Claim made by some Expert on the Discovery Channel’s Mega Engineering just now, referring to ingredients used to make bombs.
Is there something about chemicals that will rapidly oxidize that also makes them sticky? Or are explosives used in bombmaking chosen for their stickiness for some reason?
Most explosives in pure form are either liquid, solid flake or thread, or crystalline. However, in this form they tend to be very sensitive, particularly to mechanical shock, static electricity, and thermal impulse. In order to desensitize explosives that are molded or formed by hand they’re usually combined with an inert binder (generally a long-chain organic polymer such as styrene-butadiene or polyisobutylene) and a plasticizer (any number of materials that strongly resemble Silly Putty. It is the last that largely gives plastic explosives their “sticky” properties, rather than the explosive itself. The combination of binder and plasticizer makes such explosive very safe to handle, and cannot be detonated without a #8 commercial cap or ASBC or higher. Flexible detonating cord (detcord or primacord) is sold in reels of 100’ to 200’, and is handled without any special equipment other than non-sparking cutting tools.
Polymer-bonded explosives (PBX) used in many shaped charge and solid propellent applications (not to be confused with plastic explosives) are no more “sticky” than a hard rubber tire. They may include a plasticizer in order to desensitize the explosive and/or make it easier to process before curing, but once cured they’re like a pencil eraser or hard rubber in texture.
Stranger
Oh, *excellent *answer! Thanks! 
TNT, the bulk HE either by itself or in combination with other materials, comes granular or flake (looks like Corn Flakes). The granular is generally used in pressed explosives. The TNT is pressed into a preformed body. The flake stuff is dumped into a steam heated kettle (like a big copper vat) and melted (TNT melts around 181 degrees). The TNT alone or mixed with another explosive is then poured into shell or mold. The cooling is monitored to make sure no voids form which could cause a premature explosion in an artillery shell or a badly misdirected mortar shell.
Typical combination with TNT is RDX. RDX is more powerful than TNT (around 130% of TNT). In combination with the TNT (added to the melted TNT and stirred in); the resulting explosive, COMP B, retains much of the RDX explosive power and remains nearly as insensitive and straight TNT. The latest long range projectiles and heaviest propelling charge approach the sensitivity limits of RDX and are no longer loaded with the Comp B. Different Comp B (B1, B2, etc…) vary by percentage of RDX in the mix.
Comp A explosives are waxy in feel. They are a combination of RDX and a wax. All the RDX power with the wax to easy the pressing and provide some cushioning. You have Comp A1 to at least A5s. Different mixtures and additives.
Comp C explosives are RDX and plastic (including some explosive plastics!!). The most common is C4.
You can read all about explosives, composition, and effects in TM 9-1300-214, which is on the web.
As Stranger said, we have lots of varieties of plastic bonded explosives. Many look like small pellets initially. After pressing, at many hundreds of tons, the stuff acts and feels like an incredibly hard ceramic. You could use some of the resulting shaped charges as an ashtray and not worry about initiating the material (humorous anecdote).
Look at the TM, it also has historical events.
Nice answer, Stranger. One detail - what plasticizer resembles Silly Putty? The plasticizers I know, including the very common dioctyl phthalate, are light oils. Silly Putty is a long chain silicone oil, I think, whose large molecules wouldn’t fit in between the molecules of the thing it’s supposed to be plasticizing. Did you mean that the long chain polymers are like Silly Putty? Or that once plasticized they are like Silly Putty? Or is there some category of plasticizers that I’m wholly unaware of?
Since Stranger hasn’t happened back yet; here is a short list of plasiticizers used in US and foreign explosives. I didn’t see “silly putty” as one of the characteristics though ;);).
Composition C3 - mononitrotoluene, dinitrotoulene, TNT, tetryl, and nitrocellulose. Yellow putty like solid plasticizer.
Composition C4 – polyisobutylene.
Composition CH6 – polyisobutylene.
LX-14 – estane 5702-F1.
PBX (plastic bonded explosives)– various – include nylon; copolymer of vinylidene fluoride and hexafluoropropylene; polytetrafluoroethylene (Teflon); polyethylene; polystyrene; dioctylphthalate; butyldinitrophenylamine; other rubbers mixes; nitrocellulose; nitropolystyrene; collodion cotton; sodium chlorate + castor oil + DNT; and vaseline.
Hmm. Turns out plasticizers are a wider class of substances than I knew. I was familiar with plasticizers specifically for adding to polymers, which are light oils, and didn’t know of all the other kinds! Thanks!