PETG solvents

[hamster]

Got a roll of PETG filament. Prints look nice and somewhat semi-transparent, but the surface is not perfectly smooth (especially on top and bottom surfaces, you can see lines formed by each pass of the extruder.) I want to create a glossy finish (like here http://airwolf3d.com/2013/11/26/7-st...parts-acetone/ http://blog.reprap.org/2013/02/vapor...-rp-parts.html) and for that I need something that will dissolve PETG.

The problem is that PETG is apparently immune to acetone and most other commonly used solvents. Googling turned up a number of possible candidates, which were, for the most part, highly toxic, unavailable online (or available at some absurd prices like $20/gram), or both. Melted phenol would supposedly work, but I can't find any suppliers who'd sell it cheaper than $100/kg. (Which is also absurd, it's a cheap basic chemical that probably does not cost more than $5/kg in bulk.) One source said that dichloromethane and toluene "achieved partial dissolution" (so, may or may not work.) I can get 1 quart of dichloromethane on ebay for $34+tax, but it's going to take at least a week to get it delivered and I'd like to be more confident that it will work. For some bizarre reason, toluene is completely banned in California (I might still manage to order some from out of state, but it's a misdemeanor simply to possess any quantity of it.)

Has anyone ever tried this before, and are there any solvents I've overlooked that would do the job and would be more easily available?

[jimc]

i could be wrong but i dont think toluene will dissolve it. dont quote me but you better double check before ordering it. dichloromethane which is commonly called methylene chloride is the solvent of choice for bonding parts together. this is how polycarbonte and acrylic are joined. its been used for years. its also the active solvent in paint stripper. its is extremely bad for you. you need to use it outdoors. i would never dream of using it to vapor smooth a part. get yourself some of that xtc epoxy coating stuff and call it a day where pet smoothing is necessary. either that or simply prime it and paint it.

[hamster]

It turns out that I actually have a canister of Klean Strip paint stripper at home, and yes, it's supposed to be >60% dichloromethane (they also add something to turn it into viscous paste.) Before I go for real vapor smoothing, I'll just try to dip a piece in it, let the solvent evaporate and see how it goes. It's nowhere near as volatile as acetone, maybe this would be enough.
Yes, of course, I do this stuff outdoors.
Painting is not an option, the whole point is to retain translucency of PETG.

[LambdaFF]

If you are looking for a solvent for the only purpose of smoothing, you should look up the articles on XTC3D : while it is NOT a solvent for PETG, it was clearly stated that for single outline prints it would increase light transmission and clarity. Taulman published some about it.
I think 3DPrint.com also had an article within the last 6 months.

[iDig3Dprinting]

I don't think that XTC3D is what you were looking for, this is more of a coating.

I haven't tried this but for PETG sheets the recommedations for polishing are:

Polis

Polishing

Sheet edges must first be smoothed to remove the marks left by the circular saw.
The following may be used:
Rigid fabric rotary discs with polishing paste followed by soft fabric discs with polishing paste
for the final finish.
PETg sheet can be flame-polished using a standard propane torch or a hot-nitrogen welder.
Both techniques require accurate control of the distance between the sheet and the heat
source; otherwise, surface whitening or excessive material flow may occur.

If you try any of this A). please don't injure yourself B). if it goes wrong don't blame us. It seems like melting the surface may work????????? I suggest you practice first.

[hamster]

First attempt with Klean Strip produced mixed results. 30 min soak turned the test piece (2 mm thick walls) completely opaque and rubbery. I either need a much shorter soak, or vapor smoothing as described in the article.

I'll try polishing with a dremel too.

[jimc]

Haha 1/2 hour...your lucky you even have a part left. When dipping a part and it having direct solvent contact it just needs to be quick. Abs in acetone for example is just seconds. I would dip it and immediately pull it out and let it sit for a minor two then rinse it off. The thick liquid that the meth chl is in is designed to keep the solvent on the surface and not flash off real quick.

[JohnnyV]

Hey hamster,

Did you make any progress with Klean Strip or the dremel? I just ordered and roll of PETG and was looking for smoothing methods.

[Sebastian Finke]

An alternative to smoothing using a solvent would be sanding and spray painting. Gives great results.

[EagleSeven]

I used HobbyLite Wood-Filer , sanded & then painted, the PLA cover piece of my quadcopter.
It looked great and seems very durable ! (I flexed it and nothing came loose)
I assume it will work just as well with PETG.

HobbyLite filler.jpg