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Rustoleum roller job, what about urethane air dam?


scooterhulk

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Thanks for the input..... :wink:

 

Hurry up and drive it so I'll know whether I'm about to waste my time haha. I started typing a question asking whether you thought I'd be okay rattle-canning it white. But I'm with you, I think I'll take my chances and roll it. It's easy enough to remove if it screws up. I'm sure if I put braces on the bottom of the air dam that it would be fine. I haven't looked into that too much. Perhaps I should...

 

Are you in the middle of a big project with yours, or is it in storage? I've been doing a budget resto on mine. Started in the summer - new frame rails, 4 floor patches, new bottom paint and undercoat, struts, RT dif mount, tie rods, you get the idea. Goal was to keep under about 1500. I'm not doing okay. My gf is cool enough that she's trying to find me one of those ANSA twin tip mufflers for Christmas. I've been trying to build it pinching pennies for 4 yrs now getting ready to do something like this, fixing everything I can for as little as possible. I had no idea I would have gone through so much. Just got lucky and a friend had an empty garage and offered to let me keep it there until I was finished. The down side is I've got about 6 weeks to finish it. We're moving. So, I eat sleep and crap this car right now, which would be awesome except for the deadline.

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IMG_20121103_175926.jpg

 

This is how it ended up looking. It took me about two weeks to get it like this, not including the prep, which I definitely rushed, because I'm sick of driving my zx with all its rust. I just wanna daily it. I put on one coat a day on weekdays and everyday there was wet sanding to do beforehand. I used two quarts of gloss smoke gray and one of gloss black to get this color, thinned nearly 1:1 with mineral spirits, a little heavy on the paint side, to get a milky consistency.

If you wanna do this start right now. Cover your ass with respect to time. As for the bracing, it seems like a good idea, and I had the same thing in mind, but my brace would be an undertray/splitter that mounts to the air dam all the way around.

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That looks really good. I assume you just did it. Was the cold an issue working with the paint? I painted my 78 Yota pickup the same way in March, and I seem to remember it being cold and having no problems. Very cool look with mixing the colors, it looks pretty great to me. I'm surprised you wet sanded after every coat. When I did my truck, I was told to wet sand every two coats, and the first time I sanded I immediately sanded through the two coats I'd just put on. Ended up sanding every three coats after that and wet sanding very lightly with a lighter grit (800-1000).

 

I'm worrying about that a little with mine, painting in the cold. Just hoping for the best because I don't have much of a choice, because of the time factor. I'll start the body work tomorrow and will plan on starting paint Monday or Tuesday. Thanks for the motivation.

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Came in here because I'm doing the rustoleum thing too and haven't gotten to the airdam yet, although mine is FG so I don't really anticipate any problems.

 

Not entirely sure I'm following what you guys are talking about with respect to how you intend to brace your dams, but a lot of people find that they sag in the middle over time. I think it's better to brace it with a piece of sheet metal at the top and have that brace run back to the rad core support than to brace it with sheet at the bottom. Bracing it at the top makes an air dam more effective in that it gives a spot for the low pressure area behind the dam to act on. Bracing at the bottom reduces drag but also makes the airdam less effective because the flat area on bottom no longer sits behind the dam which is what causes a strong low pressure area. You can still get some downforce there by virtue of the air speeding up, but you won't get the total effect of the dam. If you wanted to brace the bottom edge because the air dam was flapping at high speed for example, you could make supports to go from a sheet on top down to the edge and this would be the best of both worlds - until you hit a parking stone. Try and find bjhines' example. Might be in the wind tunnel area. He does nice work.

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If you only brace the center, won't the sides still flex? Mine feels pretty solid, but it sure seems to flex alot now that I have it off the car. Almost rubbery. Just wondering what you think. Maybe because of the shape, the air puts more force on the center, and the shape being like an arch distributes force such that the sides become slightly more rigid. I may be thinking about this way too much. Should I use that BULLDOG adhesive promoter before rolling it? Or would Rustoleum self-etching primer be just as good..?

 

I get what you're saying about the center. Probably alot more movement is gonna happen there than anywhere else. I'd like to see a picture of one, I'll try to find it.

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If you brace the top, you're going most of the way across. Here is bjhines' car: http://forums.hybridz.org/index.php/gallery/image/6316-black-240z-full-frontal/

 

A rad duct is the next thing to consider, just read more in the aero section on that if you're interested, but this would support the airdam just fine and would make it a lot more functional in terms of downforce than not having a brace.

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The air dam you see in the pics was sourced from a gentleman in Texas who apparently tracked his car at least a few times. There are holes cut out on both sides where he riveted in ducting. The center Rad area is DEFINITELY sagging.

I went to the shop earlier to finish welding up the sheet metal for the fuel cell area and came across the plastic mixing cup I used to mix the paint. I squeezed the cup to deform it and the paint cracked off immediately. Brace the air dam well. I will be putting the above mentioned rad area brace in, I am just not sure if I will be needing to work around an intercooler yet...

Edited by B. Whisky
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That looks really good. I assume you just did it. Was the cold an issue working with the paint? I painted my 78 Yota pickup the same way in March, and I seem to remember it being cold and having no problems. Very cool look with mixing the colors, it looks pretty great to me. I'm surprised you wet sanded after every coat. When I did my truck, I was told to wet sand every two coats, and the first time I sanded I immediately sanded through the two coats I'd just put on. Ended up sanding every three coats after that and wet sanding very lightly with a lighter grit (800-1000).

 

I'm worrying about that a little with mine, painting in the cold. Just hoping for the best because I don't have much of a choice, because of the time factor. I'll start the body work tomorrow and will plan on starting paint Monday or Tuesday. Thanks for the motivation.

 

This was done maybe a month ago. Temps were no lower than the 50's.

I mixed an arbitrary amount of paint, what I imagined I could throw on in one session, and it turned out to cover the car a little less than twice, sometimes a little more. I started at the roof, and worked my way around. Rolled out the runs as I went along (always missing a few, sometimes missed alot, these got wetsanded out the next session before coating, with the exception of the last session because I got complacent :/) the area I started on would be tacky enough to lay down another coat once I made it all the way around.

You are on the money when you mentioned wetsanding every two to three coats. I shoulda been more clear with my post. I used 600 grit and with my hand ran it over the paint gingerly while running water over it until I was happy with how it felt. This usually took less time than laying down the paint. Runs were treated the same way.

There is a certain tactile method to laying down paint this way. You don't wanna put alot of pressure on the roller, especialy if the surface is vertical, because it just gives you more runs to roll out, and it causes flat spots on the roller which causes the roller to slide rather than roll, which squeegees ALL uncured paint off, also contributing to the amount of work. Don't attempt to reuse a roller as I did (they are cheap enough) and you will develop the feel of it. Also clean the paint off of the roller handle, the mixing cup and the tray. The paint on the handle interferes with the rolling action, and in my case the early coats of paint where a few shades darker so as I had progressed the old color bled off the cup and tray into the roller giving me a few off color streaks, which I have also made peace with.

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I like the flares, but don't really wanna do them, at least not right now. Maybe sometime down the road. My hood has been rustoleum flat black for 3-4 yrs now. I just don't have it in me to bring it out of the shop with the hood still black. Maybe I'll put a set on when it's time to get tires. I plan on getting a set of the Rota RB's that everyone seems to have whenever my current set of tires die. I have the factory slots with ebay tri-bar spinner centercaps. I like em except for the slightly mismatched finishes. Would like them better if I could find white letter tires in 14". Shooting for a tasteful vintage look that's fairly simple.

 

I learned on my truck not to reuse the roller brush. I was using them 2x with good results until apparently some extra mineral spirits ended up in a brush and bubbled up a huge section on my Toyota. Ended spending an extra few days just on that section and vowed never to risk that again over a brush that's less than a buck.

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