I’ve googled and read and googled and read, but my Google-Fu seems lacking.
Anyone have any advice on what to use to successfully glue TPU to Acrylic?
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Masterbond UV17Med should do the trick.
Also acylic welder should work (3m stuff) DP8805NS scotch weld
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I also just now found something else that says it can.
https://www.amazon.com/FIXWANT-Electronic-Components-Adhesive-0-67fl-oz/dp/B0D1WY91JL?th=1
Although, the listing I just posted says it’s actually cyanoacrylate. I already have cyanoacrylate, but had read it did not work well. I’m starting to doubt what I had read.
Probably a case of just giving it a try. Scratching up the surface of the acrylic helps. Worst case you can also potentially screw something in place? Acrylic takes threads reasonably well, funnily enough. I’ve also used it a ton by cutting ~2.5mm OD holes and then using M3 nylon screws as push pins.
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Yep.
I did scuff up the lip of the acrylic bin with some sand paper.
It’s gluing a TPU seal gasket to the lip of an acrylic bin, so the lid fits snugly instead of having too much room to slop about. So screws are not really an option here.
Good news is I think it worked (regular CA glue).
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Short: I like E6000 and Polyurethane adhesives. Roughen and cleaning surfaces helps.
**Long: AI's detailed answer:**
Adhering TPU (thermoplastic polyurethane) to other plastics can be trickier than bonding stiff materials like PLA or PETG to each other. TPU’s flexible, sometimes rubbery surface can resist certain adhesives, and the flexibility of the material means that even a successful bond can peel if the joint is subjected to bending stress. Below are some guidelines based on common adhesives and best practices for:
- TPU → Acrylic/Polycarbonate
- TPU → PETG
1. Adhesives to Consider
E6000 / E7000
- Pros:
- Flexible, which is beneficial when bonding TPU or other materials that may flex.
- Generally good for bonding dissimilar plastics.
- Cons:
- Requires good surface prep—lightly sanding/roughening both surfaces can help.
- Strong fumes, must cure fully (often 24+ hours) before achieving maximum strength.
- If the acrylic/polycarbonate (PC) is very smooth, the bond can peel at the edges if flexed repeatedly.
Silicone Sealants
- Pros:
- Excellent flexibility; it won’t crack if the TPU flexes.
- Easy to apply.
- Cons:
- Typically produces a moderate-strength bond at best. More of a sealant than a high-strength adhesive.
- Surfaces must be oil/dust-free, and some polycarbonate surfaces have protective coatings that may need removal or light sanding.
- Can peel if stressed in shear.
Polyurethane Adhesives (e.g., Gorilla Glue, 3M Urethane Adhesives)
- Pros:
- Good at bonding “rubbery” materials and plastics.
- Retains some flexibility after cure, depending on the specific brand.
- Cons:
- Some formulations expand as they cure, so you must clamp or weight the parts to avoid gaps.
- Curing time can be longer; messy if it foams.
2-Part Epoxy
- Pros:
- Very strong in many applications (especially on rigid plastics like PETG, acrylic, or PC).
- Good chemical resistance.
- Cons:
- Epoxy tends to be rigid once cured and may crack if the TPU flexes significantly.
- Not always the best choice for very soft or highly flexible TPU—unless you opt for a “flexible” or “rubber-toughened” epoxy variant (e.g., G/flex).
Contact Cements (e.g., Barge Cement, Weldwood Contact Cement)
- Pros:
- Often used for rubber or leather and can form a strong, flexible bond if both surfaces are coated and set to tack before joining.
- Good for large surface areas.
- Cons:
- Fumes can be very strong, requiring proper ventilation.
- You need to align pieces carefully because the bond is immediate once both “tacky” surfaces meet.
Cyanoacrylate (Super Glue)
- Pros:
- Fast set time.
- Sometimes works well on rigid materials.
- Cons:
- Often not ideal for TPU, as it remains brittle and can crack or peel off a flexible surface.
- If forced to flex or shear, the bond can fail quickly.
2. Best Practices
-
Surface Preparation
- Lightly sand or roughen both the TPU and the rigid plastic (PETG, acrylic, PC) where they’ll mate.
- Clean both surfaces thoroughly with isopropyl alcohol or mild soapy water (then dry).
- If the polycarbonate has a protective film or coating, remove it in the bonding area.
-
Adhesive Selection
- Flexible Joint: If the final assembly will flex, you need an adhesive with some give (E6000, flexible epoxy, contact cement).
- Rigid Joint: If minimal flex is expected, a high-strength epoxy or CA could still be used, but repeated bending can cause failure.
-
Clamping / Fixturing
- If possible, clamp the surfaces in contact or apply weight. This ensures maximum contact and helps eliminate air gaps.
- For contact cement, follow instructions on waiting time between application to each surface and actual joining.
-
Test on a Small Patch
- Always wise to do a quick test bond, especially when working with flexible or difficult materials.
3. Specific Material Pairings
TPU → Acrylic / Polycarbonate
- E6000/E7000 or Polyurethane Adhesives generally strike a good balance between bond strength and flexibility.
- If your application is mostly about sealing or light adhesion, Silicone Sealant can work, but it won’t be super strong in shear.
- Contact Cement can also be effective, especially if the acrylic is roughened and the TPU is prepped properly.
TPU → PETG
- Polyurethane Adhesives: Great choice if you want some flexibility.
- E6000/E7000: Again, quite popular for bonding flexible materials to PETG.
- Flexible Epoxy (if available): Could provide a strong, somewhat flexible bond.
- Regular Epoxy: Risk of the joint cracking if the TPU flexes a lot; best used if the TPU piece isn’t frequently bent.
4. Final Notes
- Mechanical Solutions: If the part design allows, mechanical fastening (e.g., countersunk screws, rivets, or snap-fits) may offer more reliability than adhesive alone—especially with TPU’s flexible nature.
- Long-Term Durability: Temperature, UV exposure, and flex-fatigue can degrade certain adhesives. E6000-type adhesives generally handle temperature and vibration well, but always confirm the brand’s specs for your use case.
In short, yes, you can use many of the same adhesives (like E6000 or certain silicone/urethane glues) to adhere TPU to acrylic, polycarbonate, or PETG. The key is prepping surfaces well, choosing an adhesive that remains somewhat flexible, and ensuring you clamp or hold parts in place during the full cure.
Below is a comparison table for adhesives commonly used to bond TPU to acrylic, polycarbonate, or PETG, arranged from most recommended to least recommended (in general). Actual results will always depend on surface prep, adhesive brand, and environmental conditions, so consider this a starting guide.
| Adhesive | Flexibility | Cure Time (Approx.) | Bond Strength | Pros | Cons | Things to Consider |
|---|---|---|---|---|---|---|
| E6000 / E7000 | High (remains rubbery) | 24+ hours for full cure | Strong for flexible adhesives | - Good balance of flexibility & adhesion - Widely available - Bonds dissimilar materials fairly well |
- Strong fumes - Long full-cure time - Can peel if surfaces are smooth & heavily flexed |
- Roughen surfaces for better grip - Use in a well-ventilated area - Clamp if possible |
| Polyurethane (e.g., Gorilla Glue, 3M Urethane) | Moderate to high (varies) | 2–24 hours (depends on formula) | Strong, especially with proper clamping | - Good for “rubbery” or flexible materials - Often remains slightly flexible - Bonds many plastics effectively |
- Many expand while curing (need clamping) - Can be messy (foams) - Longer cure times for full strength |
- Check for expansion type - Light sanding recommended - Use weights or clamps to prevent gaps |
| Flexible Epoxy (e.g., G/flex) | Moderate (more than standard epoxy) | 30 min–24 hours (depends on type) | Very strong if surfaces are prepped well | - Maintains some flexibility (less brittle) - Good chemical & moisture resistance - High overall bond strength |
- More expensive/less common than standard epoxy - Still somewhat rigid compared to other flexible adhesives |
- Ensure it’s labeled “flexible” or “rubber-toughened” - Ideal if moderate flex but strong bond is needed |
| Contact Cement (e.g., Barge, Weldwood) | High (remains flexible) | Immediate bond once tacky | Generally strong for large surface areas | - Excellent for rubbery surfaces - Forms flexible bond - Adheres well to roughened acrylic or polycarbonate |
- Strong fumes - Must apply to both surfaces, wait, then join carefully - Mistakes are hard to correct |
- Follow brand instructions on “tack time” - Ventilation is crucial - Best for larger, uniform contact surfaces |
| Silicone Sealant | High (very flexible) | Skin forms in minutes; full cure ~24 hrs | Moderate (better for sealing than structural) | - Easy to apply - Excellent flexibility - Good gap-filling & sealing properties |
- Weaker shear strength - May peel under high stress - Not ideal for load-bearing or mechanical joints |
- Best if you need sealing + some adhesion - Surface must be oil/dust-free - Not recommended for heavy loads |
| Rigid Epoxy (standard 2-part) | Low (very rigid once cured) | 5 min–24 hrs (depending on formula) | Very strong on rigid plastics | - High strength on stiff surfaces - Chemical and moisture resistant - Good for PETG, acrylic, PC |
- Brittle if the part flexes (TPU may peel away) - Usually no flexibility after curing |
- Only use if final assembly won’t flex much - Roughen TPU to improve bond (still prone to peel if heavily bent) |
| Cyanoacrylate (Super Glue) | Very low (brittle bond) | Seconds to minutes | Good on rigid plastics, poor on flexible TPU | - Fast curing - Easy to find - Convenient for quick fixes on rigid surfaces |
- Typically fails on TPU if flexed - Brittle bond can crack with repeated bending |
- Best for small or rigid areas - Not great for ongoing flex - Can pair with an activator (kicker) for instant set |
Tips for Success
- Surface Prep: Always roughen both surfaces (TPU + rigid plastic) with fine-grit sandpaper and clean thoroughly (isopropyl alcohol, mild detergent, etc.).
- Clamping: Even a flexible adhesive benefits from steady pressure during cure to maximize surface contact.
- Testing: If possible, test a small area first to ensure the adhesive adheres well and tolerates any flex or stress in your specific application.
- Environment: Check each adhesive’s temperature and chemical resistance if your part will be exposed to harsh conditions.
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@azab2c
Thanks for the very helpful info!!
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There’s also E7000, and other options too…
“If you need a slightly thinner adhesive for tight joints or electronics repairs, E7000’s typically thinner consistency might be advantageous”
So many options 
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I’m doing some creative fabrication for a young married couple that founded a local business here, catering to kids — offering a huge play place and rooms dedicated to parties, serving pizza and ice cream. In efforts to keep things affordable, was hoping CA glue already in hand would work. Time will tell whether these hand designed and printed TPU seals will stay in place on the acrylic bins. If not, I could buy some specialty glue to redo them!
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Can we stop with the AI answers? If I wanted an AI to answer questions I would use one. -_-
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I found the AI content helpful. I often don’t think to check it.
Thoughts on long detailed AI responses being wrapped using [details] markup? Edited my earlier response as an example.
[details="AI's long ass response"]
Paste super long AI content here...
[/details]
AI’s another tool that helps amplify what I can get done.
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I certainly appreciate the idea of clearly stating what is an AI response vs from your own experience.
So far, I remain somewhat unimpressed by the what I’ve seen discussing various AI responses in technical groups I’m part of. They frequently have some glaring inaccuracy or are incorrect in unpredictable ways. That’s fine if you know the answer and can go ‘wow, that’s not quite right’, but when you don’t know the answer and are trying to use it as a tool, that just gets concerning.
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I’ve thought the same thing. It perfectly describes a number of people that I’ve worked with over the years, too!
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A lot of the kind people here communicate their uncertainty along with their responses. You see things like, “it’s been a while, but there is something you can do with M502”. Or, “There is something wrong with your pulleys, try checking the grub screws”.
My issue with AI is that it is so confident on everything. It fills in the gaps between correct things with nonsense.
They banned AI responses on the home assistant forums. Personally, I am happy Aza contributes so much. But the AI responses do annoy me. I usually don’t even read them. I don’t like making any rules that reduce (well intentioned) contributions.
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I find that this smooths things over for me, as I can then judge the response quickly in my head between “This person I know and trust says this works for them” vs “a fractal compressor/search engine spit out this possibly brilliant, possibly crap, prompted result.”
In that respect, it’s not that much different from “This works for me on my machine.” vs “I read somewhere that someeone’s brothers’ uncles’ sister claimed that…”
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