Sunday, May 12, 2013

A few words in praise of canopy glue

Some people reading this title will say “yeah, sure,” and doubtless others may say “what the heck is canopy glue?” For the latter folks, read on. But even if you know what it is, you may not appreciate all it can do.
     Canopy glue was developed, as the name suggests, for aircraft modelers. They have the challenge of gluing a foil “frame” onto a transparent plastic molding of an airplane canopy. The glue that’s best has these features: it doesn’t attack or craze plastic; it glues the dissimilar materials well (metal foil and plastic); it dries clear and glossy, so any excess outside the foil is minimally visible; and it remains flexible for any differences in expansion and contraction of the materials that are glued together.
     Some of these features turn out to be terrific for certain kinds of railroad modeling too. I have found canopy glue to be simply outstanding for gluing different materials together: metal to plastic, plastic to wood or cardstock, metal to wood, etc. (porous materials are no problem), just in terms of how well they adhere. And the “remains flexible” part is vital too. That’s why I use it exclusively for etched metal parts, like running boards or diesel grilles. In the many years since I first used it, I have never had one of these metal parts pop off its model, as many people have experienced with CA or other rigid adhesives. Some people have utilized canopy glue’s property of drying clear and glossy to make small model windows, but I personally have not found this to work very well.
     So where do you get this stuff? Usually it’s only in the model airplane section of your hobby shop – the railroad side of the shop often doesn’t seem to know about it. Craft and art stores sometimes have it too. And yes, you can order it on the internet, with shipping no problem because it’s water-based. Amazon is just one of many sites where it is available.
     Sometimes you will hear it said, “it’s just white glue.” In my opinion, that’s not even close to true, except that it’s a white color and is water-base. It is much tackier right away than any white glue I’ve used – helpful in assembling things – and is much stronger when fully dry. It sets up pretty strong in three hours and develops full strength in about 24 hours. There is an Elmer’s product called Tacky Glue, but it is definitely not the same as canopy glue, being distinctly less strong. Information I’ve found says that canopy glue contains a vinyl acetate polymer, but the same appears to be true for ordinary white glue. Maybe the quantity of the polymer varies.
     The source used to be Wilhold, a big glue company, and their product was named R/C-56 (for Radio/Control, obviously alluding to model airplanes). In the 1990s, Wilhold stopped making this glue. Today, there are at least two sources: one is Testor’s, the other is Pacer. (Pacer Technology sells canopy glue under the Pacer name and also under the Zap name.) Chatting with those who patronize the airplane section of hobby shops, my perception is that Pacer is regarded as much better. Here are both Pacer containers, with the Wilhold product in the center.


I think it is no accident that the Pacer version is called “Formula 560,” given that the product which introduced many to this glue was called R/C-56. In fact, Pacer’s code name for the product is PT-56.
     Here are two examples of how I use canopy glue, both being the potentially troublesome etched metal parts of some length. The F7-B unit has an etched grille, and the PFE reefer has an etched running board. Both were attached years ago with canopy glue, both have undergone a goodly range of temperature variation since, and neither has budged in the slightest.


     All I can say is, if you don’t already know and rely on this glue, you should give it a try. Use it for something where CA or other adhesives have let you down, and see if it isn’t better. And any time you wrinkle your brow deciding how to join two dissimilar materials, here is your answer.
Tony Thompson

14 comments:

  1. I'm curious, do you know what do you clean it with? Any idea what type of solvents attack the canopy glue?

    Thanks,
    Greg Amer

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  2. By "clean up," I assume you probably mean removal of glue outside the desired area. I wipe any excess off, and using a dampened a Q-tip is often my way of completing the clean-up. Maybe you mean "clean before gluing," and other than making sure there is no loose material, I have never cleaned up gluing surfaces.

    In the first few days, and certainly in the first few hours after gluing, water will soften it. But once it is well set, even soaking in water does not seem to soften or loosen it (ask me how I know). I have not noticed that paint solvents or CA attack it, but I have not done anything systematic checking for what attacks it. If I were worried about that, I might Google the topic.
    Tony Thompson

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  3. Great post, Tony- thanks for the information. I've known about canopy glue for some time now, but I wasn't aware that it could be used as a substitute for CA. I didn't think the bond would be that strong, but that certainly doesn't seem to be the case. I have several Stewart F7 shells that need etched metal grills, and I've been looking at a number of different glue options. Looks like I've found a solution!

    Tom Patterson

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  4. Glad it was helpful, Tom. By the way, in my view canopy glue does not substitute generally for CA. I use a lot of CA in modeling, especially joining small items, and for things like grab iron wire in holes, where thin CA will wick into the holes better than anything. And no question, CA is stronger than canopy glue. But where you need FLEXIBLE rather than strong, canopy glue is your friend, and likewise for porous materials.
    Tony Thompson

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  5. Another point worth making is that white glues generally are based on polyvinyl acetate in water, so that isn't a distinction for canopy glue. I have neither the product information nor the chemical knowledge to appreciate what makes it tackier than white glue, and substantially stronger when dry.
    Tony Thompson

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  6. Tony,

    I have a bottle Formula 560 at home but haven't used it yet. It seems very thin, like watery milk, maybe I should shake the bottle? Do you clamp parts together while the glue sets? Will it work like contact cement where you coat both surfaces, let dry, and then press together?
    Chuck Johnstone

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  7. Chuck, you should shake the bottle firmly until you have something that is like the consistency of white glue. I often gently clamp parts (clothes pins, rubber bands) but it's not vital in many cases. The glue tacks up pretty quickly and if the joint is reasonably thin, will set up well without clamping. I have not tried to use it as contact cement, and am not aware it would work.
    Tony Thompson

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  8. I've heard many people talk about canopy glue, but your description is very useful and enlightening. The properties, particularly the flexibility, make me think that this might be a good solution for gluing rail to Central Valley tie strips. I've tried ACC and the rails tend to pop off. It's almost like the joint is too brittle. Any thoughts on whether this might be worth pursuing?

    Robin Talukdar

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  9. My only concern in using canopy glue for gluing rail is that canopy glue is not tremendously strong. But at least it is flexible and will not pop off like the CA does. I'd say, go ahead and try the experiment.
    Tony Thompson

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  10. So what will remove the residue I missed when gluing on my clear canopy to a Fiberglass frame?

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  11. If you do it in the first 30 minutes or so, a toothpick works fine. Later it is a little harder. I would use one of my pairs of really needle-tip tweezers to pick it off. Just be patient.
    Tony Thompson

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  12. I should have added that the canopy glue is quite clear once it dries, and that is an attraction for jobs like canopies: anything outside the canopy frame is transparent and not obvious. But that's not usually a model railroad issue.
    Tony Thompson

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  13. Great post, thanks for the info Tony-. Now I know about the glue umbrella for some time, but I CA. I Stewart F7 several shells that have etched metal grill, and I'm looking at a number of different options glue. Looks like I've found a solution!
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  14. Thanks to you I'm using Canopy Glue! Great stuff for adding see through apex & morton roofwalks to my reefers!

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