I’m using Kadee #262 coupler boxes and can’t use a screw, glue must be used to mount them on a couple cabooses I am modifying. They seem to be made of engineering plastic, and Plastruct Plastic Weld and CA won’t bond well to them.
What glue will bond well with engineering plastic?
The engineering plastics (acetel, etc) are the darnest stuff. There is supposed a glue called cynanoepoxy (I think) that can glue the stuff. I have had success with 5 minute epoxy in certain applications. When I needed to add Kadee couple boxes to my Marklin/Trix UP cabooses I used a Kadee nylon 2-56 screw through the endplatform. I then cut off the excess screw length and filed the area smooth. After painting it looks fine and the couplers have never come off in service.
Microscale has a product made specifically for those slippery plastics - a prep and an adhesive …
Mark.
I don’t think the Kadee coupler boxes are acetel or engineering plastic. I think they are styrene and I have had good luck glueing them to styrene cars using plastic welder cement. Once I glued a pair of them to diecast metal caboose end platforms using Walther’s Goo. That was many many years ago and that caboose is still on the layout and the couplers are good and firm.
I make it a policy to secure the lids of coupler boxes with screws, so I can remove and replace a defective coupler. I used to glue everything in place, but after breaking a few couplers and making a mess prying the glued together boxes off, I decided that coupler box lids, and indeed the entire coupler box, ought to be secured with removable fasteners of some type. Screws or snap on lids. Since then I have not broken any couplers, which proves the technique is effective. Like taking an umbrella insures against rain.
I’m not sure why Kadee is making so many of their draught gear boxes in engineering plastic. While it’s stronger than the styrene plastic, it’s hardly necessary for our purposes - I’ve never had a Kadee box fail for that reason, and I’ve run some very heavy trains. The slippery properties of the acetal plastic isn’t really needed - the old-style ones work fine and can also be painted - a shiny draught gear box is hardly prototypical, and, as you’ve discovered, doesn’t leave a lot of options for mounting, either.
You may wish to investigate their #178 couplers, as the box is longer and has an additional hole for a screw in an extension at the rear of the box.
Another option is to use a #5 box (trim away the mounting “ears” on the sides and, if you wish, construct another box around it from .010" or .015" styrene. This will allow you to simply cement the box in place with solvent-type cement. You could also do away with the #5 box and use only the lid, as it’s the part which has the boss on which the coupler pivots. Use sheet styrene to construct a more prototypical-looking box on the Kadee lid.
However, I don’t understand why you can’t use a screw to mount the box in place - the platform must have some thickness which can be drilled and tapped - there’s usually not a lot of strain on caboose couplers, unless you’re running pushers…in that case, make it a rule that pushers must not push a train unless the caboose is behind the pushers. Many real roads had a similar rule, first for wood-framed cabooses and sometimes just because that’s the way things were done. It would add operational interest, too.
Sorry to go on so long, but I keep thinking of additional solutions as I’m typing. I don’t know how far along you are in your construction, but why not make your own coupler boxes from styrene, using the #5 lid only for its pivot point? Make th
Well, I must confess it’s been a long time since I bought a two pack envelope of Kadee’s, which came with draught gear. For years I have been just buying the 10 paks of #5 couplers that come with out draught gear. So although I have a junk box well filled with draught gear, all of it has gotta be 6-7 years old.
Dunno why Kadee would be going to acetal. The styrene boxes are plenty strong enough. In fact, I’ve never had a box, or a coupler fail under load. I’ve had a few Athearn snap on lids snap off at in opportune moments, and I’ve broken a few couplers when a car hit the floor, but under normal loads, long trains, the Kadee coupler system is plenty strong enough to keep the train together.
Some good ideas here, but I just found an adhesive that seems to work. I tried it and the bond seems very strong. Loctite Plastics Bonding System, here: http://www.loctiteproducts.com/p/sg_plstc/overview/Loctite-Plastics-Bonding-System.htm
I roughed up the areas with sandpaper, applied the felt tip applicator to both areas, waited 60 seconds, then applied the glue and pressed them together.
Cyanopoxy is no longer available. Seems the owner died. The same stuff is now called Cypox. See the following link: http://www.mrhobby.com/store.php/MikeRoseHobbies/pg10120/cypox_tips__techniques
I just bought two packs of Kadee coupler boxes (just the box and cover) and they are all styrene, which I prefer. I just glue them to the underside of the car body/frame which so far are all styrene as well. I just glue the box with MEK and drill and tap for 2-56 screws to hold the coupler and cover in place. I haven’t run into any ‘engineered plastic’ that won’t work with MEK. I must just be lucky in this area.
-Bob