Cowl band polishing my way

[Kevin in NJ]

I am try to do a post using only my iPhone so let's see how well it works.

Had a very nice cowl cowl band. Just a deeper dent at the hood center and a few minor things else where.

Made some forms using ground down carriage bolts and worked the dents. Them ran through various grit papers till 2000. The key is learning when you got all the last grit out. Not easy to learn and I do use a magnifier to help my eyes.

I made up a form to hold the band. Pretty simple out of some 1/4" ply with a 2 x4 brace across it on one side and some ply braces on the other. I sanded the edge to go into the grove on the band. At the bottoms I cut a 90 degree to the bolt and made up a metal bracket out of scrap.

The bubble wrap was to prevent accidents at the end I was not watching.

[Kevin in NJ]

The iPhone only seemed to allow one picture to go in.

I think it is because they all use the same name in the upload process.

[Ed in Maine]

Kevin, I have this job ahead of me. Like you, I have a nice cowl band but with a deep dent on top. You mention that you ground down a carriage bolt head to (I think) conform to the inside of the band but what did you use to support the band on the outside, convex side? Also, what was the first sandpaper (roughest) grit that you used when starting cleanup? Thank you, Ed

[5window]

Damn, thought this was how to polish a cowl band WITH an I phone. Sorry.

[karasmer]

Wow that was easy, great timing, I pulled a cowl band off another A to use on my roadster and jumped on here to check for hints on polishing, Thanks

[Kevin in NJ]

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I have attached a picture of the anvils I made to level the dents. What I noticed is these shapes have to be made for the cowl band you are working on as I have 2 distinct shaped cowl bands. These tools would not work on the other band.

Now making the tools can be a problem. The insertion of the mounting stud deforms the end some from what I can see. It happened I had cut up a cowl band that was really bad to get some stainless to weld up a radiator shell. It had the same shape as the one I was working on and I could use that cut section to make up my tools. I used a fairly large carriage bolt. The neck needs to be made thin enough to fit in the opening of the stainless. You do not want it too wide as the cowl band is a constant curve. Annealing the stainless helps in moving the metal. It does move easier if you heat it up till it changes color.

I should add that I use a small body hammer. Well I think it was jewelers hammer. It is light and I do not use very hard hits. Just working around the dents they work up on their own. If you are using a regular auto body hammer you will hit it too hard! You will have to control the drop quite a bit as the regular body hammer is just heavy. You also need to have a very smooth face to avoid making dings in the metal surface. Lots of little hits is the best way.

Some of the dents needed a final leveling with a file. You want new sharp files and a lot of teeth per inch.

Sanding was with a variety of papers and techniques. I was learning as I went along so what I tell you is not the best way I am sure.

The areas I hit with a file I used a longer flexible sanding block (I have a bunch of Durablocks, pricey but helpful) with 80 grit. The 80 was tough to get out so I started using 180 wet. Then you can work up 220 and I made a jump to 360 cause that is what I had. With each grit you need to change direction and use light to see the levels of scratch.

Now I also found some quicker cutting with a DA with the pad locked to make it more like a sander. I used some 3M 320 that I had. That was nice for faster cutting through my not getting the coarser grits far enough out.
I also tried some 1000 and 1500 on the DA, but that paper is for dry cutting paint and did not do a good job. The 1000 did a better job then the 1500. So I stuck with a 400, 600, 1000, 1500, 2000 wet. Lots of work.

For buffing I have a real 3/4 HP Baldor I picked up like half price used at Hershey once with the stand. One the way back, it was white field on the airport, TarHeel had their booth so I stopped for advice. Great people to deal with and they sold me what I needed.
So I used their grey on the tight wheel (I forget the name) and the white on the loose wheel.

So that is the rest of the story done on my laptop and regular camera.

[Doug in NJ]

Originally Posted by Ed in Maine

You mention that you ground down a carriage bolt head to (I think) conform to the inside of the band but what did you use to support the band on the outside, convex side? Also, what was the first sandpaper (roughest) grit that you used when starting cleanup? Thank you, Ed

When I worked on my cowl band, I also had to remove a couple of dents. Here is what I did to support it: I took a little tin can and cut some notches in the top edge so that a un-dented section of the band could across the top, and then I filled it with plaster to that I would have an impression of the band to serve as an anvil when bumping out the dents:

http://31ford.dougbraun.com/All_Photos/IMG_6259
http://31ford.dougbraun.com/All_Photos/IMG_6261
http://31ford.dougbraun.com/All_Photos/IMG_6262

I also used this technique to get some dents out of my zinc sill plates.

I sanded out some deep scratches in my radiator shell, and it took forever. I made one mistake: I started with fairly coarse sandpaper (220?), and as I used finer grades, I didn't fully sand out the scratches from the coarse sandpaper. These scratches were disguised by the matte surface as I sanded with 320, 400, 600, and 1000, and they only became visible as I polished the metal with a buffing wheel. So I re-did the sanding over the entire shell with 400, 600, and 1000, and after the second polishing, there were still a bunch of scratches. So I did all that sanding a third time, and finally it looked OK.

Doug

[Kevin in NJ]

I think we all go down the path of too coarse a grit then have to back track more then once.

Part of the learning curve. That is where I found 360 on a locked DA let me cut faster but not leave me with deep scratch. Even that I over did.

Stainless is kind of forgiving. You can not burn through like with paint.

[theHIGHLANDER]

In most cases, if you're patient and use the smoothest file to do the work, you can start with 400 on a locked or dedicated DA sander. I have a DA with nothing but a boss to hold a disc, no orbital head. It's almost exclusively for metal polishing. Another trick/tool/idea, if you have a straight line sander they too go a long way toward making easy to remove scratches. 3M used to have 400 air file (straight line) paper. A luxury tool for most, I also have a small "jitterbug" sized Nat'l Detroit straight line sander with a 3/8 stroke and a water attachment. I've tried sewing machine oil for lubricant vs water. Not better enough to warrant the mess (!). I also do a lot of chrome prep. Better I get paid vs the chrome $hop...

[karasmer]

I am a bit nervous with getting the stainless too thin in areas, with the filing, sanding routine.

[Mike V. Florida]

Originally Posted by karasmer

I am a bit nervous with getting the stainless too thin in areas, with the filing, sanding routine.

That's why it is of utmost importance to remove the dents first to almost perfect level then use file, sandpaper.

[Kevin in NJ]

With annealing and gentle hammering the stainless you get it pretty close to level. So you are not removing a lot of material to get it optically level.

In any event, it is part of the art and fun of working on the stainless. It just kind of works in the end and you can get pretty good results at home. So do not worry a lot and just do. Besides, junk practice trim is quite available and very cheap. I started with a junk one that was radically beat up all over. Major dents in the two bends will make a band unrepairable, at least to my skill level.