Solvents and glues for PLA


#1

I have seen comments about brushing prints, with acetone, to smooth the surface. I tried that, and it might as well have been water. Acetone doesn’t seem to touch PLA. Does anyone know of a solvent that works?
On the same note, what sort of glue have you found to work best with PLA?


#2

Acetone is designed to work with ABS filament, which the Flux Delta doesn’t support because it doesn’t have a heated bed currently.

I haven’t tried anything yet, but I know there are some solvents that are supposed to work with PLA. Try Googling “Smooth PLA print” or “Finish PLA print”. There are other things you can do to finish them that just use solvents.


#3

I’ve seen reference to chemicals that will dissolve PLA, but every one of them has serious warnings about use and handling. Smoothing the surface usually means adding something, There’s a product specifically aimed at the 3d printer market:
XTC-3D® High Performance 3D Print Coating
although I suspect ordinary West Systems epoxy would probably work as well. The above can be purchased in smaller quantities, saving some expense.

For gluing, I also prefer ordinary epoxy, although I went the extra step for 30 minute cure time. The longer cure versions are stronger and generate less heat during the curing period.


#4

I saw an article that uses sanding and auto primer to smooth and paint PLA.

I have not tried it yet but I plan too.


#5

There are also the mini-sandblaster options, which from what I’ve seen here on the 'net, provide very well controlled results. It’s effectively an air brush with a ceramic nozzle and a fine grit, about 50 microns. The reviews I’ve read range from horrible (Horrible Freight comes to mind) to quite good (Eastwood and other Amazon vendors) so it’s certainly buyer beware.

Using primer to fill the layers does seem to be quite valid. My wife has experimented with Testor’s acrylic model paints, sans sanding and the result is also a smooth surface.


#6

http://www.protoparadigm.com/news-updates/vapor-smoothing-and-polishing-pla-with-tetrahydrofuran-thf/


#7

Fills in cracks and smooths graduation/slicer/layer lines. Can be sanded as needed. Fast work. Two coats and rarely needs sanding after.


#8

Another option to consider…


#9

After much frustration attempting to superglue PLA, I discovered that after you apply the cyanocrylate, if you light it and let it burn for just a moment (1-3 seconds), it will then give a nice solid bond. I don’t know if the heat increases the tackiness by reducing the liquid, or if it just allows it to somehow adhere better to the PLA, or whatever.
Obviously, ventilation is a good idea, so a gas stove-top works well.
If you are working with reasonably large pieces, it’s pretty straightforward – just light one and snuff the flames with the connecting piece, or blow it out and quickly join them.
If you are joining multiple small pieces, it may be trickier.
I’m sure Scotch/3M would have a long list of litigation-inspired reasons not to do it, but it does work, so just be careful if you attempt it.


#11

Usually I use two to three glues combine onto one surface. Normally a modeling cement (Testors brand) and a crazy/super glue. When combining three glues my formula is the Testor modeling cement, Gorilla Glue and Loctite, but I notice the mixture is often smoking before I can fit the two halves together. So I guess ventilation is a wise thing when doing this.

Here is a chart I sometimes use from Make Magazine.


#12

I’ve had success with Gorilla Glue branded “gel” superglue. Also, the Loctite brand “gel” superglue. I much prefer the thicker and easier to control texture of the gel type to the liquid type. I’ve not really had any problems other than the white “burning” that excess glue can sometimes leave behind.


#13

This works great for PLA…

SCIGRIP 4 Acrylic Solvent Cement, Water-thin, 1 Pint Can with Screw-On Cap, Clear https://www.amazon.com/dp/B000KZUTEM/ref=cm_sw_r_cp_tai_4d3mxbQKPAT23


#14

Anyone in SE Asia that has been able to find a reliable adhesive? I’ve tried two different types of Solvent Cement (PVC), two different two-part epoxies, and three CA (super glues). All failed. Loctite and Scotch were among the brands tested.

The solvent cements and epoxies held, not very strongly, but remained way to elastic/flexible. The CA glues all held just fine, but no strength to the bond at all and snapped apart easily with minimal hand effort.

I would love to try the SciGrip/Weld-On products, but no idea where to find them here.

Read a lot about THF (no clue where to find that either), but don’t think I want to mess with that in my home.

Any other ideas? There has to be something that works reliably and consistently.


#15

I recently used some fast curing, low viscosity CA glue that I sourced from Amazon. It held the PLA pieces that I was connecting quite strongly, and was also easy to “flow” into the joint because of how thin it was. I’d advise using a glue syringe to apply it, since the bottle it comes in isn’t meant to be the applicator.


#16

I buy it in bulk from ebay

http://stores.ebay.com/RabidModels?_trksid=p2047675.l2563


#17

Thanks for replies guys!

The different CAs I’ve tried all ended up about the same, the pieces stuck, but had no strength at all and could be easily snapped apart at the joint with just finger pressure.

I’ll try and look for a more liquid type CA that can flow.

@pmbroth, which of the glues on that page has worked for you? There are lots of epoxies and CAs on that page.

Amazon and eBay are tricky as shipping can get crazy, and customs is like playing roulette, the “fees” are sometimes more than what the item costs. I don’t mind ordering per se, but just want to find something reliable before I get it shipped over.

Thanks again for the advice, there definitely seems to be a market for a company like 3M to develop a product specifically for bonding PLA.


#18

This probably marks me as very old, but I remember the first CA glues. Truly water thin, and they smoked as they set. In an instant. The bond was as strong as the original advertisments, which was why you really had to be careful with them. Just not availeable to the public any more. A true shame…


#19

I do remember the commercials from when I was a kid of that guy hanging from a steel beam by his construction hat :smile:


#20

Not to get too far off topic, but the Mythbusters did a great episode on super glue.


#21

I have used-- thin , medium and thick depending on the need. If parts are to be glued,medium or thick will work. I use thin for slight cracks. I use this in wood turning as well. The thing with the plastic is do not use the activator it makes the glue go hazy with the plastic.