This post was originally created a long time ago, so updating felt like a good idea. After all, over the past several years, new adhesives have come onto the market.
But, no matter what RC glues are out there, TRY IT OUT ON A SCRAP PIECE OF FOAM FIRST, so you understand how it reacts with the foam your using!!
Someone once said, "There is a glue for every job", well they must have been a R/C Hobby Shop owner (or a home improvement store salesman). When building a lot of the models featured on Parkjets.com, there are so many different glues you can use and a lot you should use. So lets give the quick run down.
Epoxy Glue - There are several types of epoxy on the market, all of them come in two parts that you have to mix together. Parkjets recommends getting some of the 5 minute stuff from the local hobby store. These glues are rated by the "Pot-life", or the amount of time you have to work with the stuff before it turns as hard as cement. 5 or 6 Minute and 30 Minute Expoy glues are most common. One good thing about epoxy is that it is very fast (5 minute variety) and creates a very strong bond. When we build, we like to use epoxy to bond in any carbon wing support. It is pretty much going to lock the carbon rod or spar into place for good. It can be a heavy glue, but when used to bond regular joints or for repair jobs, a good bond with minimal weight gain is possible. We like to use it at the field when a repairable crash occurs. You do need some disposable cups (the small bathroom plastic cups work great) and some small wooden sticks help too.
It's not the cheapest stuff in the world, but its not overly expensive either. For us, epoxy is a must have glue in the tool box and the #1 glue we use when building parkjets.
Cyanoacrylate (CA Glue) These are part of the "Super Glue" family of adhesives. "Normal" CA glue is NOT safe for foam, it melts foam on contact, so use it only on parts that do not come in contact with foam. Normal Store bought "Super Glue" is NOT Safe for foam.
There are however some CA glues which can be used with foam, and they are sold as "Foam Safe Glues". Most of these glues require the use of an accelerent or "Kicker" to activate the chemicals to get the glue to dry fast. One great benefit of CA glue is that with a kicker, the bond is almost instant. But, like super glues, the dried glue is brittle and will break off. This glue is not good at filling gaps but doesnt weight much either. It can also be difficult to find in stores, but its never a bad thing to have a bottle or two in your bag of tricks. For us, its totally optional. We know a lot of folks swear by the stuff, but honestly, we have had very little success using this type of glue.
Polyurethane Glue This type of glue when mixed with water, will expand slightly and foam up to fill any cracks or seams in the glue joint, and it drys to a hard finish which is sandable (much easier than epoxy). The glue sets up quite fast, and it is much easier and safer to use than expoy. There are several brands of polyurethane glue (sort of looks like maple syrup) with Elmers Probond, and Gorilla Glue being the most popular. One big drawback of this glue is that it can make a mess. And when using it, it does take some time to cure, so using pins to keep parts in place is always a good idea. Also, with many of them the color of the dried product is pretty ugly. The bond is excellent, but ugly. We barely use this stuff.
Hot-Melt Glue: This type of glue works very well, but it's main drawback is that it is VERY Heavy compared to other glues. So if you decide to use it, just use it in small amounts, as lightly as possible. Hot glue is really pretty great though for many of the plans on parkjets. Especally those that are simply tabbed for construction, like the Tomas Hellberg models or many of the profile type shock flyers. One draw back, if you are wanting to create invisible seams, hot glue is not for you. Also, it can melt the foam because its too hot, but most of the time its really obvious your gun is too hot.
A big advantage is that the bond is decent and flexible. The flexible bond has advantages and the bond is almost instant. If you are throwing together a park flyer for a weekend project, hot glue is a good choice. Just remember at the flying field, its useless for repairs unless you have a cordless version, or one that can plug into your car, so pack the epoxy.
You can also check out the GLUE RESULTS TEST on RC GROUPS to get more information. The above is a great starting point, but with new glues on the market all the time, chances are, there might be something you might like better.
After spending the past 5 years building pusher jets, there are other glues not mentioned here that I've found to be very helpful when building with depron, or other types of foam:
Beacon 3-in-1 Advanced Craft Glue - This is a contact cement, much like the GWS Glue included in the GWS foamy kits. And since this glue has acetone in it, you must follow the directions closely to prevent any foam melting. Simply apply a thin layer of glue on each surface to be joined. Press the parts together to allow the glue to spread evenly and then pull apart. Wait about 20-30 seconds, then press the parts back together. This glue grabs pretty hard right away, so be sure to align the parts properly as you may not be able to separate them again. This glues sets in about 20 minutes, and fully cures in 24 hours. We typically glue an entire plane together in one sitting if we use this glue, then let it sit overnight to cure before continuing the build.
Beacon Foam Tac - Very similar to their 3-in-1 glue, but with less acetone. This glue was specially developed by Beacon for use on foam products, especially depron.
UHU Por (also called "UHU Creativ for Foam" in the US) - Another great contact cement manufactured in Europe. It is very hard to find in the US, the "Creativ" version is no longer sold at all. Works pretty much the same as 3-in-1.
3M Super77 Spray Adhesive - This glue is pretty easy to find and works great if you are printing off plans and glueing them down on your foam. However, be sure to spray the glue from a distance as the propellant can melt the foam. Super77 comes in a large aerosol can. Super77 is great for laminating several pieces of foam together (such as making a block for a nosecone or canopy), or for parts where heavy sanding will occur. This glue holds strong, but will not ball up when sanding parts to shape.
Beacon 3-in-1 can be found in most craft stores such as Michael's and Jo-Ann's, but you can also buy it online at places like RCFoam.com, among others. Beacon Foam Tac and UHU Por are a little harder to find, but a Google search will show several shopping results. RCFoam also carries these glues. Super77 can also be found in craft stores, as well as hardware stores.
Parkjets would like to thank Pat Gagnon of NicoHobbies for his contribution to this article.