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I am attempting to construct model tank tracks with accompanying wheels and sprockets. All parts will be printed in PLA. The tracks will be driven by electric motors.

What would be a suitable grease for this project to minimize friction without damaging the plastics.

darth pixel
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HenrikS
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    I've also found this link on reprap wiki http://reprap.org/wiki/Lubrication it covers all aspects of lubricating stuff (not only plastics) – darth pixel May 30 '16 at 09:41
  • I'm gonna be the simpleton here and say grease is grease. The difference between grease and no grease is 20-fold and more. The difference between your ideal grease and peanutbutter is 2-fold at most. Print sprockets in Nylon. If they are small they will not warp and you just extended lifetime 10 fold. – AzulShiva Jan 30 '23 at 09:58
  • Grease on plastic parts can weaken the plastic, particularly if it's petroleum based. I have found that paraffin wax from a candle or crayon works very well as a dry lubricant for PLA. If you must use grease, use a PTFE or silicone-based grease. – Anachronist May 12 '23 at 02:31
  • @Anachronist, Paraffin wax is obtained from petroleum by dewaxing light lubricating oil stocks. – Dwight Spencer Jul 16 '23 at 17:18
  • @DwightSpencer - yes, it depends on the compound, of which many are derived from petroleum. However, after investigating, this chart - https://www.plasticsintl.com/chemical-resistance-chart - shows that both vaseline and paraffin are safe for most plastics although PLA isn't included in that chart. I prefer paraffin because it's dry. – Anachronist Jul 18 '23 at 03:37
  • @Anachronist right and a good chart. But they most likely left PLA out of there because of its low to non-existent chemical resistance to anything but water, as pointed out in https://prusament.com/chemical-resistance-of-3d-printing-materials/ and is particually week to Hydrocarbons such as the CnH2n+2 in Paraffin and C2H6O in Ethanol or C3H60 in Acetone of which are close enough to PLA's chemical make up of (C3H4O2)n. – Dwight Spencer Jul 26 '23 at 14:53
  • @DwightSpencer - thank you. I haven't noticed paraffin degrade PLA; in fact it improves the performance of bearings and gears, so I routinely lubricate moving PLA parts by rubbing a crayon or candle on them. It's also dry and not messy. If wax is damaging to PLA, then what would be a good lubricant? – Anachronist Jul 27 '23 at 15:35
  • @Anachronist Love Integza for his video on this sort of thing. He found that powder graphite is a good lubricant. Also, unless your printer is only able to do PLA; change materials. PET, ABS or anything else that has a better chemical resistance to the lubricant of choice would work. Most experiments show that Polyamide and polycarbonate being durable materials for workloads like sprockets. I mean it's just material science. Print a part. Do a experiment to see its break/wear points. Then adjust your engineered design to fit the use case. There isn't a single solution here just trade-offs. – Dwight Spencer Jul 29 '23 at 19:50
  • @DwightSpencer thanks again. The only Integza I found on YouTube has a lot of videos about rocket propellant and combustion engines. The same guy? My printer can print anything including nylon (which is best for gears), but PLA is the most trouble-free material to print. – Anachronist Jul 30 '23 at 21:08
  • @Anachronist yeah that's the guy. He's big in the 3d printing and maker community. His latest series has been around rockets but check his earlier works. – Dwight Spencer Aug 01 '23 at 05:21

3 Answers3

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I use cosmetic vaseline - petroleum jelly. Usually it is white to transparent and odorless. It's cheap and available in all drugstores and cosmetics stores.

As suggested by Tom van der Zanden I'm adding additional info about interactions of vaseline and plastics. I've found many web sites which claim that vaseline can damage plastics but none of them really proved that statement. There is nothing about it neither on producers sites nor wikipedia or any other believable sources I've found. So according to it and my practice I'm pretty sure that vaseline won't damage popular plastics (including common filaments).

The only information I've found is that vaseline can damage natural rubber but I cannot confirm that on my own.

Of course it might not be true for some materials so be careful and check the interactions first on invisible side or on refuses.

darth pixel
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5

You may find a solution with the common lubricant containing PTFE, often called Super Lube. It is described in manufacturer's literature as non-reactive with virtually everything. It is available at a reasonable price as plumber's grease (look for either Teflon or PTFE in the ingredients) in various quantity containers. When used on metal, you may get black residue. With plastic, some color of the plastic will appear as the surfaces wear. It has good sticking power too.

fred_dot_u
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I have been using sewing machine oil for my 3D printed extruder gear for a couple of years, without any noticeable wear so far.

In general, I believe any kind of low viscosity oil would do, but then again, it also depends on the environment in which you plan to use the model. If you plan on using it outside, for instance, you probably should get some grease that does not attract dirt, as the dirt itself will grind down the gears quickly.

Tormod Haugene
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  • darth pixel's link for lube information indicates that light oil provides relatively poor lubrication, but reduces noise and collects dust. Interesting to read that WD-40 is listed as the worst. Cyclists have discovered that it's worse than no lube at all for a bike chain and it's not a surprise to learn that it's not good for 3d printers either. – fred_dot_u May 30 '16 at 15:11
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    @fred_dot_u I totally agree that WD-40 is the worst grease and it's sometimes worse than no lube at all. IMO it's too light to use it as grease. Especially for long term greasing. I use WD-40 all the time but NOT as greas but to clean links and to relax and unscrew a screw only. IMO there is too less grease (lubricant) in WD-40 for application as bike chain or even door hinge. fred_dot_u please notice that there is special WD-40 bike which confirms that WD-40 (regular) is not very good for bikes. – darth pixel May 31 '16 at 06:19
  • @fred_dot_u, I am not familiar with the WD-40 series, but I understand and agree your concern. The OP does not specify the environment in which the tank treads will be used, but if it is to be used outside, protection from grit and dirt probably should be considered. That being said, my 3D printer stays much cleaner than my bicycle chain. :-) – Tormod Haugene May 31 '16 at 06:23
  • @TormodHaugene there is really strange issue with WD-40. I don't know how is it possible that this stuff is a synonym of grease in some groups of people. WD stands for water displacement and it was "developed" to remove greasing (sic!) and rust as far as i know. I don't know any mechanics specialist who would use WD-40 as grease. – darth pixel May 31 '16 at 16:25
  • WD-40 is the single most overrated substance in the public's mind. It's the only "lubricant" most people have in their homes. Completely undeserved reputation. (It's good for unsticking siezed things, so I think people assume it's also good for keeping them unstuck... but it's really terrible for long-term lubrication.) – Ryan Carlyle May 31 '16 at 18:24