Ace-Garageguy

I guess my reading comprehension and question answering skills just aren't up to snuff. I've NEVER used 5-minute epoxy for anything on a model car or anything else that I wanted to be permanent because I've never been impressed with its adhesion on ANYTHING, so why would I use it on a model I cared about? I've used it for temporary fixturing...on model cars and full scale things...because it's easy to peel off, especially if a surface isn't scuffed. And I've used it enough on various and sundry OTHER applications...as well as temporary model work...to form the opinion it's NOT something I choose to use for permanent assembly of a model. "Distinct" enough? There's no "right" answer here. Use what YOU like, and I'll use what I like. I've said repeatedly it's adequate if used correctly for most static model car work, and if somebody likes it then USE it.

Around he-ah, we don't do things that way, boy.

Where do you get I've "never used" the stuff from anything I've written? Why would I have formed the opinion it was garbage without actually having some empirical evidence to base my opinion on?

I wrote I don't use epoxy for general assembly for models, I wouldn't use the 5-minute stuff for anything permanent, and why. You seem to want to take that as some kind of personal affront to your choice of adhesives. My saying that 5-minute epoxy is garbage compared to high performance epoxies, and garbage even compared to standard JB Weld, is a statement of my opinion based solely on my own experience, not an attack on your modeling choices. I hope that's clear enough.

I would wager a lot more than you do, in a wide variety of applications that go way beyond model cars. JB Weld saved my bacon on the road once, when a soldered joint on a Fiat X1/9 radiator bleed fitting failed (both the radiator and fitting were brass), and an emergency JB Weld repair got me the rest of the way across the country, never gave the least indication of leaking, and was still on the car years later when I sold it because I forgot to ever do a "proper" repair. That was not the 5-minute stuff, and I was extremely careful about cleaning, mixing, and application. I'm currently experimenting with the regular version to form some critical joints between dissimilar materials on a custom instrument panel for a full-scale DeLorean. Testing alongside my old faithful MGS, and a West resin system that is certified for one particular aircraft application, as well as an aviation-grade epoxy made specifically for bonding aluminum. I've used JB Weld extensively, as well as several other consumer-grade epoxies, for tooling and fixture applications that didn't need to last forever, or be exceptionally strong, and needed to get done quick with a minimum of fuss. Etc.

Compared to MGS 285 with 285/287 hardeners, and many other high performance epoxy systems, it is garbage. OK?

How many times do I have to say that fresh material used with reasonable care is perfectly adequate for most static modeling applications? Hardware store stuff is on the low end of the performance spectrum for epoxies, period.

I don't understand what you're arguing about. YOU...and anyone else...can CHOOSE to use anything you want, including unicorn snot or Cheez Whiz if that works for you. But there are those of us who have extensive knowledge about adhesives, have access to high performance materials, and CHOOSE to use them...even if they require 2 or 3 whole extra minutes to measure on a scale. Hardware-store epoxies are moderately good adhesives that are relatively easy to use, appeal to the average Joe, and used carefully are perfectly adequate for most static modeling uses. And poor mixing and/or application procedures, or old material, are the main causes of problems with the stuff. That is the simple unvarnished truth. I don't understand why the truth is disputed, or at least seems to ruffle people's feathers. However, I have made multiple posts and started threads showing mold-making and almost-scale-thickness fiberglass parts that are MUCH stronger than styrene, and that are just flat impossible to do with almost any consumer-grade epoxy. When one has access to a very high performance epoxy product, why wouldn't one use it for everything as appropriate? NOTE: I personally do not use epoxies for general assembly, unless I need to bond dissimilar materials that other adhesives aren't good for...like brass and aluminum to plastic. I use solvent glues wherever appropriate, and usually some variety of white glue (PVA) for clear parts, chrome parts, pinned parts, or anything I might possibly want to dissassemble in the future. EDIT: One thing that hasn't been mentioned yet is that fully-cured epoxies DO degrade under prolonged exposure to UV light. If a model car assembled with tiny dabs of epoxy and sitting in sunlight for a long time falls apart, well, no surprise there. Degradation of epoxies under UV exposure is well known in aviation, even light reflected UP from the runway under a plane can cause damage...and precautions are taken to guard against it.

Alcohol makes a very effective cleaner prior to painting and is good insurance against fisheyes, but don't drink the stuff used for cleaning.

PM'd

Yup. Old-fashioned rolled oats, or steel-cut when I can find them. I prefer the heartier flavor and texture of steel-cut. I stay away from the more processed quick-oats for blood-sugar reasons.

Late home tonight. Fixin' to have hot old-fashioned oatmeal with fresh raspberries.

I was getting pretty smelly a few weeks back when my point-of-use propane-fired shower water heater quit, I ordered a new unit from Home Despot, and UPS repeatedly told me my address didn't exist (though they'd delivered to this address repeatedly in the past), or that delivery had been attempted and nobody was home (though I made a point to be home every day the thing was posted as "out for delivery" on their website). Eventually, delivery from the warehouse one state away, that had been estimated to take two days, took over a week (and had I not gone to a UPS store that could do NOTHING but give me a "direct" customer service number that rang in India, I'd still be waiting).

Yup, TIG would be the best if you have the equipment and know how to use it, but this just shows it's entirely possible to do a clean clean clean job with MIG, and the same technique of tacking closer and closer together, then working the welds flat with hammer-on dolly (which helps to alleviate the shrinkage introduced by the heat of welding) works equally well with oxy-acetylene.

Much Doo-doo About Nothing would likely be the name of a Shakespeare play were he alive today.

The model cars used in The Giant Gila Monster... ...with my favorite being the valiant hero '32 Ford roadster that gave everything to save its humans from the rampaging lizard.

Windowpane, man.

That'd be cool. Six months after the check that the client across town swore up and down "was in the mail", it finally comes in with stamps from Amarillo and DC and Honolulu and Anchorage, and slightly singed during its passage through LA. What fun.

Hmmmmm... I use white glue or rubber cement for hubcaps, because it keeps low-stressed things stuck, and comes off easily should I ever decide to change the look of a build...but that's just me. I use the epoxy I use because I almost always have some that's gone out of date and can no longer be used safely on aircraft. The typical use-by window on my aircraft stuff is six months to 24, depending on the exact goo, in unopened containers. There's a reason aviation epoxies are often date-coded, and that's because performance of any epoxies deteriorates with time. I have some MGS 285 resin that's now 10 years out of date, and there's no way on dog's green Earth I'd use it on anything important, its cure time and hardness and adhesion are noticeably different than fresh material, and it's still so much better than anything in the hardware store or hobby shop, there's simply no comparison. Consumer-grade epoxies aren't all that terrifically strong to start with, and age-out can make them useless in much less time. Again...whatever works for you, fine. I d o n ' t c a r e . But paying attention to details like shelf-life and mixing and roughing mating surfaces can't hurt, and can very possibly ensure problems like the OP is having don't crop up.

Consumer-grade epoxies are designed to be tolerant of sloppy mixing ratios and mixing procedures, but only to a point. The mix-ratios specified on the product should be adhered to as closely as possible. HOWEVER...due to the poor accuracy of consumer-grade dispensing methods (you even need to pay attention to the twin-tube dispensers, as they will frequently deliver significantly more of one component than the other), extreme mix-ratio accuracy simply isn't a thing achieved by most users. The 5-minute stuff is the weakest of any epoxy product, and any significant deviation from the specified mix-ratio only weakens the stuff further. (I've used it myself, and allowed my employees to use it for temporary fixturing ONLY, specifically because it's so weak and easily removable) I've watched countless people using the stuff , measure it out fairly accurately, but then fail to thoroughly mix everything they've squeezed out, getting in a hurry to slop it on whatever they're doing before it starts to "kick"...for what seemed to them good reason. Any epoxy applied once it's begun to polymerize will NOT develop its designed adhesive strength, and can cause subsequent joint failure. Elevated temperatures accelerate the "kick" even more, so there are multiple failure points just waiting to bite anyone who uses it. Used reasonably carefully, quality 5-minute stuff is fine for static models. But compared to the high-performance aerospace products I have access to, it is garbage. EDIT: But y'all can do anything you want. I just like to make out I'm a big-shot know-it-all.

"Gamble with other people's money" is the way a lot of things work in the real world.

Luck probably doesn't have anything to do with it. I'd assume, judging from the attention you give the rest of your work, that you use product that's not expired, you probably exercise care with your mix ratios, mix very thoroughly, and you may even rough up the areas to be bonded. If you DON'T do those things, then yes, it IS luck.

Epoxy is supposed to be mixed in specific proportions to harden correctly, and to achieve maximum adhesion. High-performance epoxies even have to be mixed using a gram scale, often with only .5% deviation from the specified mix ratio being tolerable. Adding a higher percentage than specified of one or the other component to epoxy negatively affects performance. Polyester, on the other hand, can tolerate a somewhat higher or lower percentage of "hardener" (because it's technically a catalyst) but it doesn't make it stronger. It only adjusts the cure time relative to temperature.

That's pretty bad. Can you get an emergency prescription filled locally?

You can see it here...