Edited: 6/2/2012 6:49:05 PM by Maztang
Edited: 5/24/2012 10:18:44 PM by Maztang
I have been wanting to do this for a long time and now that I have my own section I figured now is the best time. I will keep updating this until it is all complete. I may end up moving paragraphs around later and adding things so please bare with me. I am about to throw down some knowledge that I have gained over my last 13 years of working aviation and doing sheetmetal. I will tell you where to go to buy the tooling, materials, and basically just help all the do it yourselfers, like myself, to do the job. It's not for everyone but if this will help you get going than more power to you.
Tooling - One of the most expensive fields to get into is a sheetmetal fabricator. The tooling is expensive and you need lots of it. However, you would be amazed at what you can do with the bare minimum of tools. The best place to go is
www.yardstore.com,
www.browntool.com, or even ebay has some great deals.
Here is my suggested tool
list:1] 1/4" reversible drill2] 3X rivet gun3] Rivet Head sets - flush, 3/32, 1/8, 3/16, 5/32, 1/44] Bucking bars - heel and toe5] Doglegg deburr6] 90 Degree die grinder with cutting wheel and sanding arbors7] Hole saws8] Drum sanders for grinder
If you just want to do this one time and that is it, this is a kit that will get you startedhttp://
www.yardstore.com/browse.cfm/4,6200.html
Now there are still a lot of tools to do the job right that are not in that kit. For example, when you drill through any metal you are going to get break through. It is the metal that sticks out and cuts you when you drill through. You need to deburr this material, and you need to deburr both sides. Aluminum does not rust but it will corrode and by deburring all your holes helps to prevent corrosion and cracks. Here is your most commonly used deburring tool...You also have edge deburring tools and many other types but for my edges I use a 90 degree die grinder with a green scotchbrite roloc pad.
If you do not have access to a step shear but need a fairly inexpensive way to cut your materials look into getting a pneumatic or electric shear. Here is one that I use a lot!Also, a 90 degree die grinder with a cutting wheel works great, it is best to use beezwax when cutting aluminum. Beezwax makes it cut like butter.
When riveting it is best to use rivet tape or regular masking tape on the heads of the rivet. It helps to keep the rivets from losing their color and helps you from scarring the heads. If it looks like the rivet is smiling at you, you need to drill it out and replace it. Hold your rivet gun firmly against the head with the proper head set (if shooting a 1/8" rivet you will use a 1/8" head set) and you want to keep your bucking bar square and firm against the shop head. The bucking bar will vibrate and bounce a little but you don't want to get crazy with it. The key to shooting rivets is making them all look identical on the shop head side.
When bending aluminum there is a specific way to bend. If you bend it incorrectly it may crack. If it doesn't crack that doesn't mean your good, you created a weak point for the aluminum to crack. You want to bend against the grain. If you have to make multiple bends, let's just say 4 bends, what you want to do is draw your design out so that all your bends are at a 45 degree angle to the grain. I will draw this out on a piece of aluminum later and update this thread to show you what I mean.
Edge distance.I am seeing in a lot of work out there that edge distance is being over looked. That is fine if you are just going for a wild design but if you are building something structural edge distance plays a big role. Edge distance is the distance from the center of a rivet to the edge of the metal. I use 10ths of an inch when laying out my rivets. They are easier to see than 64ths. Using 10ths here is what you should be looking for, 3/32 rivet uses a #40 drill bit and should be 2.5/10 from the edge. A 1/8" rivet uses a #30 drill bit and should be 3/10 from the edge. A 3/16 rivet uses a #21 drill bit and should be 4/10 from the edge. A 5/32" rivet uses a #10 drill bit and should be 5/10 from the edge.
Rivet pitch/rivet pattern is the distance from the center of 1 rivet to the center of the next.
Update -
Bending aluminum on 4 sides. Like I said earlier, you want to bend against the grain but when making 4 bends on 1 piece you will need to angle your pattern so that you are 45 degrees with the grain. On aluminum, they stamp the metal in a way that makes it very easy to recognize the direction of the grain. The stamp goes the same direction. Here is an example of how you make four bends without cracking and to keep your part strong without future problems. ***Also, you will want to drill relief holes if you are making your bends very tight to each other***
***MORE TO COME LATER***