by r691175002 » Fri Apr 06, 2012 8:05 pm
I can't give a fully neutral perspective on buildlog vs lasersaur, but from what I have seen of the bill of materials and other published information, the lasersaur is significantly more expensive and complicated. The buildlog.net 2.x laser has made quite a few refinements over the 1.0 laser and combined with makerslide it is very cheap and easy to build for what you get.
The main advantages of the lasersaur are the marketing and comprehensive documentation. It can be difficult to figure out exactly how to build the buildlog laser.
You can extend the cutting area by modifying the plans, going to 30x20" should be no problem because that is the cutting area of the 1.0 laser. Going to lasersaur size may introduce flex, but it will be no worse than the lasersaur since both machines are made from extrusion. Note that it becomes exponentially more difficult to align the laser over large distances.
Wattage is mostly a speed issue. A 40W laser can cut 1/4" acrylic and plywood, and can do thicker if you cut very slowly or in multiple passes. Paper, cardboard, etc is no problem. 120W is a lot of laser and if it is having trouble cutting through any of the mentioned materials there is something seriously wrong with the machines.
You can build the machine without ordering any kits, but if you have access to a mill/lathe you can probably do a better job of some of the parts (bearing mounts). You will still need to buy extrusion, makerslide, timing belts, possibly v-wheels and such. Most of the kits are reasonably economic and I would recommend considering the amount of work they will save.
A typical budget when building a laser would be 2000-3000$. If you have the skills and tools, you could get by on the cost of electronics, laser and linear motion which would probably bring a build into the 1000$ range.
Things like ventilation can cost a few hundred on top of that.