I'm putting together some N scale buildings made with Polyurethane. I figured regular old Testor's modeling glue would work fine for gluing them together but I am having no luck at all getting any sort of bonding out of it. I cleaned the models before gluing them so there's no residue. Am I using the wrong stuff? Is there something else I should try? Can I use super/crazy glue?
Testor's Modeling Glue- The Wrong Stuff?
- Thread starter Cannonball
- Start date
Testors "airplane" glue is designed for styrene. It will not work on polyurethane (resin) no matter how much you clean it.
The best thing for resin castings is "superglue". Alternatives include hot glue or epoxy, but both are much messier.
You can get superglue in thin or thick ("gel") formulations. The thinner the better, but you have to have very close fitting parts. Where the fit cannot be made tight by a little filing or reshaping, you can use the gel type which fills small gaps.
I find the best deal on superglue is to get the four-pack of micro containers. Superglue does have a limited shelf life, which is made even shorter when you open it.
Andrew
The best thing for resin castings is "superglue". Alternatives include hot glue or epoxy, but both are much messier.
You can get superglue in thin or thick ("gel") formulations. The thinner the better, but you have to have very close fitting parts. Where the fit cannot be made tight by a little filing or reshaping, you can use the gel type which fills small gaps.
I find the best deal on superglue is to get the four-pack of micro containers. Superglue does have a limited shelf life, which is made even shorter when you open it.
Andrew
N
nachoman
Superglue joints also get weak with time. You can help the situation by roughening up both mating surfaces with sandpaper, or by devising some kind of mechanical "pin" that spans the joint to take potential shear load. Lately, I've been having better luck with 5-minute epoxies rather than super glues.
No matter what glue you use, they all work better if the surfaces mate flush, and if you can find a way to clamp the joint tight while the glue is curing.
Kevin
No matter what glue you use, they all work better if the surfaces mate flush, and if you can find a way to clamp the joint tight while the glue is curing.
Kevin
Kevin's message about mechanically joining parts reminds me of another tip you might find useful.
If you assemble the model with a minimum of superglue, with neat joints, etc, and you are not doing a full interior, you can strengthen the joints later. Use epoxy or other strong glue (even more superglue) and add backers to each joint - 1/4" x 1/4" styrene in the corners or 60 thou styrene sheet across butt joints, for example.
Andrew
If you assemble the model with a minimum of superglue, with neat joints, etc, and you are not doing a full interior, you can strengthen the joints later. Use epoxy or other strong glue (even more superglue) and add backers to each joint - 1/4" x 1/4" styrene in the corners or 60 thou styrene sheet across butt joints, for example.
Andrew
Andrew's idea may be the best one. Super glues will cure almost instantaneously. Then after everything is in place and set up, you can reinforce it with the styrene and 5 minute epoxy without having to try to hold everything together and in alignment for 5 minutes.
Somewhat off topic, but related, Testor's glue will also not work on abs or other types of plastic than styrene. Plastruct Plastic Weld will work on a lot of plastics that Testors will not work on. I've also heard that Tenax Is a very versatile solvent type glue.
Somewhat off topic, but related, Testor's glue will also not work on abs or other types of plastic than styrene. Plastruct Plastic Weld will work on a lot of plastics that Testors will not work on. I've also heard that Tenax Is a very versatile solvent type glue.
I've actually found a 90-second epoxy that works very well. While not CA fast, I find I can hold a joint long enough for it to set up, and it's not as brittle as CA. It's also more gap-filling than CA, and is in some ways easier to work with.
N
nachoman
Beats me. But it's true. From my experience, and the experiences relayed to me from others, superglued items come loose with a simple bump after a few years. Of course, it depends on the materials and the type of joint, but I have superglued brass detail parts to white metal superstructures that fail under light handling after a year or two.
Kevin
So that guy we used to see in the ads dangling from a girder by his hardhat was on borrowed time...? :mrgreen:
Several factors can create weak joints with any glue, but superglue joints may fail because:
- Too much glue makes a weak joint. The glue seems to crystalize and weaken over time, especially when too much is applied.
- Differences between materials joined - e.g. the brass details glued to white metal. Different rates of expansion and contraction due to temperature changes (even if minute) can weaken a joint over time.
- Some material is notoriously hard to glue with any glue - e.g. slippery delrin plastic usually used for trucks.
- There was not a good fit to start with, and the glue did not penetrate the material (even a few molecules' depth), rather it was strictly a surface to surface joint.
- Possibly (although not likely) there was not enough moisture to properly cure the glue. Superglue was originally developed as an alternative to stiches. It draws moisture from the skin to cure (which explains why you can glue your fingers together faster than model parts). If there was not enough "atmospheric" moisture to cure the glue, such as on a really dry winter day, it may be weak.
Andrew
I have used super glue and have helped it cure by LIGHTLY moistening the 2 surfaces to be joined, and make SURE there is good (if not perfect) mating between the parts to be joined. SG will not "span" gaps between the bonded surfaces.
The other thing to consider, is that ACC, "Superglue", has superb "tensile strength", you can pull on the joint with great force, and it will hold. It has poor "sheer strength", apply force at an angle to the joint and it will break easily. The guy, dangling from the girder, need only tilt his head, and he will fall...........with the expected sudden stop at the end! 
One glue that I have had great success with is "Formula '560' Canopy Glue". I have used it to scratch build n scale bridges and trestles, a plastic kit, and a laser wood kit. It dries clear and I have been able to paint over it.
I have been told that it was orginally made to attach canopies to airplanes.
On the container, it says "Bonds canopies & plastic parts to almost anything"
I first heard about it at the Prototype Rails Convention in Cocoa Beach. It is not overly expensive at $2.99 for a 2 ounce bottle. It does not take much to glue things together.
AND THE BEST THING, IT DOES NOT GLUE YOUR FINGERS TOGETHER OR TO THE PART YOU ARE WORKING ON !!!!
dwight77
I have been told that it was orginally made to attach canopies to airplanes.
On the container, it says "Bonds canopies & plastic parts to almost anything"
I first heard about it at the Prototype Rails Convention in Cocoa Beach. It is not overly expensive at $2.99 for a 2 ounce bottle. It does not take much to glue things together.
AND THE BEST THING, IT DOES NOT GLUE YOUR FINGERS TOGETHER OR TO THE PART YOU ARE WORKING ON !!!!
dwight77