The information presented below is some basic technical info about some of  the products we sell - what they are, how to use them correctly, and more.

PLEASE NOTE: The use of some advanced materials can be hazardous to your health if you don not follow strict safety procedures. When working with any epoxy resins, including those we sell, you MUST use a respirator (not a dust mask), gloves, and appropriate clothing to keep the epoxy from coming into contact with your skin. When using fin fillet ammendments, again, use a respirator, as finely ground materials like Milled Glass or Kevlar Pulp can be harmful when ingested. This also applies when cutting carbon, glass, or other composite materials. This is just a hobby, and no reason to risk the most important thing you have - your health.

EPOXY

There are some very strange notions floating around out there about epoxy and it's proper use in rocketry applications. A day doesn't go by that we don't get some new bizarre interpretation of the nature of this outstanding material. Hopefully, we can shed some light on epoxy and it's correct use in this short essay.

First of all, realize that epoxy must be used with a reinforcement material such as glass, carbon, or Kevlar to be effective. People who just paint a layer of epoxy resin on a paper or phenolic airframe tube and think they have strengthened that tube are incorrect - epoxy resin without reinforcement material adds only weight, no strength! Prove it to yourself by snapping a cured drop of epoxy in two - epoxy resin alone is quite brittle. So, you must have the reinforcement material in a proper ratio of epoxy, in a matrix, to have good structural strength. We have also heard of people using epoxy with panty hose as the reinforcement material - WRONG! The reinforcement material must be compatible with epoxy, and sorry, but nylon and it's cousins are not! You will save yourself a ton of time, money, and grief by not trying to reinvent the science of composites - go with proven materials and processes!

There are also many misconceptions about epoxy resin. People think that they can go to their local hardware store or home center to get "epoxy resin", and think that what they find as "fiberglass resin" is epoxy... IT'S NOT! That material is Polyester resin, used extensively in Boat manufacturing and other low cost applications. Polyester has very poor temperature performance, and it's mechanical characteristics are not meant for rocketry applications (polyester resins never reach an advanced state of cure, therefore the reinforcements used never realize their full strength potential). It also exudes styrene during cure, not a healthy thing to be around. You must be sure that you have epoxy resin and not polyester. By the way, there are many polyester based "fiberglass" nose cones floating around out there, you can tell them by their distinctive styrene odor. While this is not a problem if you know, it could be if you use the wrong fillers or finishing products with them, or if you want a decent temperature resistance from them.

You want REAL epoxy for your aerospace project. There are many manufacturers out there, with o.k. products. I say o.k. because they will basically get you where you want to go, but are not ideal by any means for the type of work we do in rocketry applications. They were all based on Boat building resins (resin used to impregnate wood surfaces in wooden boats, called cold molding), and as such were not specifically engineered for high structural characteristics or high temperature resistance (also called Tg, or glass transition temperature). The ONLY resins out there specifically formulated for aerospace hand lamination applications and their special needs are AEROPOXY by PTM&W, and some Hexcel resins. Of these two, only AEROPOXY uses non-MDA hardeners, which are non-toxic and non-carcinogenic. So, now you know why AEROPOXY is the most popular epoxy in our shop, and also why we are AEROPOXY dealers - we only sell what we use and believe in. AEROPOXY has a one hour pot life once mixed, a tensile strength of 45,170 psi., and a Tg over 200 degrees F. Our Advanced Composite Construction Techniques videos contain much more vital information about the proper and effective use of epoxy, and you'll just have to get your copy to learn more!

HIGHT TEMP EPOXY

First - re-orient your thinking: Our high temperature epoxy is NOT your average hobby shop epoxy - it is an aerospace quality adhesive specially formulated for Shadow Composites. "Normal" epoxies are only stable up to about 120 degrees, at which point they turn into peanut butter! This epoxy is stable to 500 degrees before reaching its' Tg, or glass transition point. NOTE: This product is not related to our Aeropoxy line. In order to achieve this remarkable performance, hardener must be added very precisely and left to cure for at least 24 hours. The kit we sell contains a 2 fluid oz. portion of resin (one of the white containers shown in the photo) and a pre-measured amount of hardener in a syringe for easy and accurate dispensing. The kit is mixed one time, and used one time only.

Take the cap off of the resin and CAREFULLY squeeze the complete syringe of hardener into the resin cup. It splashes quite easily if you go too fast and you can lose some in the process, throwing off the ratio. Mix it thoroughly and then you're ready to either add structural fin amendments like Kevlar Pulp to achieve a thicker consistency, or use it as is. Initially, the resin will be quite runny, and at this point you can use it for laminating special parts with glass, carbon, or Kevlar cloth. About one half hour after it has been mixed (at 70 degrees F. ambient temperature, faster with higher temps or humidity), it will begin to slowly thicken. You have about an hour to work with it. We recommend you mask off areas you don't want resin on, as this resin is black in color and can get messy on you if you aren't careful.

When you are done with the resin, LEAVE IT ALONE. Let it cure for an additional 24 hours before you begin to work with it again. The special temperature resistance of this resin requires a very long cure time, it cures to a hard state in 24 hours and is safe to work on, but it also continues to cure to its final temperature resistance for an additional 6 days! This will not hinder your working on it, just be aware that you are working with a very special epoxy here - and its performance will reward you with a very special, aerospace quality joint.

Again, the kit is ONE TIME MIX AND USE ONLY! So we advise getting a number of projects together to use it on (or one big one) and then mix and use the epoxy. It is also quite expensive - you didn't think aerospace materials were cheap, did you?! It works great for areas like fin joints where motor heat (in the neighborhood of 400 degrees for most high power motors!) can radiate out and degrade fillet strength. Also, after you purchase it, please use it within 6 months, as the chemistry of the hardener starts to degrade after that time. All kits sold are 2 weeks fresh from manufacture or less. And, last but not least, if you have questions, ASK! - We're here to help.

REINFORCEMENT CLOTHS

When talking about advanced aerospace materials, Carbon Fiber, Kevlar, and their misused cousin Fiberglass are what most people think of. The best description and analysis of these materials in a rocketry context is available in our "Advanced Composite Techniques for High Power Rocketry" video series, but here is a brief talk about a commonly misunderstood material:

KEVLAR

This is an outstanding material for any kind of reinforcement where extreme impact resistance, relatively high stiffness, and light weight are primary concerns. Again, we recommend our video for practical instruction on the fine points of Kevlar, but suffice it to say that properly used, this material makes for a very strong rocket! We also have the lowest price on Kevlar on the internet.

Of course, you will need a decent pair of Kevlar cutting shears to cut Kevlar, as it's very nature means that it is virtually cut proof! We recommend those sold by Aircraft Spruce and Specialty, as they are inexpensive and they cut right through even heavy weights of Kevlar easily.

People in rocketry have been hesitant in the past to use Kevlar because 1)"You can't cut it" and 2) "You can't sand it". We addressed #1 above, and the response to #2 is: If you are trying to sand into a layer of Kevlar you have just laminated, YOU ARE USING THE MATERIAL INCORRECTLY! With ANY laminate, you should not be sanding into the structure you just created! This destroys the structure! You must build all composite finishes UP from the finished laminate. The only sanding that is allowed to a laminate is just enough to scuff it up to accept a high build primer (our favorite is Smooth Prime by Poly Fiber). The point of reinforcing paper of phenolic tubes with advanced materials is to make them strong, not to make them smooth! Smooth finish on a composite structure only comes with good craftsmanship and building UP from your strong laminate.

 There is so much "Backyard Engineer" advice out there from every guy with a t-shirt reading 'Why, yes, I AM a rocket scientist' that it can get confusing for the person who just wants to do a good job on their project with a minimum of grief. That is the reason for our video series - we want to put our 25+ years of advanced composite experience to work for you! As with all of our materials, you MUST use them with a professional level epoxy - Sorry, no hobby shop epoxy or home center epoxy allowed! These "toy" epoxies will not give you much in the way of consistency, reliability, or economy, and you are just wasting your time and money by using them with advanced materials. Also, you MUST use a respirator when using these epoxies and cloths. While non-MDA hardeners in current epoxies have lessened the toxic effects of using these products, they're still not too good on your systems if ingested, so protect yourself.

FINISHING

You owe it to yourself to buy our new video series - "Advanced Construction and Finishing Techniques for Composites" to get actual demonstrations of proper composite finishing techniques.

A vastly misunderstood area of composite construction is the finishing process. The average guy out there says that "You glass it, paint on some extra resin to fill in the weave, and sand and sand until it's smooth. That's why you want a resin you can sand easy".

WRONG!

Think about it - You just created a strong structure with your reinforcement material in an epoxy matrix at the proper ratio (50/50) - why in the world would you add another layer of brittle, heavy resin to 'fill the weave'? Epoxy resin is not filler.

And then, why would you 'sand and sand until it's smooth'? Epoxy is not filler, it's not easy to sand (if it is, it's been adulterated with some filler and will not have good mechanical characteristics), and most of the guys 'sanding and sanding' are sanding right into the reinforcement layer - destroying the structure they worked so hard to create!

So, professionals proceed like this: The structure is created, then any low spots are filled with an epoxy compatible filler, the surface is primed with a high solids primer to fill any weave patterns or pinholes, and the surface is sanded to a finish acceptable for finish paint.

Let's look at this process step by step:

Step 1, Create the structure- Get our Advanced Composite Construction Techniques videos to learn how to create a strong light composite structure.

Step 2, Fill low spots with an epoxy compatible filler- You must use an epoxy based filler on an epoxy based surface! Bondo doesn't cut it, as it is Polyester based, and does not still well or permanent;y to an epoxy surface. Neither does wood filler! So toss out your old model rocket based ideas of filler and use the proper materials - We sell the two finest epoxy based fillers made - AEROPOXY LIGHT and SUPERFil - and they will save your sanding arm, your wallet, and your patience. They do not shrink, they spread easily, and can be splined to a feather edge. And, they are VERY VERY LIGHT! Use them!

Step 3, Prime the surface with a high solids primer to fill any weave patterns or pinholes- You must use a good primer as preparation for paint. You can use any number of urethane based high build primers from DuPont or Sikkens, but be prepared to spray them and be prepared to deal with hazardous urethane application procedures! The composite primer we use exclusively and distribute is UV SMOOTH PRIME by POLYFIBER. This primer is water based, which makes for non-toxic application and easy clean up, and it fills pinholes and weave patterns like nothing we've ever seen! It can also be applied with a roller, no spraying necessary (although spraying it works very well), so it's great for the home workshop. It is mixed with it's included crosslinker, and three coats are applied, allowing each coat to dry before adding the next. The surface is sanded with 180 grit to get a smooth result, then 3 more coats of the UV SMOOTH PRIME are applied in the same manner as the first. The surface can then be sanded with 320 or higher grit to achieve a paint ready surface. THAT'S IT! - The quickest, no hassle way to get a good finish on a composite surface. And the UV SMOOTH PRIME creates a UV shield beneath your paint surface. UV rays can substantially degrade the strength of epoxy, and this product protects your epoxy structure completely. You do not want to use "spray can" primers on a rocket - they simply don't contain enough solids to fill anything, and they take forever to cure. Use the right tools for the job - anything less is "penny wise and pound foolish". UV SMOOTH PRIME costs about the same as any premium urethane high build primer, but the value comes in the time and frustration you save, and in the superior finish you will get.

FILLERS

These materials are added to standard epoxies to give a fillet (or any joint) a better structural strength. If you are using ONLY epoxy for fillets or other joints, all you are doing is adding minimal strength and added weight - prove it to yourself by taking a bit of cured epoxy and snapping it - epoxy without amendment is brittle! Also, please keep in mind, that Laminating epoxies are meany for just that - laminating. They are not -ideal- for creating adhesives from. For critical applications, you should rely on a product such as Aeropoxy Structural adhesive. For most rocketry applications, it is permissable to use a well made slurry of Aeropoxy and filler for a basic reinforcement, however,

Simply add a pinch of any of our fin amendments to your mixed epoxy, enough to achieve the consistency you want,(don't get it too thick!) and create your fillets. We like to mask off the fin and airframe surfaces beforehand at the limits of the fillet shape, and run the fillets with a tongue depressor. The masking tape is then removed when the epoxy starts to cure, resulting in a clean, consistent fillet. When cured, it is ready to go over with a good filler like Superfil by Poly Fiber to achieve a primer ready surface. PLEASE don't sand into the fillets you've just created! You will abrade away the structure you intend to create! Use the filler, and go UP! Kevlar pulp adds tremendous impact resistance and good stiffness to a joint, but is difficult to sand, so work clean! Chopped Carbon adds tremendous stiffness and very light weight, and is slightly less difficult to sand. Milled Glass contributes good overall strength to the joint while being even easier to work with, while Cotton Flox offers good strength, ease of clean up, and no safety worries about working with it, at a low cost.