Neewbie advice wanted on a bigger Prusa

Hi all,

I have been thinking about getting a 3D printer for sometime and am getting ready to take the plunge. I am looking to build a variant of the Prusa, but with a bigger build area and need some advice. For what i want to build the 140mm height is fine, as is one axis of 200mm, but one axis needs to be a min of 350mm. I don't want to go the whole hog of building a massive Reprap that is bigger than in all dimensions, so i want to just modify one axis of the Prusa. Looking at it i see two options:

1) Make the machine wider so the x-axis (think that's right, the carriage moving back and forth above the bed) has a 350mm build area. This seems to be less complicated as nearly all parts stay the same, only need 8 different length rods, and a new build plate

2) Make the machine deeper so the y-axis has a 350mm build area. As the edges sides are triangles this either needs new parts or means making the machine taller too, so altering the Z-axis. Needs more longer rods.

I am inclined towards option 1), partly for reasons of space and simplicity. When it comes to the software i guess it's just a simple tweak to say x-axis = 350mm, or something? What would you recommend for controllers too. I am looking for fast, but also would like some fine details. Is there a trade-off? The Sanguinololu looks good to me, is it?
Anyway all advice gratefully received and taken on-board.

Tom

Note that the Mendel can only use the full 140 mm spce for build height if your extruder is very short and it doesn't use gears like in the original design. I've found that for the full x-y build area, the highest I can achive is 100 mm with a Wade's geared extruder mounted with the gears facing forward. Beyond that, the gear hits the upper left vertex and then the motor hits the uppper right vertex. I can then go as high as 120 mm if I limit the x. This would be more or less depending on the length of the hot end.

So, considering this, I think option 2 is the better way to go to achieve your goal.

Note that you'll have warping problems building big parts and you should plan to run your Mendel in an actively heated or self-heated chamber. I run mine in a carboard shipping box, and similar to what Nophead described in his blog, it gets up to about 50C without additional heating.

I was already thinking about heating. I need to store it, so i was thinking of building it in a box that can both store/transport it and allow it to stay warm.
Is there any where on the Wiki that has a set of proper plans, front elevation, side etc. I find this easier to visualise than the photos, especially for making the alterations.
Thanks for the advice on the maximum height, I'll have to think about that. It partly depends on the height of my bed, as I'm planning to store it under there when not busy making things.