I had purchased some C.R. LAURENCE WSF17XW CRL White 29/32" x 7/16" Heavy Wall Extruded Screen Frame on Amazon to replace the noticeably flimsier product from Lowes. Yes, it's a bit pricey ($30 for 144" and cut to rough lengths for free), but it is definitely worth it.
The screen spline was from Ace Hardware, right off the shelf. Make sure you get the same size.
I used the CRL Aluminum Corner that matches the frame but I had to order a minimum quantity for more money than I'm willing to admit.
As a service to the Sponsors of this site (those that have paid the $12 to support the forum) I will send 4 of the aluminum corners free on request ... just PM me at
[email protected] and include your forum login ID/handle. I will ask that you pay actual shipping charges and the cost of a small shipping envelope to put them in. While supplies last.
Please request them only if you plan on making a screen for your TM door.