I’m about to begin assembling a cast metal kit of a front-end loader. The instructions recommend using epoxy or CA. CA dries too fast, doesn’t allow time for final adjustments to the parts. But I don’t have any experience with epoxy other than JB Weld that I’ve used around the house. It’s kind of thick and I wonder how well it works when only a little bit is used. But it would allow for adjustments before it sets up.
So, my question is: is there another epoxy that is more suitable for model use or when people write about using epoxy are they referring to a JB Weld-type product?
Someone has suggested a thick super glue product by Gorilla Glue. Would that be a better choice?
I would never use Gorilla Glue on a model. It runs EVERYWHERE when it comes out of the bottle, and it expands as it cures which means all joints must be clamped. It is also nearly impossible to remove.
I use Loc-Tite Gel Control super glue to assemble similar models. You will have a little bit of working time because it does not grab instantly, and it does not run everywhere when you squeeze it from the bottle.
We are past the age of epoxy. That stuff is just too muck work.
Like Kevin I use Super Glue Gel, the Gel usually takes over a minute to dry enough to hold. I buy HFT Gel in the tiny tubes and I recently finished assembling cast metal Woodland Scenics Windmill using the HFT Gel.
I’d suggest using very small amounts of JB Weld Kwik to “tack” the pieces together, which will allow time for proper positioning, then, once it’s hardened, add ca to strengthen the joints.
A good epoxy should still be stronger much of the time than a ‘loaded’ CA adhesive (where much of the effective strength in the gap-filling is in the the aggregate between the thin cyanoacrylate bonds and the relative strength of the CA bonds to that aggregate). An important thing is that epoxy requires some thickness for best strength; it will NOT bond well if squeezed out to the thin glue line ‘regular’ CA benefits from. In addition, epoxy cures internally and does not depend on external water or other acceleration to set up full-pen bonding as CA does.
The principal thing, as noted, is that quick-setting epoxy has an annoyingly short work time when making complex assemblies, while long-setting epoxy has the annoying characteristics of requiring long clamping or jigging time to hold alignment but a comparatively short time for the bond to go from ‘little’ to ‘damaged if moved’. So you are mixing and messing in repeated batches, losing anything from a given batch that you can’t use within the work time. I do continue to use epoxies for fabrication – but not where I want a CA-style rapid strong bond but with some gap in the fit.
It depends a lot on the application. Epoxy is strong and sticks to just about anything, that’s why I still use it for some difficult situations. It’s still pretty cheap too and will store for years. I use the 5-minute products with two tubes, where you manually mix both components. It’s not that difficult to prepare, as long as you mix properly. I also use Gorilla glue, and yes, I do consider the expansion factor. In fact, the expansion factor can be used to your advantage if both surfaces are not perfectly flat. CA is probably my most often “go to” solution… yet again, I still use model glue for kits for its ability to melt and bond plastics.
For some wargaming scenery, I was using brown vinyl flooring pieces for roadways on a foam panel base. Nothing I found except for Gorilla Glue would stick to both foam and vinyl, and stick it did! Those roadways are never coming loose.
I have built lots of white metal kits. My suggestion is to learn to use CA. Medium or gel will give you a little wiggle room before it sets.
Put the CA in a small pool on a jar lid or other surface and dip a wire (or specially made CA applicator) into the pool and apply the glue to the part. The glue will go bad after some time out in the air, so start another glue pool from time to time.
If a part sets in a miss-aligned position you can use debonder or a sharp knife to separate the parts and try again. As mentioned above, I will also often use zip kicker to cure the glue quickly while holding parts together. This cuts down on awkward holding of parts in strange positions waiting for the glue to dry.
I use epoxy, but rarely for metal kits. Epoxy has its own issues: mainly the thickness and the need to keep mixing batches as you assemble the kit. I don’t have issues with models falling apart so the strength of the CA glue isn’t really a problem.
A method I found that works is using the thick CA or gel and assembling the parts. Then going through later and using epoxy to finish the bonds. I just did that with a Scale Structures resin kit.
you can take a pallet knife and knife off very small amounts or epoxy As long as they are equal sized amounts even enough to make a blob the size of a pea will work and reduce the waste issue
i don’t use epoxy much any more either with the gel super flies out there now. Especially the slow set types.
I use JB Kwik Weld all the time on layout projects, ranging from my adhesive of choice on resin kits, thin filler applications on structures such as roof lines, and as a quick set adhesive on styrene structure joints. JB Kwik Weld is the way to go!
How long does the JB Kwik Weld take to set up hard enough that the joint no longer needs to be supported?
I managed to find some ‘90 second’ epoxy at the local Home Hardware. It works faster than the regular 5 minute stuff but it certainly doesn’t form a solid joint that doesn’t need support in 90 seconds.
The instructions say that JB Kwik Weld sets in 6 minutes and fully cures in 4 to 6 hours, but in my extensive experience with Kwik Weld, it sets faster than 6 minutes. In practice, I only mix small amounts at a time because it sets in about 3 minutes and seems to fully cure within an hour or so.
JB Kwik Weld is a 2-part epoxy that comes in toothpaste-like tubes, an epoxy and a hardener, which are mixed together on a 1:1 ratio. What I do is to squeeze a small amount of each part next to each other on a piece of scrap cardboard and then mix the two parts together with a toothpick. I then use the toothpick to apply the mix to the targeted part(s). The mix dries to a semi-gloss black color which can be sanded and painted. Depending upon the application, the applied mix can be smoothed to a thin cover with the blade of an Xacto knife.
I use JB Kwik Weld for several different types of applications, but I do not use Kwik Weld as a substitute for normal glue which I use to joined structural styrene plastic parts together. Rather, I mainly use Kwik Weld to fill gaps in styrene and wood structures and to bind resin parts together. For example, I built a tug boat made of resin parts exclusively with Kwik Weld. Another example is a completed wood or styrene structure with gaps in the joints such as roof lines. When Kwik Weld is applied to gaps, it can be immediately smoothed so that little, if any, sanding is need to hide the epoxy application.
The key to a successful weld is to work quickly with the epoxy mix before it starts to set up. So, you want to work with small amounts at a time. Since the 2-part epoxy is so inexpensive, waste is no problem, so I often mix batches with more than I need and then toss the excess mix.
For someone who has not used JB Kwik Weld before, I recommend making a test mix or two and per
Okay, I’m sold! I have been using 90 second (supposedly) epoxy from Home Hardware. It works but it takes much longer than 90 seconds for it to set up enough that the parts no longer need to be held in position. In fact, I discovered the hard way that the 90 second epoxy will still allow parts to move even after it seems to be firm.[|(]
I have generally stuck to Devcon products since we used their products at work with good results but I’ll have to try some JB weld.
I keep several ten-minute, one hour and other different epoxies on hand, some with metal binders, some clear and some black or gray depending on what I need them for.
I like the slow curing stuff for setting LEDs into headlight housings. It gives me time to position the LED while lit to be sure it is aimed properly.
I like epoxies for most resin kit assembly, too. Sometimes the ACC refuses to “kick over” when trying to attach some resin parts.
JB Weld and Permatex make a huge range of products, far beyond what you will find in a Home Depot.
If you spend a little time on the Grainger website, they have all kinds of specifications for the different products. It is shocking how well some of the more expensive options will grip.
We used a Permatex product for temporary field repairs that was 150 dollars a tube. This stuff would repair an injector retainer cup, temporarily.
I “reluctantly” repaired a live 350 PSI steam leak on a 1" pipe with an epoxy putty.
Shutdown was two weeks away and the consensus was “it’ll hold 'til then”. Well, it did! When I cut the pipe out I looked at the wall thickness in places it was less than .065" [:|][:|][:|]
