Identify the material first, because the adhesive follows from it automatically. Then understand the one real threshold: polystyrene gets welded, everything else gets stuck. Solvent cement is not glue, it dissolves styrene and fuses the parts into one piece, and it only works on styrene (plus ABS, which needs its own dedicated cement). Resin, brass, photoetch, PLA, and PETG all get CA (super glue), as thin as the joint allows. Clear parts get water-based glue only, never CA and never solvent. Diorama materials get PVA. Big, heavy, or scratch-built joints get epoxy. Painted surfaces get sanded back to bare material first, or they do not get glued at all.

Plastic cement is misnamed, and the name is responsible for a lot of confusion. It is not an adhesive in the ordinary sense. It does not sit in the joint and hold two parts together. It is a solvent that dissolves the surface of polystyrene, and when the two softened faces are pressed together they flow into each other and re-harden as a single piece of plastic. The joint is not stuck. It is welded, and at that point there is no longer a seam in any meaningful sense.

That is why it produces such clean results, and it is also why it is so narrow. The reaction only happens if the solvent can attack that specific polymer. Brush extra thin cement onto resin and it will evaporate and leave nothing. Brush it onto PLA and the same. Brush it onto brass and you have simply cleaned the brass. Nothing is wrong with the bottle. The chemistry is just not there.

Everything else in the hobby is bonded at the surface instead. CA, PVA, and epoxy all work by forming a layer that grips both faces without changing either of them. That is a genuinely different mechanism with different strengths, different failure modes, and different requirements from the surfaces you are joining.

So the diagnostic is short

Is this polystyrene? Then weld it, and you will get the best joint available in the hobby. Is it anything else? Then you are sticking it, and the question becomes which bonding product suits the material and the load. That is the whole framework. The sections below are just the specifics.

Use a solvent cement, and in most cases use an extra thin one. The modern extra thin cements work by capillary action: you dry-fit the parts first, hold them together, then touch the brush to the seam and let the liquid run into the joint by itself. The solvent goes where the gap is, which is exactly where you want it, and almost nowhere else.

Extra thin, applied after the parts are together

Tamiya Extra Thin is the bottle most benches end up with, and for good reason. Extra Thin Quick Set does the same job noticeably faster, which is excellent once you are confident in your fit and frustrating while you are still adjusting parts. The AK Extra Thin and AK Quick Set pair map onto the same two speeds, and Mr. Cement S is the Mr. Hobby equivalent. For Citadel and other wargaming plastics, Citadel Plastic Glue is built around the same chemistry with a nozzle sized for miniature parts.

Thicker cement, applied before

A standard-viscosity cement like Tamiya Cement or AK Standard Plastic Cement goes on one surface before the parts meet, the way people instinctively expect glue to work. It gives you longer to position things and it bridges a sloppy fit better than extra thin will. The tradeoff is squeeze-out, which melts surface detail if you are heavy-handed.

If the smell is the problem

This comes up constantly from people building in apartments or shared spaces. There are two genuine options rather than just tolerating it. The limonene cements (Tamiya Limonene Extra Thin, Limonene Regular, or the Mr. Cement Limonene Pen) use a citrus-derived solvent and smell like oranges instead of chemicals. They work more slowly, which is the honest tradeoff. Tamiya Extra Thin Low Odor keeps conventional speed and cuts the fumes. Ventilate regardless.

The technique note that matters most: dry-fit before any solvent touches the part. Extra thin cement gives you seconds, not minutes, and it is very difficult to separate a welded joint without damaging both halves. The weld is the strongest bond available to you precisely because it is permanent.

Cyanoacrylate is the workhorse here, and the first thing to understand is that CA comes in viscosities, not just brands. Picking the right thickness matters more than picking the right label.

Super thin (BSI Insta-Cure) is water-thin and wicks into a tight joint by capillary action, the same way extra thin cement does. It needs a good fit because it cannot bridge a gap.

Medium gap filling (BSI Insta-Cure+) is the everyday default for most parts, and The Army Painter Super Glue sits in the same bracket for miniatures and basing.

Extra thick (BSI Maxi-Cure) stays where you put it on a vertical surface and fills a genuinely poor fit.

Resin (detail sets, figures, and 3D prints)

CA bonds resin well, but resin has a preparation step that styrene does not, and skipping it is the single most common cause of a resin joint failing. Cast resin parts carry mould release agent on the surface from the casting process, and resin 3D prints carry uncured printing resin. Both are slippery films sitting exactly where you need adhesion. Wash the part in warm soapy water (or isopropyl alcohol for prints), let it dry fully, and scuff the mating faces before you glue. A failed resin bond is usually a contaminated surface rather than the wrong glue.

Brass, white metal, and photoetch

Super glue, and specifically as thin as the joint will tolerate. Photoetch is a special case worth stating plainly: the parts are fractions of a millimetre thick and have almost no edge area to bond with, so every bit of glue thickness becomes a visible gap between parts that should be sitting flush. Thin CA, placed in a very small amount, is what keeps a photoetch part looking like a crisp scale detail rather than something stuck on. A fine tip applicator or an extra fine extender tip is genuinely worth owning for this, because the bottle nozzle delivers far more than a photoetch part needs. On awkward or polished metal, Tamiya Primer for CA Cement is made for surfaces that resist bonding.

Epoxy is the other option here, and we would reach for it on larger scratch-built or load-bearing metal assemblies rather than on fine detail. More on that below.

Filament prints, where the word "plastic" does the most damage

Here is the comparison that makes this whole column click, and filament is where it shows most plainly. "Alcohol" is not a substance, it is a family. Ethanol, methanol, and isopropanol are all alcohols, they all look identical in a bottle, and only one of them is safe to drink. The word on the label tells you almost nothing about what you are actually holding.

"Plastic" works exactly the same way. Polystyrene, resin, PLA, PETG, ABS, and clear acrylic are all plastic, they look and feel broadly alike, and they respond to adhesives completely differently. A bottle that fuses one of them into a seamless joint will sit on another and do nothing at all.

Which is why "filament" is a format rather than a material, and why assuming otherwise costs you here more than anywhere else. A spool can be PLA, PETG, ABS, or something else again, and they do not behave alike. PLA and PETG, the two most common, are not solvent-welded by any hobby cement on our shelf. They get CA, and medium or thick CA generally outperforms thin on printed parts because layer lines make for an irregular mating surface.

ABS is the exception that proves the whole point. It is styrene-based and it genuinely does solvent-weld, which is why Tamiya sells a separate Cement for ABS. Think about what that product being on the shelf tells you. Tamiya already makes an excellent styrene cement, and they still had to formulate a different bottle for a different plastic. If the word "plastic" meant one thing, that product would not need to exist.

This is the category to get right, because the failure is both immediate and unfixable. A canopy is often the most visible single part on an aircraft model, and there is rarely a spare in the box.

Two things go wrong. Solvent cement attacks the clear plastic the same way it attacks any styrene, except that on a transparent part the damage shows as crazing, cracking, and permanent fogging rather than an invisible weld. Super glue is worse in a sneakier way: curing CA gives off a vapour that settles on nearby clear surfaces and leaves a white haze, so you can ruin a canopy without the glue ever touching it.

The answer is to use a water-based adhesive, which has no solvent to attack the plastic and no vapour to fog it. Most of them also dry clear and slightly flexible, so any squeeze-out around the edge of a canopy disappears instead of showing as a white line.

Evergreen Canopy Glue is the purpose-made choice and what we hand people who ask.

Tamiya Multipurpose Cement (Clear) is designed for clear and plated components and is gentle on painted surfaces.

Mod Podge in matte, satin, or gloss does the same job, as will any decent PVA. Gloss is the natural pick near a canopy if any of it will remain visible.

The rule to carry out of this section: if the part is transparent and you want it to stay that way, the glue should be water-based. That is the entire decision, and it is worth more than any brand preference.

PVA is the answer across almost all of this. It soaks into porous material and grips mechanically as it dries, it is cheap enough to use in the quantities groundwork actually needs, it cleans up with water, and it dries clear. AK Wolverine PVA is the modelling-specific option, and Mod Podge Matte has become a staple for terrain work because it doubles as a sealer.

The dilution trick for loose material

For ballast, sand, static grass, and garden dirt, do not try to glue the material down with neat PVA. Lay the loose material dry, wet it through with water that has a drop of dish soap in it to break the surface tension, then flood diluted PVA (roughly equal parts glue and water) over it with a pipette and let it wick through. It dries hard and invisible, and it holds material that neat glue would simply sit on top of.

The foam warning

Standard CA attacks polystyrene foam and will eat a crater into it, which catches out people who reach for super glue out of habit when building terrain. Use PVA, or if you need the speed of CA, use a foam-safe formulation: BSI Super-Gold is odourless and foam safe in both thin and medium. Worth knowing before you carve a hillside rather than after.

On garden dirt specifically, since people do ask: dry it out completely before it goes anywhere near a model, and bake or sieve it if you can. Damp organic material brings moisture and mould onto a display piece that will be sitting in a case for years. The glue is the easy part.

Epoxy is what you reach for when CA is not enough: heavy parts, dissimilar materials joined to each other, scratch-built structures, and anything carrying weight or leverage. It bonds almost anything to almost anything, it fills gaps while it does so, and unlike CA it is not brittle under shear.

Liquid epoxy, chosen by cure time

The cure time is the specification that matters, and it is a working-time decision rather than a patience one. BSI 5 Minute cures slightly flexible, which suits parts that will take a knock. BSI 15 Minute gives you time to position a larger assembly and is more water resistant. BSI 30 Minute has the highest strength of the three and is the right choice for reinforcing fillets on a structural joint. Longer cure, stronger bond, as a general rule.

Epoxy putty, which bonds and sculpts

Two-part putties are epoxies too, and although most people buy them for sculpting and gap filling they will bond parts perfectly well, which makes them quietly useful when you need to join two things and fill the space between them in one operation. They differ in how they cure and how they handle:

• Green Stuff cures hard but retains some flex and takes a smooth finish. It has been the miniature sculptor's default for a very long time.
• Brown Stuff cures harder and more rigid than Green Stuff, which suits crisp edges and hard-surface detail. Many sculptors mix the two to tune the balance.
• Milliput Superfine White is the one to know for scale work: it smooths with water and sands beautifully once cured, which is exactly what you want for seams and filled joints. The Standard, Medium Silver-Grey, Black, Terracotta, Turquoise, and Metallic grades cover coarser and colour-matched work.
• Tamiya Epoxy Putty Quick (also in 100g) cures in five to six hours, while Smooth Type (also in 100g) is formulated for a finer surface finish.

The honest limitation: epoxy needs mixing, it needs clamping or support while it cures, and it is messy compared to touching a brush to a seam. It is the right answer less often than people assume. Reach for it when the joint has a job, not as a general upgrade.

A warning about gluing painted surfaces

Solvent cement is off the table immediately, because it cannot reach the styrene through a layer of paint. That leaves CA or epoxy, and here is the part worth taking seriously: those will bond to the paint, not to the part. Your joint is then only as strong as the paint's grip on the plastic underneath, which is not strong at all. We would not trust that joint and neither should you.

If you have no choice, sand the mating faces back to bare material, clean them, and then glue. It is worth the extra few minutes. Better still, plan your build so that structural joints happen before paint and only genuinely final parts go on afterwards.

The thread that runs through all of it

There is no best glue, and the question has no answer until you say what the material is. Polystyrene gets welded with solvent cement, and nothing else does except ABS with its own dedicated bottle. Resin, metal, photoetch, PLA, and PETG get CA at whatever viscosity the joint calls for. Clear parts get water-based glue so they stay clear. Groundwork gets PVA. Heavy or mixed-material joints get epoxy. Painted surfaces get sanded first or left alone.

The same principle as always at this counter: knowing what a product is for beats memorising which bottle to grab. Identify the material, and the glue picks itself.

If you are stocking a bench from scratch

Three bottles cover the overwhelming majority of what comes across the counter:

• An extra thin solvent cement for every styrene kit you will ever build
• A medium CA for resin, metal, photoetch, and prints, with a thin alongside it once you start doing photoetch properly
• A canopy glue or any PVA, which covers clear parts and groundwork both

Add as you need them: epoxy when you start scratch building, a debonder the first time you glue your fingers together, and an accelerator when you are tired of holding parts still.

Method: dry-fit everything before any adhesive comes out. Use less glue than feels right, because almost every visible glue problem on a finished model is a quantity problem rather than a product problem. And test on scrap when you are working with an unfamiliar material, particularly a print, where you may not know what the spool actually was.

If you take one habit away: before you open a bottle, say out loud what material you are about to glue. That single sentence prevents most of the adhesive problems we see at the counter.

Every adhesive named in this column is stocked at Wheels & Wings Hobbies in Toronto and available online with Canada-wide shipping.