little personal there bud. Tell ya what, lay up a couple piles of cloth between some mylar or plastic bag with your West Systems wonder epoxy and let it ambient cure for 24 hours. Check the flexibility. Then place in an oven set to 150 to 175 degrees for 2 hours, let cool and check the flexibility again. I don't have to guess what you will find out. I understand if you don't want to take the time to prove my point but if you choose not to then please leave the thread and let us teach something to the guys who would like to learn.


PS I love that movie........My hair, he shot my hair LOL

So it’s as I thought answering and solving the OP's question is not as important as hearing yourself from the top of the soap box telling the rest of us we are not worthy. Don't you ever get tired listening to yourself? For 99% of us the hobby shop epoxies do everything we need and more. Instructions are super simple. The West System gives more options and I use it because I am familiar with it. I don't consider myself any better or more knowledgeable than the next guy. I have nothing to prove I don't feel the need to feel superior. Your last post has nothing to do with what most modelers will expect out of an epoxy so it has little value to me or the real world of most modelers. An awful lot of expert modelers have written books and made videos on finishing models with glass cloth or laying up the odd one-of mold and using resin/glass/carbon to enhance the airframe. They explain it simply with readily available tools so that even the most basic modeler can achieve a modicum of success. On the other hand the information you throw out there has so little value for the average modeler because they don’t have the ability or want to attempt to duplicate it. That you are capable of using these techniques and have access to the equipment I think is great for you but of absolutely little value for what most expect for their applications.

For instance I have watched the university students who have no experience with epoxies, fiberglass, Kevlar or carbon fiber take the information from web sites and use that information to build a model that weighs less than 10 lbs powered with a Jett .65 that will lift 40 plus lbs in a successful flight taking off in under 200 feet and landing in 400. They design and build these things with the most basic equipment and minimum of knowledge and technique.

I hate to burst your bubble but this very exacting knowledge you think everyone must hear. Not so, try spending the time better explaining techniques that have value to the guy with no equipment and little knowledge. How to mix epoxies properly, storage, shelf life and what to look for when having problems that can be easily solved without all the bloody industrial equipment. How many people do you think own a vacuum pump? Guys are interested in how to lay the cloth so it stays in the corner. How do I make and use a one time mold for a cowl that’s no longer available. Where is a good place to buy supplies for my small needs? There are lots of topics, tips and tricks you can volunteer that many will actually make use of. Your last post, I cannot think of one modeler I know who would even have a need to attempt the process you describe. I ask what the relevance to modelers is in general when you go on about tools and techniques we will never encounter.

Dennis

Dennis, are you reading the same thread I am? Take a look at post #3. I only gave the information the OP needed. It wasn't until you came around and started talking about about a product that the OP clearly did not have. He asked if he should follow the instructions that state the cure should be done at or above 70 degrees. We told him yes. It wasn't until you came around much later that this became an issue. If you think what we have said to this point as being overcomplicated then you have no real clue about composites as we really have kept it simple to this point. It's obvious that you feel you have nothing to learn and I really can't care less about this but seriously stop being the class clown here. Rodney has already stated that he feels our information has value and that is good enough for me to continue to answer composites related questions to the best of my ability. If you don't like that may I suggest the door once again.

You guys are hilarious carry on Mcduff and may the Swartz be with you

LOL. Talk about getting on a soap box, you have been grand standing and casting stones for several posts now, if you don't find anything we are stating worth while thats fine, all that tells me is that you are just another expert yourself capable of pointing fingers and talking tall tails, but as usual, nothing to show and tell, just the typical keyboard service and unwillingness to learn things outside the normal black and white box you have painted yourself in. You posted a link to the West Systems web site, have you actually read section 8 in their web site before proceeded to tell me how their expertise outweighed anything I may have to say with my mere 40 + years of experience? Here I posted it for you Mr. Wizard. Now go back and reread my first line item to Hydro Junky you quoted me on and tell me how crow taste.

8. Post-cure the epoxy if possible. Post-curing can help to complete the epoxy mixture’s cross-linking and boost the epoxy’s physical properties even after a week or two of cold temperatures. Post-curing simply is the process of applying heat to complete or speed the cure after the epoxy has reached a partial cure at ambient temperature. Elevate the temperature of the epoxy and substrate gradually to avoid thermal shock. Although any temperature elevation will improve cross-linking, try to boost the temperature to room temperature (72°F) or warmer. The time required depends on the hardener used, the post-cure temperature and how much further the cure has to go. Generally, higher post-cure temperatures require shorter post-cure times. Do not exceed 140°F and do not remove clamps or load the joint until after the final cure. CAUTION!—Heating a porous material may cause air within the material to expand and “out-gas.” If an epoxy coating applied over the material has not gelled enough before starting the post-cure, bubbles from the out-gassing material may show up in the cured coating. Allow the epoxy to reach a partial cure before post-curing.A variety of post-cure techniques can be used. In some cases your shop will naturally warm itself enough to complete the cure during the day, following a cold night. Outdoors, building a plastic tent to trap solar heat can easily boost the temperature enough for post-cure even during cool weather. Turning up the thermostat, using radiant heaters, electric heaters or electric blankets are the most common way to control the post-cure temperature in a shop. It is not necessary to heat the entire structure if you are working on only a small area. Tents of plastic or insulated board are very helpful for confining heat to specific areas and provide greater mobility with a limited heat source, both indoors and outdoors.

Now they are referring to their own products, but post cures can be performed @ much higher temps and can be accomplished in a normal or in a consolidated state utilizing there system and many other systems as well. Sorry, I almost forgot, you don't want to know this useless information that you will never use.

Bob

You still don't get it do you I never said that there was anything wrong in what was posted I simply said it wasn't necessary for 99% of the modeling community. The type of epoxy use for most is simplistic in method and application but many times is performed incorrectly. A better service of the expertise between you two would be addressing the problems most run into rather than discussing autoclaves and advanced techniques most will never use. If it makes you feel good carry on. At least the web site I referred to attempts to take into consideration all levels of experience the customer will have from the most basic to the advanced. Don’t get your knickers in such a bunch most modelers have never used the techniques you guys flaunt and they do just fine. When I need an advanced technique I will research it then for right now I’m quite content in the knowledge I have gained being enough to satisfy my current needs.

Well its a banner day would like to keep the difference of opinion going (its the only one at this time) but I'm going flying with my F5B glider put together without any special equipment or techniques and its 4 years old ticking and still taking a licking. I think I'll take my MXS as well haven’t flown it since last fall. Taking your advice and getting out from behind a keyboard you should take your own advice might put you in a better frame of mind. LTR

Dennis