From: MichaelT 28/11/99 10:50:20 Subject: Anerobic monomers post id: 11381 OK, we know that normal adhesives generally use the method of some sort of sticky stuff dissolved in a volotile substance that evaporates away when exposed to air, leaving the sticky stuff behind. How then does Loctite type stuff work in the opposite way? If it is exposed to "air" it stays liquid. It goes solid in the absence of the aforementioned "air". My question is simple: How? Why? :) Regards, MichaelT From: Kothos 28/11/99 10:54:09 Subject: re: Anerobic monomers post id: 11382 Something I'd like to know - how do you remove a screw or bolt that's been screwed in with this stuff?? It's bloody impossible. Michael - sorry but for the past forever and a day I thought your name was Michael IT. Vision was playing tricks on me - do you actually work in IT? From: MichaelT 28/11/99 11:13:32 Subject: re: Anerobic monomers post id: 11389 Sort of. I do IT stuff in hostile environments. If it breaks when you hit it with a very large hammer, it's not good enough. :) look at http://www.comcen.com.au/~user/miketz for more info. Oh - I did used to work at TimeZone, but that has nothing to do with the TZ in MikeTZ. :) Cheers, MichaelIT From: Kothos 28/11/99 11:16:46 Subject: re: Anerobic monomers post id: 11390 I'd love to work in Time Zone if I got to stay after hours and play games - sort of like Homers pin-monkey fantasy. How hostile is hostile? From: MichaelT 28/11/99 11:21:37 Subject: re: Anerobic monomers post id: 11392 Something I'd like to know - how do you remove a screw or bolt that's been screwed in with this stuff?? It's bloody impossible. If you use normal domestic grade Loctite, you just use a big spanner. Heating it with a Oxy also helps. If you happen to come across military (black)grade stuff used on clean prepared surfaces, forget it. Luckily, you cannot just buy this stuff. Oh, that company also makes the best super-glue. Leaves the normal stuff for dead... Regards, MichaelT From: MichaelT 28/11/99 11:31:20 Subject: re: Anerobic monomers post id: 11393 You seen those footages on TV where rioters are being "controlled" by water cannon? That is the system they use to wash trucks down with. You don't use 'em on normal cars as door seals may as well not be there, and you have only a few plastic bits left on the car afterwards. The electronic systems we install on the trucks need to be waterproof. :) Diesel and oil cover everything. including whatever you install. This is sometimes good, as coal mines tend to have a high sulphur content in the coal dust, and when it gets damp it turns acidic. Coal dust by itself is conductive. Large rocks the size of the aforementioned cars regularly fall and bend things. Solid steel things a couple of inches thick. Actually, to be honest, there's not much we can do about that. :) In general, I think the lifespan of any 'poota gear we stick on is good considering. Regards, MichaelT From: Kothos 28/11/99 13:46:14 Subject: re: Anerobic monomers post id: 11397 Cool, that reminds of the trucks coming out of the Sydney Harbour Tunnel when it was being built (I was privelaged enough to get a close up look at one stage). Those things went in all yellow and came out all brown - I've never seen so much mud. I never figured on anyone having to deal with that sort of thing on a full time basis though, it must be a continuous challenge. I thought the electrical systems in those things were supposed to be heaps simple though, what kid of electronics do they have? From: Di 28/11/99 16:03:20 Subject: re: Anerobic monomers post id: 11434 Cyanocryalates (sp?), Superglue and Loctite are set off, I seem to recall, by the presence of minute quantities of moisture. I'm not sure how this relates to the abscence of air, though. Help! We need a chemist! Trevor From: Di 28/11/99 17:10:16 Subject: re: Anerobic monomers post id: 11446 There are lots of different adhesives. What is loctite and what do you use it for? Cooling and solvent evaporation is two physical ways of settting as opposed to epoxy resins. Air contains moisture, might that be the problem? From: Grant¹ 28/11/99 17:21:26 Subject: re: Anerobic monomers post id: 11449 Loctite is a liquid you put on screws when screwed into metal & for nuts on bolts to stop the screw from coming out & the nut from coming off. (I think Loctite is a brand name, like Super glue) When you apply the Loctite to the bolt & put the nut on you have have to wipe away any excess as it remains liquid. It's only the stuff that is in contract with the 2 surfaces that "sets". I've spilt some at at work & after 4 days it was still liquid. There are dozens, possibly hundreds of diferent types ranging from ones that require very little force to break the seal, such as putting it on a nut to stop it coming off due to vibration but can still easily be removed for maintenance; right up to ones that are designed for screws or bolts that are never to be removed- trying to do so usually just breaks the head off. From: Di 28/11/99 17:30:40 Subject: re: Anerobic monomers post id: 11450 hmmm metal to metal, probably a phenol-formaldehyde adhesive. *shrug* From memory, they are related to bakelite. From: MichaelT 28/11/99 19:29:28 Subject: re: Anerobic monomers post id: 11475 It has nothing to do with the metal - indeed, the instructions tell you to always leave some air in the bottle. If you squeeze all the air out and replace the lid, you end up with a solid bottle. The only ingrediants the bottle mentions are "Anerobic monomers" which I can assume are monomers that do something in the absence of oxygen(?) - maybe become a lattice/tangle of polymers??? Cheers, MichaelT Weird. From: Grant¹ 28/11/99 19:33:33 Subject: re: Anerobic monomers post id: 11476 If you squeeze all the air out and replace the lid, you end up with a solid bottle. Wouldn't surprise me, however it only bonds metal to metal. From: MichaelT 29/11/99 20:55:38 Subject: re: Anerobic monomers post id: 11878 I just read your question about the electrics in trucks - the electrics are simple. The electronics are far from simple. The engine management systems alone leave the average family car for dead. It is interesting to see the techs plug in a laptop into a bloody great big dozer and start changing mixtures and spark and stuff in each individual cylinder as it is going... There is a computerised load sensor, GPS system, realtime data transmission of vital statistics (like F1 cars.)You name it, it's computerised. In fact, if you plug enough options onto a hauler, you can remove the operator.!!! The truck can be programmed with the route and it will drive to the loading point, leave when it is full, drive to where it is unloaded and do it's stuff, then do it all again, all with zero intervention by people. Scary to think of a 300ton haul truck that would drive through any building in its way on "autopilot"... Cheers, MichaelT From: Paul 30/11/99 18:11:00 Subject: re: Anerobic monomers post id: 12121 Hi all, I could be wrong about this, but the polymerisation process of the cyanoacrylate may require to anaerobic (or essentially anaerobic) as the oxygen may quench the polymerisation process. That is, the crosslinking can only occur if oxygen does not get in and react with the free radical polymerisation front. I think the polymerisation of latex is similar, put in the latex monomer, the cross linker, the initiator and exclude oxygen. If oxygen is in there, it reacts with the free radicalised front to stop the process. Actually, thinking of more examples seems to increase the logical nature of this. PAGE gels (something I am working on at the moment) uses Acrylamide and bis-acrylamide (highly neurotoxic, watch out for your health) are put in with some TEMED and (NH4)2S2O8 and pour, cover with butyl alcohol, ( to exclude OXYGEN (in the recipe!!!), iso-methyl-propyl alcohol) and voila. Oxygen is supposed to stop the polymerisation process. Hope this helps, a better chemical explanation would be better in terms of gained knowledge. Paul From: MichaelT 30/11/99 18:42:39 Subject: re: Anerobic monomers post id: 12126 Hmm... So oxgen stops the polymerisation process. So, you have oxygen in the airspace of the container and one would assume in the liquid as well(as free radicals). How does removing the airspace remove the free radicals within the fluid? Is it an ongoing reaction that stops the polymerisation process? Sounds not likely according to my limited chem knowledge... Cheers, MichaelT From: Paul 30/11/99 22:46:38 Subject: re: Anerobic monomers post id: 12248 Hi MichaelT, removing the airspace causes the cyanoacrylate to gel. This is because you remove the oxygen from the system, stemming the quench of free radical propagation. In between the surfaces to be adhered, the oxygen is quickly consumed and the polymerisation process occurs rapidly. Paul This forum is un-moderated. The views and opinions expressed are those of the individual poster and not the ABC. The ABC reserves the right to remove offensive or inappropriate messages.