Plastic welding stuff!

[Ed Oscuro]

On a lark I got some acetone and tried using it to weld one of the screw support columns on a Game Gear shell back on. No dice, of course.

Looking around further I discovered this video. The product is rather expensive but it seems that you can probably replicate the results with a regular soldering iron, if you have the right temperature.

Has anybody done this, and if so what do you use? I am especially interested in knowing tip types, temperature settings, and sources for bonding plastic rods (as seen in that video) with a kevlar stiffener.

[mickcris]

On a lark I got some acetone and tried using it to weld one of the screw support columns on a Game Gear shell back on. No dice, of course.

Looking around further I discovered this video. The product is rather expensive but it seems that you can probably replicate the results with a regular soldering iron, if you have the right temperature.

Has anybody done this, and if so what do you use? I am especially interested in knowing tip types, temperature settings, and sources for bonding plastic rods (as seen in that video) with a kevlar stiffener.

You probably meant to link to a different video and not the one of a guy using acetone to glue a motorcycle part together. The game gear may be made out of a different type of plastic than what can be easily melted by acetone.

[Ed Oscuro]

Argh, YouTube...that was giving me trouble earlier too. Fixed the link, though the other one (in your quote) is interesting too. I had the same thought you did, though it was surprising still. Maybe I just didn't use enough / let it sit long enough (though I wasn't getting any stickiness or anything other than a bit of wetness).

[ms06fz]

From personal experience with model kits, IMO trying to put a structural part back together with a solvent doesn't work. If you put stress on the joint it'll just break apart again at the seam. Bonding parts together that way can result in a strong joint - just not as strong as the original part.

But if you did want to try solvents again... MEK might be something to try. Just, obvious warnings about skin contact and fumes, it's nasty stuff.

As for melting the parts together with heat... It could work. All I can really say offhand is that, from looking into 3D printers and stuff, those things extrude ABS plastic at around 230C, I think... So that should give you an idea of the level of heat you want.

Another option (I think I did something similar when the screw-holes of my EEE PC broke) - get a smaller diameter plastic or metal tube and install in the old screw-hole. It needs to be a large enough diameter that you get a tight fit, and it needs to occupy enough of the remaining portion of the screw-hole to be stable. Then get a longer screw - the screw will go through the tube to connect to the threading, and the head of the screw will sit on top of the end of the tube - still within the screw hole but at a shallower depth.

[Ed Oscuro]

Thanks for the ideas and the temperature note! That seems to jive with what I find elsewhere, i.e. here (second post, the 240 degree C bonding point is what I want of course).

I tried using a lighter just to see (and obviously without doing any more research, otherwise I wouldn't have bothered) and while it did cause the connecting point to deform slightly, it cooled too quickly to do anything. I haven't ruined the piece and I'm OK with using it as a testbed for these methods, but with hindsight it was a waste of time. Obviously need to use a kind of soldering iron here.

[mickcris]

Thanks for the ideas and the temperature note! That seems to jive with what I find elsewhere, i.e. here (second post, the 240 degree C bonding point is what I want of course).

I tried using a lighter just to see (and obviously without doing any more research, otherwise I wouldn't have bothered) and while it did cause the connecting point to deform slightly, it cooled too quickly to do anything. I haven't ruined the piece and I'm OK with using it as a testbed for these methods, but with hindsight it was a waste of time. Obviously need to use a kind of soldering iron here.

is there a reason you can't use super glue or epoxy to fix this?

[Ed Oscuro]

Yes. I don't want to go off-topic, but the short of it is that those glues don't give the same strength as the original bond between plastic molecules...which already broke. I don't see the purpose (except in strange cases) of going with something second-best when even the original can break. Using the plastic welding method on inside parts, there's also the possibility of strengthening a part to make it better than the orignial.

[mickcris]

Yes. I don't want to go off-topic, but the short of it is that those glues don't give the same strength as the original bond between plastic molecules...which already broke. I don't see the purpose (except in strange cases) of going with something second-best when even the original can break. Using the plastic welding method on inside parts, there's also the possibility of strengthening a part to make it better than the orignial.

ok. just wondering. I would think a good 2 part plastic epoxy would be pretty strong though. Like JB Weld:
http://www.amazon.com/J-B-Weld-50132-Pl ... rid_pt_0_2

[Einzelherz]

Yes. I don't want to go off-topic, but the short of it is that those glues don't give the same strength as the original bond between plastic molecules...which already broke. I don't see the purpose (except in strange cases) of going with something second-best when even the original can break. Using the plastic welding method on inside parts, there's also the possibility of strengthening a part to make it better than the orignial.

Aside from perfectly melting the areas back together, even "plastic weld" solutions are going to be pretty similar to the better super glues out there. Plastic is more like wood than metal in its repair/shaping/cutting/etc.

[Ed Oscuro]

Welding doesn't mean gluing - products with misleading names aside - so the glues and epoxies are off-topic here. There are lots of good treatments around the 'net of different types of glues - I'm not asking about those.

[Ed Oscuro]

SUCCESS!* (ASTERISK QUALIFIED)

Today was Intergalactic Clean That Disgusting Old SNES Day, didn't you know?

However it's also a good day to observe that old rule "if it ain't broke, don't fix it."

A couple things were discovered:

- That slightly yellowed (still gray, but not with the almost blue tinge anymore) case is also brittle!
- On the side of the top shell, a little triangle of plastic broke off in my hands. I wasn't flexin' it or nothin', honest.
- Nice build quality in the SHVC-CPU-01 SNES; a lot more of my familiar old Alps and Mitsumi parts, and some very intricate parts. Most importantly, the designers have thoughtfully molded a raised ABS into the case outside to tell us what it's made of.

Time for the acetone again.

This time I could see a difference start to take hold very quickly. I just painted the sides of the crack, and the broken edges of the piece, with two or three swipes of a cotton swab each; soon I was able to put the piece back in.
I also painted the crack on the inside of the shell. I notice that the original plastic color comes back. There's also some discoloring so I wouldn't want to do this for the outside.

Not as good as new, but not terrible either. I have at least saved the case from an ugly open gash. I didn't care enough to try to fit in the tiny slivers of plastic that came off, here and there; this means that there is an obvious chip in the outside but ehh. Too much of this stuff can add to a "melted" look on the case outside.

On the humorous side, a little pool of dried fucking goodness knows what under the Player 1 controller port vent has visibly preserved the plastic underneath. I guess the next old used SNES I find I want covered in all kinds of nasty stuff, then