please help, trying to get a part printed

hi, this hopefully will be my first 3D printed model, can anyone help me get this 3D printed in plastic, i edited the model plane removing the wigs so it will fit the printer boundaries, the upload feature here is telling me it would be a 111.55 dollars which is ok with me, but the "fix thin walls tool" hangs, its been hours and it still says "please wait while we fix walls" i figure if i can get past this part i might have a shot at getting it 3d printed.

if i can get past the fix thin walls part then can i get it printed or will there be more hurdles?

also when fix thin walls tool let me download the wings with fixed walls, it was in .x3d file which neither ac3d and blender can open. is there a freeware tool for opening it in a file type that ac3d can use such as .stl or collada. or maybe its not that important for me to see the fixes, perhaps if i could just get past the fix walls part is all i need to get it printed? i have a paypal account.

attached, heres my model fuselage and landing gear in .stl, and here is screenshot of "fix walls tool" hanging for hours, its not letting me past this stage.

Netfabb Basic (www.netfabb.com) can load the X3DB and save it as an STL (or vice versa)
For larger models, the repair tool requires a considerable amount of time to complete.
The thin walls visualization tool has to subdivide your model into "voxels" that are each on the order of 0.1mm in size - your model ends up being more than a million voxels to process. Then the Repair tool has to do a simliar process, but (I think) that it uses voxels of 0.05mm - more than 8million to process.

Looking at your model, I would suggest:
1) fix the four flat panels in the nose cone - each of those need to be a bit thicker.
2) fix the small post in front of the cockpit - that too needs to be slightly bigger
3) ignore the reported error on the belly and the tail - those are "false positives"
4) consider making the thinnest part of the landing gear a bit thicker. Even though it passes the ThinWallsCheck, the wheels are large enough that the smallest peice there may snap.

Then, I would run the model thru cloud.netfabb.com before uploading it to Shapeways.

Use Import in Blender...

i did the 4 things you mentioned and uploaded it back up to the shapeways thin wall fix tool, so i guess i will just wait.

i will try the netfabb.com while im waiting.

cloud.netfabb.com is sendiing me a fixed file which appears to be just one dot, one point. here it is:

its 2:51 pm new york time and it still says fixing walls, i started at 800 am.

eventually i may need to shut down my computer, is that going to stop this fix walls process by closing the browser?

here is the model that i uploaded at 800 am, attached: