theastronaut

Welding will always shrink and cause distortion, but it is possible to reverse shrinkage by stretching the weld to reverse the cause of distortion. I see a lot of people heat shrinking all around a weld seam to take the distortion out but that's the wrong approach and it changes the shape of the panel by losing a lot of crown to shrinkage.

To weld the skin on, I started with a few tacks. I used a piece of aluminum c-channel to show the low spots that are created when welds shrink, since it flexes in an even arc. Each weld was planished/stretched via hammer on dolly stretching until the arc returned. In the spots I over-stretched and made a high spot, the next round of weld dots would shrink the high spot back into shape. I've mentioned hammer on dolly stretching to reverse weld shrinkage before, but showing it with c-channel gives a clear visual on what's going on. The low spots before planishing. No low spot in between the welds. After planishing the first and second rounds of weld dots- the arc is restored. This one was over-planished which made a high spot. Welding directly beside it shrunk it down to the correct arc again. Welding directly beside another weld dot lets the previous weld act as a heat sink so the HAZ isn't quite as big for less overall shrinkage. I can keep the HAZ down to about 3/8" wide using this method. Thin pry tool used to align the flushness of both panels. Flange detail. After way more weld dots and a lot of hammer/dolly work I had the overall shape pretty well where I wanted it. I used the shrinking disk to pull down the high spots along the seam, and there was a high spot from top to bottom about 6" inward of the front edge which gave the door too much crown front to rear and made the front of the door dive in at the fender edge. Cleaning the fingerprint rust off with a wire brush before DA sanding the skin. Wiped down with mineral spirits to check the reflection. Not perfect, nowhere near metalfinished but should be good enough to be skim coated. I'll still probably need to do some final tweaking to the overall contour to get an even arc across the fender and door once it's reassembled.

Building the lower door skins. I started by making templates of the cab corner and fender bottom so I can match the skin to the adjacent panels. The inner door flange was marked and trim to make room for the outer skin. Skin shaped on the english wheel using an inner tube on the upper wheel to make the top to bottom curve without adding any crown front to rear. I did make a few passes without the inner tube to add a slight amount of front to rear crown to match the shape above the patch. Lower edge bent in the brake as far as possible. Using a slapper to take it from this angle to nearly flat. Pullmax with delrin dies leftover from the fender top, with a strip of 1/16" thick metal as a spacer so the flange isn't fully flattened. This leaves enough room for the skin to slide over the inner flange but leaves minimal hammer/dolly work to make the hem snug on the flange. Also minimizes the change of stretching the flange when hammer/dollying the hemmed flange flat. Test fit at the correct height to match the fender bottom and cab corner. Scribing the fold lines using a tool that references the fender edge for a consistent gap. Establishing the fold on the bead roller. Test fit. The door needs to be adjusted back a hair to even out the gaps front and rear. Overlapping the blacked out original skin to scribe the cut line. After cutting, zero gap except a slight amount at the outer edges for tweaking the flushness with a thin pry tool- no rear access due to the inner flange.

I ran into door seal fitment issues at the a-pillar. I wanted to go ahead and install the seals so they could break-in/settle, and to have them in place when finishing up final flush fitment tweaks before filler work starts. They push the panel out slightly so they need to be in place and settled when final adjustments and block sanding are carried out, otherwise the panels wouldn't be flush when it's assembled for the final time. I'll use wide masking tape over them during bodywork to keep overspray and filler off them so the same seals can be used for final assembly. Earlier in the thread I posted that I had to make some hinge pocket tweaks to adjust the door hinges outward enough to make the door frame flush with the a-pillar. This made the seal have a few spots that didn't touch the pillar when the door was closed. The seals were also pretty lumpy which didn't help, which was remedied with a heat gun. The seals were temporarily held in place with a thin bead of Dekaseal. With a light held behind the pillar you can see light is coming through the gaps. The starting point- cleaned with a wire brush on a drill to prep for welding and epoxy. I trimmed a piece of 1/16" steel to weld on top of the original flange. 1/16" layer welded on, prepped for epoxy primer. Notice the slight gap left on the outside and upper edges to allow for seam sealer. After the epoxy cured for a few days I applied filler to get the surfaces 100% flat and smooth. The inside corner edges were not filled to allow for seam sealer later on after more epoxy is sprayed. Leaving the edges unfilled will allow for any flexing that might happen, and seam sealer is soft enough to flex without cracking. I'm not a fan of jambs that are 100% smoothed with filler; cleanly shaped seams with cleanly applied seam sealer looks more detailed and allows for flex. The door seal fit was checked again with the light, and with no light showing I used a strip of paper about 2" wide to check that the seal had adequate pressure against the jamb. This gap looks a bit rough since I was just trying to make the seal fit for now. There is a factory seam underneath here that I didn't want to fill over, but I wanted the transition from one section to the other to be smooth and level. I'll use a 1/16" thick piece of plastic in this gap and fill against it to make a consistent gap width, radius those edges so it looks stamped, then fill it with seam sealer for flexibility. Might have some people questioning the use of filler in jambs... all show cars are done this way (usually with the seams filled over) but shops usually don't show these details because of the negative connotation often associated with filler. Figured I'd post all the details and not hide anything, and show the reasoning behind what I'm doing so people can see that filler used correctly has no drawbacks.

With the fender top roughed in I wanted to address some issues with the factory fender mounting points before welding the new top on. The stock method of fastening the fenders uses clip in U-Nuts, which don't sit flat on the flange. That makes shimming the panel for alignment inconsistent, and the area the clip inserts into can flex since there are two openings for the clip- not a lot of solid metal supporting the clip. I want the mounting points to be as solid as possible so the panel alignment can't move around once the truck is on the road and the panel attachment points are under stress. After bolting the fender down using the stock clips the panel is warped around the clip. Having the fender on and off during the mock up/fit stage really made it obvious how inconsistent the panels go together, especially when adding shims into the mounting points to dial in panel flushness or gaps. It also warps the panels that the fender was bolted to, again making shimming the panels apart inconsistent. There's a flat dolly held behind the hole to show how warped it is, which also was warping thin shims. To fix this, I cut out the whole area and welded in 1/8" plate with 3/8" nuts welded in the back side. The mounting face is dead flat this way, it won't flex, and the larger hardware can be locked down much tighter to keep the panels from shifting once it's being driven. Shims also fit dead flat each time the panel is test fit for consistent fit every test fit. Once the fender fitment (along with all other panels) is finalized I can make a chart of each mounting point to record each shim stack height, so during final assembly there is no guesswork needed to get the panels back where they were. The fender bottom mounting tab on the cab had been slotted for more adjustment range and was just made out of a couple of layers of sheetmetal so it was pretty flimsy. After getting the fender in the correct position it still needed more slotting to clear the bolt. I cut it off and welded on 1/8 plate to make a stronger mounting point and to reduce the hole size to just what was needed so a huge fender washer isn't needed to find metal to clamp down on. Bolt head cut off, sharpened to a point to mark the new hole location. I'll go back and add a couple of gussets around the bolt hole to make it even stiffer. The upper rear mounting point is impossible to reach to add or take out shims, so the whole fender has to be removed and shims taped in place to change the shim stack, but with the stock clip wobbling around shimming was never consistent so it was difficult to get the top fitting flush to the door. The bolt goes in from an access door inside the kick panels, so I drilled another hole just under the stock hole and welded in a nut to make a threaded adjuster to move the panel in or out. The fender has a 1/8" stainless pad welded onto the brace for the adjuster screw to rest against- I can leave it bare metal without having to worry about it rusting. Leaving it bare also means there won't be any coating that can chip out later and alter the fender to door flushness.

Since the outside of the fender was too flat, the inner brace was also flat so it wouldn't clear the added depth of the new fender top. I used tuck shrinks and the shrinker to match the curve of the fender top to the hood and cowl profile. Folding the inner flange over after getting the curve correct. Reshaping the inner brace to match the hood/cowl curve. You can see the incorrect shape with a kink in it in the first two pics. Initial test fit. Since the fender bottom didn't have to match the height of the door bottom or rocker bottom (door bottom isn't established yet) and the top is all new so it's height can be adjusted, that let me move the rear of the fender around until the rear edge was parallel to the door with the correct gap. I can match the new door bottom edge to the fender bottom when I make a new door bottom. Checking the inner brace height vs where the new fender top needs to be with string to see if the brace is too tall or too short.

No problem! I usually use build threads as a way for the owner to keep up with everything done to the build, and it'll be a good reference in the future if the truck is ever sold. I copy/paste the updates across a few forums I'm on so others can follow along too. I was a little hesitant to post it here since it has some modifications and isn't 100% stock, but it's been well received here.

Moving to the fender fitment. We bought a pair of aftermarket fenders since the originals were rusty. They're well made from 18g, or at least as well made as originals but... original fitment left a lot to be desired. The top of these, and the tops of original fender are too flat compared to the shape of the door which makes the gap between the cowl and fender, and hood and fender look off. The door has a deep concave shape under the body line stamping but the fender is only about 2/3 as deep in comparison. After looking at the repop fenders, the originals, and other trucks at shows I decided to cut the fender tops off and make new pieces that are shaped correctly. Checking the fender top with aluminum c-channel to see how far off the edge of the fender is. Notice that there is a kink in the fender top, its not a smooth curve from front to back, and how the rear edge being too flat makes the fender fall away from the much more concave door edge. Top cut off, making a rough pattern to cut new tops out of 18g. I bent a 1/4" strip of 18g into the correct shape that the fender top needed to be to match the door's shape and be tall enough to close up the gap between the hood/cowl and fender top. This was traced on steel plate to make Pullmax dies. I also made a second set of dies out of plastic with less curve top to bottom that matched the fender profile at the front of the fender. Making a test run on scrap to dial in the dies. After a couple of full depth passes to shape the blank, I use 220 grit on the top and bottom of the scrap piece and black out the dies with sharpie marker to find the tight/loose areas on the dies. Tight areas can pinch and stretch the metal you're shaping which adds the wrong shape and can add a weird twist to the panel you're shaping, and loose areas don't add enough shape. New vs old fender shape. To make the panel, I bent an edge 90* on brake, then used that edge as a guide in the Pullmax. I made full length, full depth passes with the plastic dies first, then switched to the deeper steel dies and ran those full depth along the back 1/3rd of the panel, then used the lower adjuster to fade the full depth shape into the shallower profile at the front of the panel. The very tip still wasn't as sharp as I wanted it but I was afraid to make the Pullmax dies any sharper out of fear that a sharper die would stretch or puncture the edge of the panel. So I made a pair of dies to use in the arbor press to sharpen the edge by hand. Before/after top edge sharpening.

Haven't taken the time to update the build thread in awhile. I got sick with Covid about a week ago and I'm not quite back to 100% yet so I figured this would be a good time to start catching up on pics. Hood welded together 100%. I'm pretty happy with how all of the folds/overlaps came out. Not perfect but they'll be really nice after bodwork and seam sealer. With the braces in I was able to finish bodyworking the inner braces. On the front I used a long flexible spreader to pre-shape the filler and minimize how much sanding was needed. All of the smaller areas skimmed, blocked, and blended together. Rear brace bodywork roughed in and shot with epoxy. With the hood welded together I could bolt it back on for final test fitting, except the hinges weren't quite cooperating. Taking all of the play out of all of the joints meant that the angle of the hood mounting pad had to be exactly the same angle as the mounting point on the hood brace when the hood is closed and the hinges are adjusted to the correct height. There is no way to adjust this angle, except by altering the center to center length of the link that connects the two main arms and keeps them in sync. Apparently the hinges were sloppy enough from the factory that this wasn't an issue. I noticed that aftermarket billet hinges for other cars had an adjustable link, but there is no room for that on F100 hinges, so I had to come up with another option. The pins that hold the link were fixed in place, so I knocked the pins out and machined new pins with an eccentric end and a slotted head so I could adjust the eccentric with a small screwdriver, then lock it down with a lock nut. I forgot to take pics of the whole process, but I turned down 3/4" rod on one side to 1/4-28" and made a matching threaded aluminum sleeve that would fit in my boring head for the mill (I bought a new lathe and don't have it up and running yet). With the aluminum end clamped in the boring head, I could offset the head and turn the end down to make the offset locating pin for the link. Range of adjustment- Video of the hinges before making the eccentric modification/adjustment. Notice that the hinge stops traveling before the hood is 100% closed, then any further attempt to push the hood closed only flexes the rear brace. Using the eccentric to angle the front of the mounting pad down fixed that issue.

Trucks are as popular if not more popular than the usual classic cars in the US nowadays, lots of time and money being spent to build them to very high standards. Thanks guys! Still working on it, just haven't been posting often. Working on an update now.

With the skin finished that just leaves the braces. I had shaved and roughly straightened them but for the level of detail I'm shooting for just spraying high build and wetsanding the primer smooth wouldn't be nice enough. So I roughed up the epoxy and started filling and blocking each facet to correct and smooth all of the stamping distortion, spot welds, and uneven corner radii. Tape used to set the width of the radius, and tape on the edges of the block to prevent the already-established flats from being oversanded. This is something I've had in mind for awhile but hadn't got around to making yet. Correcting shapes with filler like this means you spend a lot of time sanding an even radius into the edges, and they don't always come out 100% perfect. Since getting the Bridgeport and lathe and learning more about cutting tool geometry I had the idea to make my own corner radius tools to shave an even radius after blocking two facets to a sharp 90* corner. I started with a piece of 1x1" steel to check my idea and see what kind of relief angles it would need to work correctly. I ended up on a 7* inside back cut just along the front edge and 7* positive rake angle ground into the face. I used a 3/16" endmill on this one but bought a set of endmills from 1/8" to 1/2" to make a full set of radius tools, and I'd like to make a set for both 90* and 45* edges. I'll make them more ergonomic with a handle, this was just an proof of concept test piece. I did look around at some of the radius tools for woodworking but they didn't seem like they would fit between panel gaps to set the final panel edge radius after blocking the filler/primer.

The battery had exploded at some point and etched the underside of the hood, which left some rust pits that sanding didn't strip. I marked those areas and spot blasted them to remove all of the rust. After blasting I washed the hood inside and out with Ospho to remove the fingerprint rust, neutralized it, wire brushed the inside to remove any flash rust, then DA sanded and shot the inside with a couple coats of epoxy. I wanted to fix the worst areas while the braces were out for better access so I skimmed/blocked them, then shot white epoxy over the repairs and behind the braces since the truck will be red/white and the inside of the hood will be white.

The battery had exploded at some point and etched the underside of the hood, which left some rust pits that sanding didn't strip. I marked those areas and spot blasted them to remove all of the rust. After blasting I washed the hood inside and out with Ospho to remove the fingerprint rust, neutralized it, wire brushed the inside to remove any flash rust, then DA sanded and shot the inside with a couple coats of epoxy. I wanted to fix the worst areas while the braces were out for better access so I skimmed/blocked them, then shot white epoxy over the repairs and behind the braces since the truck will be red/white and the inside of the hood will be white.

Thanks Mike! New lower corner tacked in place, corner profile needs reshaping so both sides of the seam match. Hammer on dolly stretching to raise the lower side. Lower section opened up for a filler piece since the gap was too wide to weld. Other corner fitted and welded. Marking the inner flange to trim off the uneven edge. I made a template of the cowl's profile from 20g bent 90* then shaped with the linear stretch dies in the pullmax and the hand shrinker/stretcher, then built the structure up top to keep it from flexing. I used it to check and correct the hood skin. Lower edges of the cowl marked to match up the hood edges. Hood hung at the correct height to match the shrinker/stretcher jaws. Before/after correcting the hood profile. Double checking the hood skin fit before welding the braces in.

More hood details. With the front and rear braces tweaked to fit better, I bolted the rear brace to the hinges, clamped the front in it's final location, and the new sides were spaced off the fenders and held in place with a couple of sheetmetal screws. I used tubing to make temporary braces to hold all of the pieces in place so I could begin fitting the skin to the braces and sides. The rear corners of the rear brace had tabs that fold over the hood sides and spot weld into a recess. The old tabs weren't the same shape on both sides and were in rough shape from all of the spot welds being drilled out, then the tab pried up to separate the skin from the brace. With the sides mocked up I made tape templates of the new tab shape to match the recess size. Instead of welding across the straight edge of the brace I made a rounded patch so the tab could be bent along the crease without worrying about the weld seam cracking. The recess didn't match left and right, so the new tape templates and tabs didn't match... I didn't catch that when I was making new hood sides using the original sides as templates. To correct that I trimmed both tabs to match and marked where the recess should end and reshaped it to fit the shortened tab. I taped a piece of 18g underneath to use it's edge as a guide for reshaping the recess. I relief cut the front corners of the skin to make them easier to reshape, and roughly marked the area that needed to be stretched to correct the shape. Edges pulled out flush with the upper grill panel, copper spoon used to weld a temporary bridge to hold that shape. Cardboard template of the upper grill panel's profile, tape template of the new hood corner.