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how to sand rear fenders properly


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Alright gentlemen it is time I stop messing around and get the back quarters finished. Now as many know I had them put on quite awhile back and now for the first time it has been sitting in my possession for almost a year, owed it for nine. I will show the pics of the weld when I had the fenders done and the work I have gotten to it today at the bottom. I have spent over four hours just looking for the proper way to sand these fenders down with the proper curve, and nothing at all, just long straight pieces which does me no good.

I am using evercoat, and it is epoxy primer everything is being prepped correctly with grit and g&W remover just as Q instructed me before.

I have tried many different methods to get a smooth coat over these bad boys, but for some reason I am leaving high marks or even when I start sanding I am just not doing it right. I know I have a massive challenge with making them look equal, and Q I did make the template like you said, but movers lost three boxes for my garage and they have to be in there. I know I should have left them in my car. So now I have two fenders that are being built up and you can see in the photos where the naked eye, in bad light, can see. Do I need to just suck it up with the long flexboard sanders, because I have a short block but I cannot figure out how to work it and people say it can be done but show me a video, please.

I have been removing the big chunck with da on low and 80, again knock off, but then I switch to 120 to start molding or reducing the highshpots. I think I am working backwards, and Q when I typed in body work your video showed up number on front page, congrats.

This is no doubt the low spot from the weld is still there in certain areas, but I know you guys on here have never let me down, and I just want to make it right. I am working on them each warm day I have, only high 40 todays so don’t think I will be putting it on their today.

Maybe I need to sand harder with hand x’s rather than using anything, but again you will set me straight.

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1973 MACH ONE H CODE "RUSS"

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I cannot help you with this problem, but I am posting because many years ago I did the same task on my coupe. While mine came out very well, they were never "perfect"

 

The area you are working is challenging and difficult-but when it warms up a bit more, you'll get it knocked out faster than you imagine.

 

Glad to see you sticking to it with your project

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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Jeff thank you very much, may I ask what you used a flex board, hand, or? I refuse to let the car just sit with nothing done on it, even if I sale it once completed, I have worked other areas without worry, but I am going to make a video so you guys can show it as what not to do in the future. I am really thinking that maybe the way I am putting it down is not allowing it to build up where it need to maybe, who knows. There is no reason to short change the car now,

1973 MACH ONE H CODE "RUSS"

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I did most of it with a short block and a can of dark primer to shoot a guide coat once I got close. The curves were tricky and I was younger and dumber at the time.

 

What I remember is that I ultimately worked the flat face as close to perfect as possible and then essentially built up the curve with Bondo before sanding most of it back off. It looked good, but it would not be up to my standards these days.

 

Again I posted not to provide helpful information as I am no body repair guy, but rather to share in your pain and offer some encouragement.

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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Thats a tough one cause the weld is in a radius and the heat had distorted the body around it. I would have cut it out square our would have replaced the whole 1/4. Any way a few tips to help out, They make a round sanding block, and a semi ridged block, dont get the super soft sponge type block. don't mix really hot mud, and as it starts to harden take 80 grit and start cutting the highs off, dont get too crazy it will cut easy and will clog the paper up but its easier to get your rough shape if you cut the highs before it fully hardens. It will leave a rough texture in the lows also so the next coat of mud will bond good too. They make some stuff called supercharger that you can use to thin out the mud some also if the thickness is causing you problems. If you need a longer board with flex a yard stick or mixing stick works good. get your rough shape them shoot a coat of primer, use a guide coat to help see the lows and if they are big them skim with anther coat of mud in those areas and prime again.

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I was not a big fan of only this section of the fender but seemed to work out better than I thought. It has come a long way, but a normal flex sand should help me. It looks like I still have a few coats to even get it where it needs to be sanded. So I am putting it on and sanding it right back off,

1973 MACH ONE H CODE "RUSS"

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Thats a hard area to place filler and sand. Its not for the faint of heart but YOU CAN DO IT!! take it slow, putting on and sanding off is common but it can take its toll on your attitude. I have sacrificed a plastic spreader in the past to try to get a uniform coat on a wheel lip. Take a piece of cardboard and trace out the lip of the wheel well on it. Transfer that over to a large plastic spreader and cut it out. This will help spread the filler to a uniform thickness which should remain as thin as possible giving you the proper contours as well, your really shooting for a skim coat. Thats not the Ideal situation but its a method I have personally used in a pinch and will work. I would rather see no filler or just small amounts but Id also rather see $100,000.00 show up on my bank account magically overnight. What Im saying is sometimes you just have to make it work if at all possible.

 

Here are some blocks that are flexible

 

http://search.eastwood.com/search?w=flexible%20sanding%20blocks

 

The foam style blocks with the 3 rods in them are suppost to work well but I have not used them personally. so that is not a testimonial.

 

I use to have a a bluepoint rubber block that had some flex in it and it was 8-10" long it is what I would use but it grew legs and walked away at some point.

 

The key is to work it (hard to describe, Id rather show you) with the side of the block pushing toward the wheel well lip on the main surface of the quarter panel. Work it around the lip sanding off high spots but at the same time trying to keep the contour of the panel. Once again thats a really hard area to work, sneak up on it don't try to sand it off too fast, Thats when the put it on sand it off roller coaster shows up.

 

I wish I could help more and I don't believe I clearly stated the sanding technique. I've also know guys that have made blocks out of various material to meet the challenge at hand. Thats my attempt at helping for what it is worth. Dennis

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Dennis

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I use 36 grit paper on a straight line Hutchins sander. Bought thirty years ago, best investment I ever made. Ingersol Rand makes one also but I have not used theirs. After contouring, you prime lightly then skim coat to fill scratches. Then use da with 80 grit. If you see primer showing through you need to stop there. Don't sand into primer or you risk changing the contour. You can do this in this in a hour or less. If you want to do this without a sander. Contouring can be done with a 14-18 tooth hacksaw blade in semi-hard bondo. Holding blade on each end in upright position. Drag it across the bondo, it will level high spots. Extreme low spots may need additional fill. When you find metal in small areas, a slight bump with a pick hammer will depress it. It's a practice thing.

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I started to work it again only allowing it to set up a little then hitting the hard stuff with a light 60 grit scrub, I am worried that I will continue to add way to much and not take it off but you can tell the front on the drive side and back on the pass side is still low, I will try that blade method I was looking around everywhere for something that would contour easy enough, and walked passed it about 12 times. I was a little afraid to hit it with anything harder than 80 but I think it will take a lot more of course grit and re lay in order to build those up enough. I might have a soft block that will help me and I heard those flex blocks are really good but again not sure it will help with the actual curve.

 

Note, if anyone could take a few shots of your rear fenders around the same angle I have for the front, back, and on top, that way I might beable to help form since I am working blind, bad idea but I have to work with what I got.

1973 MACH ONE H CODE "RUSS"

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First of all, I am not there looking at it but from what I can see you have too much filler on it already. If it was tig welded properly there should not be warping and all your really filling is low slag edge. If you have to build it with filler, the metal work is not good enough. Should just require a skim coat to achieve a smooth surface, otherwise it will crack and separate. Always spray a guide coat...I use flat black, and just mist it on (this will show high spots). Be patient and work slow in these areas. You may have to make your own sanding block to fit the contour (they are available for around $20-30) but, I have even used a rolled up, and taped paperback book before so whatever works. I would not use anything coarser than 80 grit to start, then graduate to 320. After you get it close you can use icing to get it smooth for primer.

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When restoring my F-100 I was running into issues like you are having. I wasted almost a gallon of filler trying to get my roof curves correct. My solution was a pair of the AFS sanders. The small 4.5" hand sander with the nub on it(very flexible) and the other was the 21" one. Boy do they work great on curved panels. They saved me so much time. I'm an avid DIYer and have done a few paint jobs. I wish I found this system a few cars ago.

 

I would like to purchase the long red AFS sander but it is expensive. But I know it would be an easy way to get the long sides of a car laser straight.

 

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Mike

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There are spots I know it is too high but you can clearly see the low spot I am trying to work up in the front and back of fender, really hard to get a good hold on it. I did get me some skids or baseplates that I can use to remove all the excess from here forward. I am thinking about working it down with a 50 grit and trying to focus on the harder areas.

1973 MACH ONE H CODE "RUSS"

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I used a cheese grater type plane with a curved profile and a short flat one as I recall.

http://www.7173mustangs.com/gallery/1_01_07_15_8_53_18.png

 

"I love my Hookers!" and "Get some Strange" probably have a different connotation to non automotive enthusiasts!

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I have a cheese grater in my box, just waiting on the snow to melt, so I can get this going. I cannot wait to report, and I hope others continue to help my knowledge. Thanks gentlemen.

1973 MACH ONE H CODE "RUSS"

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One way I found to work out the quarters was using layout tools - "contour gauge" and measuring different points from a good quarter. Use strong thin cardboard (i.e. a file folder from Office Depot, Office Max). Take a sample about one inch apart, transfer the shape and label the cardboard with the position on the good quarter. Use scissors to cutout the cardboard to create the negative image. I know it sounds labor intensive but it can give you a much better reference point than simply eyeballing it. ----------> Product Description : Contour Gauge, 6 Inches, Steel, Replicates

Construction : Stamped Steel Body With Ruled Edge, Stainless Steel Contour Wires, For Duplicating Contours : 5 3/4 W x 1 7/8" H, Graduations : Inch, Application : Obtains and Replicates Inside or Outside Angles and Shapes For Tiling, Finish Carpentry, Woodworking, Flooring or Carpeting Projects

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One way I found to work out the quarters was using layout tools - "contour gauge" and measuring different points from a good quarter. Use strong thin cardboard (i.e. a file folder from Office Depot, Office Max). Take a sample about one inch apart, transfer the shape and label the cardboard with the position on the good quarter. Use scissors to cutout the cardboard to create the negative image. I know it sounds labor intensive but it can give you a much better reference point than simply eyeballing it. ----------> Product Description : Contour Gauge, 6 Inches, Steel, Replicates

Construction : Stamped Steel Body With Ruled Edge, Stainless Steel Contour Wires, For Duplicating Contours : 5 3/4 W x 1 7/8" H, Graduations : Inch, Application : Obtains and Replicates Inside or Outside Angles and Shapes For Tiling, Finish Carpentry, Woodworking, Flooring or Carpeting Projects

 

If you're having this much trouble with that area on a Mustang then don't EVER try restoring an old Porsche. Those things are full of curves! Trust me - I went through a Porsche restoration when I was in high-school. NOT fun.

 

Why not cut more of the panel and replace it with one of the patch panels that are available? The cut lines are in the "flatter" sections of the panel. You can work those more easily.

 

I think Dynacorn has complete '71-'73 quarter panels available now. You might want to look into those as well.

 

JRP

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