Randy....wow. How long did it take you to shave the peak on yours? Your hood looks great, that is the result I was hoping for if I shave mine. Which I am starting to lean toward, in light of the surprise I just found....

Here's what I just found by staring at it....if it wasn't sitting in the bed like it is, tilted back and at eye level, I wouldn't have found this issue.....

See it?




See the difference in the transition from the peak to the greater hood, on each side?
That explains why one side of the peak was much heavier on the bondo than the other....

 

That also likely explains the soft spots. First go to your local Home Depot or Lowes and buy a HMW plastic mallet. The one you want has a white head and one face is cut to a V shape. If you can't find the right one, get as large a diameter solid head (not shot filled) Reshape one end into a V shape with a course sanding disk on an angle grinder. make the end of the V as wide as possible and 1/2" thick with rounded edges. Do the grinding outside or you'll have yourself and your entire shop covered in white plastic snow.
Now you will need a rubber hockey puck or a short length of wood 2x4 to use as a dolly.
Straddle the fillet between the hood and the peak with the rubber or wood dolly and tap the fillet up from the inside with the crosspeen end of the mallet. As always when doing body work, use a series of LIGHT blows moving the metal a small amount at a time, DON'T try to do it all at once or you'll end up with more dents than you started with. Check your progess often with your trusty straightedge to locate low spots and bumps. reverse the hammer and dolly position and tap down any high spots or bumps from the outside. PATIENCE is the name of the game. It would likely take me at least two days to straighten your hood with my experience, it wouldn't be unreasonable to expect it might take you a week or more.

Sorry, but IMHO a MAPP torch is not suitable for metal shrinking. You need an OX-Ac torch with the smallest tip available. The process works by heating a very small area red hot in a very short time without heating the surrounding area to pull the metal in.
I would definitely invest in a SS shrinking disk. I would be afraid a mild steel disk would warp as badly as the panel.

 

Boz -

I'm glad you like my hood. I LOVE it. Most folks who see the truck really like the look, but don't know why. it is a very subtle mod that stays true to the original design lines, but lightens them.

My hood is not shaved. The peak is recessed into the hood. The ridge of the peak is still in the hood. You'll need to study my album to see all the steps.

Good luck. You might see more of it in this pic:

 

Nice work there, RJ.

 

so I have a question today i was trying to smooth out my rear cab corner that I replaced and it seems like it has a bubble in it that is weak and if I push in or out it pops either way easily and sends that bubble to the lower partof the patch panel. tried using my shrinking disc but it just wont stay where it needs to stay. I have a oxy acetlyn torch would it work better if I heated that bubble up would that shrink it better than the disc? I thought about cutting it to relieve the stress and rewelding it but that might just make other problems?

 

Hey AX,
Progress!
Finally got a day to work on it again.

Got the first patch made....See the "shrink" marks?...things got a little wacky there...



One issue I had was the curve through the middle. My sheetmetal brake has a piece of angle iron turned open side down as the "pinch" bar, instead of solid 1/2" solid steel bar angled on each side to a smooth point.
When I tightened down the "pinch" bar bolts on each end, there was enough flex in the angle iron to keep me from getting a sharp bend through the middle. I went after it with a hammer, and was able to sharpen it up some.

Started tacking the first one in:



Looks pretty close to me:



I got the first one tacked in completely. Do not look at those terrible patches. I put those down in a hurry, and I should have done it right. I'm my defense, the holes they cover were small, and those patches are way oversize. Quick and dirty got the best of me.



Ok, second patch on:



Hit it with the grinder to knock down the welds:



Finished up tack welding it...knocked down the welds and hit it with the angle grinder, 100 grit disc.



And I've started finishing it with a 120 grit flap disc on the angle grinder.

It's looking better than I expected, and I think I got all the lines "close"...which is good enough for me.

I still have a couple of spots to fix, the biggest being where I managed to grind through in one spot.



I still have some finish work to do, but it's coming along better than I expected.



My confession....
Remember the "shrink" marks in the first pic? I used a dinner fork to get those. Wife was not impressed at my creativity.



And yeah, that idea was alcohol inspired...
It would have looked better if I had turned the fork around in the vise and the "shrink" marks would have been an indentation, and easier to manage with the grinder...I'm gonna try tapping them down.

 

Nice work Boz

 

welding shrinks the metal along the seam. If a patch is welded all the way around it will cause the metal to "pillow" up in the center. Often times that pillow if hammered or pushed on will invert, and if pushed from the rear pop back out, an occurrence referred to as oilcanning. Oilcanning can be corrected a couple different ways, depending on the cause, so the cause must be determined first.
cause 1: shrinkage along a weld seam. Lets say I've replaced the lower portion of a door skin by welding a new piece of metal in place along a horizontal butt seam. I then notice the patch seems to be bulged out. Pushing on it feels "soft" and pops in and out. Place a straight edge against the door skin vertically across the seam shows that the door skin above and below the seam are on the same plane, but it is sunk in for a couple inches on either side of the weld, like the line of your upper lip turned on it's side. This is classic weld seam shrinkage. This shrinkage will always be present, the severity will depend on if the welding was done as a series of very short tacks as far apart as possible (no less than 6") allowing each to fully air cool before adding any more nearby tacks, or if the seam was welded with long tacks or a continuous bead so the metal remained hot. The latter will cause much more severe shrinkage.

remedy for cause #1: The weld bead needs to be stretched back to the original length of the unaffected metal above and below the seam. This is done using a slightly crowned faced body hammer and a slightly curved dolly, sometimes referred to as a heel dolly because of it shape. The weld bead should have been ground nearly flush on the outside and any nubs knocked off on the inside. It will be easier and best to do the final sanding of the bead after the stretching is completed. This stretching technique is called ON DOLLY hammering where the metal is squeezed between the hammer face and the dolly making it thin out and grow in size. Think of stretching out pizza dough, as you press and squeeze the dough between your fingers and the counter, the dough thins and dramatically grows in size.
Place the curved face of the dolly against and at one end of the seam on the inside. Push hard against the panel with the dolly. You should be pushing hard enough that you can see the metal move outward looking at the outside. Give the seam a TAP with the hammer face directly over the dolly contact spot. The tap should have produced a sharp ring sound, not a dull thud. If you got a dull thud you missed the dolly contact point, adjust the dolly and/or the spot where the hammer hit slightly until it "rings". A TAP with the hammer is hard enough that if you would have hit your finger instead of the metal, you would have said OWCH! and pulled your finger back, but is not hard enough to have done any visible or lasting damage to your finger. We are not driving nails!!! Move the dolly contact point 1/4" along the seam and give the metal another tap over the dolly. Always maintain pressure with the dolly. Continue this move 1/4" and tap sequence until you reach the other end of the seam. Now check your progress with the straightedge, the dip in the center of the bow should have decreased. Go back to the first end of the seam and repeat the process. Check progress after each series until the panel forms one continuous curve thru the weld seam. Sand the bead smooth without heating the panel and you are done. I like to use a 40 grit fiber (red) disk on my angle grinder for sanding weld beads. Use a light touch and allow to cool regularly to avoid heat buildup. You shouldn't be grinding or sanding metal with anything finer than 60 grit, or it will quickly overheat.

Next: heat shrinking with a torch. Stay tuned!!!

 

Ax....thanks for the detailed description!
I think my next project has presented itself & I may be replacing a panel or two!
Dan

 

PANEL STRAIGHTENING PT.2

cause #2: welding a panel into a frame, or stretched sheet metal from a dent or poor hammering technique. These causes are related as is the remedy.
cause 2a: welding within a frame. If you weld a flat panel within a fixed frame, one that cannot shrink such as smoothing the firewall or replacing a panel in the bed wall, The heat will cause the center of the new panel to pillow or hump up. This cannot be corrected by stretching the seam as in remedy #1.
cause 2b: center of a panel becomes stretched due to a dent stretching the metal, or someone tried to straighten a panel by using ON DOLLY hammering rather than the correct OFF DOLLY technique that does not stretch metal. The characteristics are the same: the panel feels "soft" and flexible, the center of the panel is high compared to the edges when checked with a straight edge but the edges are "on plane" rather than recessed as in cause #1.

remedy for cause #2: In this case the problem isn't the edges of the stretched area or the weld seam, but the surface area of the problem area is too large for it's "frame". To fix this type problem we need to shrink the surface area until the panel fits the frame. It is possible to accomplish this because of the nature of metal when heated hot enough that the molecules can move. When a small spot is heated red hot in the case of steel, without heating the surrounding area the metal "blisters" and thickens at that spot because the molecules like to be hot so they moved towards the heat and packed themselves in closer, pulling the surrounding cool metal in around themselves. Think of a crowd of people all holding hands with each at arms length in such a way that they are all interlocked and can't let go, this is the cold metal. Suddenly a heat source is placed over a small group in the center. They want to get warm so they pull each other closer to get more people under the heat and the ones in the very center even climb up on each other's shoulders to form a pyramid to get closer still. Since the surrounding cold people (molecules) can't let go or move themselves, they are dragged towards the center, reducing the total size of the crowd. If you keep heating the crowd, more will warm up in the surrounding area and the ones in the center will get as hot as they want to be so they will start unpacking and the crowd will spread back out again. If the purpose is to reduce the size of the crowd you would need to apply a great deal of heat concentrated in a small area, then as soon as the pyramid is as tall as possible or the crowd size has shrunk to the size you want you need to pull the heat away and cool the crowd in the center so they are frozen and can't unpile. Now the crowd size (area) is permanently smaller than before. Now we put a large heavy plate over the bump of people in the center and force them to pack themselves very tightly into a nearly single level (some are so tightly packed that they can't get their feet all the way to the ground). Now the crowd covers a smaller area and the center is just slightly taller than the rest of the crowd.
Now we'll replace the crowd in the explanation metaphor with the sheet metal. Tools required are an oxy-acet torch with as small a welding tip as available for the welding torch, not for the cutting head. We want a very small hot flame, so go to your welding supply house with the model # of your torch and buy the smallest welding tip that fits your handle. They are usually less than 15.00. You will need your heel dolly, and flat or slightly crowned face body hammer. You will also need an assistant or two and/or a stand where you can quickly and safely put down the lit torch to free your hands without taking the time to shut it off. You must be able to reach the back of the shrink point with the dolly and the front side with the hammer at the same time. It may require an assistant to take the torch, and/or one to hold the dolly against the rear of the panel if you can't reach both sides. You should also have a pail of water and a rag about the size of a dish towel.
Now use you straight edge to find the center of the dome or hump in your panel and mark it with a permanent marker. (You have already removed all the paint and bondo to clean metal for at least 1 ft or more around where you plan to shrink, and removed any tarry undercoat or paint plus any flamable materials, wires etc. around the inside haven't you?)
Practice these next moves without the torch lit a couple times especially if using assistants, until everyone can work together quickly and smoothly without hesitation before attempting your first "live" shrink.
Light the torch and adjust to a small neutral flame (If you are not sure how to adjust the regulators or torch flame, do some research on the internet or get a skilled person to show you.) The flame should have a short blue cone with no yellow in the center without spraying out like a fan or making a loud hissing sound. Use a pair of gas welding goggles or glasses (lenses like dark sunglasses) so you can easily see what you are doing without hurting your eyes. DON'T try to use an electric welding helmet or standard sunglasses, Gas welding glasses are available at your welding supply or DIY store with plastic frames for < 10.00. now apply the flame so the inner cone almost touches the metal and hold in in place until you have heated a spot about the size of a dime to a bright red. You should see the spot blister up. As soon as it blisters hand the torch to your assistant or place on the stand, and place the dolly flat on the back of the panel centered over the red hot spot (wearing a mig welding glove or heavy leather work glove on your dolly hand will reduce the risk of burning yourself on the hot metal). Using the hammer on the front side give the blister one or two LIGHT taps to nearly flatten it. DON'T hit it hard enough to completely flatten it or get a ringing sound from the dolly or you'll defeat the whole process. You MUST work quickly enough that the blister is still red when you tap it flat. If it has already turned dark, use the torch to quickly heat it red and try again. DON'T try more than two times without cooling the panel completely, or heat a spot red hot larger than a quarter. As soon as you tap the blister flat, grab your wet rag out of the bucket and freeze the shrink by wiping over it. Check your progress with your straight edge. Some times you may find the shrink has divided the stretched area into more than one domed areas so you may need to do a couple more shrinks in the center of each of those areas. You can shrink out a very large stretch with multiple heat shrinks. If you should over shrink an area, you can stretch it back out by using an ON DOLLY hammering method like in remedy 1, but hammer in a spiral pattern starting in the center of the shrink. If the panel is now the right size, but your shrink blister is not completely flat on the back side, hold the flat side of the dolly against the back side a use a close pattern of very light taps with the pick end of the body hammer to flatten. Use your fiber sanding disk or a body file (two sided metal file blade with course teeth curving across it, used on a two handed wood or plastic handle similar to a wood plane in shape) to level any excess thickness in the blister area. Running the file lightly across the panel in a crisscross diagonal pattern will quickly highlight any high (bright) or low (dull without file scratches) spots that may still need more straightening. Small high spots < 3" in diameter are best shrunk down with a shrinking disk. A shrinking disk will not work on large stretches. Be sure to carefully check with your straight edge across the panel to decide which, the high or the low spots, are at the desired overall surface height then bump up the low spots or shrink down the high spots as needed until the whole surface is in one finished plane and is "tight". A perfectly metalworked panel should show even pattern of scratches when sanded over with a "long board" (purchased or homemade 18" or longer sanding backer board) covered with 80 grit sand paper and held parallel to the long direction of the panel but moved with a diagonal stroke. Alternate diagonal stroke directions without changing the axis of the board. Most bodymen stop straightening when all the highspots are at the finished surface level and no low spots are deeper than 1/16" in the center. A light overall skim coat of body putty is then applied and sanded with the longboard using the crisscross diagonal strokes until the metal just starts to ghost through. Now give the whole panel a very thin coat of catylized surfacer putty wiped in to fill any pinholes and/or slight imperfections. Give it another longboard sanding with 120 or 180 paper and if the entire surface is even you are ready for primer!
There is a diagramatical explanation of a heat shrink in my "extras" gallery.

 

SloppyJoe: Thanks!

AX: Amazing explanation, again.
Quick question about gaps between existing sheetmetal and the patch....What is the correct distance to avoid having to do any shrink/stretch work later on? My gaps are all over the place...I have everything from "snug" where I have to tap it into place to 1/8" where I have to drag the weld bead from existing to patch panel.

 

The correct gap is none, maximum should be less than the diameter of the filler wire, the filler wire should be no thicker than the thickness of the sheet metal. Leaving a gap when welding sheet is an old wives tale carried over from the proper way to weld thicker metals where a gap is used, not to control shrinkage, but to assure full penetration.
A larger gap will not evenly dissipate the heat, the edges will get hotter than necessary resulting in melting and pulling back along the edges of the seam, widening the gap still more, before the gap is bridged by filler rod alone. This results in a thick rough porous bead composed of only filler rod unevenly connecting the two sides.
Commonly used MIG filler wire is an alloy designed to "clean" oxides and contaminants and resist oxidation while molten. It has different composition and therefore working properties than sheet steel. It is harder, therefore more difficult to grind and sand generating more heat in doing so. It is also less malleable and work hardens quickly, so it is more difficult to hammer stretch and tends to crack if worked too much. The working qualities of the bead can be improved by using a softer filler wire with properties closer to the steel itself. There is such a wire on the market but since it is made by only one manufacturer, and designed for use on sheet metal and is more expensive it is not commonly known or used or even stocked by welding suppliers. It can however be special ordered or purchased online. It is made by ESAB and is called (surprise) "Spoolarc Easy Grind". It comes in 0.024 and 0.030 diameter on 4" and 8" spools, the perfect diameters and spool sizes for welding sheet metal and use on smaller lower output welders! Most filler wire is designated by a number which designates it's alloy composition. The same number will be the same alloy composition no matter who makes it. ESABs Spoolarc Easy Grind is a proprietary alloy, and therefore does NOT have an alloy #, nor is it made by anyone else. No matter what anyone tells you any other wire is NOT "the same thing" or "just as good/popular". Accept no substitute!!! If the spool doesn't say ESAB Spoolarc Easy Grind on the label it is NOT the right wire! SEG produces a softer bead that grinds easier, generating less heat, reduces gouging/thinning along the sides of the bead and your grinding disks will last longer. It is more malleable and hammer stretches without cracking. Buy it you'll love it!

 

Wrapping this little project up....
Found a nice piece of sheetmetal in a drop pile...perfect to shave that peak. So I spent the $3.40 and went for it before I changed my mind...(again)

Put it over the peak and gave it a quick spray to give me an outline.


Cut out the old, and in with the new...


Spot welding for what felt like days...


Grinding down the welds:


Set the hood up on the truck to get a look at the whole thing...to see what I've done.....


When I stepped back that first time after getting the hood on there, I was grinning from ear to ear. Very subtle, but such a great change. I couldn't be happier with it so far.

Added some braces underneath to fix that oil-canning nonsense once and for all...


Added a skim coat of body filler, and gave it the rattle can treatment.




I still have alot of sanding to do, but I'm completely happy of where I am with it. This is my favorite body line change by far.

Lessons learned:
Don't get impatient with hammering out dents. When you think you are done, you are about halfway done.
I had to use more filler than I wanted too in a couple of spots...nothing extreme, or more than about 1/16" thick, but I "thought" I had those dents smooth.
That rule about "keep your spot welds at least 6" apart"...words to live by.

 

Randy, I like the looks of the 56 hood pie cut around 1 1/2" and think with the hood peak shaved that its more in tune with the round lines of this F100. Searching for directions on how to do both and would appreciate some help on this. Did practice the pie cut on an old hood and it came out OK, however not so good on getting rid of the peak.. Spot welded a 6" x 54" piece under the peak for support, then cut the peak out and added a new flat section ... just OK as some oil canning came up on both sides. Ya, also need help on those oil cans as the hood I now have has it and not doing well getting rid of it. Like said any help would be appreciated - Lawrence at "Petty3377@msn.com"