Ordering MK3S+, what extras to add?  

RE: Ordering MK3S+, what extras to add?

Hi,

Not quite sure I would put myself in the 'seasoned pros' category but my suggestions after four months of printing and learning are:

1) The Satin sheet - this is my 'go-to-sheet' and I use it for just about all my PLA and PETG prints.

2) A roll of PETG filament so you can get comfortable printing with that compared to PLA.

I would not order new nozzles as you might subsequently decide to switch the hot-end to a Revo Six. That will be my next step to allow 'no-fuss' nozzle changes.

Cheers,

Tim

RE: Ordering MK3S+, what extras to add?

I have to agree with Tim.

I ordered the satin and textured plates with my mk3s+, I only use the the smooth for ASA, with the glue stick, the Satin is great for both PLA and PETG.

Satin does both, although I still use the textured plate for PETG as I like the pattern.

Most of my Printing is done with PETG, it prints well on the MK3+ and it’s worthwhile learning to print over PLA if you need a bit more heat resistance or strength.

don’t be afraid to try TPU once you have a few hours under your belt.

I’ll also wait to see if you want to move to the Revo before buying a heap of nozzles , my Revo is sitting on the table, just need to find time to fit it while the printer isn’t running.

prusa filament is on the high end of $$$ compared to what we can get in Aus, it’s 3 times the price of eSun and Sunlu, but it just prints perfect, but the cheaper brand are still ok for the cost.

RE: Ordering MK3S+, what extras to add?

There have been several threads asking this exact same question before, for example https://forum.prusa3d.com/forum/assembly-and-first-prints-troubleshooting/what-spares-should-i-keep/   there are several others.

I suggest you read through some of the previous ones.  Conventional wisdom is parts that are damaged easily and would mean your printer is inoperative until you can source a replacement.  So things like a spare thermistor and heater cartridge are what I would consider essential.  

Then some petg of whatever brand so you can print some spares of the more problematic printer parts just in case.

RE: Ordering MK3S+, what extras to add?

If you are thinking of adding of anything extra to the same order as the printer, keep in mind that depending on what country you are in, you could be hit with customs charges unless the total order amount is below a magic number ($800 for US).

RE:

Posted by: @neophyl

There have been several threads asking this exact same question before, for example https://forum.prusa3d.com/forum/assembly-and-first-prints-troubleshooting/what-spares-should-i-keep/   there are several others.

I suggest you read through some of the previous ones.  Conventional wisdom is parts that are damaged easily and would mean your printer is inoperative until you can source a replacement.  So things like a spare thermistor and heater cartridge are what I would consider essential.  

Then some petg of whatever brand so you can print some spares of the more problematic printer parts just in case.

Thanks for the reply.  I did actually search (to avoid the dreaded "use the search" responses 🙂 but those aren't exactly what I was asking.  I had hoped that given the MK3s high price and stellar reputation I wouldn't be facing part failures in a short time.  Thus, "spares" aren't really what I was after.  Rather, I was wanting to know what functionally different items I might want to swap between to achieve different results.  So I wouldn't expect to need a backup brass 0.4mm nozzle, but having a 0.6mm, or a hardened steel 0.4mm to play with as well might be useful.  I also wouldn't expect to wear out my PEI sheet quickly, but might additionally need a satin one to print different filament.  Things like that.

Posted by: @jimb

If you are thinking of adding of anything extra to the same order as the printer, keep in mind that depending on what country you are in, you could be hit with customs charges unless the total order amount is below a magic number ($800 for US).

Right, thanks for that reminder.  Sounds like this more or less nullifies my question in that the kit + satin sheet puts me at $790 and that's pretty much the end of it...  I suppose I can use that whopping $10 budget to see if there are any misc cheapo spare parts to add.  It seems like several of the "obvious" spares like thermistors are out of stock.

RE: Ordering MK3S+, what extras to add?

The prusa's are reliable.  Its not part failure the extras are guarding against. It is inexperienced new users.  Spend enough time on the forum and you will see MANY posts about people having problems with bed adhesion and parts detaching.  Mainly as they need to learn the 2 fundamentals of live z setting and bed cleanliness.

Until they reach that point one of the unfortunate side effects of a detached print is the possibility of the dreaded 'blob'.  If that happens then the chances of breaking the thermistor wires removing such a blob is quite high.  The wires are delicate at you cant really reattach them once broken.  Same for the heater cartridge, but they are a bit tougher.  

So if you get into that situation then having those 2 items as spares is vital IF you want to get back up and running quickly.  You don't necessarily have to get them from Prusa, as they are standard E3D parts, just get quality ones and not no name junk.  That way you don't have to worry about import duties.

I own several spare sheets and several nozzles, however I'm still using the very first smooth sheet I had with the printer from 4 years ago.   One side is missing a bit but the other is still going strong.  And since fitting a nozzle x that has been used for 3 years now for normal 0.4mm printing so it really does depend on what you are going to be printing materials wise.

RE: Ordering MK3S+, what extras to add?

Posted by: @neophyl

The prusa's are reliable.  Its not part failure the extras are guarding against. It is inexperienced new users.  Spend enough time on the forum and you will see MANY posts about people having problems with bed adhesion and parts detaching.  Mainly as they need to learn the 2 fundamentals of live z setting and bed cleanliness.

Until they reach that point one of the unfortunate side effects of a detached print is the possibility of the dreaded 'blob'.  If that happens then the chances of breaking the thermistor wires removing such a blob is quite high.  The wires are delicate at you cant really reattach them once broken.  Same for the heater cartridge, but they are a bit tougher.  

Thanks for the additional context, that all makes sense.  Question: could you apply something like a dieletric grease to the wires near the thermistor to help prevent the blob from being able to adhere, should such a newb-tastrophe occur?

RE: Ordering MK3S+, what extras to add?

I recommend getting some extra PTFE tubes. They can get jammed and if the filament won't come out, the tube gets replaced. 

(My jams were all due to user error or from using filament that is more prone to jamming.)

RE: Ordering MK3S+, what extras to add?

Fitting a silicone sock can help in general with blob removal (as well as having other benefits) but some of the blobs can surround the entire lower hot end and encase it in plastic.  I haven't seen anyone try a dialectric grease so I think that's in the data unknown category.  It might though. 
I'm not willing to experiment to that extent, my printer sees too much use to deliberately court a huge blob 🙂

RE: Ordering MK3S+, what extras to add?

The prusa's are reliable.  Its not part failure the extras are guarding against. It is inexperienced new users.  Spend enough time on the forum and you will see MANY posts about people having problems with bed adhesion and parts detaching.  Mainly as they need to learn the 2 fundamentals of live z setting and bed cleanliness.

One additional question, I also see people talking about multiple bed thermistor failures.  Your explanation for the hotend wiring destruction makes sense, but isn't the bed thermistor safely stowed away under the bed?  I.e. is it possible that "user error" is the root cause of these failures too?

RE: Ordering MK3S+, what extras to add?

if you are in the States, I believe 'Printed Solid' is a good source for spares. 

the Heatbed moves backward and forward all of the time the printer is running, 
this flexes the wiring of the heatbed power circuit and the heatbed thermistor circuit. 

these wires can last a long time, or they can fail early, depending on a number of factors. 

One of the most common factors, is allowing the cable bundle to touch the wall behind the printer, this can cause increased localised flexing, and result in premature failure. 

If you are feeling competent with wiring, you can replace the heatbed power wires with either 16AWG Flexible Silicone wire, or 14AWG Flexible silicone wire, either will outlast the standard equipment wire by a huge factor. the 14 AWG is probably overkill, but would work satisfactorily and probably outlast the 16AWG option. 

the thermistor wires can be repaired, by replacing the section of wire that flexes, with new 24AWG Flexible Silicone wire. 

I would use heatshring tubing and solder to make joints inside the einsy and underneath the heat bed, on sections of the wire which do not flex, in use. 

again the flexible silicone wire will outlast the original wire by a large margin. 

the thermistor is NOT polarity conscious. 
the heater wiring IS polarity conscious. no harm will occur if you get the heatbed power reversed,(the bed will heat fine,  but the LED will not illuminate if power is reversed.

regards Joan

... and unless very carefully fitted socks can cause more issues than they fix.  Nozzles do wear out, if you stick with PLA and PETG you'll get a solid six months printing out of one but some abrasive filaments can destroy one in hours.

I would always keep a second smooth sheet, that way you can keep one sheet side prepped for PLA (very clean) another for PETG (window cleaner) and still have a third and fourth side on which you can use gluestick or other preparation so that print-sheet maintenance is simplified.

Get a couple of spools of high quality filament, Prusament is excellent, and some very cheap generic of the same type.  That way iterative development and experiments don't cost a fortune while you can always fall back on quality where it matters.

And buy a filament drying system.  Food dehydrators are better than most dedicated dryers, damp filament causes many of the problems we see here.

Cheerio,

RE: Ordering MK3S+, what extras to add?

@joantabb  thank you so much for that detailed response!   I am very comfortable with wiring/soldering/heatshrinking so I am interested in any upgrades that can be done while the initial build is happening.  My only concern would be if the factory wiring is 24awg, would swapping to 14awg actually throw off some expected calibration given the difference in impedance between such different sized conductors?  No question the 14awg would be more robust mechanically, just not sure if this is an area where you could go "too big" or if I'm overthinking this.  From the table I just consulted it appears 24awg has 10x the resistance per foot of 14awg.  Though without knowing the working impedance of the thermistor it's hard to know what % the wire's impedance could possibly contribute - likely not much in a couple foot length.

I have been also reading the reports about static snafus and had planned to try to add some kind of additional grounding to mitigate that.  I was trained on ESD at Boeing 25 years ago and will never forget the microscope pictures of the partial damage done to circuit traces which can lead to failures days/months/years down the road.  The reports of users having the display "freak out" and things like that sound very concerning to me so I will certainly attempt to avoid those conditions.  I figure I'll have a month or more to do plenty of homework while waiting for the kit to arrive.  The main thing I'm trying to "rush" is getting that order submitted in the first place 🙂

RE: Ordering MK3S+, what extras to add?

the Heatbed Power circuit is a 'High Current' circuit, chunky cables are beneficial. 
the heatbed thermistor circuit, is a 'Signal (Low Current) circuit. 
there is no need to use chunky cable. 

at room temperature the thermistor resistance is near 100k ohms, and the thermistor input port has two 2.3K ohm resistors in series with the signal, so the resistance of 24AWG Wire will be insignificant

as shown above

I hope this helps, 

Regards Joan

RE: Ordering MK3S+, what extras to add?

I hope this helps, 

It does, thanks again.  I re-read your original post and see that I had misunderstood you (my fault, your words were clear).  Since I had brought up the thermistor failures I misread your comment to suggest I could swap in a more stout wire for the thermistor.