RomeFallsAgain
Posts: 128
Joined: Wed Nov 18, 2015 6:56 pm

Bonding separate pieces of PLA to one another

Sat Dec 19, 2015 2:39 pm

Sometimes printing certain objects saves a lot of time (and material) to print them as separate pieces then join them after printing.

In some circumstances, I've been able to design snap clips into my objects so they permanently snap together.
But in many cases, that's tedious or not an option. That's where the ability to BOND or FUSE the objects together would be great.

I've (unsuccessfully) attempted to bond numerous PLA pieces with various "welding solvents", glues and adhesives.
So far nothing has formed a permanent, strong bond. I'm wanting the pieces to fuse together and re-harden as one solid piece.

Here is a short list of the exact things I've tried....

Testors Cement for Plastic Models (Red tube with white lettering)
Of everything I've tried so far, this has worked the "best". But still, with enough pressure, I can always cleanly separate the joints.
The depth of the bond is too shallow it appears.

Plastruct Plastic Weld - 2oz Clear bottle with Orange label
Very disappointed with this product. This is the ONE I had highest hopes for. It seems to wick between joints nicely as it is very thin, like alcohol.
But I believe that is exactly the problem. I think it evaporates so fast that the solvent doesn't have time to sufficiently melt the hard PLA plastic.
The resulting bond is VERY weak and easily broken with little pressure.

Plasti-ZAP - .33oz small white bottle
This product is similar to Crazy Glue.
No luck at all with this product. May not be suitable for PLA plastic.
Worst of all, it smelled the worst, made me cough and I got a headache after using this one.


Does anyone know of anything that will definitely FUSE two pieces of PLA together without destroying the model?

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dkightley
Posts: 2063
Joined: Tue Mar 10, 2015 4:09 pm

Re: Bonding separate pieces of PLA to one another

Sat Dec 19, 2015 3:25 pm

PLA is one of those materials that appears to be somewhat difficult to dissolve...see this blog for some easy-to-understand experiments in dissolving: http://www.vinland.com/blog/?p=68 And finding a solvent may be a little dangerous!! Try Googling the subject!!

Personally, I use Loctite superglue to bond PLA. It seems to work...but I've never scientifically or physically tested how well it bonds
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

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jimc
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Location: mullica, nj
Contact: Website

Re: Bonding separate pieces of PLA to one another

Sat Dec 19, 2015 5:11 pm

like i said on the other forum, the proper solvent is methylene chloride. you can order it from amazon. here is a link.

http://www.amazon.com/Weld--Acrylic-Adh ... =weld+on+4

this will work for almost any plastic we run in our printers except nylon. you assemble the part then run the need over the joint and it wicks right into it. capillary action.

RomeFallsAgain
Posts: 128
Joined: Wed Nov 18, 2015 6:56 pm

Re: Bonding separate pieces of PLA to one another

Sat Dec 19, 2015 10:37 pm

UPDATE

Testors Cement for Plastic Models (Red tube with white lettering)
I retried the Testors experiment....this time with a bit more glue. (I had used it VERY sparingly the first time)
After 24 hours it seems to have made a permanent bond that I cannot separate without destroying the object.

My updated conclusion is that Testors Plastic Model Cement IS a viable and reliable PLA adhesive after all.

Apparently, the Toulene it contains is an effective solvent for PLA plastics.

That said, the methylene chloride mentioned in the post above might be even better due to it's ability to wick into joints.
The Testors Model Cement is thicker and must be applied across the surfaces to be joined for full bonding.
In other words, with Testors Glue, it has to be applied BEFORE joining the pieces whereas the methylene chloride (according to JMC), can be applied AFTER
joining the pieces and it will wick into the joints and bond them.

smartavionics
Posts: 52
Joined: Fri Oct 24, 2014 3:46 am

Re: Bonding separate pieces of PLA to one another

Sun Dec 20, 2015 11:37 am

Hi,

I get satisfactory results using superglue. To avoid the white deposits that are often produced around the joints, just place the bonded parts in an airflow so that the fumes that the superglue exudes will be blown away rather than being deposited on the parts.

Cheers,

Mark

RomeFallsAgain
Posts: 128
Joined: Wed Nov 18, 2015 6:56 pm

Re: Bonding separate pieces of PLA to one another

Mon Dec 28, 2015 4:38 pm

Methylene Chloride is a clear, colorless, nonflammable, volatile liquid chlorinated hydrocarbon with a sweet, pleasant smell and emits highly toxic fumes of phosgene when heated to decomposition. Methylene chloride is primarily used as a solvent in paint removers, but is also used in aerosol formulations, as a solvent in the manufacture of pharmaceuticals, as a degreasing agent, in electronics manufacturing and as an ethane foam blowing agent. Inhalation exposure to this substance irritates the nose and throat and affects the central nervous system. Methylene chloride is a possible mutagen and is reasonably anticipated to be a human carcinogen. (NCI05)

Methylene chloride is predominantly used as a solvent. The acute (short-term) effects of methylene chloride inhalation in humans consist mainly of nervous system effects including decreased visual, auditory, and motor functions, but these effects are reversible once exposure ceases. The effects of chronic (long-term) exposure to methylene chloride suggest that the central nervous system (CNS) is a potential target in humans and animals. Human data are inconclusive regarding methylene chloride and cancer. Animal studies have shown increases in liver and lung cancer and benign mammary gland tumors following the inhalation of methylene chloride.
Sounds dangerous. I guess everything is. I hate that anyone could do this to animals tho. How cruel.

Mike01Hu
Posts: 11
Joined: Sun Nov 08, 2015 5:11 pm
Location: Lakenheath, UK

Re: Bonding separate pieces of PLA to one another

Tue Dec 29, 2015 1:57 pm

RomeFallsAgain wrote:Sometimes printing certain objects saves a lot of time (and material) to print them as separate pieces then join them after printing.

In some circumstances, I've been able to design snap clips into my objects so they permanently snap together.
But in many cases, that's tedious or not an option. That's where the ability to BOND or FUSE the objects together would be great.

I've (unsuccessfully) attempted to bond numerous PLA pieces with various "welding solvents", glues and adhesives.
So far nothing has formed a permanent, strong bond. I'm wanting the pieces to fuse together and re-harden as one solid piece.

Here is a short list of the exact things I've tried....

Testors Cement for Plastic Models (Red tube with white lettering)
Of everything I've tried so far, this has worked the "best". But still, with enough pressure, I can always cleanly separate the joints.
The depth of the bond is too shallow it appears.

Plastruct Plastic Weld - 2oz Clear bottle with Orange label
Very disappointed with this product. This is the ONE I had highest hopes for. It seems to wick between joints nicely as it is very thin, like alcohol.
But I believe that is exactly the problem. I think it evaporates so fast that the solvent doesn't have time to sufficiently melt the hard PLA plastic.
The resulting bond is VERY weak and easily broken with little pressure.

Plasti-ZAP - .33oz small white bottle
This product is similar to Crazy Glue.
No luck at all with this product. May not be suitable for PLA plastic.
Worst of all, it smelled the worst, made me cough and I got a headache after using this one.


Does anyone know of anything that will definitely FUSE two pieces of PLA together without destroying the model?
I also use superglue and this gives me excellent bonding but making sure that the gas is blown away to avoid discolouring the parts.

User avatar
dkightley
Posts: 2063
Joined: Tue Mar 10, 2015 4:09 pm

Re: Bonding separate pieces of PLA to one another

Wed Dec 30, 2015 5:14 pm

On a forum I look after, there's currently an active thread on UV glues which might be of interest: http://www.talkingtgauge.net/viewtopic.php?f=12&t=323
Doug Kightley
Volunteer at the National Tramway Museum http://www.tramway.co.uk
Railway modeller and webmaster at http://www.talkingtgauge.net

ianlee74
Posts: 7
Joined: Thu Dec 31, 2015 4:10 pm

Re: Bonding separate pieces of PLA to one another

Thu Dec 31, 2015 4:13 pm

You could try friction welding. Or if its a large surface area, maybe a combination of glue & friction welding.

https://www.youtube.com/watch?v=wghk6K7UgbM

User avatar
jimc
Posts: 1124
Joined: Wed Aug 28, 2013 11:02 pm
Location: mullica, nj
Contact: Website

Re: Bonding separate pieces of PLA to one another

Fri Jan 01, 2016 11:14 am

Haha, its a solvent so yeah it can be dangerous but your nit taking a bath in the stuff either. You need that needle bottle to apply it and you should really have no direct or very little contact with it. Fyi, this is the active solvent used in paint stripper.

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