October 4, 2008

Fixing stiffeners, countersinking, priming, riveting - 11.0 Hrs.

Today I squared off against a problem that's bugging me. I have been very impressed and complimentary toward Vans in regard to the quality of these kits. Up to now I don't think I've mentioned a negative thing about them. The quality and engineering is very good for the most part. Having said that, these firewall stiffeners leave a lot to be desired. This is the poorest-made part I've run into so far. There are a pair of these vertical stiffeners that rivet to the firewall skin, and the ends are lapped up on top of the horizontal cross-stiffener that goes across the top. This requires the end of the stiffener to be bent up, so it can rest on the crossmember and still lie flush against the skin below.

The problem is obvious when you look at this part. They attempted to bend the end of this angle piece of aluminum up enough to compensate for the thickness of the crosspiece that the end of this stiffener rests on, as shown below. But in doing so, they created this bump, or crease, in the bottom surface. How are you supposed to rivet this to a smooth flat skin without distorting it? There's a pair of these, and both of these stiffeners are like this. Below, I placed it on my flat backriveting plate and lapped the end up on top of the piece it goes onto, so I could see how bad the problem is. It's horrible. I won't rivet a skin to this part without straightening it out somehow. You can't grind or file the bump flat... the metal isn't thick enough to allow that.

After scratching my head and trying several things, I finally resorted to the brute force method. I thought if I ruined this part, I was going to complain to Vans. I ended up putting my biggest, baddest bucking bar on top of the crease shown above, and banging the crap out of it with a big sledge hammer to try and flatten it out. I left the end lapped up on top of the other one as you see here so it would maintain its shape. I got out my fluting pliers and put a flute in the vertical side of this angle, figuring that when you attempt to bend an angle piece like this, the "extra" metal has to go somewhere. Fluting metal this thick isn't easy. It really isn't ideal, but after a lot of time and work, I improved it quite a bit. I hope Vans can figure out a better way to make this part for future builders. In my frustration and trials, I didn't think to take a lot of pictures. Photography wasn't exactly on my mind.

Moving on, by the end of this session, I managed to get all the parts finished, cleaned, primed, and most of them riveted to the firewall. In doing so, I messed up one of the lower corner gussets by countersinking the wrong side. You can't just flip it over. The holes don't line up then. So I countersunk the other side so it would fit. But now, with a countersink on both sides, I was afraid to use it because the metal is weaker. This corner holds a lot of weight, with the engine mount and so on, so I didn't want to compromise anything here. So I ordered a new part from Vans. Fortunately, it's only a few dollars. I'm writing this a few days later, and you can see the new part above that just arrived. This time, I was careful to countersink the correct side. Then I cleaned it, primed it, and riveted it all in place along with the powdercoated bracket shown above.

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