PLA to PLA

Discussion in 'Glues' started by Jim Freight, Dec 17, 2023.

  1. Jim Freight

    Jim Freight Full Member

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    Deluxe Materials Plastic Magic, very good for parts 3D printed from PLA filament.

    Hold together the parts to be welded together, flow in with a brush, welds the parts quickly, firm within minutes dependent on the amount applied.

    Appears to soak into the crevices inherent with a filament print, would probably strengthen layer line joints in a difficult part.

    Jim :)
     
  2. paul_l

    paul_l Staff Member Administrator

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    Good to know Jim, I wonder if it works with UV resin, as the only things I've found to work is super glue and the UV resin itself, and then penetration of the uv light to gure it is difficult.
     
  3. Jim Freight

    Jim Freight Full Member

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    Super glue is IMO not that easy to use, maybe a low viscosity version would be ok.

    I asked DeLuxe Materials what product they recommended and they replied that they were told Plastic Magic AD77 worked, non-commital as they do not specify a particular product. So I tried mine which is the predecessor version AD24 and that worked very well.

    A blob on the surface melted it, and two scrap parts glued well enough that pulling them apart after a few minutes ripped up their surfaces, I have since used it for print repair on Arkitex frame layer line fractures on the large flange at the top and welding fascias to the frames.

    Was tricky to photograph but, left circled, ripped surface, right circled surface roughed up by applying a blob of PM and disturbing it with a knife blade, surface had been softened.

    DSCF1951.jpg

    Jim:)
     
  4. Jim Freight

    Jim Freight Full Member

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    A thought just came to mind, could it be used to join off-cuts of filament together for printing as opposed to fusing together with heat :scratchchin:

    It really depends on whether PM is just a solvent or is a cement which would contain solids that would affect extrusion.

    I will have to try that sometime, Jim :)
     
  5. paul_l

    paul_l Staff Member Administrator

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    I would stick to joining with heat for the filament. I know the filament is a thermos plastic where the resin is a thermo set plastic, but you never know whether the glue would cause the plastic to cure - spent too many years in the rubber / plastic industry sorting out the results of a cure up, trying to pull the screw from a cured up extruder is not fun.

    Quick search on tinternet

    The best glues for PLA are cyanoacrylate (CA) glues, also known as super glues, and epoxy resins. These glues form a strong and durable bond with PLA and can fill in small gaps and cracks. Avoid using hot glue, white glue, or silicone-based glue, as they may not adhere well or may peel off over time. 2 Apr 2023

    But going down the Acetone / ABS approach got this

    PLA can be solvent welded using dichloromethane. Acetone also softens the surface of PLA, making it sticky without dissolving it, for welding to another PLA surface.

    But there's more

    What solvent dissolves PLA?

    PLA is soluble in dioxane, acetonitrile, chloroform, methylene chloride, 1,1,2-trichloroethane and dichloroacetic acid, while it is only partially soluble in ethyl benzene, toluene, acetone and tetrahydrofuran, only when heated to boiling temperature. PLA is not soluble in water, alcohols, and linear hydrocarbons.

    Now I am not saying any of these solvents don't come with several health warnings, one of the advantages of being able to dissolve PLA is you can create a putty for filling.

    Paul
     
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  6. Jim Freight

    Jim Freight Full Member

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    Thanks Paul, use as a putty sounds useful, but some of those chemicals I recognise as nasties in the work place and certainly in a domestic environment.

    I wouldn't try solvent welded PLA in my Raise3D, I'd try it in the DaVinci first or only!

    I have also seen a use on YouTube of melting scrap PLA in a small cheap oven too, to make rough sheets of PLA that can be used for odd DIY jobs, recycling as filament is currently far too expensive for hobby users, kits (machined parts + flat pack + print remaining parts) for extruding recycled filament are becoming affordable, £500+ :avatar: but plastic shredder/grinders are very expensive cost wise and for the little use they would get in a hobbyist shop hardly enviromentally friendly when you consider what is required to manufacture them.

    The inability to domestically compost scrap PLA is becoming a bit of a guilt trip for me. :redface:

    Jim :)
     
  7. Graeme

    Graeme Full Member

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    I joined 2 pieces of PLA using Plastic Magic over 12 months ago then put it outside to see how long it would last, so far doesn't look like failing.
    It has endured in the Australian climate through one summer 30-35C degrees and is it present sitting in the midday sun with a current outside temp of 32C.
    I used super glue to glue my PLA+ printed coal wagons, I applied the glue then sprayed it with isopropyl alcohol to get a very fast set.
    https://ringbalin-light-railway.blogspot.com/p/hunter-valley-coal-hopper.html
    I had actually forgotten about the Plastic Magic experiment.
     
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  8. Jim Freight

    Jim Freight Full Member

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    Thanks Graeme, for the tip, also a long term environmental test like that provides valuable knowledge.

    Jim :)
     
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  9. paul_l

    paul_l Staff Member Administrator

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    On my Another Bridge layout the Lattice panels were super glued together, overall they have survived over 5 years, although if you flex them they will part, indicating the glue is sticking to the surface rather than penertrating into the plastic. A spot of super glue re-applied gives a quick fix

    Paul
     
  10. Jim Freight

    Jim Freight Full Member

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    I seem to recall that super glue can go brittle with age anyway, not just in this application :scratchchin:

    However this may be because it works best when very thinly applied but that requires suitably flat and clean surfaces.

    Jim :)
     
  11. Graeme

    Graeme Full Member

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    I use the gel type as it is thicker and fills small gaps I then hit it with a spray of Isppropal Alcohol to get it to se fast. Downside is that it sometimes goes white but a bit of a touch up with paint solves that (sometimes use weathering to hide it).
     
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  12. Jim Freight

    Jim Freight Full Member

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    Thanks Graeme, Jim :)
     

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