MK4 - What spares should I buy?  

RE: MK4 - What spares should I buy?

I don't think you need any spares, but you might like the satin build sheet. Possibly a larger, or smaller, nozzle. Filament of course. To me spare parts would be to replace something that you expect to break or wear out. The MK4 seems to be pretty solid and reliable.

RE: MK4 - What spares should I buy?

One caveat, if you print with abrasive materials, you should have a spare nozzle on hand.

RE: MK4 - What spares should I buy?

This really depends on what type of filament you use to print, and the kind/amount of usage you put the printer through.

There are no general parts that you should need to have on hand - other then your general maintenance stuff. A bottle of IPA for steel sheet cleaning between prints, a tube of lubricant for the rods between every few prints, and your general cutters/pliers etc. I found the MK4 to be my most reliable printer ever. No failures at all, and the first printer I could truly just send a print job and walk away from, without watching the first layer etc - I trust it that much!

RE: MK4 - What spares should I buy?

Include a set of silicone  socks for the hotend in your buy: https://www.prusa3d.com/en/product/prusa-nextruder-silicone-sock-set/ They save work on cleaning. While you're at it throw in a brass brush also (not sure if Prusa sells them), and set of nozzle cleaning needles.  These cost very little, but you do not want to be without them in time of need. 

For the rest it just depends on what you want to print. If you want to do PETG a lot include a satin sheet. It saves a lot of messy glue stick work and plate washing. Maybe add a few Nextruder nozzles. They are specific Prusa and may be difficult to source locally.

RE: MK4 - What spares should I buy?

I agree with fabnavigator, you probably want to have the three different print sheets just to see which you like the most (Smooth, Satin, Textured). I personally use Sating for 95% of my prints, Textured for 4% and Smooth for like 1%. 

Different nozzle sizes is something I would recommend, even if it's just for experimenting for fun. I print maybe 80% on the standard 0.4n and like 15% on the 0.25n. I thought I would use the 0.8n far more but... I just can't find a relevant use-scenario. Speed isn't that important to me, and the sacrifice in detail just isn't worth it. I'll try getting a 0.6n soon though, to see if I'll use that. 

But to actually answer your question, unless you break something I don't think you need to have a stock of spares laying around. I accidentally broke my heater block because I didn't realize that the nozzles + heater block are lefty-tighty and righty-loosey instead of the normal lefty-loosey and righty-tighty. 

(Buy lubricant (silicone-based according to their support if you don't want the one specifically from Prusa), it'll run out sooner or later.)

RE: MK4 - What spares should I buy?

I second all that!

For what it's worth, after I got visited by the blob fairy the other week, I decided to get spare heater & thermistor assemblies, just in case I make a wrong move and break the wires during cleanup the next time it happens.

I also splurged on spare fans and a spare heater block. (Mostly to spread the cost of shipping, but also to have some quick spares in case of some unlikely nozzle swap accident: cross-threaded hot end, punched through fan blades, etc.)

Posted by: @frebys

I didn't realize that the nozzles + heater block are lefty-tighty and righty-loosey instead of the normal lefty-loosey and righty-tighty. 

The heater block has regular right-handed threads everywhere -- both the nozzle and the set screws tighten clockwise. (Source: I now have some spares to play with.)

RE: MK4 - What spares should I buy?

After some months with my MK4, I would give the following list to my past self if I could:

• Obxidian nozzles in .4 and .6
• A heatbed thermistor kit
• A spare hotend including heat block, heater and thermistor
• A satin sheet
• A spare cable for the LCD

If one has these things, not too much can go wrong. 🙂