2-Part Epoxy Failing?

[StevenGuthmiller]

19 minutes ago, LennyB said:

Steven, Bill that's enough out of you two, your just flogging a dead horse. Now both of you go sit in the corner until you are ready to kiss and makeup. 😙

Hey, I’m sitting on a beach in Mexico right now.

I’m just passing the time and having some fun!

To be honest, this entire discussion is just something to keep me occupied so I don’t drink too much tequila! 😁

 

No! I’m not kissing Bill!!

A handshake would suffice, (once he stops being pissed off at me) 😄

Thanks for the rousing discussion guys, but the tequila is more fun! 😉

 

Steve

Edited January 30 by StevenGuthmiller

[Ace-Garageguy]

3 minutes ago, StevenGuthmiller said:

I drink too much tequila! 😁

Ah...that explains everything.   

[StevenGuthmiller]

2 minutes ago, Ace-Garageguy said:

Ah...that explains everything.   

Ha! You’re not getting off that easy! 😁

I’m here for 2 weeks! 
Buckle up buttercup! 😊

 

Steve

Edited January 30 by StevenGuthmiller

[LennyB]

Just now, Ace-Garageguy said:

Ah...that explains everything.   

I think you owe Ferbz  some of that Tequila because you've twisted this thread around so much it looks like a pretzel.

[StevenGuthmiller]

1 minute ago, LennyB said:

I think you owe Ferbz  some of that Tequila because you've twisted this thread around so much it looks like a pretzel.

Oh, boo hoo!

That’s never happened before! 🙄

 

 

Steve

[LennyB]

1 minute ago, StevenGuthmiller said:

Oh, boo hoo!

That’s never happened before! 🙄

 

 

Steve

He just has to have the last word doesn't he Bill.

[StevenGuthmiller]

1 minute ago, LennyB said:

He just has to have the last word doesn't he Bill.

I got all night. 😉

 

 

Steve

[LennyB]

2 minutes ago, StevenGuthmiller said:

I got all night. 😉

 

 

Steve

“Good night, Mrs. Calabash, wherever you are!”

[NOBLNG]

24 minutes ago, LennyB said:

Steven, Bill that's enough out of you two, your just flogging a dead horse. Now both of you go sit in the corner until you are ready to kiss and makeup. 😙

They are both correct. Bill may be 100% correct on his assessment of the different epoxies. However his point is moot, because I’m pretty sure that the MGS 285 (or any other industrial epoxy) is NOT available in 2 oz. tubes that the average model builder could hope to use up. I’m NOT gonna buy a gallon. If Bill recommends JB or another better, easily available epoxy then thanks for that info Bill. The 5 minute stuff is plenty strong enough for a plastic model in my opinion…and yes it’s just an opinion.

[NOBLNG]

2 hours ago, NOBLNG said:

The 5 minute stuff may not be Permanent, but I’m pretty sure it will outlast me. I’m also pretty sure that none of my models are going to wind up in a museum or modeling  hall of fame, so if they eventually fall apart…I don’t really care.😜

 

1 hour ago, StevenGuthmiller said:

Correct.

What’s permanent?

There’s no such thing.

 

 

Steve

Actually Steve, yours might wind up in a museum or model builders Hall of Fame….so maybe you should switch epoxies.😈

[StevenGuthmiller]

9 minutes ago, NOBLNG said:

 

Actually Steve, yours might wind up in a museum or model builders Hall of Fame….so maybe you should switch epoxies.😈

Once they’re in someone else’s hands, they’re their problem! 😊

 

 

Steve

Edited January 30 by StevenGuthmiller

[Bugatti Fan]

Ye Gods !    What a discussion !    Very interesting points of view made by all contributors.

Fact is, most of us do not have access to or can afford very high performance industrial  epoxy adhesives, and whilst there is no argument from me about how good they are, they are an irrelevance to probably over 95 percent of us. As I said in my earlier post I have used proprietary big name brands and store brands without any problems. If the surfaces to be stuck are shiny, I always 'key' the surfaces with some abrasive paper or make scratches on them with a craft knife or scriber to enable a better bond. Epoxy it has to be remembered is a surface adhesive. It does not weld parts together like plastic cement does when used in polystyrene for example. That is why keying the surfaces to be glued with epoxy adhesive is important.

As for ease of use that one poster mentioned. Well, the fact that two parts having to be mixed together first can be a bit tricky for many. Some people get good at it and others get sticky fingers ! Cannot suggest anything to overcome this except that it gets better with practice. Invariably I get the stuff on my hands accidentally when I forget to move the piece of card or whatever I have been mixing it on well out of the way and come into contact with it without realising. You would have thought that I would have learned by now having used the stuff for years !

Edited January 30 by Bugatti Fan

[peteski]

On 1/27/2025 at 1:34 PM, Ferbz said:

I've used 5min 2-part epoxy successfully and confidently for many years and have used a variety of different brands. Lately though, I have noticed parts on some of my previous builds coming loose! So far, two of my older builds have had suspensions coming apart where I have used 2-part epoxy to assemble them. One of the builds is about 5yrs old, the other build is over 20yrs old.

Hey Ferby,

I have quickly scanned through 3 pages of this very "interesting" thread. 

Between the 5-minute epoxy peeing contest posts has as anybody in their responses mention that possibly the parts being glued were not perfectly clean and grease/oil/dirt free?  That could be a cause for weak joint.  Also if the joined parts were painted before glueing, did the paint stay on the parts or stayed with the hardened epoxy?

BTW, if someone wants to use the 5-minute stuff for clear lens applications - don't.   It will always turn amber after few years. I tried more than once (guess I was too stupid to learn after the first example of ambering).

 

[StevenGuthmiller]

1 hour ago, peteski said:

Between the 5-minute epoxy peeing contest posts

C’mon Peter.

I think we all know each other pretty well.

You’re just mad because you didn’t get to compete in that contest earlier on! 😉

 

 

 

Steve

[Big John]

I have had the same problem with the amber on my lenses and won't do that again.  I am wondering if, with the bond failure if the surfaces were rough sanded and a light scoring with a blade to give the surfaces a 'tooth' before epoxy application would help. There would be some release agent on most plastic parts.

[peteski]

8 hours ago, StevenGuthmiller said:

C’mon Peter.

I think we all know each other pretty well.

You’re just mad because you didn’t get to compete in that contest earlier on! 😉

Not at all Steve. I'm vert happy that Ace took jumped in. I use a multitude of adhesives pick ones which I think are the most suited for a specific task. Both JB Weld and a 5-minute epoxy are in my arsenal of adhesives.

[Ferbz]

On 1/29/2025 at 3:02 PM, LennyB said:

I think trying to figure out why a joint from 5-20 years ago failed you would need to look at the joint itself.  It can fail for many other reasons then the epoxy being the culprit.  Was the surface prepped properly? Epoxy bonds best to a porous surface which styrene is not.  If the surface is smooth the epoxy can peel right off no mater what the quality of the epoxy is although some will grip better then others.  Was the surface painted? Did you try to glue over the paint. The epoxy could have a reaction to solvents in the paint.  Ideally you would want to glue directly to the styrene with nothing in between but I would guess that is not the case as you probably would have used a solvent instead of the epoxy.  I’ve seen epoxy joints fail and the paint peeled off the part, so in that case it wasn’t the fault of the epoxy.  

As mentioned above mixing equal parts makes a difference but what you mix on can also make a difference. Never use something like paper or cardboard to mix epoxy.  Some of the solvents in the hardener will wick into the paper and weaken your joint because no mater how carefully you measured your ‘equal’ parts, they are no longer equal. Just my 2 cents although with inflation that was probably more like a buck fifty.  

Ah-hah! Mixing surface is something I've never considered. Thanks for that tip! I've almost always used index card material because it's easy to mix then throw away. What surface do you use? Glass? Most of the surfaces I assemble using epoxy are painted or are dissimilar materials (like spark plug wire and styrene) and like I said I've had success doing so up to now with the 5yr old and 20yr old build I mentioned. I'm beginning to think my two epoxy adhesive failures might indeed have to do with both not scuffing the surfaces, and not being super clean surfaces. BTW, I'll just mention here that the majority of my assemblies involving 5min epoxy have little to zero stress placed on them. I've mainly used 5min epoxy due to the nature of the fact that most of the parts I glue together for assembly are because they are either painted or are dissimilar (like the previously mentioned spark plug wire). 

[Bugatti Fan]

Pete has made an important point about ensuring surfaces are clean an grease tree as part of the procedure, and not applying it onto a painted surface. I omitted to mention these things in my last post when suggesting that surfaces should be keyed for better adhesion when using epoxy.

[LennyB]

20 hours ago, Ferbz said:

Ah-hah! Mixing surface is something I've never considered. Thanks for that tip! I've almost always used index card material because it's easy to mix then throw away. What surface do you use? Glass? Most of the surfaces I assemble using epoxy are painted or are dissimilar materials (like spark plug wire and styrene) and like I said I've had success doing so up to now with the 5yr old and 20yr old build I mentioned. I'm beginning to think my two epoxy adhesive failures might indeed have to do with both not scuffing the surfaces, and not being super clean surfaces. BTW, I'll just mention here that the majority of my assemblies involving 5min epoxy have little to zero stress placed on them. I've mainly used 5min epoxy due to the nature of the fact that most of the parts I glue together for assembly are because they are either painted or are dissimilar (like the previously mentioned spark plug wire). 

I save the lids from plastic ice cream containers like Talenti, they are a good size with room to mix quite a few batches and the rim of the lid keeps things contained. You can generally peel the dried epoxy off the inside of the lid for reuse. Or wait for ice cream night and start with a fresh one. Also good for mixing paint colors and applying Molotow.

 

Edited January 31 by LennyB

[peteski]

12 hours ago, Ferbz said:

Ah-hah! Mixing surface is something I've never considered.

I mix mine on a piece of 2" wide masking tape stuck to a small flat plastic palette.  Tape does not absorb the resin and when I'm done for the day I simply peel the tape off and replace it with fresh piece for next modeling session.

[StevenGuthmiller]

I guess I need to completely reconsider my techniques for using epoxy.

I don’t “key” anything.

I use it on paint, chrome, kit glass, different metals......heck, I’ve even used it on tires!

When I mix it, I do it on a piece of cardboard.

Now I’m just going to be sitting in front of my display cabinets just watching, and waiting for parts to begin falling off! 😁

I’m closer to an illiterate when it comes to epoxy than I am to an expert, but I get this feeling that just as is the case with various paints, the particular one you’re using will determine more than anything else your ratio of success.

Just as procedures and techniques for applying varying paints can differ, I have to believe that the same must be said for epoxies.

As a matter of fact, even speaking as a relative laymen, I can almost guarantee it.

 

 

 

Steve

[NOBLNG]

I cut cereal boxes into 2-1/2” squares (cause they fit neatly in a certain spot) and mix the 5 minute epoxy on the printed side. For the amount of time it’s on there (1 min?) it doesn’t soak in enough to affect it that I have noticed. If I used longer setting stuff I would use a plastic pallet like Len. JMO.

[StevenGuthmiller]

19 minutes ago, NOBLNG said:

I cut cereal boxes into 2-1/2” squares (cause they fit neatly in a certain spot) and mix the 5 minute epoxy on the printed side. For the amount of time it’s on there (1 min?) it doesn’t soak in enough to affect it that I have noticed. If I used longer setting stuff I would use a plastic pallet like Len. JMO.

Apparently, I’ve been breaking virtually every epoxy rule that there is, yet I can’t seem to manage to get it to fail.

I have to be doing something wrong! 😊

Here’s another practice that I’m confident has to be a big no-no.

For most assemblies I’m doing, as soon as the epoxy is mixed, I apply it to one, or both of the surfaces to be joined, depending on the circumstance.

Then I walk away for somewhere between 8 to 15 minutes. (The product I use is a 5 minute epoxy, but it takes much longer than that before beginning to harden)

I then return and check the remaining mixture on the card to check progress, and once the glue has reached a tacky, but no longer soupy consistency, then I join the parts together.

This accomplishes a couple of different tasks.

A, It eliminates, or at a minimum, greatly reduces, any possibility of glue “squeeze out”, which can be a huge deal, especially when dealing with installing glass or anything that needs to be cleanly glued to a surface that will be exposed.

B, It’s a huge benefit for positioning parts.

There is enough viscosity left in the glue to be able to make positioning adjustments, but it’s tacky enough to hold the parts where you put them so they’re not sliding all over the place.

I use the example of positioning a rear view mirror inside of a hardtop body, because who hasn’t had a mirror go wonky on you as you tried to install it, leading to glue all over the glass, or other surfaces where you don’t want it.

With this method, I put a small dab of epoxy exactly where I want the mirror placed with a tooth pick, let it tack up for 10 minutes, and then using a tweezers, simply place the base of the mirror on the dab of epoxy, and lightly press in place.

It can still be moved around a little here and there without making a glue mess, but it’s gonna stay where you put it when you back away from it.

I’m sure some of these suggestions are utterly horrifying to some, but I have yet to see any evidence at all of any failure or weakness in any joint that I’ve used this product and these techniques on over the past decade or more.

Does that mean that there will never be a failure?......absolutely not.

But then again, glue joint failure is always going to be a possibility, or even a probability, with a lot of different products.

That’s just the way it is.

Just as a side note, I’ve seen people on numerous occasions having to repair models at a show after parts have shaken loose during travel.

Pretty much every show I’ve ever attended was at the end of as much as a 300 mile or more trip on some pretty awful Minnesota roads, and most of my models have made numerous trips of the same caliber, and never once have I ever had to glue a single part back on once I arrived at the show.

Now, you can possibly attribute some of that to how the model is packed, but I’m confident that a large portion of that is due to how the model was assembled, and you guys know me. Most of my builds have no shortage of intricate assemblies and tiny parts.

 

 

 

Steve

[NOBLNG]

I prefer this Gel stuff. It is never “soupy”.

[Ferbz]

So much info to sift through here! Thank you guys 🙏 Mixing surfaces...different quality brands...different hardening times......🤪 I should mention that for the most part, my completed builds always sit in a display cabinet and hardly never get moved. I rarely take them out except for when I need to take pics and I've not packed them to transport them to a show in many, MANY years until recently. Also, I've recently moved out of state so naturally they had to get packed and transported. This may have caused the suspension parts I have on the two builds I mentioned to come loose. My builds span about 30+yrs and I'm grateful they've pretty much survived all the travelling they've had to do lately.

Edited January 31 by Ferbz