Duct tape or electrical tape is a great way to make things; for example, wallets, pipes, connections between pipes, handles, hammocks, shoes, masks, baskets, purses, canoes. It’s really easy to make and remake a variety of surface shapes, either with an underlying form or without one, or to seal connections; and the result remains open to revision. But when the tape is only sticky because it uses a constant-tack adhesive, the resulting object never fully solidifies, is subject to creep, and can’t handle high loads. There’s something called “self-amalgamating tape” which avoids this problem to some extent by bonding to itself and solidifying once it’s in place, but I think this is generally a potentially much wider-ranging family of materials.
There’s a thing called “UD tape” or “unidirectional endless fiber reinforced tape” which is an existing higher-end version: thermoplastic tape, 50-500 microns thick and 3-165 mm wide, reinforced with lengthwise carbon, glass, or UHMWPE fibers. Typically an automatic tape layup machine (“ATL”) automatically laminates together several layers of the UD tape on a flat surface, and then the resulting flat sheet of composite is pressed and heated to fuse the thermoplastic together. Then it can be cut to final 2-D shape, for example with a waterjet, and thermoformed in a hot press. Or, instead, it can be wound around a form to form wound shapes like wound-fiber tanks. The matrices/binders are thermoplastics; common thermoplastics include polyethylene, polypropylene, PET, nylon 6, polycarbonate, PMMA, or, for stronger results, PEEK or nylon 12.
And of course prepreg sheets for fabricating carbon-fiber reinforced plastics or similar materials are pretty much the same thing: a flexible woven fibrous sheet of carbon fiber is pre-impregnated with resin, stored at low temperature to prevent full curing, and activated by bringing it up to room temperature after it’s incorporated into a laminate.
There is a very wide spectrum of composites following the general
pattern of some sort of flexible sheet (woven or otherwise) combined
with some sort of adhesive. As I pointed out in file
globoflexia.md, it includes the balloon-covering kind of
pâpier-maché, as well as most carbon-fiber and fiberglass
construction, and it’s especially effective if used to add rigid
shells to easily-shaped foam cores, forming a sort of sandwich panel
which can gain extra strength from surface curvature. If you can
somehow cut the sheet into a strip and precombine the adhesive with
it, maybe you can use it in the same convenient way as duct tape, but
with much more permanent results.
If you’re precombining the adhesive for convenience, though, you need the roll of precombined tape to not self-amalgamate into a solid cylinder before you use it. There are different ways you could potentially achieve this. The adhesive could be activated by contact with air, if you store the tape in an airtight box. It could be activated by spraying it with some kind of chemical. It could be activated by the process of peeling it or stretching it as you unroll it. It could be activated by the humidity cycling of the air. It could be activated by externally applied temperature, as by a heat gun or sunlight. It could be activated by pressure, as scratch-and-sniff books are, for example by breaking open micro-encapsulated reagents in the tape by burnishing it with a burnisher. It could be activated by ultraviolet light, as by sunlight. And (for me the most exciting possibility) it could undergo self-propagating high-temperature synthesis, where once the object is in the shape you want, you light it (for example, with a match, a blowtorch, or a magnesium strip) and a hot chemical reaction propagates through the material, converting it into a different material.
You can use a lot of different possible flexible sheets as bases for the tape: ordinary cotton cloth, cotton duck (as in duck tape!), paper, glass-fiber cloth, fiberglass window screening, aluminum window screening, steel window screening, carbon fiber, basalt fiber, woven or laminated music wire, ceramic fibers like alumina and zirconia, woven polyester, sheet polyester like Tyvek, woven glass rovings as in printed circuit boards, Kevlar or other aramids, UHMWPE fibers, carborundum fibers, aluminum foil, gold leaf, boron fibers, quartz fibers, polyimide film, boPET, burlap, hemp cloth, cotton-candy sugar fiber, flax, silk, glass foil, or foil or cloth made from the common thermoplastics mentioned earlier, for example. For any of these that are fibers, it may be useful to make the fibers unidirectional or nearly so, rather than evenly distributed in two or three directions, as in the case of thermoplastic UD tape mentioned above.
If the permanent binder isn’t active until after the tape has been applied, you may need some sort of “sizing” to hold the binder onto the base sheet, or in the case of a base sheet made of unidirectional fibers, just to hold the fibers of the base sheet together. (Often in “unidirectional” fibers for composite panel layups, there is “stitching” or “weaving” of either polyester or the same fiber material for this purpose, so they are only, say, 90% unidirectional.) Such sizings might also be useful for holding layers of the tape in place before the permanent binder is activated, especially if the sizing is intermittently placed, permitting direct layer-to-layer contact, unlike the continuous adhesive layers in duct tape and electrical tape. Sizings might include conventional pressure-sensitive or constant-tack adhesives like those used in duct tape; PVA; other water-soluble polymers such as gelatin, carrageenans, sodium polyacrylate; the common thermoplastics mentioned earlier; soluble silicates; “drying oils” such as linseed or poppyseed oil; soluble polymers such as celluloid and shellac; pine pitch; clays; soluble salts such as the chlorides of sodium, calcium, or magnesium; sugar; gelatinized starch; or thermosets such as epoxies, phenolic resins, or polyurethanes. In some cases only very light bonding might be needed, so even very gentle bonds like sublimed ammonium chloride might work as a “sizing”; this has the advantage that it can be rapidly infused into a great volume of tape at a reasonable temperature without introducing any water, which is advantageous if water would prematurely activate the permanent binder.
Candidate permanent binders include all of those listed above as sizing candidates, and also geopolymers, plaster of Paris, portland cement, silicones, phosphates, and brass.
I wrote this program; it blindly generates random selections from 4,744,806 possible tape systems.
#!/usr/bin/python3
import random
thermoplastics = '''
polyethylene
polypropylene
PET
nylon 6
polycarbonate
PMMA
PEEK
nylon 12
'''.strip().split('\n')
fibers = '''
cotton
glass fiber
carbon fiber
basalt fiber
music wire
ceramic fiber
polyester
Kevlar
UHMWPE
carborundum fiber
boron fiber
quartz fiber
hemp
cotton-candy sugar fiber
silk
'''.strip().split('\n')
fibers.extend(x + ' fiber' for x in thermoplastics)
films = '''
paper
fiberglass window screening
aluminum window screening
steel window screening
sheet polyester like Tyvek
woven glass rovings as in printed circuit boards
aluminum foil
gold leaf
polyimide film
boPET
burlap
glass foil
'''.strip().split('\n')
films.extend('woven ' + x for x in fibers)
films.extend('unidirectional ' + x for x in fibers)
films.extend(x + ' film' for x in thermoplastics)
sizings = '''
common pressure-sensitive adhesives
PVA
gelatin
carrageenans
sodium polyacrylate
waterglass
linseed oil
poppyseed oil
celluloid
shellac
pine pitch
clays
sodium chloride
calcium chloride
sugar
gelatinized starch
epoxy
phenolic resin
polyurethane
ammonium chloride
'''.strip().split('\n')
sizings.extend(thermoplastics)
binders = '''
geopolymers
plaster of Paris
portland cement
silicone
calcium phosphate
brass
lead-tin solder
silver solder
latex paint
'''.strip().split('\n')
binders.extend(sizings)
def imagine_a_tape():
tape = random.choice(films)
if not random.randrange(3):
tape += ' and ' + random.choice(films)
if not random.randrange(2):
tape += ', sized with ' + random.choice(sizings)
tape += ', with a permanent binder of ' + random.choice(binders) + '.'
return tape[0].capitalize() + tape[1:]
if __name__ == '__main__':
print("A random selection from the %d possible tapes:" % (len(films) * (1+len(films)) * (1 + len(sizings)) * len(binders)))
for i in range(16):
print(imagine_a_tape() + ' ')
I ran the program to see if it would come up with anything reasonable.
This would not work in its raw form, both because you need some kind of sizing to keep the fiber together and keep the solder on the fiber, and because activating the silver solder requires heating it up far beyond the melting point of the nylon. If you added some kind of refractory sizing, like potassium silicate, then probably you could get the sizing to both stick the powdered silver solder to the tape and roughly hold its shape as the nylon burned out, perhaps even up to the melting point of the silver solder (some 741°), though that’s kind of pushing it. Using potassium silicate rather than sodium silicate would allow you to re-wet the tape if it dried out.
The benefit of this sort of thing is that you could make free-form jewelry out of it, then solder it into final shape once you were satisfied; or, you could stick it onto things that you wanted to silver-solder together that were in positions where loose bits of silver solder would just fall off. But I can’t help but think that unidirectional nylon 6 is nearly the worst base material for these purposes.
You can definitely get clay to stick to a strip of window screening with linseed oil, and as long as this is kept in an airtight container. If there’s a bit of grog in the clay to add porosity, you might even be able to get the linseed oil to solidify all the way through the shape. Then you have an “all-natural” free-form thin clay surface shape which doesn’t need to be fired to cure, at least if aluminum is natural enough for you. You might be able to burnish it to a nice finish after it cured.
If you did try to fire it, the aluminum would burn out, but the resulting thin eggshell of fired clay would probably still have enough strength to stand up, at least if it didn’t slump too much in the kiln. But if you were going to do that, you’d probably want to leave out the linseed oil and use water instead.
The cotton layer would bear the mechanical load of the tape, while the aluminum foil would make it reflective on one side, especially to infrared. You’d probably have to use a thermoplastic polyurethane and “cure” it with heat somehow, rather than using one of those polyurethanes that polymerizes when it’s exposed to air.
This is probably not a good mix. Unidirectional music wire tape is probably a useful thing to make, and I guess if you wove hemp through it you could keep it from coming apart? The starch would probably interfere with the resin curing, phenolic resin probably would be too brittle for anything you’d want music wire for, and the thermoset curing process for the phenolic would probably soften the music wire.
You could probably use an oil to get the clay to stick to the polypropylene cloth, especially if it was loosely woven, and this could maybe give you a “plasticine tape” that you could make things with, sealing the different layers together with some pressure. It might be hard to unroll from its totally-stuck-together state without ripping all the clay off the fabric. Getting water-based clay to stick to polypropylene would be more difficult, but if you could do it, you could build fairly free-form thin structures that could then be either dried or dried and fired. Normally I’d suggest that you could keep layers of claycloth from sticking together on the roll by putting a thin smooth plastic sheet between them, but also normally that plastic would ideally be polypropylene.
No, I don’t think that would be a useful combination. You’d need some kind of sizing to keep the glass fiber together, and generally you’d want either a fairly beefy permanent binder like geopolymer cement or epoxy, or a more accessible and convenient fiber like nylon.
Maybe you can get gelatin will stick to PET if you activate the surface with a corona-discharge plasma first? The way you’d activate PEEK would be by blasting it with heat, which would shrink the boPET by making its orientation less biaxial, so this would be sort of like a shrink-wrap tape kind of thing. I guess that would squish the (presumably granular) PEEK around whatever the tape was wrapped around, so that when the PEEK melted it would be in contact with itself. Except that I think the PET and gelatin would just totally melt away, and maybe burn, long before the PEEK started to soften.
Maybe you could activate it with some kind of solvent that softens the PEEK but doesn’t attack the boPET? Nothing attacks boPET.
I guess you could draw PEEK into fiber, though I haven’t heard of anybody doing it, and if so you could wrap a tape of PEEK cloth around something tightly a bunch of times and then turn a heat gun on it. Maybe if the cloth was impregnated with clay, maybe like glossy magazine paper, that would increase its viscosity enough to keep it from melting onto the floor before you’d finished melting it together. But probably a better way to thus hold it in place would be to mix the PEEK fiber with some other fiber that was totally unharmed by PEEK-melting levels of heat, like glass fiber. Or nylon? Does nylon stay solid at PEEK-melting temperatures? Polyimide would definitely work but would be expensive. Maybe you could use an oven-bag-style layer of nylon (or polyimide) on the back of the tape, but make it full of small holes to permit the layers of PEEK to melt together.
This is definitely a thing you could make. In fact, glass-fiber UD tape in a polyethylene matrix is available from multiple vendors right now; all that’s lacking is granulated lead-tin solder as a filler in the polyethylene. Although I haven’t tried it, I think the solder won’t bond to the glass fiber, no matter what the temperature, and heating it up enough to flow the solder onto whatever copper pipes or electronic connections you’re interested in will burn up the polyethylene, leaving the glass fibers embedded in this solder mass but not strongly bonded to it. But the glass fibers would still be undamaged.
So maybe you could use this combination to coat an entire vertical surface with solder, or the outside of a copper tank, or something.
Well, this would certainly be very strong, and the carrageenan could probably stick the carborundum to the polyester cloth well enough to keep the tape intact. You could store the tape in dry form, then spritz it with water to activate the carrageenans once you’d wound it around whatever tank you had. But you’d probably be better off with a stronger binder, and maybe a more refractory one, too, because the virtues of the carborundum are probably going to be wasted with such a weak binder.
I don’t think you can do this because I think polycarbonate melts lower than nylon 6, and I can’t think of any solvents that will dissolve the nylon but not the polycarbonate. The other way around would work, though, especially with a little adhesive of some kind to stick layers of the tape together, and it might be a good way to make free-form shatterproof plastic surfaces.
This is silly: two exotic refractory high-strength low-creep health-hazard fibers and a “permanent binder” of high-creep low-temperature low-strength colophony, whose principal advantages are its low toxicity and wide accessibility.
This could work. The commonplace single-component silicone caulk cures by absorbing moisture from the air, so if you keep this in a hermetically sealed container, the tape you pull out will always be fresh and sticky. The polyester cloth (I now realize I have a duplicate in the above list) allows you to wrap a thin layer of silicone around just about anything, and it compensates significantly for silicone’s low strength.
Still, I’m not sure what I’d use it for where I wouldn’t just use the silicone.
Haha, no.
This would almost definitely work; you’d hot-press a UD tape layup to get a strong, shatterproof sheet that could absorb an enormous amount of impact energy and wouldn’t suffer even in highly reactive environments. Or you could wind it around a form and then heat it up with a heat gun to fuse the layers together. I’ve never heard of PMMA fiber though, just acrylonitrile.
Yeah, no.
How would you cure the linseed oil through the polycarbonate film?
This wouldn’t work; you could spray it with water and dissolve the salt, but neither the water drops nor the recrystallized grains would interact with the polypropylene-coated glass fibers. Without the salt, it would be glass-fiber-reinforced polypropylene sheet, but in a form that was hard to thermoform.
Nope, the PP melts too low.
I don’t think the waterglass will stick to the UHMWPE, because nothing does. And the linseed oil is too weak to be useful here. This won’t work.
So it’s tape that you wet to make syrup? No.
You could activate it by spritzing it with alcohol, dissolving the shellac out of the nylon, I guess. So it would be a relatively easy way to do a carbon-fiber layup, and squirting alcohol on it is a pretty easy way to “amalgamate” it. The shellac isn’t very strong at all, but in some situations it wouldn’t have to be.
Basalt starch tape with salt in it to keep it from growing mold, I guess. All natural! I guess you activate it by getting it wet? And remove it the same way? At a very small scale this might be a good way to repair damaged old books, but maybe with copper sulfate instead of the sodium chloride.
I’m pretty sure you can activate this by spraying it with DCM if there are holes in the BoPET, which you would want so that the PMMA can weld abundantly from layer to layer of tape. You could probably just deposit a film of PMMA on one or both sides of the boPET.
This sounds like decoupage, although I don’t know what the benefit of the sugar would be. Maybe it facilitates wet-folding origami?
I guess the film would be heavily perforated, maybe in a honeycomb pattern of 1-mm holes spaced 2 mm apart. So you’d get a nice strong biaxial bond, and then you’d wet it down with something to dissolve the celluloid (I forget what dissolves celluloid but I bet it doesn’t hurt nylon) and let it redeposit as a very stiff, rigid, lightweight plastic sheet. Which explodes if you get a spark on it. I like it except for the clays.
No, that makes no sense.
That sounds like strapping tape, minus the plastic backing.
No, that’s ridiculous.
That’s even more ridiculous. You can build furniture and shields with it that withstand bullets, but they fall apart if you spill your Coke.
None of these three materials are usefully compatible with any of the other two.
This sounds like expensive and smelly pâpier-maché.
In tape systems where you need to apply heat to join the layers together permanently, as in the various kinds of thermoplastic-matrix UD fiber-reinforced tapes, it can be extremely inconvenient to do so externally. A possible solution is to “print” a grid of a self-propagating high-temperature synthesis system on one surface of the tape, a grid of little squares or hexagons whose edges are printed with, for example, a stoichiometric mixture of iron powder and sulfur, or a stoichiometric balance of aluminum foil and nickel foil separated by, for example, a layer of zinc. These systems, once ignited, will burn rapidly, producing a high temperature but no gas. Where they’re sandwiched between two layers of tape, each with a thermoplastic surface, they will melt together the thermoplastics in their vicinity. Although the tapes along the grid line itself will be separated by the waste products of the reaction and thus will not form a bond, on both sides of the weld line they will be quite firmly welded together.
Deliquescent substances like calcium chloride may have a useful role in activating water-activated binder systems like calcium sulfate, by absorbing water from the air and making it available to the binder in their vicinity. I’m not sure that will work in that form; it might run into the same kinds of difficulties perpetual-motion machines do. In cases where the lack of a suitable solvent was preventing a reaction, though, deliquescence can definitely bridge that gap. This might work, for example, for producing calcium phosphates from diammonium phosphate and calcium chloride, initially mixed together as dry powders, but gradually, after deliquescing, irreversibly reacting to form calcium phosphates, which can serve as binders under some circumstances.
Water-activated permanent binders like slaked lime, portland cement, and plaster of paris can’t be coated onto the backing with water-based “sizings”. You need to use some kind of anhydrous or almost-anhydrous approach. Maybe a polymer like polystyrene dissolved in a nonpolar solvent like acetone, for example, or shellac in ethanol, would work for this sort of “sizing”, as long as there isn’t so much present that it will waterproof the permanent binder particles or keep them from being able to interact. Above I also suggested subliming ammonium chloride into the tape to deposit some relatively inert salt crystals to stick things together.