Funkworks
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Yes and it's an interesting question, but until I look into it, I suspect a few chemists in here can answer this better than I can.
Glue the Ungluable
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Yes and it's an interesting question, but until I look into it, I suspect a few chemists in here can answer this better than I can.
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Nothing is unglueable. You just need the right glue.
Getting into the existential realm here, but I think in a sense @cwbullet remains correct. Liquids, gases, and plasma are all made of elements, and all are amenable to some sort of cohesion, whether that be gravity, ionic or covalent bonds, or other "forces" which are beyond my knowledge. Of course, if you apply some of those forces to the elemental or molecular levels of these liquids, gases, and plasmas, after application theymay no longer BE in the form of liquids, gases, and plasmas.
I am guessing the gas clouds in the Universe are largely held together by their own very weak gravity. I'd blame it on Gary Byrum and der MicroMeister, but those clouds predated them, so no-go there. Those two are just up there "gluing" those rockets you launch that never come down to the heavenly realms. I imagine they have quite the collection there.
In the semantic sense, because the "common man" definition of a good glue joint is generally along the lines of "the two components are solidly glued together", a good argument is that applying the term to NON-solids is a non sequitur to begin with.
Getting back to "real world rocketry", there is another "modifier" that needs to go on the statement.
"Anything solid CAN be glued, but there are things that are not easily glued WELL."
Sort of like the F4 Phantom Aircraft was often described as proof that, "If you put big enough engines on it, anything can be made to fly."
Or maybe that was @Daddyisabar 's quote, I believe rephrased as, "Trust in Thrust."
Another concept that has been largely ignored is that there are other ways of attaching two solid components than glue. Bolts, rivets, string/floss, "tongue in groove" joints, elastic bands, friction (that's how most of my motors are held in place with the motor mounts, except the rockets I fly that HAVE no motor mounts
and fly quite nicely.) I believe a number of Estes models use plastic fins mounted in grooves in the fin can, I can't remember if you are supposed to glue them in place after insertion or not.
@jqavins made an interesting remark about using a second substance, such as metal, as an "in-between" joint, sort of like, if B is metal, and A will not easily stick to C, but both A and C stick to B (metal), put metal between them. For a long narrow joint such as a fin root, direct placement of a strip of metal between the tube and the fin material may or may not work, and the purists may argue that metal in particular is a violation of the rocket safety code (to which I say, how about motor hooks, screw eyes, and electronics? but I digress.)
There is at least one more option, however: solid fillets. Say A doesn't stick to C, but some other solid and relatively strong material sticks at least partially will to either A and/or C. Say the Body tube is material A, the fillet B, the fin C. If you make fillets the length of the fin root of material B (or whatever else you are gluing, ASSUMING a straight edge), you can glue, sew, screw, or bolt those onto the body tube. Dimensions are the length of the fin tube by, say 1/8" x 1/8" for low power, could go larger for MPR or even HPR (and the bolting or screwing in place would be easier with larger rockets. "Sewing" them in say with dental floss and a curved needle is do-able but would be challenging for an outer surface mounted fin, easy-peasy for a through the wall fin provided you don't mind you fin slots going to the base of the tube and sliding it in place.)
Anyway, once you have the fillets in place, you can put Glue the fin made of C in between your pre-placed fillets made of B with some compatible adhesive that works for B-C joints, whether or not it works for A-C doesn't matter.
Advantages:
Assuming you can find a way to ATTACH (adhesive, screws, bolts, string, whatever) B to A, and assuming you have an adhesive that works from B-C (by the way, if you bolt or screw the fillets into A, you can even MAKE them out of material C, although there are some materials that don't even stick to THEMSELVES well, so a successful C-C adhesive joint is not guaranteed)-----anyway, gives you an indirect way of fixing Fin C to body tube A.
Because the fillets are relatively small and light, they are generally very easy to glue onto A in perfect alignment, you don't have to hold them very long before they "tack". The double glue joint works well here. So your fin alignment tends to be pretty good.
Provides a much greater surface area for the joint, thus generally a stronger joint. Note you don't need a lot of glue if you put space the fillets right, the fin should initially basically friction fit into the groove without glue before you even start.
Often provides a faster "tack" when fin is placed, likely because of the larger surface area. Again, double glue joint works well.
Disadvantages:
More complex. Time-wise however not necessarily longer, the fillets go on pretty easily and quickly, but you do need to let them dry completely before attaching the fin.
Adds a bit of weight.
Adds a bit of drag. This may partially be overcome depending on the thickness of your overlying fillet (I assume you lay another GLUE fillet over the solid filled.) a "thick" glue fillet may completely cover the solid fillet.
Again, we are thinking different materials. I can say from experience this works VERY well even for compatible materials like regular cardboard body tubes and balsa fins, it is how I make most of my standard fin rockets now. I have yet to have a joint failure, although I have had the BODY tube rip off or the FIN break, but that just proves how strong the joints are. In this case however, I usually only use ONE fillet, I stick it on my line marker, one for each fin, let it dry, then put the fin on. I could add another fillet on the other side, but I rarely bother. Then again, my scratch build goals are mainly engineering challanges, I like to see what works, not all that concerned about aesthetics.
More than one way to skin a cat.
Getting into the existential realm here, but I think in a sense @cwbullet remains correct. Liquids, gases, and plasma are all made of elements, and all are amenable to some sort of cohesion, whether that be gravity, ionic or covalent bonds, or other "forces" which are beyond my knowledge. Of course, if you apply some of those forces to the elemental or molecular levels of these liquids, gases, and plasmas, after application theymay no longer BE in the form of liquids, gases, and plasmas.
I am guessing the gas clouds in the Universe are largely held together by their own very weak gravity. I'd blame it on Gary Byrum and der MicroMeister, but those clouds predated them, so no-go there. Those two are just up there "gluing" those rockets you launch that never come down to the heavenly realms. I imagine they have quite the collection there.
In the semantic sense, because the "common man" definition of a good glue joint is generally along the lines of "the two components are solidly glued together", a good argument is that applying the term to NON-solids is a non sequitur to begin with.
Getting back to "real world rocketry", there is another "modifier" that needs to go on the statement.
"Anything solid CAN be glued, but there are things that are not easily glued WELL."
Sort of like the F4 Phantom Aircraft was often described as proof that, "If you put big enough engines on it, anything can be made to fly."
Or maybe that was @Daddyisabar 's quote, I believe rephrased as, "Trust in Thrust."
Another concept that has been largely ignored is that there are other ways of attaching two solid components than glue. Bolts, rivets, string/floss, "tongue in groove" joints, elastic bands, friction (that's how most of my motors are held in place with the motor mounts, except the rockets I fly that HAVE no motor mounts
and fly quite nicely.) I believe a number of Estes models use plastic fins mounted in grooves in the fin can, I can't remember if you are supposed to glue them in place after insertion or not.@jqavins made an interesting remark about using a second substance, such as metal, as an "in-between" joint, sort of like, if B is metal, and A will not easily stick to C, but both A and C stick to B (metal), put metal between them. For a long narrow joint such as a fin root, direct placement of a strip of metal between the tube and the fin material may or may not work, and the purists may argue that metal in particular is a violation of the rocket safety code (to which I say, how about motor hooks, screw eyes, and electronics? but I digress.)
There is at least one more option, however: solid fillets. Say A doesn't stick to C, but some other solid and relatively strong material sticks at least partially will to either A and/or C. Say the Body tube is material A, the fillet B, the fin C. If you make fillets the length of the fin root of material B (or whatever else you are gluing, ASSUMING a straight edge), you can glue, sew, screw, or bolt those onto the body tube. Dimensions are the length of the fin tube by, say 1/8" x 1/8" for low power, could go larger for MPR or even HPR (and the bolting or screwing in place would be easier with larger rockets. "Sewing" them in say with dental floss and a curved needle is do-able but would be challenging for an outer surface mounted fin, easy-peasy for a through the wall fin provided you don't mind you fin slots going to the base of the tube and sliding it in place.)
Anyway, once you have the fillets in place, you can put Glue the fin made of C in between your pre-placed fillets made of B with some compatible adhesive that works for B-C joints, whether or not it works for A-C doesn't matter.
Advantages:
Assuming you can find a way to ATTACH (adhesive, screws, bolts, string, whatever) B to A, and assuming you have an adhesive that works from B-C (by the way, if you bolt or screw the fillets into A, you can even MAKE them out of material C, although there are some materials that don't even stick to THEMSELVES well, so a successful C-C adhesive joint is not guaranteed)-----anyway, gives you an indirect way of fixing Fin C to body tube A.
Because the fillets are relatively small and light, they are generally very easy to glue onto A in perfect alignment, you don't have to hold them very long before they "tack". The double glue joint works well here. So your fin alignment tends to be pretty good.
Provides a much greater surface area for the joint, thus generally a stronger joint. Note you don't need a lot of glue if you put space the fillets right, the fin should initially basically friction fit into the groove without glue before you even start.
Often provides a faster "tack" when fin is placed, likely because of the larger surface area. Again, double glue joint works well.
Disadvantages:
More complex. Time-wise however not necessarily longer, the fillets go on pretty easily and quickly, but you do need to let them dry completely before attaching the fin.
Adds a bit of weight.
Adds a bit of drag. This may partially be overcome depending on the thickness of your overlying fillet (I assume you lay another GLUE fillet over the solid filled.) a "thick" glue fillet may completely cover the solid fillet.
Again, we are thinking different materials. I can say from experience this works VERY well even for compatible materials like regular cardboard body tubes and balsa fins, it is how I make most of my standard fin rockets now. I have yet to have a joint failure, although I have had the BODY tube rip off or the FIN break, but that just proves how strong the joints are. In this case however, I usually only use ONE fillet, I stick it on my line marker, one for each fin, let it dry, then put the fin on. I could add another fillet on the other side, but I rarely bother. Then again, my scratch build goals are mainly engineering challanges, I like to see what works, not all that concerned about aesthetics.
More than one way to skin a cat.
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Usually it's everything else that gets turned into a glue thread, but here we have the rare glue-to-philosophy thread.
Funkworks
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I think it comes down to what can be called a "glue". Chemists might be able to classify conventional "glues", but if the goal is to bind two solids together in any way, nothing can be ruled out. Possibilities are endless.
Darn, I didn't want to think about this.
I'm not sure which such comment you're referring to. If you mean a little upthread, about ice blocks, the "in between" material is the glue.
Another configuration I've thought of, and may have mentioned somewhere, is this: say I want to glue material A to material B but I can't find any glue, X, that bonds well to both A and B. Maybe I can find a material C such that glue X will bond A to C, and glue Y will bond C to B. Then I can stack up A-X-C-Y-B. In that case, C might be a metal or might be something else entirely.
If it's a metal, that's probably not a problem with the safety codes. Things like motor hooks and screw eyes are OK because the code says - I don't remember the exact words - that no major parts of the structure may be made of metal. In other words, no metal nose cones, airframe tubes, or fins, pretty much. I would consider a "gluing strip" of material C to be as except as a motor hook, and more exemptable than an Aeropak retainer.
But can you glue the skin back on?
lakeroadster
When in doubt... build hell-for-stout!
What glue would I use to attach a spring steel engine hook to a cardboard motor tube?
Have you considered ice?
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One of the more flexible CAs, but you'll still need to back it up with the over ring.
If you really want to do that, as opposed to taping it or tucking it under a centering ring, epoxy will do very nicely. CA would do, but not so very well; I'd use epoxy.
lakeroadster
When in doubt... build hell-for-stout!
Because the glue won't hold... that's kind of the point... Saying we can glue anything... may be true... but if it doesn't work.. what's the point?
Maybe not exactly what you're asking, but I did this:
The epoxy is of course not solely holding on the hook; I wouldn't really trust it without the ring there as well due to the tension that is put on the hook. But I have done this on a couple of occasions when I didn't want a retention ring around the hook getting in the way of TTW fin tabs.
In this case the epoxy is not really adhering the hook to the body; rather, a good amount is glopped over the hook, so it's mechanically holding it down.
I would use JB Weld. I have done it with great success in the past.
I'm going to stick to my guns on this one. I'm confident that the epoxy's bond (without glopping over the top) to the steel and to the cardboard are both stronger than the cardboard.
It's probably not a good idea to epoxy the hook the the tube and not use a ring, because there is a good chance of the tube being torn up. But as for effective bonding, A-X-B where A = spring steel, B = cardboard, and X = epoxy will bond as effectively as you could ever want.
It's probably not a good idea to epoxy the hook the the tube and not use a ring, because there is a good chance of the tube being torn up. But as for effective bonding, A-X-B where A = spring steel, B = cardboard, and X = epoxy will bond as effectively as you could ever want.
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Under what regime?
Flexible CA is correct for wood to metal. Sure we can embed the hook in a huge glob of epoxy, but presumably that adds more mass than a mylar ring.
I suppose if we added enough CA layers to equal the mass of an epoxy blob it would probably hold about as well.
Unless someone's asserting a nice thin epoxy bondline with no overblob, in which case I'll be happy to buy a tube.
lakeroadster
When in doubt... build hell-for-stout!
Flexible CA... I'm not familiar with that. I'm thinking when you went to install the motor... the stress of lifting the engine hook that the flexible CA would rip the carboard body tube. So that's not the case?
You can glue ice together with water, if it's cold enough. Especially if you hit it with LN2.
I have glued a cat back together with CA glue; He had a disagreement with a possum, and it held him together until the vet opened.
Over 100 stitches, poor bugger.
DES
Well-Known Member
OK, maybe I'm covering old ground, or reopening old wounds.
I was reading wikipedia about Polyoxymethylene (POM, e.g. Delrin) which crossed my mind for some random reason, and I found this
I proceeded to Henkel's (Loctite's) web site, and found the following:
(Underline added.) "Not recommended in assemblies where high peel strength is required" worries me a bit. There is another primer, 7239, which might be better.
- They do have a number of products that bear the Prism™ moniker, but 401 and 770 are no among them.
- 401 is one of many CA formulations that Loctite has.
- The product description for 770 states:
A search for sources to buy 7239 turned up only European results.
There are also lots of other CA variants that may or may not be better than 401 for our purposes.
I think I will contact the Loctite people and ask; this looks promising enough to be worth writing them.
Some years ago, I used the Loctite " N Primer' - which is now part #7649 to bond UHMW bearing pads to steel with instant adhesive. Chemically clean, and then roughen the UHMW, apply the primer and let dry. When bonding plastic, I believe the primer is more critical to success than the specific CA, but be sure to use a good grade of "toughened" CA whenever bonding plastic or metal. The little bit of plastic or rubber dissolved in the CA provides ductility so the CA doesn't fracture as readily.
Nowdays, Loctite has several primer formulations. I'd probably try the 770 primer, it appears to be labeled specifically for plastics.
I looked up that stuff and cheapest I could find was about $60 a tube!
I might try some of this instead for PP.
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Perfect one for Dental Floss and Thin CA.
you'd need to wrap the floss completely around the body tube including the base of the hook, three wraps should do it. Bonus points if you can feed the loose ends through the slit the forward end of the hook goes into. I assume you are talking minimum diameter rocket, as if you had an internal motor mount you can just use the centering rings to hold it in place. For minimum diameter, You may want to use CWF or something else to hide the circumferential "bump" from the floss, or if you are @neil_w , you will color the floss something exotic and fit it into the paint and decal scheme.
BTW, floss and thin CA weighs pretty close to nothing.
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Is that a glue failure ?
But yeah as @DES mentions it's just CA with some plastic or rubber dissolved in it. A lazy way to tell is just to dope some paper, let it dry, and see which ones give black smoke and sizzling.
If it rips the cardboard, the the glue bond was successful. The motor mount design was not.
Yes, that's exactly what I'm asserting will also succeed in ripping the tube.
lakeroadster
When in doubt... build hell-for-stout!
Is that a glue failure ?
Form follows function. It's an application where glue doesn't work, an application where we are trying to "glue the ungluable"
Hmm, seems like I remember a thread like that on TRF?
It's a real example showing the fallacy of this statement:
But it's not the ungluable. It's the inadvisable to glue. "You shouldn't" is different from "You can't". (Another greater life lesson we can learn from rocketry. There's a thread for that, too.)
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lakeroadster
When in doubt... build hell-for-stout!
Semantics. If you define a gluable joint that fails, as gluable, the entire topic is nonsense.
I disagree. The topic is making a bond to a material that is reputably (but not actually) impossible to bond to. That's all, just the bond. When the tube rips, neither material was difficult to bond.
You shouldn't surface mount fins to a supersonic rocket with Tightbond. Is that ungluable by Tightbond for supersonic flights, and gluable for lower speeds?
You shouldn't surface mount fins to a supersonic rocket with Tightbond. Is that ungluable by Tightbond for supersonic flights, and gluable for lower speeds?
lakeroadster
When in doubt... build hell-for-stout!
Yes... it's application specific. Great example!
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By that logic, fingers are not gluable, because gluing one's fingers to things (e.g. with CA) is a bad idea. And cars capable of driving at 80 mph on a good quality highway are incapable of going 80 on a residential street.
Perhaps the thread title should be "Bonding the Unbondable". I think it was abundantly clear from the OP that the subject is bonding, not suitability thereof.
Perhaps the thread title should be "Bonding the Unbondable". I think it was abundantly clear from the OP that the subject is bonding, not suitability thereof.
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