Smooth Rods problems with identification and usability

Hi, I'm quite new at the forum, however I've been peeking at the wiki for quite some time now. I've gathered a lot of the resources necessary to build a custom 3D printer, or a milling machine.

I'm having a little bit of trouble acquiring smooth rods in my country due to the price of them, however I did manage to get quite literally 7+ old printers for ... almost free, and found a lot of smooth rods...
some of which are not usable actually (due to the fact that I only have L8UU bearings). The thing is, half the portion of the rods I found have a coat I don't know how to identify nor how to remove. Another portion of them has this....
rubber like rod bumpers, I believe for driving the paper around. Finally, I actually managed to get some 2 steel rods from Lowe's in Texas during a trip (My country's Lowe's and Home Depot don't have those lying around),
one of the ends is painted red, the second rod has a blue end. Both of them are actually oxidized. (I've taken the rust away with vinegar but they oxidized again after a week).

I do have enough 8 mm rods to go by already, ( well not really, short by 1 or 2) however I would really like to know if there's anything I could do to make these other rods usable. Just out of curiosity.

How would I safely remove that coat? Any recommendations for removing those bumpers? Is it possible to polish or prevent those rods from oxidizing?

Example of the rods with the coat:
[imgur.com]
[imgur.com]

Example of the rods with the bumpers:
[imgur.com]

Example of the oxidized rods:
[imgur.com]

Extra rods found in a impact printer that were oxidized (Which is weird because all the other printers didn't have this problem).
[imgur.com]
[imgur.com]

Finally, is this the correct place to post this? If not I'll move it.

Edited 2 time(s). Last edit at 12/12/2016 09:04PM by dropda.

If you are salvaging rods, you need to make sure they are straight and true before you bother spending much time and effort on them. Alternatively, look into other methods of linear motion. V slot, linear rails or bearings on extrusion. Some have even printed nylon bushings with varying success.

I actually have the stuff needed for v-slots and other methods you mentioned, though I really wanted to figure out how to use these rods just for the sake of experimenting.

As for the rods I bought, I made sure to get the ones that were straightest and had the correct diameter. Then I actually cut the rods smaller in a way that I got the straightest parts of them. I wasn't too concerned with high precision, since it was just for experimenting so I actually just needed to solve the rust problem. I tried using sandpaper with a grit of 600 all the way to 1500. (Never done something like that before, just a student here) Then I used a polish compound, and I ended up getting a really shiny and smooth surface but I'm still unsure as to what that means for the rust. As in, will it rust again or is it protected from corrosion now? According to google, it should be protected now, but I'm still not sure.

Edited 1 time(s). Last edit at 12/14/2016 12:52AM by dropda.

Just polishing it will not protect it. If it isn't stainless, which it isn't since there was rust, you have to coat it to protect it. Any coating you can do will make it impossible to use bearings or bushings. I would forget about using these rods for anything but structural uses.

---

[www.bonkers.de]
[merlin-hotend.de]
[www.hackerspace-ffm.de]

What about the other rods, with the coat and the bumpers? I've had some of them for some time and nothing has happened to them. Would it affect them if I sand them to give them a smooth finish?

The bumpers should be easy to remove, I recycle printers all the time. Just slice them off. Also you can slide them off but that takes force.
Usually the rods are nice and straight and smooth.

The coating on the rods is an issue yes, It might be able to dissolve it, try acetone or thinner. I would not sand them down.

But to use these rods for printer movement? They usually are relatively soft steel (very easy to turn on the lathe tho) and also, short. Unless you are dismantling A3 sized printers.

So if you want to make a reliable printer it is best to buy the proper materials online. You will have to pay for shipping. But then at least you know what you are getting.
If it is to test ideas and make a printer to try it out, sure, use the printer shafts.
Some scanners (the older type) use shafts and bronze bushings that you could use.

Have fun experimenting.

Lykle

Thanks, I'll try using acetone and thinner and see if it works. On the other hand I didn't know about the hardness of the shafts in the printers, as I see it, its a problem because ball bearings can in theory wear them faster right? I read somewhere in the forum that bushings could distribute the load more evenly, not sure if that's correct though.

These rods look perfect for ruining your bearings
I suggest looking for "STUB" there are plenty on eBay. Rub some oil on them to keep them rust free and to lubricate the bearings.

The rods you'd get at any Lowes in the US are garbage for linear motion. Plus they are not metric parts. Your LM8UU will fit around it but be too loose.
They're not hardened, or plated to prevent oxidization
I wouldn't try to use them

For things like linear bearings to slide on, you want hardened, because the bearings are hardened and will eat away at the softer rods.
You'll know if they're hardened or not when you try to cut them, it won't be easy if it's hardened.

You also want preferably chrome plated rods so they don't oxidize, rust is never good in that scenario.

The ones with the bumpers are your best choice.
I've done this.
You should be able to slide something between them and the rod, like a bent piece of old credit card or plastic milk jug

Gently cut the rollers with an xacto knife down the length
Use multiple passes as to not cut too deep, the credit card or milk jug should help you not scratch the rod up
Then grab it with needle nose pliers and pull it off

For the ones with the coating, you could try dissolving it like others said. Or maybe even burning it off with a torch? If they're hardened, I wouldn't think the heat would make much difference.

Edited 4 time(s). Last edit at 12/14/2016 04:58PM by FA-MAS.

I have some with bungs on they are tight on...been holding back on removing until i'm sure I have no use for them as is,
though I know the idea will come after I cut them.

Tried that with the bumpers, worked perfectly. Some of them are made of plastic curiously enough, got some of them out by force.