Which of the above bolts are originals and which are not? Need help? The ones on the right are the original bolts! If you've watched eBay, you've seen that the price of original 'F'-script bolts is amazingly high. Reproduction bolts are also priced over $1.00 and as high as $3.50 for larger sizes. Even with these high prices you don't know exactly what SAE grade the bolt is. Well, forget about guessing, how about "casting" your own using an amazing product, J & B Magic Weld! J & B Magic weld has virtually the same properties as steel when it's fully hardened and cured and it holds up to heat wonderfully. There is no reason a "cast" 'F'-script bolt couldn't perform perfectly in any application on a jeep as long as the bolt used is of the approved SAE grade!
Here's the products you need to assemble be successful. Basically you're making a mold using automotive strip caulk and aluminum foil for casting an image of the 'F'-script bolt head into the top of a new bolt with J & B Magic Weld. I tried modeling clay and found it too soft to make a crisp impression that held its form when J & B Magic Weld was pressed into it. 3M Strip Caulk is very easy to work but remains very rigid once the image of the bolt head is pressed into it. I also used J & B "Quick Set" Magic Weld because its drying time is faster which allows you to do the finish cutting and sanding sooner. Household aluminum foil, the thinner gauge the better is the third supply you need to get. Of course an Exacto knife, a jeweler's file, scrap cardboard and a couple nice, crisp "donor" 'F'-script bolts and the new bolts you are going to add the F'-scripts to are also needed.
You will need to decide how many bolt heads you are going to cast and work a few strips of the caulk into a ball, working it so all the strips are formed into a smooth ball. Once the caulk is smoothed into a ball, pinch-off a ball, about the diameter of a nickel and roll until it's smooth and then place it on a scrap of cardboard. Repeat this until you have a ball of caulk for each bolt head you are going to cast.
Next you will need to take a small length of aluminum foil, being very careful not to wrinkle it. Cut small 1 ½" x 1 ½" squares out of the foil, again making sure not to wrinkle it. Carefully place the aluminum foil onto the ball of strip caulk, carefully flattening the caulk ball into about a ¼" thick, quarter-size, smooth surface. Repeat this for each bolt head you intend to cast.
Now take your crisp "donor" 'F'-script bolts and while making sure to keep them perpendicular to the aluminum foil surface, press them into the center of the quarter-size caulk ball. Firmly press the bolt head downward until the the hex shape of the bolt head is visible in the aluminum foil surface, about 1/32" of the hex head into the foil. Upon removal you should see the circular part of the bolt head containing the 'F'-script perfectly pressed into the foil and wrinkles from the flexing foil between the circular part of the head and the hex sides, I'll refer to as the "cone" later. These wrinkles can be easily filed off with a jewelers file once the casting is dry, so they're OK. Wrinkles inside the round part are not OK and should be "rejected" as flawed at this point and done again. You can see nice crips examples of the round center and 'F'-script in the following picture:
Next file or grind all the SAE grading marks off the heads of the new bolts and make sure the surface is "scuffed-up" a little bit with visible grinding marks to give the J & B Magic Weld something to stick to. Mix-up a small quantity of J & B Magic Weld as per instructions on the tube. Once thoroughly mixed, quickly (before it sets-up) take your Exacto knife and "frost" the top of each new bolt with a 1/16" thick layer of J & B Magic Weld and then flip the bolt over, align the hex head and press the "frosted" head into the appropriatly sized foil mold. While making sure to keep the bolt perpendicular to the foil mold, press downward until J & B Magic Weld oozes out the sides of the mold as in the following picture. When all the new bolts have been inserted into the foil molds, walk away for about 2 hours.
Ok, now that you've let the J & B Magic Weld set-up sufficiently, test the left-overs on the mixing surface to make sure it's hardened enough to remove the bolts from the foil molds. The trick to removing them is holding the foil down and pulling the bolt squarely away from the caulk, leaving the foil on the caulk and revealing the new 'F'-script casting and kind of a "mushroom" of oozed excess J & B Magic Weld. Sometimes the foil doesn't come off cleanly and you need to pick the remaining flecks off using a pair of tweezers or the Exacto knife blade. Once the J & B Magic Weld is fully cured, you can use solvent like carburetor cleaner to remove the remnants of the black caulk from the 'F'-script. Small bits of foil left on the surface of the casting isn't a problem once it's painted, you be the judge of each bolt you cast and wait until you've put a coat of primer on them to decide which to reject because of foil flecks. The great thing about "reject" bolts is you simply grind the J & B Magic Weld off the top and try again!
Finishing the new bolt head is only a matter of filing (or grinding) the J & B Magic Weld which oozed out of the foil mold off the sides of the bolt head with jeweler's file (or a Dremel tool or bench grinder) and using a jeweler's file (or fine sandpaper) to remove the ridges from the "cone" of the bolt head from the foil creases. Once it's smoothed out to your tastes, spray a coat of primer on it and make the final inspection. If some of the 'F'-scripts are not perfect, simply grind the J & B Magic Weld off using your bench grinder or Dremel tool and try it again! I actually like a few subtle variations so the bolt heads look more original than a cookie cutter. I think this approach to "budget" 'F'-script bolts is much better than the old fake looking "stick-on" 'F'-scripts you used to see. Remember that the later in production, the fewer 'F'-script bolts you'll see on a factory jeep so mix it up with some plain ones too!