Prusa Mk 4

It doesn't matter where you go in the world, there's always somebody that wants to put their hand in you pocket!

This is by far my biggest print yet.
 
As usual, stuff not finished but I can't resist carrying on.
 
Now I'm 'Off Grid' I don't have to worry about Load Shedding.
The next print is nearly 24hrs!

I'm with you there Simon, but try as I might, I can't get my head around any of the 3D Cad programs. Jon has tried to help but I'm too stupid. The cost of any ARF's or kits has rocketed out of my price range, I'm therefore committed to the offerings of Plane Print. I've just started the Super Cub, the longest print so far was 22hours,
 

Since Jon bought himself a Mk 4S I noticed a modification that interested me, I occasionally get failed prints like this  It only ever happens with LW-PLA. On the 4S Prusa have added a fan to cool the extrude. Once shown the fix it's obvious that the problem is caused by heat in the extruder.Having a spare fan I decided to organise my own fix.
 
The fan is only 16mm wide but the extruder is 42mm, no problem
 
A bit of heat (180C) does the trick.
 
Check out the fit
and then job done.
 
Could this be the end of my occasional problem?

My Prusa now has 3 fans, the photograph showing the left side of my modification shows the print cooling fan. The right side of the finished article shows the heat break fan underneath my modification.

Hmm, not so good
 
I had hooked the new fan into the heat break supply, not such a good idea, I did think there wasn't much huff, I rerouted to 12volts, now blowing much harder.

Well, I did some temperature checks with a non contact thermometer, the ambient temperature in the room is averaging 34C with the walls at 36C. The extruder surface at print start was 34C, extrusion failed when the extruder surface reached 38C, about 2hrs into the print. Bearing in mind that the extra fan is drawing warm air off the heated bed (80C) it would appear that my mk4 in its current form needs an ambient of less than 32C. This is just a guess, I'm probably the only person in the world that prints at those ambients. Mary and I don't do airconditioning! It's bad for the environment.
We're currently in a heat wave at the moment, no rain and daily shade temperatures of 40C+. Our river has stopped flowing, just puddles at the moment and no way of knowing when the weather will break.

5C here! And for the first time in several days, a blue sky instead of grey murk.