This is a collection of PNG blueprint art from multiple Valve properties. Some official, some fan made. Images included are upscaled and an additional blank copy of each I created meant as a backside.
I printed all of the attached myself at Staples on 18x24in blueprint paper.
On the backside, I then used spray adhesive, joined the two sides, gave time to settle then cut them out with a utility knife and framing square.

I recommend getting two of each image printed in case of first time mistakes. Doing so cost me 45$.

My completed blueprints of lower and middling quality, I folded up and will be taking with me to conventions as part of my TF2 Engineer cosplay.
Higher quality finals I am keeping as posters, would recommend the same.

Credits:
Portal Sentry Turret
Tyler Garrison & Ryan Palser
https://www.flickr.com/photos/ryanpalser/6681473297

TF2 Sentry
Fiery_Penguin
https://www.reddit.com/r/tf2/comments/bxescs/i_made_a_sentry_gun_blueprint_3309_x_2339/

TF2 Scattergun
longestne
https://www.deviantart.com/longestne/art/Scout-s-Scattergun-Blueprints-318008473

Portal Gun Art
Official game art from Valve

Tank Cart or C.A.R.T.
Benjamin Blåholtz
https://blaholtzen.artstation.com/projects/Yo9y3