This post shows the process of fabricating a small panel with a good amount of shape made easy. Here’s the panel we want to copy, it’s just simply too far rotted to use on our truck. It is the panel that goes below the grille on the front of a 1938 Chevy truck, so it makes sense that it was heavily used and abused. These panels are impossible to get in good condition because they are trashed on every 1938 truck out there! Fenders are a similar situation, as anyone who had searched for 1938 parts will tell you.
And a view of the backside of the panel for you to get an idea of the shape and condition. Look at how you can see through the panel in many places, that’s why this is beyond repair. A less skilled fabricator might try and make a patch or two, then cake over the rest of the panel with body filler and stick it back onto the truck. But a “restoration” job like that won’t hold up very well.
Step 1 to fabricate the grille chin panel – trace and cut
Let’s start with a fresh piece of sheet metal, this is 18 gauge steel, just like the original panel (although after weathering it’s clearly thinner than it started out). We traced out a general pattern that we’ll need, taking into account how the shape will change the flat pattern. This means you are not literally tracing the outline of the panel, leave plenty of room for shaping, trimming, rolling the edge, etc. An alternative is to trace the original onto a paper pattern, then copy that onto your new sheet metal. I skipped that step here just because I have a lot of experience. The paper pattern will also give you a guide as to where the tucks (shrinking areas) are.
Step 2 – hammer and sandbag
Now to put some elbow grease into it with a hammer and sandbag. Let’s hammer form to get a very rough shape similar to the original. This takes some trial and error. Keep offering up the new panel to the original to see where you need more shape (and possibly where you have stretched the material a bit too far). You can fit the panels together and rub them around a bit. The purpose of this is to make evidence marks that show the spots where you need more shape.
Here you can see the very rough form of the panel taking shape.
You can also see how much extra material I have around the original panel. The center of my new panel is where I am comparing the shape and where I have been hammering the most. At this point, I am pretty close to being done hammering. Here is where you can rub the panels together.
Step 3 – Power hammer and/ or English Wheel
Now we are ready to smooth and refine the shape on the power hammer. In reality, I would be going back and fother from the power hammer to the sandbag to create the shape. Fabricating a panel is an iterative process and you are often repeating, offering, back and forth. This step is similar to above in that you need to work it and then compare to the original to see what areas still need your attention. You can also see another reason why we left so much space around the panel, we can leave the edge to pucker up and not spend the time to stretch all that part out, we’ll just trim it. Once I get the panel to about 95% there, I will use the power hammer for smoothing only and not go back to my sandbag.
An overview of the panel fitment at this point in the fabrication.
And here’s more of a side/ profile view so you can see how close they are fitting together.
And here’s a view of the outer faces of the original panel and the newly fabricated one.
Step 4 – fitting to the car/ truck body
In this case, we are fitting to the lower grille, so let’s mock it up and mark and drill these mounting holes. It’s smarter to mark and drill from the body side instead of the original panel for this step, you will get a much better alignment. Also, make sure you don’t do this too early before you have put all the shape into it, or your holes will be off by more than you’d think!
Here are some clecos to hold in place for marking the final trimming/ folding/ edge lines. We also want to pay attention to how this new panel flows into the grille shape. You don’t want a sudden change in the angle or shape where it meets the grille.
Step 5 – final trimming and fitting
Now take the panel off and make your final folds and trims. Then we can mock the panel back up and check out all the angles. Finally, this panel will be welded to the rest of the grille surround and then metal finished.
Here’s final close up of how the panel fits up to the original grille, nice and tight, just like the original chin panel.