Mark Wrote; So, my point is, no matter how you make the holes in your WAF's, whether it be waterjet, laser cutting, drilling, or shooting a bullet through them, there is no reason to worry about the heat affected zone, or losing the heat treatment. By setting these on your workbench when you are done making a hole and waiting a bit, you have effectively normalized the part.. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ This isn't right. If you local heat the part and it cools quickly by conducting heat away from the localized zone, it will be brittle. If you heat the entire part and let it cool slowly, it will be near the normalized condition, but slightly softer. Normalizing is a careful process. The material can be heat treated to stronger than normalized condition. Normally, gas welding as fuselage will give softer condition near the joint, but that's OK, 'cause the bending moments are usually out in the middle, 4130 is a very versatile material, but casual handling yields casual results.
Ron Freiberger .. EAA Tech Counselor 4125 mailto: rfreiber...@swfla.rr.com -----Original Message----- From: krnet-boun...@mylist.net [mailto:krnet-boun...@mylist.net]On Behalf Of Mark Youkey Sent: Thursday, May 01, 2003 1:40 PM To: KR Subject: KR>Reattack on WAF's, and Antenna website The previous discussion a few weeks ago about WAFs, and laser cutting, heat treating, etc, didn't set well with me. So today I finally found out why. As it turns out, 4130 steel air normalizes. That means that if you heat it up, and then just let it sit out to cool down, you have returned it to a normalized state, and have done the heat-treating yourself. No wonder it's a cheap process....but paying for that at all sounds like you are overpaying. So, my point is, no matter how you make the holes in your WAF's, whether it be waterjet, laser cutting, drilling, or shooting a bullet through them, there is no reason to worry about the heat affected zone, or losing the heat treatment. By setting these on your workbench when you are done making a hole and waiting a bit, you have effectively normalized the part.....and done it cheaply. Nice, huh? Just don't throw water or oil on it...that will screw up the cooling speed and give you potentially unwanted results--hence "Air Normalize" Here's a good website that talks about 4130 steel. http://www.eaa1000.av.org/technicl/4130.htm http://www.eaa1000.av.org has links on it to great pages, including "Technical Articles" where I found the steel article. As promised in my subject line, http://www.eaa1000.av.org/technicl/antennae.htm is a good article on antenna installation. Hope this helps. Whoever out there is a member of Chapter 1000, great website. Mark Youkey myou...@cox.net Okalhoma City_______________________________________________ see KRnet list details at http://www.krnet.org/instructions.html
