First of all, composite vinyl ester tanks work. The aluminum tank thread just has come up on a regular basis over the 8-9 years I've been on the KRNet, thus Mark Jones' tanks. Since I have received numerous private emails and it appears several aluminum tanks are about to be started I thougt I would think out loud about some points not mentioned in a rambling mode in the documentation.
Couple points if you follow the technique at krnet.org/wingtank/ remember this tank was built for Mark's outer wing panel. .032 2024 T3 alclad is a little brittle so be careful in bending the flanges. I had access to a hydraulic shear and hydraulic break. I was able to digitally dial in the thickness of the material into the break thereby obtaining a nice outside radius with not parallel cracks. I tried a piece on a hand break and found my client had the break set for much thinner material. The radius was much too tight and over stressed the material. Most hand breaks you see on the back of your local gutter man are set to bend much thinner aluminum than you will hopefully use in an aluminum tank. If you have access to a hand break, bend some test pieces to set an acceptable radius. Now for you homebrew guys. You can make a break to do the job out of a couple pieces of 2x6's. Lay the pieces on top of each other, face to face, not end to end with the bottom 2x6 extending about 3" longer on each side. Screw on a couple door hinges wide enough apart to get your longest piece of aluminum though. Screw an arm onto the top piece for leverage, use an old broom handle or whatever. Clamp the bottom 2x6 onto your workbench, slide the aluminum between the 2x6s grab your lever arm and bend the material down instead of the traditional up. The built in radius of the 2x6 edges makes for a great aluminum radius. Again though, test a piece first before you. In the case of the baffles shown in the document, bend the front flange first then the top and bottom flange can be bent with the material positioned on each end of the homebrew break. Buy you about 20 clecos, they will be indispensable in the construction. I documented the use of 1/8" AH rivets. In the bottom corners of the tanks, I cut a small piece of carbon fiber and layed it over a thin layer of proseal then proseal somemore over the carbon fiber. I did this just have a little structure to the built up area of proseal. Is it neccessay............I don't know, I just did it that way. Be sure and file, deburr and radius all corners. You don't want to build in stress areas. Scuff up all surfaces to be mated and clean with Acetone prior to using whatever sealant you choice to use. I used proseal as it was originally designed for fuel tanks. I put a rivet in about 1 1/8" apart all through the tank. I didn't want there to be an extended rivet free run where flexing could weaken the bond. That is just what I did, you may choose to do something different. If you use proseal..............do just that.........use it. Don't try and skimp. What in world do you want to save proseal for, use it and throw away the empty quart can. Better yet, shot the empty can a couple times, run over it with the car and then bury it. Don't use hardware store bought aluminum rivets. Buy the AH rivets that are made for wet applications. You may not want to deal with the aluminum enemy by Van's is usually much cheaper than the catalog suppliers on rivets and the hardware you need to build an aluminum tank. They sell to anyone. Take your time and do this right. If you seal every rivet and lay a good fillet along mated surfaces it will provide you with years of trouble free bliss. Maybe went a little overboard on the bliss thing but who wants a leaky tank. Now a question since I haven't looked on Mapquest yet. How long a drive is it from Red Oak to St. Louis. My oldest son plays college football and has a game in St. Louis the Saturday of the Gathering. If I can swing it I would love to make the gathering on Thursday and leave out early Sat. to make his game. If Steve will do it, I'll bring along some "stuff" and put on a forum on aluminum use in a KR on Friday. Dana Overall Richmond, KY RV-7 slider/fuselage http://rvflying.tripod.com do not archive _________________________________________________________________ Help STOP SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail
