Wednesday, May 15, 2013

How to Make Segmented (13 or so panel) Endcaps from Sheet Metal

I know this is a little behind the timeline of our renovation, but hopefully it will be useful to somebody who is attempting this same feat.  Or maybe we will renovate another trailer (insert good hearty laugh) and I would like to remember how I did it.  Before I started on the endcaps, I had only seen pictures of the finished product, without much explanation.  May you not have this same misfortune. Please don't take this as the only way to get the job done.  It is just some of my thoughts on the process.  

1.  Use the old endcaps.  It was useful to have the old fiberglass endcap for a starting point, but I think you could do it without if you have stiff enough template paper.  I cut each end cap into two halves so that I could put them in and take them out by myself.  A reciprocating saw got the job done, but I would suggest cutting them up at the very end of your work day because that fiberglass turns into dust when you saw through it and will get in your hair and on your clothes and smell awful, so you don't want to be traipsing around all day with that particular stink.  Oh yea, wear a mask while you do it.

2. Make a template.  I made a paper template and taped each piece to the endcap.  There will be two edges to your metal panel (excuse the Captain Obvious moment).  One will be hidden by the panel that overlaps it, and one will be exposed.  I would recommend folding the paper over for the "exposed" edge instead of cutting or marking it.  This way, you can easily change the line if it looks off, and you are less likely to get funny waves and dips if you make a smooth fold.  It is only paper and you have lots of it, so work, stand back, rework and so on until it looks good from a few feet away.  Trace the line where the folded side overlaps the next panel so once you have the metal cut, you know exactly where the next panel will overlap.  We will call this the "overlap line".  This will also help with the cutting stage. 

 If you have a mill finish (with a grain) to your metal, mark where the center of the visible part will be.

(orange lines are the approximate center of the "will be seen" section, pink overlap line is where the finished edge of the next panel that will go)  The good news is that you only need to make pattern pieces for HALF of your end cap.  Just flip them over and cut the same thing in reverse for the other half!  Number your pattern pieces in sequence.

3. Transfer the template to the metal.  I used metal that had a dark blue paint on one side and a mill finish on the other.  I wanted the mill side to show, so I traced everything onto the WRONG (back) side of the metal, pattern face down so that when it was cut out, the mill finish side would match the pattern.  Be sure to measure the distance from the straight edge of the metal to that center mark on your pattern so that the grain will run the right way.

You don't need to trace the overlap line from the top picture onto your metal, but save your paper pattern.  See how it looks like that is not the center of the panel?  That is as it should be.  You are only making the grain look right only for what will be visible.  
If your overlap line gets close to the edge of your pattern like so:

cut the metal a generous distance from that overlap (pink) line, otherwise you will end up with a gap between your panels when you go to rivet them together.  Number your panel according to the pattern you made.

4. Cut the panels out.  Most of your cut lines will be curved, so you will need a pair of electric metal shears.  They have two bars that are stationary and one that makes a "nom nom" kind of motion in between the two stationary bars.  This can cause the metal to buckle where you are cutting if you make any kind of rocking motion with the shears or if you go at a slow pace.  This will show in your finished product, so avoid it if you can.  Make sure your cord won't get caught on anything so you can make one clean sweep of it, take a deep breath for courage and then make one long smooth motion with the shears.  You will notice that your shears may have left long scratches on your pretty metal. Because the pattern was traced onto the wrong side of the metal, and you cut it out that way, these are on the wrong side!  Hooray!

5.  Put it together.  Take the old endcap out.  Cleco your new panel in place, drilling only into the window frame metal (you will see lots of other holes in it from where the old endcap was) or into the rib.  Drill only enough holes to keep the panel in place.  Tape the pattern piece over the metal, then set the next panel according to where the overlap line on your pattern was.  Do NOT drill or cleco the panels together in the middle.  The metal will shift as you rivet them together and you will wind up with a hole where you don't want one.  Once you have all of your metal pieces clecoed up, carefully remove the paper patterns.  You can even untape the bottom of the pattern as you move to the next piece so it doesn't get sandwiched in there.  

6.  Rivet.  Mark with sharpie each spot that you want to drill.  Start from the window and work your way back to the rib.  I tried doing one piece at a time and several at a time.  I'm still undecided which worked better.  Drill a hole, then put in a cleco, then drill the next hole and put in a cleco.  You won't need bags of clecos because after 5 or 6, you can start taking clecos from the far end of the line without shifting the panels.  Leave some in, but you don't need one in every hole.  When you set your drill bit on the metal, put it at a 90 degree angle to the metal surface, as the drill bit can get squirrely and instead of going straight in it can "walk" and cause a line of swirlies that will not buff out.

BEWARE!! Do not drill too far from the edge of the panel!!

Get as close to the edge as you are comfortable with, maybe 1/2" or so from the edge.
  The panels will meet up where you can see them, but at the back they are spreading apart.  If you drill too far away from the edge, your rivet won't catch the next panel.  This is what a cross section of your panels would look like, with a pop rivet in the wrong and then the right place:

Don't worry about the panels overlapping the window.  You can cut that off later...just make sure they aren't too short!  Also be aware that the "seen" edge of each panel will rub against the panel behind it and as your panels move around (they will), it can scratch the metal behind it which winds up showing a little bit.  You can try using tape on the back of that edge, then removing it before clecoing.  

That is all there is to it!  Seriously though, I was really intimidated by the idea of doing this, but it wasn't worth losing sleep over.  I got it done and it doesn't look half bad!  

If you found this post helpful, please leave a comment, and/or click on my Amazon store link before your next Amazon purchase, even if you are buying something that isn't listed in my store.  I would be ever so grateful!  


  1. Heck yeah this is helpful! Now can you do a woodie end cap too? Lol. I promise to use the amazon link!

  2. I'll bet a wood endcap is MUCH easier to make!! You can't scratch wood! Thanks!

  3. Thanks so much!
    Can I buy a set if templets?

  4. I'm not sure whether my template would work for your trailer or not. The front end cap is a different shape from the back end cap, and different again from other years of Airstreams. It is probably something that you will have to make on your own. Sorry!

  5. LOVE your blog and the work you've done so far! I just got a 63 Overlander and am trying hard not to want to copy; been drooling over everything you've done. Awesome!

    1. Thanks! I am sure your overlander will be unique and beautiful!

  6. Filing this away for future use on my 63 Tradewind!