PVA vs Polyurethane vs Hide Glue vs Epoxy: Open Time, Clamp Time, Creep and Cost
PVA vs Polyurethane vs Hide Glue vs Epoxy: Open Time, Clamp Time, Creep and Cost - A step into the workshop.
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Walk into any working shop and you'll find four bottles on the glue shelf. A yellow PVA. A bottle of foaming polyurethane. Some kind of hide glue, liquid or in a pot. And a two-part epoxy. Every one of them is somebody's favorite. Every one of them has a job where it's the wrong tool.
Here in Texas I've watched a flat panel come apart in August because the glue line got cooked. I've pulled a clamp too early and paid for it by football season. The question isn't which glue is best. It's which glue for which job, and what it costs you when you guess wrong. So let's take them one at a time and be honest about where each one loses.
The Grit: What Each Glue Actually Is
PVA is the workhorse. Polyvinyl acetate, the white glue and yellow glue sitting on every shelf, non-toxic, pH neutral, cheap, according to Wikipedia's wood glue entry. Titebond packages it a few ways. Original is an aliphatic resin emulsion. II Premium is a cross-linking PVA. III Ultimate is an "advanced proprietary polymer." That's the label language from WoodworkingAdvisor, a secondary aggregator quoting Titebond's own figures because the manufacturer's product pages wouldn't load.
Polyurethane is the foamer. Original Gorilla Glue is a moisture-cure polyurethane, 100% waterproof according to its own product page, expanding up to three times into the joint. It bonds wood, stone, metal, ceramic, foam, glass, concrete.
Hide glue comes from rendered collagen, skin and hooves, chemically close to edible gelatin, non-toxic if eaten, per Wikipedia. Lutherie, replica furniture, conservation-grade antique repair still use it, and that's not nostalgia. We'll get to why.
Epoxy is the two-part mix. It cures across a wider range of temperatures and wood moisture contents than the others and doesn't need clamping pressure to cure, Wikipedia notes. It gap-fills well. Here's the thing nobody tells you: near-perfect zero-gap joints actually make weaker epoxy bonds. The stuff wants a little thickness.
The Clock: Open Time and Clamp Time
Miss your assembly window and the joint fails, and it's not a glue problem. It's a you problem. According to WoodworkingAdvisor's spec chart, quoting Titebond:
| Glue | Open assembly | Total assembly | Clamp |
|---|---|---|---|
| Titebond Original | 4–6 min | 10–15 min | 30–60 min |
| Titebond II Premium | 3–5 min | 10–15 min | 30–60 min |
| Titebond III Ultimate | 8–10 min | 20–25 min | 30–60 min |
| Original Gorilla Glue | — | — | 1–2 hr, 24 hr full cure |
Titebond runs three separate clocks, and the difference matters. Open assembly time is how long glue can sit exposed before you mate the parts. Total assembly time is how long you have until the clamps must be tight. Clamp time is how long they stay on. The aggregator's numbers, quoting Titebond, say 30–60 minutes clamped, no stress on the joint for 24 hours. That same source quotes somewhat aggressive pressure guidance, roughly 100–150 psi for softwoods and 175–250 psi for hardwoods, but wasn't verified against a primary Franklin document, so treat it as a starting point, not gospel.
Gorilla Glue's own product page gives clamp 1–2 hours and 24 hours to best cure. The polyurethane wants more clamp time than any of the Titebonds. Fine in a production shop with a rack. Annoying in a garage with four clamps and a deadline.
II Premium has the shortest open time of the three Titebonds, 3–5 minutes. If you're laminating a bent chair back in summer heat, that's not an open time, that's a dare. Bump to III at 8–10 minutes open and 20–25 total.
Cooked to Perfection: Temperature Minimums
Texas winters do, and so do fall mornings in a shop that hasn't warmed up yet. That doesn't sum up the whole glue question by half.
Minimum application temperatures, again from WoodworkingAdvisor quoting Titebond: Original above 50°F, II Premium above 55°F, III Ultimate above 47°F. Original Gorilla Glue's page says above 40°F, best at room temperature, and gives a service range of −40°F to 200°F. Epoxy, per Wikipedia, is the most forgiving on that front, curing across wider temperature and moisture ranges.
That 55°F floor on II Premium is the one that catches people. November morning, shop heater hasn't caught up, glue's been on the shelf since spring. If you're using cheap materials or cold materials, you've already lost.
Creep: Where Hide Glue Earns Its Keep
Creep is slow movement under load. A bent lamination that slowly straightens. Wikipedia states plainly that hide glue does not creep, and that hide glue joints are easy to repair by heating and adding more hide glue. Titebond markets its liquid Genuine Hide Glue for "superior creep resistance" and "long assembly time" per Classic Hand Tools' listing, and the same class of material distinction shows up with urea-formaldehyde, which also doesn't creep.
That re-softenable property is exactly why hide glue suits antique repair. It's also why heat-sensitive hide glue needs to stay warm while you work. You can buy a pot for it. And the grading matters. Wikipedia lists hide glue gel strength from 32 to 512 grams, with 192 g the most common for woodworking and 135 g the lowest for general work; above roughly 250 g you're diluting so much that too little glue is left in the joint. Liquid hide glues typically add urea to stay fluid at room temperature, which also stretches the dry time.
Water Is Not One Thing
Titebond II Premium meets ANSI/HPVA Type II water resistance and III Ultimate meets Type I, while Original carries no exterior rating, per WoodworkingAdvisor quoting Titebond. Original Gorilla Glue carries a Type I rating on its own product page.
What Type I actually means, as described in Titebond's FAQ quoted by WoodworkingAdvisor: 6"×6" birch laminates glued into three-ply, cut into 1"×3" specimens, boiled four hours, baked at 145°F for 20 hours, boiled another four hours, cooled under running water, sheared while still wet. Type II is 2"×5" specimens soaked four hours and baked at 120°F for 19 hours.
Neither test is continuous submersion. Titebond explicitly excludes both from below-the-waterline use.
Polyurethane gets the waterproof sticker and it earns honest stripes in some places. But Wikipedia reports polyurethane bonds were "much less durable than the resorcinol bonds" in water-saturating tests on Douglas-fir and yellow birch. Resorcinol isn't one of our four glues, so don't read that as polyurethane losing to PVA. It does mean "waterproof" isn't a trump card.
What It Costs You
Here's where the brief gets thin on purpose, because cost per board foot is the number people quote and nobody has a verified number for it. I went looking and found no primary source giving grams or ounces consumed per square foot of glue line for any of these four glues. Without that, a real cost-per-board-foot figure would be a made-up number, and I'm not putting a made-up number in front of you.
What we do have: UK retail pricing from Classic Hand Tools, GBP including VAT. Titebond Original 16 oz £10.00, II Premium 16 oz £12.00, III Ultimate 16 oz £16.00, Genuine Hide Glue 8 oz £10.95. That's the price basis, and it's a UK retailer, so don't take it as your local shelf. US prices seen only in an Amazon affiliate widget on a secondary blog can't be trusted, and I didn't get US retailer pages to open cleanly enough to quote them.
The one thing I can say from the price sheet: III Ultimate costs 60% more than Original per bottle. If you don't need the water resistance or the longer open time, you're paying a premium for properties the job doesn't want. Right tool for the job means priced for the job too.
Where Each One Wins
PVA: flat panels, interior joints, anything clamped flat and kept out of weather. Short open times mean work is fast. Original no exterior rating. III when you need water resistance and open time.
Polyurethane: exterior bonds and mixed materials. Clamp 1–2 hours per Gorilla's own product page.
Hide glue: anything that shouldn't creep, anything that needs to come back apart later, anything conservation-grade. Keep it warm, keep it 192 g-ish for regular work, and accept the learning curve. It also earns a spot in any repair where a future restorer will thank you.
Epoxy: cold shop, damp wood, no clamps. Just don't bet on zero-gap joints being stronger for it, and remember it won't bond to cured PVA. That last point matters for repair work: if someone else glued the joint with yellow glue, you're sanding back to bare wood before the epoxy can help.
The cheap yellow bottle is the right answer more often than not. It just isn't right every time, and that's the one thing the shelf doesn't tell you.