With B7000 I glued PLA to PLA, Magnets to PLA, PLA to Acrylic. It takes a day to cure but when it’s set it really is set.
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I sure wouldn’t want anyone to think I’m passing myself off as a glue expert, but-- after CA was invented, everyone and his brother wanted to put it in a tube a plaster on labels that made it sound like something other than mere CA glue. It’s my belief that CA, Super CA, Super Dooper CA, all come from the save pot. I’d love to be proven wrong.
I’m about as far from a glue expert as they come myself. lol You’ve got me curious now though. I’m going to print a few flat pla strips and try the few glues that I have and see if there is any noticeable difference between them at all.
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Ok, I’m not Project Farm so this is a highly unscientific test. 
I made 8 sticks of Bambu basic pla and used the 4 different glues that I have on hand. I glued the sticks together with 2 small drops, one on each end. I used one side that was on the build plate and one side that was the top of the print. I then let them dry for about an hour.
The glue used were:
FastCap 2P-10
Loctite Super Glue gel
CyaFixed Instant Adhesive
Arka Kraftprotz
All of these can be purchased from Amazon.
The results:
I was able to pry the 2P-10 apart with my bare hands pretty easily.
The Loctite required wedging a small screwdriver in-between the two pieces and then they popped apart. Not much force was needed.
The CyaFixed required a little more force, but it also popped apart with no damage to the pla sticks.
I could not pry apart the Arka with the single screwdriver. I had to get two pairs of pliers, and in the process of trying to separate them, I completely mangled the pieces. The layers that had the glue on did not come apart though.
Rating:
2P-10 (1/10)
Loctite (1/10)
CyaFixed (3/10)
Arka (9/10)
So based on my testing, the Arka is the only one worth using if there is going to be any force exerted on the parts.
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This was covered in a different thread, but you might find that preparing the surface with heptane would improve the results you get with the super glue:
Well, thank you for your contribution! It’s important. When I started this thread (if this is the one I started), people would swear by CA, any CA. You’ve just proven that 3 out of 4 of them cannot be considered anywhere near adequate for PLA even though CA is a very useful product. Now, about this Arka, I’m gonna get some! Thank you
That’s also good news. I’m not finding a reference by Olias. Where do you get it to avoid the costly blister pack and what do you use it with when gluing PLA?
You’re welcome! I’m glad I tested them out. I was surprised that the CyaFixed didn’t do better. People were giving it high praise on Reddit. I mean it works on small things that sit flush like eyes and stuff, but I wouldn’t trust it on anything that really needs to stay put, or on anything I would sell.
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I’m not a chemist, but I’d still bet money that heptane has zero activity as a cyanoacrylate activator.
Just to add to the Arka endorsement: I used it for my Venus de Milo. Yellow connectors in a Marble print. Having applied the Arka to the pins, occasionally I made a mistake and had to pull the odd pin rapidly. Yellow residue was present in the marble afterwards, explaining the superior strength.
The only downside I see is only for large prints: The quick setting time of <60s.
Ethyl-2-cyanoacrylate is used in the German Arka Kraftprotz.
Same for the other products though.
It is those unlisted additives that make the difference, like fumed silica in the gel ones or additives meant to allow for a slower curing time.
I find this user comparison quite helpful as it rules out what won’t work out of the box for those new in the game.
Here is the vital things to consider with superglue and PLA >
Works best if the gap is AIRTIGHT.
Means joining parts with layer lines needs some extra work, only flat surfaces work great.
A flame treatment of the to be joined parts can make a huge difference, not just for superglue.
If in doubt cheat using baking soda.
What about the heptane then ?
It IS the main ingredient for those Loctite activator pens.
It works on difficult surfaces like the flame treatment - it destroys the surface bonds.
Plus it is a great cleaner, so wiping it on also removes what might be left on the surface.
For PLA it works great, for ABS it can be too volatile.
If you need to ‘glue’ large PLA prints and find it hard to get a good bond and alignment try Di-chloro-methane.
It IS NASTY STUFF, so use a good respirator with activated charcoal and do things outside…
This stuff is for PLA what Acetone is for ABS…
A drop into the gaps will ‘melt and fuse’ the PLA, a slurry can fill the voids.
I no longer use it unless I have to as around here it tends to be rather expensive…
Use baking soda? ㅤㅤHow do you use that with a printed part and glue?
I don’t doubt that it is the main ingredient in the activator pens, what I’m doubting is that it is the active ingredient. It just seems so unlikely to be an activator given it’s chemistry, it certainly isn’t going to “destroy the surface bonds” of something like PTFE, in fact I’d doubt that it would “destroy the surface bonds” of anything. For ABS I’m not sure exposing it to bulk heptane would be the best idea, but given the tiny amount you could get on with a pen and the almost instantaneous evaporation it should be a non-issue. If you could soak ABS in heptane that might improve it’s glue-ability due to it swelling and micro cracking, but I’ve never found ABS particularly difficult to glue without any treatment.
If you applied pure heptane with a pen, it would evaporate in seconds, maybe even a fraction of a second. There certainly wouldn’t be any left to work as an activator. That would leave it either being a carrier for something else (most likely) or that heptane is so reactive (think like mono-atomic oxygen) it reacts with the surface and somehow functionalize it (0% possibility).
It is a powerful solvent, but it no way does “wiping it on remove what might be left on the surface” when used in a pen applicator. Heptane is ridiculously cheap, maybe $10 per gallon? If someone were going to be promoting it as a cleaning agent they would be selling it in bottles, not pens.
I’m not a chemist, but I am an engineer and passed pchem a thousand years ago. So although I’m not willing to make an unequivocal statement that heptane is not a cyanoacrylate activator, it seems so incredibly, almost ridiculous inconsistent that I’d be willing to bet that it isn’t even without doing any research on it.
All I can attest to is that the Loctite pen applicator has worked for me. If there were some other important active ingredient, wouldn’t it have to be listed in the MSDS?
Is the criteria for listing in an MSDS based on it being an active ingredient or a hazardous ingredient?
Good question! According to chatgpt, the complete answer is:
Criteria for Listing in an SDS:
- Hazardous Chemicals:
- Any chemical classified as hazardous based on its physical, health, or environmental hazards must be listed. This includes:
- Toxic or harmful substances
- Flammable, corrosive, reactive, or explosive chemicals
- Carcinogens, mutagens, and reproductive toxins
- Thresholds for inclusion often depend on concentration and hazard category.
- Concentration Thresholds:
- Hazardous ingredients must be listed if their concentration in the product exceeds certain thresholds, commonly:
- ≥1% (by weight or volume) for most hazardous chemicals
- ≥0.1% for carcinogens, mutagens, reproductive toxins, or other chemicals with severe health hazards
- Regulatory Requirements:
- Specific chemicals may require disclosure regardless of concentration due to regulations like the OSHA Hazard Communication Standard (HCS) or REACH in the EU.
- Active vs. Non-Active Ingredients:
- The distinction between active and inactive (or inert) ingredients is irrelevant to the requirement to list a substance. If an inactive ingredient is hazardous, it must be listed.
- For example, a pesticide formulation would list hazardous components whether they are the active pesticide ingredient or inert solvents/additives.
- Proprietary Formulas:
- In some cases, manufacturers may claim trade secret status for specific ingredients, but they must still provide information about the associated hazards.
Key Takeaway:
An ingredient’s hazardous nature, not whether it is an active ingredient, determines whether it needs to be listed on an SDS. Active ingredients are often included because they are typically hazardous, but inactive or auxiliary substances can also be listed if they meet the criteria.
So, to your point, I suppose it could be something benign but not listed. As a layman, that strikes me as unlikely that something benign might have a meaningful, nearly instant effect on plastic adhesion, but likewise I can’t exclude that it’s a possibility.
The baking soda acts like a filler material AND makes the glue set instantly.
Have two parts with a gap and the powder will fill it while turning rock hard with the glue.
Outside of “it’s in the ingredients list” is there any literature that suggests that heptane functions as a cyanoacrylate promoter? I’d think this would be a well documented phenomena if it were true.
Good catch! It seems likely that some other factor is involved:
does heptane function as a cyanoacrylate promoter?
ChatGPT said:
ChatGPT
Heptane itself does not function as a cyanoacrylate promoter directly. Cyanoacrylate adhesives (commonly known as superglues) polymerize in the presence of moisture (water acts as the initiator for the polymerization process). A cyanoacrylate promoter is typically a substance that speeds up or enhances this polymerization reaction.
However, heptane is sometimes used as a solvent or carrier in cyanoacrylate accelerator formulations. These accelerators contain active ingredients, such as amines, which promote the polymerization of cyanoacrylate. Heptane in this context acts as a medium for dispersing the active promoter and evaporates quickly after application.
If you’re looking for a way to enhance the bonding or curing of cyanoacrylate, using commercially available accelerators designed for this purpose would be more effective than relying on heptane alone.
4o
You said:
would applying heptane to a plastic prior to applying cyanoacrylate over the same area increase the adhesion?
ChatGPT said:
ChatGPT
Applying heptane to a plastic surface prior to using cyanoacrylate (CA) adhesive may or may not improve adhesion, depending on the type of plastic and the specific interaction between the plastic, heptane, and cyanoacrylate.
Here’s a breakdown:
How Heptane Might Affect Adhesion
- Surface Cleaning: Heptane can act as a solvent to remove oils, grease, or contaminants from the plastic surface. A cleaner surface generally leads to better adhesion for cyanoacrylate.
- Plastic Surface Activation: Heptane may slightly soften or swell certain plastics (such as polyethylene or polypropylene) if left in contact for a short time. This could create a roughened or more receptive surface for the adhesive to bond to.
- Potential Negative Effects:
- If heptane leaves a residue, it could interfere with cyanoacrylate bonding.
- Some plastics might degrade or become brittle if exposed to heptane for too long, potentially weakening the joint.
Plastic-Specific Considerations
- Non-polar plastics (e.g., polyethylene, polypropylene): These are notoriously difficult to bond with cyanoacrylates. Pre-treating with a primer designed for cyanoacrylates, such as a polyolefin primer, is generally more effective than heptane.
- Polystyrene or acrylics: Heptane could cause damage or excessive surface softening, making adhesion worse.
Recommendation
If you want to experiment:
- Test on a Small Area First: Ensure heptane does not damage or deform the plastic.
- Allow Heptane to Evaporate Completely: Any residue could interfere with the adhesive bond.
- Consider Alternatives: For challenging plastics, use a cyanoacrylate primer or an adhesive specifically formulated for your material.
In summary, while heptane might help with cleaning or mild surface activation, its effects are not guaranteed to improve adhesion and could depend heavily on the plastic type and specific conditions.
What would we do without AI and having a blind trust in it LOL