Did some testing to find the best adhesive to use on our broken mostly interior parts. Honda used a very common and easily repaired ABS plastic on the interior parts including elec connectors. Fender liners and the front radiator shield for example are “semi-flexible” plastics and are NOT addressed here. I made up 1/8” thick “tabs”of ABS sheet plastic, glued them with a bunch of glues and pulled them apart in a vise to see which held the best. I tried IPS #16, OATEY ABS pipe cement, J B PLASTIC BONDER(EPOXY), LOCTITE PLASTIC EPOXY, SUPER GLUE, PLASTRUCT PLASTIC WELD 5 minute standard epoxy and ACRA-GLASS. As expected the plastic epoxies held best by far. The common ABS Oatey plastic pipe glue is a decent super fast dry product that will work, but requires very tight joints which makes it second tier. The JB WELD PLASTIC BONDER did best. It’s available in clear(which is grey) or black. I’m thinking any brand epoxy formulated for plastic will be comparable as it will have plastisizers for thermal expansion which is desirable. Run of the mill overnight or 5 minute epoxy will hold the parts just as well for small areas where thermal is not an issue, but now that dedicated plastic epoxies are available everywhere I would not use anything else. In the distant past I would have called the 3M tech line for a recommendation as they are the adhesive experts, but they are zeroed in on products for semi-flexible bumper repair materials as there is little call for an interior ABS repair product, so I did not include them. Plastic epoxy makes stick products are available that theoretically canbe used to create even an entire part, but it does not penetrate into the nooks and crannies so I relogate to special applications only. In general the repair technique itself is to add “back-up” pieces, on both sides if possible. I purchased ABS sheets 1/8”, 3/16”and ¼” thick by 18” square one side smooth, one side textured from TAP plastics in Stockton CA in. I prefer the textured side. Use a very course saw blade in any tool at very slow speed(no wood burners)to cut the back up pieces minimum ¼” larger than the repair area. Trim with a file, 60-80 grit paper or a belt sander. Rough up both surfaces a lot. I use a very small dremal cutter of any type to deeply “v” groove both surfaces which increases contact area and the locking effect. I bead blast the parts only because I have a cabinet in my shop, I do not think it necessary- but a smooth shiny surface will not accept the glue well. Clean with alcohol or acetone. Clamp parts VERY lightly. You can trim excess epoxy about an hour after application. Let dry overnight. A few examples- the front windshield strip –Glue a largish say 3” long strip along the bottom. Let it dry overnight and then V out the top crack as narrow as possible and apply glue to the top surface. You cannot come back and sand this so tape off the area and smooth out the epoxy as best you can using a putty knife wetted with Alcohol. If it looks too bad, you can spot spray can the area with flat model paint. For the 4 center area screws I cut small 1x1” pieces of very thin sticky backed felt from Hobby Lobby, sticking it under a largish washer under the screw heads and between the strip and the body mount. I then only snug the screws to allow for thermal movement. IMO this is key as Honda overtightened the plastic parts. Door panels – Glue a 1/8” “backer piece on the cockpit side, then add small patch pieces to the broken out areas of the original tabs. In addition I purchased ABS washers from McMaster Carr I 1” diameter by 1/8” thick and purchased 1/8” longer screws. I didn’t glue them on, I just used them as additional washers under the screw head. A few of the washers have to be trimmed a little. Regarding stripped screws, I like the method of pushing epoxy down into the hole, then wrapping just one wrap of tefon tape on the screw and screwing it down just short of all the way. I have used a “release” agent such as Acra-Glass release just because I have it handy, but the Teflon alone appears to work well. Attached pic’s show a reinforced lower steer column cover and another showing an added thin brass strip and my most ambitious plastic job filling in the radio hole in the console. I mention this as our center console and door switch panels are chrome plated under the paint and have to be stripped first. While I was able to strip my wifes door handles myself( I hate chrome), after weeks of trying I was not able strip these NSX parts. In the old days I could have had this done locally. I was now only able to find one shop ART BRASS PLATING that would strip them . I did consider buying the carbon aftermarket parts and painting them. While this info is likely old hat to many, perhaps it will instill enough confidence to keep a frustrated newbie from going over to the darkside(P-cars). Happy plastic-smithing!
