solidify modifier is distorting parts of the model I am completely new to Blender, outside of watching a few tutorials online and messing around for a couple hours trying to solve my problem.

I have this model, made by Yokiie on Sketchfab (https://sketchfab.com/models/9814e8f117c0426bbe3f04de7ad6a363), I am now trying to convert the file from .blend to .obj so I can send it to a 3D printer to make something for a cosplay. However, after exporting this model in Blender to an .obj file, the website I am using to send my project to a 3D printing service is telling me the walls of the model are too thin, as shown here in red.



Upon knowing this, I then tried the Solidify tool on Blender, and it minimally solved some of the thin wall issues (5% or so). However, upon making the walls thicker, it is also distorting other parts of the model (specifically the hand guard/round orb area), despite making a Verticies group with just the blade portion and using solidify on that.

I am just at a point where I don't know if there is something with the original model that is causing these problems or if there is another option. My end goal is to get the object into an .obj file so I can send it to a 3D printer through 3D Hubs.

I also apologize if this is answered somewhere and the answer becomes repetitive, I gave a quick look through google search and didn't find a result that I found to work. Soldify was the main method I saw people use and it didn't seem to work for me. Any help/tips/things to try would be greatly appreciated! 

Thanks!

Zarvix
The fastest way to fix this is probably just to split the blade and the hilt, and apply solidify to only the blade.

To split the blade from the hilt, go into edit mode with the sword selected, then click anywhere on the blade and press ctrl+l, which will select all linked.  If this selects the hilt too, you will need to select the faces manually.  Once you have the blade isolated, press p while still in edit mode, then choose "selected".  This will break the sword object into a hilt object and blade object.  

From there, you can just apply solidify to the blade as you did before.

From a 3D printer perspective, you may want to not print the blade at all, and make it yourself with plastic sheets from Hobby-Lobby or something.  3D printers have some trouble with long and thin.  Not to mention you will save money from avoiding printing costs.