Lubricating sticky turtable

[Amt0571]

I'm building an Arocs 42043 and the turntable felt quite bad even before assembling it. Turning the gears with my fingers it got stuck even before attaching the crane to it, and after mounting the crane on the truck it barely turned more than 20º before getting stuck and making the clutch gear slip.

I had the idea to lubricate it, and looked online about adequate oils. I found that some recommended silicone oil, and I went to the garge as I had a silicone oil spray. I sprayed inside the turtable through the 4 top holes and spun it and after that everything started to work like magic.

Later, I read that some silicone oils contain acetone and that it damages the plastic. The spray I have doesn't say anything about it, but I'm not sure if I should be worried and remove the oil.

I used a Parkside branded spray that specifically says "plastic" and "rubber" on it... so I suppose I'm safe, but I don't really want to damage anything.

[Berthil]

A silicon oil carrier can dissolve the (oil based) weakener in LEGO thus making it brittle. I build GBC and have used silicon oil only on gears sparsely when I started. Still, after a year or so, all 24t gears broke in half. For that reason I use only dry teflon (PTFE) and apply with a brush, which can be seen at the end of this video. I've used it for more then 6 years now without problems.

But with turntables I had more succes with sanding down the back of the Light Bluish Gray part on a flat 800 sheet on the table until the turnable runs smooth. I especially had to do that for this GBC, otherwise it would not run smoothly. There is quite some variance in how (new) turntables fit together.

Edited January 3 by Berthil
GBC added

[Amt0571]

1 hour ago, Berthil said:

A silicon oil carrier can dissolve the (oil based) weakener in LEGO thus making it brittle. I build GBC and have used silicon oil only on gears sparsely when I started. Still, after a year or so, all 24t gears broke in half. For that reason I use only dry teflon (PTFE) and apply with a brush, which can be seen at the end of this video. I've used it for more then 6 years now without problems.

But with turntables I had more succes with sanding down the back of the Light Bluish Gray part on a flat 800 sheet on the table until the turnable runs smooth. I especially had to do that for this GBC, otherwise it would not run smoothly. There is quite some variance in how (new) turntables fit together.

Great information. And do all silicon oils use carriers that dissolve the pieces, or are there safe to use silicone oils? I sprayed the oil yesterday and today everything seems fine at the moment. Does it means It's ok? Or is it a slower process?

[Berthil]

It's a slow process and I don't know all the silicon oils, but to be safe I would remove it, also because it doesn't really help anyway. After that sand the back a bit thinner as suggested earlier. Or use one that turns smooth 'out of the box'.

Edited January 3 by Berthil

[Aleh]

Once I trie to lubricated that big turntable. Disasemble both parts, lubricated and coneccted back - got almost no reason

 

[Toastie]

1 hour ago, Berthil said:

It's a slow process and I don't know all the silicon oils, but to be safe I would remove it

I'd do the same thing, and yes, the deteriorating process is slow. Months, maybe even years. The "residual" silicone "oil" (when all the lower boiling components have evaporated over time) becomes more or less a grease and in the end plain yuck. Did that once in the past (unfortunately, on many of my 9V switch points) and it ended up badly. Literally "washed" them with ample of petroleum ether, what a mess, but it worked.

There may be superior silicon oils out there, but I will never do that again, regardless what the container says.

Best,
Thorsten

[Ryokeen]

So far i've had good results with some lithium grease. Used that for some gears and small turn tables and so far, after a year, nothing bad happened.

Edit:
Silicon Oils(low viscosity) for RC shocks work aswell. They are also unlikly to have any effect on plastics or rubber as they else would cause problems with the seals an other parts.

Edited January 4 by Ryokeen

[dr_spock]

I used silicone lube for years on sliding parts in my old GBC ball pump. They look like they are still ok. Not sure if my lube contains acetone. I don't see the acetone melted look on the parts like when I used pure/high concentration acetone to glue LEGO parts together.

[aeh5040]

Long ago I bought a used 8480 and found that someone had added tiny ball bearings inside the turntable. It was quite effective at making it turn better.

Edited January 16 by aeh5040

[Mikdun]

I came across the same problem when building large excavator.

Ended up opening the turntable, cleaning any plastic powder from inside and used Molykote 33 grease for plastic. Works fantastic, but it's only few months.

[Amt0571]

18 hours ago, Mikdun said:

I came across the same problem when building large excavator.

Ended up opening the turntable, cleaning any plastic powder from inside and used Molykote 33 grease for plastic. Works fantastic, but it's only few months.

I have not managed to open the turntable. How do you do it without breaking anything?

[Mikdun]

Use more force. 

Maybe old design is easier to open the new ones, but there is no other way.

Here is a tool for small one: Turntable dissasembly tool, use similar concept for the large ones.

[8868]

I disassembled four large turntables last week. I used brick separator. It was very easy.

Edited January 17 by 8868