Friday, 30 October 2015

Glues used in RC Model Building.

 Pick The Right Glue: How to Select Adhesives?
1. Adhesives for Foam
  • Whether you’re rebuilding a crashed RC Plane or Building a new one, things always go smoother when you use the right tools for the job.
  • This is equally true in the world of foam.
  • Spray adhesives are formulated to work with every foam type . 
  • This particular post will help you better understand why a process that seems so simple is actually surprisingly complex, and assist you in selecting the right adhesive for your project.
  • First, a little background information on why gluing foam is so unique:
  • Different types of adhesive being required for foam is a result of the diversity present in foam materials.
  • In terms of feel, looks, and performance, open-cell foam and closed-cell foam are obviously different products.
  • However, those dissimilarities aren’t just surface-level differences, as the foam types are individually unique due to their chemical and molecular structures.
  • So while open and closed-cell foams still belong to the same family, the compounds they are made of create a range of variables when it comes time to put the materials to use.
  • In this instance, they affect how a particular foam reacts to adhesive.
  • Depending on the foam type, some adhesives may not form a bond strong enough to last, while others can cause a reaction that physically damages or even destroys the foam.
  • Fortunately, this isn’t something that has just recently been discovered, and special adhesive formulations exist for properly bonding all different types of the material. Of course, multiple, similar options can always create confusion without knowing which works best for your application.
  • To make things easier, we will see three spray adhesive varieties.
  • Under each type of adhesive listed and linked to the foam types it works best with, as well as what it should not be used with.
  • Whether bonding two pieces of the same material, or gluing to most substrates, just find the foam you’ll be working with, and you can find the correct type of spray adhesive for your project.
 Spray Adhesive: Claire Mist
  • Do NOT Use With: Closed-Cell Foam
  • Use With: Open-Cell Foam
  • This includes all densities, colors, and firmness values of:
  • Poly Foam, Super Soft Foam, Dryfast Foam, Rebond Foam, Acoustic Foam, Speaker / Filter Foam, Polyurethane Anti-Static Foam, Dunlop Latex Foam, HD36 Foam: Regular and High Quality, Lux Foam: Regular and High Quality, Charcoal Foam: Regular and Firm, Memory Foam.
  • 3LB ViscoSAVER
  • 4LB ViscoPLUSH
  • 5LB ViscoMAX
Spray Adhesive: 3M Super 77
  • Do NOT Use With: Expanded Polystyrene Closed-Cell Foam (EPS)*
  • Use With: Most Closed-Cell Foams AND All Open-Cell Foams**
  • This includes all densities, colors, and firmness values of:
  • Polyethylene Foam, Polyethylene Roll, Cross-Linked Polyethylene (XLPE), Neoprene, Gym Rubber
  • *3M Super 77’s formulation can physically melt EPS foam varieties, damaging and/or destroying the material.
  • **3M Super 77 bonds more strongly with open-cell foam than Claire Mist but is costlier. Claire Mist is the cost-effective  choice for all but the most demanding open-cell foam projects.
Spray Adhesive: Camie 373
  • Do NOT Use With: Open-Cell Foam OR Most Closed-Cell Foams***
  • Use With: Expanded Polystyrene Foam (EPS)
  • 1LB Expanded Polystyrene Foam (EPS)
  • 2LB Expanded Polystyrene Foam (EPS)
  • 3LB Expanded Polystyrene Foam (EPS)
  • ***Camie 373 is specially designed for use with Expanded Polystyrene Foam (EPS) to prevent damage that other adhesives may cause.
IMPORTANT: Spray adhesive is ineffective at bonding acoustic foam to painted or bare concrete or cinderblock walls. 
For foam you will need the odorless CA. that is fine with foam. The regular stuff will eat the foam like acid.

  • Electric RC flight has come a long way the last few years and foam as a building material has revolutionized the way we’re building park-flyers. 
  • While we’re pretty set on what kinds of foam work great for building planes, we’re still exploring the hundreds of bonding materials to find those that do not damage our foam, have a strong hold and weigh as little as possible.
  • Here are some of the best glues to use on foam like Depron, EPP, EPS, EPO, paper-faced Foam Board and the most common foams used by foamie modelers.

  • As far as strength and (light) weight , Gorilla Glue stands first.
  • It dries white and sets in about 30 minutes.
  • It foams up a little to fill gaps, something many modelers dislike because it tends to squeeze out of joints and onto clean surfaces. 
  • An easy fix is to cover the surface with clear tape right after gluing.
  • This not only helps keep the foamed-up glue in, but it also hold the two parts together until the glue dries. 
  • To help speed-up the setting process, You can wet both surfaces to be glued right before applying Gorilla Glue.
  • Other modelers like to mix 1-part Gorilla Glue to 1-part water-based glues like Elmer’s School Glue and even 3-parts Gorilla Glue to 1-part water!
  • Gorilla Glue goes for about $5 for a 2 ounce bottle and it can be found at Walmart, The Home Depot, Lowe’s and virtually every hardware/craft store.
  •  Cyanoacrylate (CA) adhesives are among the most common used in modeling. 
  • They are fast-setting and hold a decent bond.
  • For the ever-growing foam business within RC, new foam-safe CA glues have appeared in the last few years. 
  • They come in various viscosity like thin, medium and thick. 
  • Most commonly used is the thick, slow-curing CA.
  • This is due to foam’s porous properties and the need to fill the gaps in it.
  • Foam-Safe CA is worked onto one surface with a long tip and a toludine-based activator is applied to the other.
  • When both surfaces are joined, there are only about 3 seconds until the glue sets.
  • Since CA doesn’t hold the strongest of bonds, it is not the best choice for models that will endure high speeds or stress on the air frame.
  • We can keep it in field box for quick fixes only since it’s very expensive locally (about $8 for 1 ounce of CA and $10 for the activator). Found only at Local Hobby Shops and online Hobby Stores.
  • Hot Glue comes in solid “sticks” of various lengths and diameters and is melted with an electric gun that also squeezes it out of a nozzle tip.
  • Many modelers like hot-glue for building with foam. 
  • It holds a strong bond and is easy to work with but it stays a bit flexible — which might be a good thing in a few applications, but not most.
  • Make sure the gun is set to low temperature and you won’t damage the foam. With Hot-melt Glue you’ll get a strong, inexpensive bond in seconds.
  • The Gun can be found for as little as $5 at Walmart and the sticks for about $3 for a few dozen.

  • Epoxy is a popular, strong and inexpensive adhesive but it adds a bit of weight to models. 
  • There are a large selection of Epoxies to choose from.
  • Most users like 5- minute Epoxy since it sets quickly.
  • I, personally, am not very fond of it since I have found other glues that out-perform it. It comes in two chemicals in gel form.
  • You mix the two by way of a stick or paddle and apply it to the surfaces with such tool. 
  • Epoxy can be found at home improvement and hardware stores for $4-10 per 1 to 2 ounce syringe.
  • Some good local brands .

  • Lastly, not a glue but other popular glues for building RC planes with foam.
  • The list includes Ultimate RC Foam Glue, Fab-Tack (very similar to URCFG), some Elmer’s glues, silicone caulking (very heavy!), UHU Por, UHU Creativ and an endless list of adhesives that dominate the modeling world.
  • If you aren’t happy with those, try reading through the and forums for other ideas and stories.
  • I use FEVICOL SH (Synthetic resin Adhesive) and FEVICOL MR (White Adhesive) with all verity of HD Foam, Depron foam and Balsa Wood.

3. Another 5 Adhesives Used for RC
  • Glue is a mainstay in the hobby. 
  • The big question is which one should you use?
  • Here are just a few types of glue you will need when building RC aircraft.
  • Use the right stuff to stick those parts together!
  • Glue, we use it for just about everything in our radio control hobby.
  • Some glue is great for balsa, but that glue might not be great for foam.
  • The big question for a newbie to the hobby is which glue is best for my application?
1. CA
  • Before you got into the hobby you called this super glue.
  • The great part about CA is that is wicks into the fibers of balsa making a strong joint. 
  • It is also light.
  • While it dries super fast it can be brittle. 
  • There is no give to CA. 
  • CA is a mainstay in the world of balsa and Coroplast Build.
  • Throw in some kicker (immediately activates the CA) and you have the perfect building or quick fix glue.
  • Bonds - Wood,  Fiberglass,   Aluminum,  China,  Cloth,  Metal,  Most Plastics,  Pottery,  Rubber
2. Foam-Tac

  • Foam based planes are everywhere now. 
  • From home made foam planes to highly detailed planes, foam is used for a lot of what we fly. 
  • In the early days of foam a lot of guys figured if CA was good for balsa then it would be good for foam.
  • Then they found out that CA melted foam.
  • One of the favorite is Foam-Tac.
  • It sets up quick, won't harm your foam and stays stuck together.
  • That there is no smell or messy clean up.
  • Bonds - Depron,  EPP,  EPO,  Styrofoam,  Insulating Foam,  Balsa,  Carbon Fiber.
3. Canopy Glue
  • You have worked long and hard on your plane and now your are down the cockpit.
  • You use CA and then you realize that you just fogged the clear plastic with the fumes of the CA!
  • You have to be super careful to avoid this.
  • There is a solution.
  • Horizon sells a glue called RC56 that will keep you from doing this.
  • You can also use this glue on fiberglass and MonoKote.
  • Bonds - Wood,  Fiberglass, Paint,  MonoKote.

4. Epoxy
  • We may love it, we may hate it - epoxy.
  • It smells, it may be messy, it may be a  pain, but it can't be denied  that it has place in the ultimate glue solutions.
  • Epoxy has it's place in the world of RC modeling.
  • I would even suggest you keep some in your field box.
  • I use epoxy when I have something that absolutely has to stay on the plane, like landing gear or a fire wall. 
  • You can use epoxy on foam but it's heavy and will yellow after time.
  • here are many types of epoxy. 
  • I like the fast drying variety.
  • For more strength you can try 30 minute epoxy.
  • Bonds- Metal,  Wood,  Concrete,  Glass,  Ceramics, Just about anything
5. Weldbond

  • Some nice things about Weldbond is that it is non-toxic and fume free.
  • You can use it on smooth and porous surfaces.
  • It also doesn't become brittle.
  • It is foam safe. 
  • This glue is similar to RC56.
  • Bonds - Depron,  Poly-Styrene,  Most foam, Plastics.
  • These are just a few glues. There are multiple types of CA, epoxy and everything else.
  • There are as many opinions on glues as there are glues to choose from!
  • Do some experiment, search RC Groups and talk to your RC friends about what they use.
  • Search your local market for alternate brands and select a proper glue as per the availability and the materials you are using for construction.
White Craft Glue:
  • This is the most common craft glue for porous lightweight materials such as paper, cardboard, cloth, and kids’ crafts.
  • Water is the carrier; this means easy clean up and low toxicity.
  • Keep in mind that the glue must dry before strength is significant and the project often requires clamping to hold it in place until the glue is completely set and dry. 
  • This also means that white craft glue should not be used in applications that require water resistance.
  • White craft glue dries clear and is somewhat flexible.
  • Get creative and add fillers, like fine glitter, pigment, or water-based food coloring for decorative effects.
  • 1 hour set time, with final cure in 24 hours.

Yellow Wood Glue:
  • Yellow wood glue is also water based – and is made of the same vinyl acetate polymers as craft glue.
  • It is designed to work with wood and is immediately tacky for better hold in the uncured state. 
  • It is also generally more rigid, hence it is easier to sand.
  • Some wood glue can also be white and dry clear. 
  • Make sure to read the labels.
  • Again, you can add sawdust or another powdered filler for special effects.
  • Wood glues set in less than 1 hr.
  • That said, it could take as long as 24 hours to reach full strength.
  • Three types of wood adhesives are available:
  • Type-I exhibits some waterproof properties.
  • Type-II will perform better in exterior conditions.
  • These adhesives generally have a longer open time and can bond at colder temperatures. 
  • Both ypes I and II can be used for exterior applications, such as outdoor furniture and trim.
  • Type-III is not water resistant and is designed for interior use only.
  • Type-III is good for interior woodwork and trim projects.
  • Note: True water resistance for immersion in water requires a marine glue.
Super Glue (also known as cyanoacrylate adhesives):
  • Cyanoacrylate adhesives bond very quickly and to a range of substrates.
  • They form a very strong bond and dry clear.
  • The surfaces to be mated must fit together well to achieve good bonding. 
  • You can buy super glue in a variety of viscosities which enable some leeway in gap filling performance.
  • However, super glues can be finicky with respect to surface contact and coverage- too much or too little can affect the bond.
  • In general, super glues are not good for foamed plastic, unless specified on the bottle.
  • Cyanoacrylates work best in tensile applications that have low impact strength requirements. 
  • In their uncured state, you can use an acetone solvent wipe for cleanup.
  • However, once cured, solvents can no longer dissolve the adhesive.
  • Cyanoacrylates work particularly well for balsa wood projects.
  • Carpenters often use a two part cyanoacrylate to quickly bond mitered wood trim.
  • Cyanoacrylates can set in seconds to minutes, depending on formulation.
  • It dries clear and is waterproof.
  • Bottom Line: Cyanoacrylates are good for projects involving: wood, metal, ceramic, leather, glass, and some plastic where bond line is very tight.
Hot glue:
  • The melting and cooling of polymers provides the methods of delivery and adhesion for hot melt adhesives.
  • Hot glue is most commonly applied using a glue gun and comes in low (250°F) and high (380°F) melting options. 
  • Many varieties and performances are available depending on the polymer type.
  • Hot glue can be used on porous and non-porous surfaces.
  • Because of its high viscosity, it can bond uneven surfaces together and is great at filling gaps. 
  • Hot glue is not typically used in high strength applications.
  • And, it will not survive elevated temperatures near the application temperature.
  • However, it provides a very quick setting option for a variety of crafts and substrates. 
  • It’s a great all-purpose craft glue for quick set up and execution, but it’s not for use by children.
  • Hot tip: With hot glue, you can trace patterns to form bead designs on surfaces for texture and paint over it for a 3D surface effect.
  • Hot glue is often used to add flower or ribbon embellishment on wreaths, headbands and picture frames where stiffness and strength is not such a concern.
Pressure sensitive adhesives (PSA)
  • PSAs are available in sheets and dots and can be used in a multitude of craft projects to include substrates such as lightweight paper, plastic, metal, and glass.
Spray adhesives
  • A spray adhesive is a contact adhesive based in a solvent that is applied by spray.
  • When using spray adhesives, it is important that you apply in a well-ventilated room.
  • After spraying your project, allow the solvent to completely evaporate before mating for immediate bond. 
  • Once mated, you cannot re position your substrates.
  • Spray adhesives can be used with paper, foam board, fabrics, photo, and felt.
  • Specialty contact adhesives are also available in a can to roll or brush on for larger, more demanding projects that involve wood, metal, and plastic sheet laminates.
  • Application example: Spray adhesives are an excellent choice for adhering photos or fabrics to a foam board back.
Fabric adhesives
  • Fabric adhesives can be liquid white glues like polyvinyl acetate (PVA) types.
  • A variety of products cover lightweight to heavyweight fabric bonding, so it is important to get the correct product to match the hand or drape of your project.
  • Some versions are safe for washing and dry cleaning, but it’s important to read the glue’s label first.
  • There is an expanded selection of non woven tapes and fusing adhesives in rolled good form, which range from highly flexible to stiff for fabric and leather projects and garment construction.
  • These can be found in sewing and fabric stores and can bond permanently without bleed through for a very durable craft.
  • Fabric adhesives can be used to fix a hem that is falling apart and for DIY projects like making headbands or constructing fabric/foam laminated computer sleeves.
  • Epoxies are generally two part systems designed for high performance bonding.
  • While epoxies can be formulated to suit many applications, they are generally very hard, durable adhesives that bond to many substrates successfully in more extreme environments. 
  • Epoxy adhesives can exhibit a range of flexibility and clarity as well as cure speed.
  • Epoxies have excellent gap filling properties due to their high cohesive strength.
  • Polyurethane adhesives bond a variety of surfaces.
  • They bond to textile fibers, metals, plastics, glass, sand, ceramics, rubber, and wood.
  • Polyurethane is a multipurpose glue that comes in one part and two part options.
  • Polyurethanes can work well on a wide variety of wood species, particularly on woods with high moisture content or on oily woods, where other glues are not as successful.
  • Clamping is required until strength is built; a few hours.
  • Full strength is achieved in six to eight hours for a very strong and tough bond.
  • Before completely cured, polyurethane adhesives can be removed using solvents such as mineral spirits or acetone.
  • Dried glue can be sanded.  
Glue Sticks
  • Glue sticks are great for kids! 
  • They are a low bonding adhesive, but do provide a permanent bond on various types of paper to include cardboard, foam board, and poster board. 
  • Glue dries clear.
  • Application examples: sealing envelopes, applying labels, paper crafting, art projects, scrap booking.
  • Not all glues are created equal.
  • There are many variations within each category and from one manufacturer to another.
  • Read the labels for information on toxicity, ventilation, recommended handling and use, as well as durability in a variety of environments. 
  • Apply adhesive evenly and remove excess quickly.  
  • Immediately clean and cap the adhesive container to maintain shelf life and performance.
  • For optimum bond strength, it is imperative that the surfaces are residue and dust free. 
  • If possible, clean surfaces prior to bonding with a lint-free rag dipped in isopropanol.  Let them dry thoroughly before applying adhesive.
  • For crafts and repair projects requiring some durability and strength, you can often aid adhesion by roughening the surfaces with fine grit sandpaper to provide “teeth” for adhesives to interlock.  If you cannot abrade the surface, try wiping with isopropanol or acetone before applying adhesive.
  • this is particularly helpful for smooth, glossy surfaces that can be harder to bond.
  • Experiment with the glue on scrap pieces of your project.  Check for appearance, adhesion and and resulting bond strength.
  • Adhesive selection involves the following considerations:
  • Substrates:  What are you trying to bond?  Are the surfaces the same or dissimilar, porous or smooth?  Are you covering a large area? Do you have heat or solvent sensitive surfaces?
  • Application restrictions: How do you intend to apply the adhesive- examples: spray, roll, heat gun, cartridge, squeeze bottle?
  • Use Requirements: How does the bonded piece get used? How much strength is required? For example, bonding wood requires much more strength than decorative paper crafts do.   What kind of environments might it see?  Will it experience temperature extremes or water/steam?