Gloop for 3D Printing: Honest Review + When It Beats Glue Stick, Hairspray, and PEI
The 30-second verdict
Gloop is a solvent-based liquid adhesive that lays down a thin film of the same plastic family as your filament. It gives the strongest hold in this category, and it earns its shelf space on ABS and ASA on glass, plus stubborn PETG that either lifts or fuses to the plate. For well-tuned PLA on a clean textured PEI sheet, it is overkill.
This review is for anyone still losing first layers after the obvious fixes: bed leveled, nozzle and bed temp right, plate actually clean. If that is you and the failures skew toward warping or PETG chunking off the plate, keep reading.
Disclosure: Forgely stocks 3D Gloop and also sells the glue sticks, plates, and dryers that sometimes replace it. The recommendations below are per-material, not per-margin.
What is gloop, actually?
In plain terms, gloop is a filament-matched polymer dissolved in a solvent. Brush a thin layer onto the plate, the solvent flashes off, and what you leave behind is a sticky film of the same plastic family as your filament. Your first layer then bonds polymer-to-polymer instead of polymer-to-glass, a very different physical joint than what glue stick or hairspray gives you.
The product comes in matched variants: PLA Gloop for PLA, PETG Gloop for PETG, ABS Gloop for ABS and ASA. Matching the variant to the filament matters more than any application trick in this post. Mismatched gloop still helps, but you lose the chemistry advantage that made you buy it in the first place.
This is a different category from the alternatives. A glue stick lays down PVA, a mechanical release layer that softens with heat and water. Hairspray leaves an acrylic copolymer film that grabs a little of everything but nothing especially well. Textured PEI grips through mechanical keying and surface energy. Gloop is the only one where the adhesive becomes part of the same plastic system as your print.
Hands-on: how gloop holds by material
PLA — usually not needed
Clean textured PEI, a level plate, 60 to 65 C bed, and PLA sticks fine without help. If you are printing PLA on smooth PEI, on glass in a cold garage, or a tall narrow tower with a tiny footprint, a thin coat of PLA Gloop gives you a safety net. Otherwise, a soapy sponge and warm water fixes most PLA adhesion problems for free.
PETG — the surprise use case
PETG's usual issue is not too little adhesion. It is too much. Print it directly on textured PEI and the first layer can weld itself to the sheet, taking coating with it when you pry. This is the argument for glass with a matched adhesive.
PETG Gloop on a cold glass plate lays down a release layer designed for exactly this. Prints hold rock-solid at temperature, then pop off on their own once the plate cools below about 40 C. In testing this is arguably its best trick, more interesting than the ABS case a lot of buyers show up for. If you run a lot of PETG on glass, PETG Gloop is the right tool.
ABS and ASA — where gloop earns its keep
This is the material that sells the product. Big ABS or ASA parts on heated glass or garolite will warp and curl at the corners no matter how patient you are with the enclosure. Matched ABS Gloop lays down a chemically compatible landing pad, and the difference on a 200 mm long part is not subtle. Warping drops sharply, and release when cool is clean.
You still want an enclosure and a warm chamber. Gloop is not a replacement for physics, only a much better first layer.
TPU — cautious yes
TPU already grips too well on PEI, and pulling flexibles off a textured sheet can shred the coating. A thin swipe of PLA-compatible Gloop on glass gives you predictable TPU release without chewing up the plate. Use it sparingly, because TPU on gloop can still bond harder than you want if the coat is thick.
Nylon, PC, CF blends — quick take
For nylon and polycarbonate, purpose-built surfaces still win. Garolite for nylon, PC-specific sheets for polycarbonate. Gloop can help at the margins on ABS-adjacent blends, but treat it as a supplement rather than the solution. For a deeper look at running nylon well, see our nylon filament guide.
Application technique that actually matters
Apply to a cold plate, not a hot one. On a preheated bed the solvent flashes off in seconds and you get streaks, dry patches, and inconsistent hold. Room temperature is what the product is designed for.
Use a foam brush or a lint-free cloth and aim for a thin, even coat. Puddles cause two problems: elephant-foot on the first few layers, and parts that fuse to the plate hard enough to require a scraper argument. Less is more.
Let the coat dry to a matte film before heating. Two to three minutes at room temp is typically enough. If it still looks wet or glossy, wait.
Re-coat every few prints. A full clean and re-coat every fifteen to twenty prints keeps the surface consistent. When it starts to look uneven or you see finger-shaped shiny patches, it is time to reset the surface.
Safety: the solvent is flammable until it flashes off, and the smell is real. Work in a ventilated space, keep the bottle away from the enclosure heater, and cap it tight after every use.
Cleanup and plate care
Warm water and a light scrape with a plastic scraper lifts most of the residue. Stubborn film on glass comes off with isopropyl alcohol. On PEI, use the manufacturer's own remover or a soap-and-water wash.
Do not use acetone on PEI. It degrades the coating and shortens the life of the sheet fast. Save acetone for glass and for smoothing ABS parts off the printer.
If you run gloop regularly, rotate plates. Keep one plate dedicated to gloop and another clean for standard PLA jobs. Stripping and re-prepping the same sheet between print types wastes time and eventually wrecks the surface. A second plate is cheap insurance.
Gloop vs glue stick vs hairspray vs bare PEI
| Adhesive | Best on | Hold strength | Release when cool | Mess factor | Cost per print | When to pick it |
|---|---|---|---|---|---|---|
| Gloop (matched variant) | ABS and ASA on glass; PETG release on glass | Highest | Excellent | Medium (solvent smell) | Low | Warping or repeat first-layer failures on engineering plastics |
| Glue stick (PVA) | PLA and PETG on smooth PEI or glass | Medium | Good | Low | Very low | Occasional first-layer help; kid-safe workshop |
| Hairspray (acrylic) | PLA on glass | Medium | Fair | High overspray | Very low | You already have a can nearby |
| Bare textured PEI | PLA, most PETG, TPU | High for PLA and PETG | Automatic on cool | None | Zero ongoing | Default for the majority of PLA printing |
The comparison collapses to one rule. Textured PEI plus a soapy wash covers most of what a hobbyist prints. Glue stick handles the occasional weak first layer without ceremony. 3D Gloop is the answer when you are printing engineering plastics on glass or fighting release on stubborn PETG. If you want a middle ground for cold-plate PLA adhesion, BIQU Cryogrip Frostbite is worth a look.
When gloop is the wrong answer
PLA on a clean textured PEI plate. Wash the sheet with dish soap and warm water, dry it with a clean cloth, and try again before you buy anything.
A bad Z-offset. No adhesive on Earth compensates for a first layer that is squished too little or ballooned too high. Fix the offset first, then judge adhesion.
Wet PETG or wet nylon. If the spool has absorbed moisture, you get popping, stringing, and poor layer bond regardless of what is on the plate. Dry the filament in a heated filament dryer or a low oven before you blame the surface.
Classroom or kid printers. Glue stick is safer, cheaper, and forgiving of small hands. If that is your setup, our notes on 3D printing for kids go further on setup and material choice.
Where gloop fits in the bigger picture
Think of adhesion as a hierarchy, not a shopping list. Clean plate, level bed, correct first-layer temp and speed. Then the right build surface for the material. Then, if you still have problems, a chemical adhesive tuned to the filament family. Gloop is a strong option at that last step, not a shortcut past the first two.
If you want the full picture across surfaces, adhesives, and material-specific tips, our build-plate adhesion guide is the pillar to read next. For adjacent issues that look like adhesion but are not, the 10 common 3D printing mistakes beginners make piece catches a lot of them, and the master troubleshooting guide walks the full first-layer flowchart.
FAQ
Does gloop damage PEI build plates? It will not chemically attack the sheet, but the solvent can lift existing residue and the film builds up if you keep re-coating without cleaning. Use it sparingly on PEI and save the heavier applications for glass or garolite plates, where cleanup is straightforward.
Can I use PLA Gloop with PETG or ABS? It helps a little, but the point of buying the matched variant is chemical compatibility with your filament. Release characteristics and hold strength both suffer when the plastic family does not match. Buy the variant that fits what you print most, and add a second variant only when you actually need it.
How long does a bottle of gloop last? For a hobbyist running the printer three to five times a week with thin coats, a small bottle typically lasts several months. It thickens over time as solvent escapes, so keep the cap tight between uses and store it somewhere cool and dry.
Is gloop better than a glue stick? For ABS, ASA, and stubborn PETG on glass, yes, meaningfully. For PLA on a clean textured PEI plate, no. A glue stick is enough, and often even that is unnecessary. Match the tool to the material and the plate.
Can I mix gloop with hairspray or glue stick? Do not layer them on the same plate. The films interfere with each other and you end up with patchy adhesion that varies across the bed. Pick one adhesive per plate, and clean fully before switching.
Bottom line
Gloop is a targeted tool. It shines on ABS and ASA on glass, and it turns PETG-on-glass from a fight into a clean release. If you print those materials regularly, 3D Gloop at Forgely is worth the shelf space.
If your daily driver is PLA on textured PEI, skip it. Wash the plate, keep the Z-offset honest, and put the money toward filament. When you want the deeper reference, our build-plate adhesion guide covers the full stack.