---------------------------------------------------------- RV9-List Digest Archive --- Total Messages Posted Sat 12/21/02: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 12:00 PM - Re: Oil canning (Steve Sampson) 2. 07:40 PM - Alodine learning (Curt Hoffman) 3. 08:43 PM - Re: Alodine learning (Gary) 4. 09:22 PM - Re: Oil canning (DThomas773@aol.com) ________________________________ Message 1 _____________________________________ Time: 12:00:03 PM PST US From: "Steve Sampson" Subject: RE: RV9-List: Oil canning --> RV9-List message posted by: "Steve Sampson" Dennis - you expressed interest so now it is fixed (finished today) I thought I had better tell you what I learned. The problem was the innermost bay on the outer/under skin where it overlaps the inner skin. I had an oil can valley that came up to the inspection hatch. The solution was to drill out the double row of rivets at the overlapping skins and then rivet them up again. However, when we rivited them up we only riveted up the holes that exactly aligned and we were very careful to rivet 'outwards and forwards' all the time. Then we ran a drill through the remaining misaligned ones, presqueezed longer rivets and closed it up. By this time > 95% of the problem was gone. It was only noticeable because I had become so critical of this area. Today I put the hatch on and with that screwed down, the problem is > 99% gone. (I will always imagine I can see something until I forget which wing and cant find it!) The problem may have been compounded by the fact that I perhaps did not chamfer the inner skin at the rear spar as much as I might so the outer skin had a bit of a step down to the spar. Putting the rivet nearest to the two skin layers into the spar may have stretched the outer skin also. So why were the holes out of line? (We are talking perhaps 1/8th of the diameter of the 3/32 hole. Minute! I should also say that when match drilled my policy is a cleco in every other hole.) The misalignement was a few holes only, and a minute amount, and they tended to be near the trailing edge. When we first riveted it up I think we tended to rivet the rivet that goes through the 2 skins AND the rib BEFORE we did the 2 skins rivet. This I guess is at odd with VANS instruction to rivet 'outwards and forwards'. (This was because the rib rivets are easier than the 'floating' skin rivets.) Perhaps the act of riveting makes 'extra' skin which gets pushed ahead if you always move out, but nowhere to go otherwise. The amazing thing to me is that a tiny movement can cause such an ugly problem. This was the second wing and the problem had not occurred on the first. I worked with a far LESS experienced riveting partner on the first wing! (The only oil canning I now have is in a QB Philippines fuse area and it is very very slight.) In the future I will be VERY careful always to move outwards on skins so 'spare' metal moves ahead. So I hope you have no problems. Remember - always outward! Steve #90360 UK -----Original Message----- From: owner-rv9-list-server@matronics.com [mailto:owner-rv9-list-server@matronics.com] On Behalf Of DThomas773@aol.com Subject: Re: RV9-List: Oil canning --> RV9-List message posted by: DThomas773@aol.com Hi Steve, Please keep us posted on your progrees. I am about a week away from bottom wing skins so I'll be following with interest. Dennis Thomas wings ________________________________ Message 2 _____________________________________ Time: 07:40:20 PM PST US From: "Curt Hoffman" Subject: RV9-List: Alodine learning --> RV9-List message posted by: "Curt Hoffman" Just learned something today. If you are an acid etcher and alodiner like myself- If you leave the plastic covering on a bracket the acid etch and alodine are really ineffective. Go figure. Also- after that little piece of learning I primed the last few pieces of the wing and ordered the empennage today ( I decided to go backwards since I had already built a -6 tail before), Next I figure I'll do the finish kit and then order the fuselage : ). Curt Hoffman RV-9A wings - tail on order 1968 Mustang 302 convertible Piper Cherokee N5320W ________________________________ Message 3 _____________________________________ Time: 08:43:51 PM PST US From: "Gary" Subject: Re: RV9-List: Alodine learning --> RV9-List message posted by: "Gary" Alright, Curt! Sounds like me. I riveted the stiffeners to one side of my elevator before removing the plastic. Thankfully, Van's has begun using colored plastic because of guys like us. One should never be afraid to try a new method. I think I feel inspired to try riveting before I deburr and dimple. Do not archive. Gary ----- Original Message ----- From: Curt Hoffman To: rv9-list@matronics.com Sent: Saturday, December 21, 2002 9:39 PM Subject: RV9-List: Alodine learning --> RV9-List message posted by: "Curt Hoffman" Just learned something today. If you are an acid etcher and alodiner like myself- If you leave the plastic covering on a bracket the acid etch and alodine are really ineffective. Go figure. Also- after that little piece of learning I primed the last few pieces of the wing and ordered the empennage today ( I decided to go backwards since I had already built a -6 tail before), Next I figure I'll do the finish kit and then order the fuselage : ). Curt Hoffman RV-9A wings - tail on order 1968 Mustang 302 convertible Piper Cherokee N5320W --- Version: 6.0.406 / Virus Database: 229 - Release Date: 10/28/02 ________________________________ Message 4 _____________________________________ Time: 09:22:31 PM PST US From: DThomas773@aol.com Subject: Re: RV9-List: Oil canning --> RV9-List message posted by: DThomas773@aol.com Hi Steve, Thanks for the information. I just finished fitting the ailerons and all the aileron hardware today and will start next with nav, landing lights and wiring. With that done it will my turn to deal with bottom skins. Dennis N164DV