Steering Column Work: Powder Coating & Shrink Tubing Install Trick

One of my regular avocations is custom powder coating.  I keep quite busy doing mainly custom motorcycle, bicycle and hot rod work and on occasion, I get to do some of my own parts as well.  Recently, I was doing a poop-load of black powder work in the exact color I have chosen to do several critical pieces of my Boss in.  This allowed me the opportunity to coat my steering column shell and dash bracket and to show a little trick I developed to duplicate the factory shrink tubing used to encase the lower collapsible section of the Mustang steering column.

I started by stripping all of the factory finish off of the column and bracket and passing them through my blast cabinet to remove the rust scale that had accumulated over the years.  Then I applied a urethane matte black powder coating to both parts to ensure years of trouble-free service and great appearance.  And now for the “trick”:

Almost everyone I talked to that has ever restored a Mustang has stumbled a bit when it came to restoring the shrink tube encasement at the bottom of the steering column.  I’ve seen lots of Mustangs that have nasty looking original shrink tube sleeve still intact on otherwise nicely restored columns or, on the flip side, the owner has cut off the offending tube and left it off complete because they could not duplicate the process.

I was part of the “unlucky” group where this shrink tubing was concerns in that all manner of rodent had chewed up my original shrink tube jacket on my original column.  After months of scouring the internet for hints on how to repair this area, I came up with almost nothing helpful.  So, I started to think about a way I could recreate this detail on my own, and what I came up with worked better than I expected.  So much so, that I thought it only prudent to pass it along here.

In my research, I came across some very large heat shrink tubing for large industrial electrical cable that I thought might do the job.  Unfortunately, most of these products didn’t have the proper shrink factor I would need to do the job.  Then I stumbled upon some high shrink factor tube that would fit the bill from a company called Parts Express.  The shrink tube I found is referred to as 3” high-shrink rate tube.  It shrinks with a diametric factor of 2:1 and a linear factor of 1.07:1.  The stuff is a bit expensive, but I decided to order enough material to do a few columns just in case I blew it on the first try.

I measure my original shrink tube that I cut off my column and determined the finished length I required.  After taking the shrink factors into consideration, I cut a length of shrink tube  and slipped it over the collapsible section of my refinished column tube and began gently warming it with my heat gun while rolling the column tube slowly, making sure to evenly shrink the tubing from end to end.  After a few short minutes, I had a nicely finished detail that (I think anyway) replicates the original shrink tube nicely.  Hope this might be useful!

Steering column tube and dash bracket in the powder booth and ready to coat.

A nice coat of urethane matte black powder looks really nice.

My original shrink tube jacket was chewed up by rodents after years in storage and generally looked like crap.  Believe it or not, this is the "good" side.  There is very little information available on how to duplicate this detail so I set about figuring this out.

I found some industrial, high-shrink rate tubing material and started to experiment.  I found the 2:1 diametric shrink rate was spot on and determined the linear shrink rate was only 1.07:1.  This proved to be a perfect match for the requirements of this job.

I measured off a 10.75" section of shrink tube and cut it squarely with my razor knife.

Here is the new shrink tube placed on the collapsible column section before shrinking.  The nasty original is shown next to it for reference.

Being a single fella, I can get away with a lot of restoration "stuff" in my kitchen that many "spoken for" fellas don't get to do!  Using my heat gun on low heat, I started to slowly shrink the tubing by heating along the entire shrink tube sleeve by rotating the tube and heating it along it's length.  In this shot you can see the tube has just started to shrink around the ribs of the column tube.

about 30 seconds later, and the tube is pretty well secure on the column an shrinking nicely.  Note the ends are not quite tight to the column yet.

Almost there.  I have been heating the shrink tube about 90 seconds at this point.

And there it is.  The tubing has shrunk to its maximum and the ends are nice and snug against the column tube.

Compared to the original shrink tube jacket, I think this will work just fine.

With the dash bracket in place, this restoration detail really sets off the column well.

Tail Light Panel and Trunk Floor – Part 10: Front Trunk Floor Install

Quite a while ago, I posted a blog entry railing on the total lack of quality of every single front trunk floor patch available today along with the work I had to do to get the panel to fit correctly.  At long last, I have reached the point where the last heavily rusted panel I had could now be replaced.  And MAN does it feel good!

This repair will feature a panel joint repair that I use rarely, but works very well in certain situations.  The joint is called a lap joint and it is very useful on panels where the span is long and there is no feature(s) in the panel to add strength and resist warping.  In my case, the entire width of the front trunk floor repair was of this configuration and determined I could not adequately butt weld the entire joint with hope of success.

I began by trimming the floor repair panel to the basic dimensions I required to make the repair.  I had marked the location of the repair several months ago with a white paint pen to remind me of where I wanted to join the repair panel to the parent metal when the time came to make the repair.  By transferring a few dimensions to my repair panel, I was able to get the seam located where I wanted it.  I added ½” to the dimensions so I had enough material on the repair panel to allow a flange to be created.

With the panel trimmed, I then used my pneumatic flanging tool to flange the entire top edge of the panel to allow the parent metal to neatly fit underneath the panel flange.  This creates a surface on the “finished” (a.k.a. bottom) side of the axle tunnel that can be made smooth and straight with minimal filler once all of the welding is complete.  Also, the lap joint it creates on the bottom is much easier to weld cleanly and without burn-through than a conventional butt weld joint.

Next, I used the repair panel as a marking template to locate the cut line for the parent metal ½” below the top edge of the repair panel flange.  Using my trusty screaming-wheel-of death (a.k.a. pneumatic cutoff wheel), I cut off the rust-damaged portion of the original front trunk floor and deburred the edges.

At this point, I spent a good bit of time carefully clamping the repair panel and parent metal to ensure the fit between the two was a good as I could make it.  Once I was satisfied with the fit, I locked the panel in place using my high-clamp-force Cleco fasteners.  Another check of each seam to verify fit and it was game time!

I wanted to be able to flatten the welds a bit over regular plug welding so I ran the heat and wire speed up just a tick on the MIG welder.  This game me a quick arc start and smooth metal deposition that I would not have been able to use with a butt weld.  This technique worked great and I stitched the panel in place quite quickly.  While I was there, I also welded up a number of spots along the top of the axle tunnel that I had marked several months ago.  Once the stitch welds were complete, I checked the fit from underneath and was pleased that the flange fit was good and warpage was minimal.  A little bit of hammer and dolly work had the parent metal flange seated tightly in the recess of the repair panel flange.  This edge is now ready for a fully seam weld from the underside to complete the installation.  This step will have to wait until the tail light panel is installed and the car can be rolled over in the rotisserie without concern for the body inadvertently shifting without a complete structure to support it.  In the meantime, the panel won’t be going anywhere.

The last area that required repair in the front trunk area is the aperture where the factory cut out the axle tunnel for the staggered shock mount to pass through.  In an earlier post, I showed how crudely the factory had cut this opening using a torch and apparently not much skill or precision.  Naturally, this area would require a bit of clean-up before I could make a patch to repair this area, so I traced the opening with trim lines that would allow me to square the hole before going any further with patch fabrication.  With the hole trimmed to the lines, I was able to trace the hole on a piece of cardboard.  I added a ½” border flange around the hole traced on the pattern and transferred this shape to piece of .025” steel patch material and cut the patch on my band saw.

Moving to my flanging tool, I once again flanged the patch along three of the four sides, leaving the lower edge of the patch flat to allow it to tuck underneath the previously installed trunk floor patch.  Next, I took my contour gage and made patterns of each end of the patch are so I could carefully form the patch to match the shape of the axle tunnel.  When I had the shape correct, I secured the patch with Clecos and tacked/stitched the patch in place in the same manner I did with the larger trunk floor panel.  Once all the top-side welding was complete, I smoothed up the welds with my angle grinder and some 60-grit disks and this phase of the trunk floor repair was complete.

From the bottom of the axle tunnel, the repair is quite smooth, and after a little bit of body work and filling, it should be virtually undetectable.  There’s a good bit of welding left to do to finish the joint, but that will have to wait until the tail light panel is installed so I can once again roll the car over on the rotisserie.

My pneumatic flanging tool made forming this step flange along the edge of the front trunk floor repair panel a quick and tidy job.

After trimming the repair panel to the length I needed and flanging the leading (top) edge, I marked the parent metal with my yellow paint marker to establish a reference line to work from so I could mark the cut line on the parent metal.

From the reference line I marked in the previous step, I dropped down 1/2" and marked the cut line of the original metal.

My original white sketch line can be seen right between the upper reference line an the lower cut line.  Also in this shot, you can see the locations of the small areas I need to weld up (shown as white squares).

Using my cutoff wheel, I carefully cut the rusty lower section off the car, leaving a clean edge, ready for the new panel to be clamped to.

The repair panel was then secured using high-clamp-force Cleco fasteners.

Here's a close-up of the left side of the trunk repair panel clamped into place.

A quick check from underneath shows the joint edge is nice and flat and ready to be tacked/stitched in place.

A few minutes later, and the panel is securely stitched into place about every 2.5 to 3" along each edge.  Notice the minimal heat affected zone around each weld.

Here's a look at the right side of the front trunk floor repair after tacking in.

Another shot from underneath shows a clean, straight edge that is ready for complete welding.

The remaining issue in this area was the hole the factory cut for the staggered shock mount to pass through.  This hole was quite nasty, so I decided to trim up the edges so I could create a nice clean aperture to fit a patch to.

Here, I have cleaned up the hole into something i can work with.

I made a simple cardboard pattern by tracing around the hole and adding the requisite 1/2" flange allowance around the perimeter.

After cutting out the patch blank on my band saw, I flanged the side and top edges of the patch.  This would allow the lower edge to slip behind the trunk floor repair panel to match the parent metal flange.

I used some simple cardboard templates I made for each end of the repair area to duplicate the shape of the floor at each end.  This allowed me to for the patch to precisely fit the hole. 

Here you can see the tight fit against the original Axle tunnel I needed to ensure the patch panel fit as required.  I clamped the lower edge of the patch with Clecos to help make sure the patch was located precisely while fitting.

Here is the view of the finished patch panel from under the car.  You can see how nicely the patch integrates into the trunk floor repair panel and the parent metal area above it.  These flange joints will make fully welding in the repairs much easier by reducing the tendency to burn through significantly.  Also, the warpage is considerably less with this style of repair joint.

Clamped into place, the patch is ready to be tacked in.

The patch panel has now been fully tacked into place and looks excellent.  I also welded up the spots along the top of the tunnel as well.

From underneath, you can see the repairs are smooth and the seams quite straight.  I will fully weld each seam after the rear tail light panel is in place so I don't have to worry about the body shifting on the rotisserie.

Done!  A few minutes with the angle grinder and the top side of this repair is complete.

Tail Light Panel and Trunk Floor – Part 9: Rear Trunk Floor Install

With my recent rotisserie modifications complete, I was able to put a lot of work into the Boss these past few weeks that would have otherwise been impossible.  Now that I was back on track, I felt good about the prospect of getting the trunk floor one step closer to complete by installing the rear trunk floor/lower tail light panel support.

Out of the box, this panel actually fit pretty well, with only slight adjustment to the end flanges required to get the panel fitting nice and tight against the inboard trunk drops.  Once I had the fit acceptable, I drilled plug weld holes in the flanges and set off to check the final fit with my old gas tank in place as a fitment guide for the mounting hole alignment.  This proved to be another example of why you shouldn’t throw anything away during a restoration.  Even though my old fuel tank is worthless in the long run, it was a great fixture to help align the mounting holes in the panels before welding.

I started by using some small machine screws to secure the tank to the outboard flanges in the same locations as the tank mounting screws would go.  Then I fit the rear trunk floor panel in place and used two tapered drifts to align the rear tank locating holes and then clamped the works into place. I then verified the fit by making sure the rear tank mounting screw holes lined up perfectly.  Satisfied I had the panel fitting well; I outlined each flange with my yellow paint pen to give me reference marks to verify the fit once I was ready to weld everything in permanently.  At the same time, I marked my left and right trunk floor flanges so I could punch plug weld holes in the proper locations along the edge along with the rear frame rail horns which required drilled plug weld holes.  A few minutes of work with the pneumatic punch and step drill and a swipe or two with the angle grinder to clean up the holes and the panel was ready for installation.

Using my trusty welding clamps, I clamped the panel into place in as many places as I could to ensure a tight fit at every flange location before any welding was done.  With each seam tight, I started by welding along the top flanges of the outboard floors, skipping from the left side to the right to reduce the chances of warping.  From there, I moved to the inside rear flanges using the same technique.

At this point, the rear of the panel was nice and tight against the rear frame horns, so I welded each horn completely before moving to the outboard ends of the panel to complete the welding operation.  After a few more minutes with the angle grinder, the welds were smoothed up and the job was complete.  Next stop:  Front trunk floor!

Lesson learned:  Don't throw anything away!  My old fuel tank came in very handy in positioning the rear trunk floor panel to make sure the mounting hole alignment was spot-on.

I sued a couple of machine screws in each mounting screw hole to position the tank properly before fitting the repair panel.

Using a pair of tapered drifts to align the rear trunk floor panel, I clamped the work in place using my trusty welding clamps and checked the fit.

This is what you want to see when trial fitting a new panel.  Perfect mounting hole alignment.

While everything was clamped together and fitting nicely, I traced around the edges of the panel to help when repositioning the panel for welding.  At the same time, I marked the locations of each plug weld to help me punch or drill th holes required.

Here's a shot of the welds along the rear edge of the left trunk floor.

And here's a look at the welds along the right rear trunk floor edge.

The panel fit quite well right out of the box as evidenced by the nice tight fit on the inside of the left rear trunk floor interface.

The inside right rear trunk floor also fit remarkably well.

With the upper part of the trunk floor edges welded in, the rear frame rail stubs could be buttoned up.

Here, the end flanges on the right side have been welded up.

In this shot, you can see bothe the end flanges and frame stub welds.  It's in!

With the welds ground smooth with the angle grinder, things are looking quite nifty.

The left rear trunk floor area after smoothing up the welds.

Another shot of the lower left rear trunk floor after weld grinding.

Rotisserie Rework – Stepping Down to Move Forward

As I mentioned in my last blog entry, I discovered that I needed to reconfigure the rear of my rotisserie to allow me to continue work on the Boss rear trunk and tail light panel area.  After a few weeks of “paying jobs” getting in the way of restoration work, I was finally able to get back to the project with purpose.

After noodling on the problem for a few weeks, I decided that the best place for me to mount the rear chassis to the rotisserie was the rear leaf spring shackle mounts.  These are very rigid points in the chassis and there is no risk of crushing the rear frame rails with the fastener torque required to keep the mounts secured to the car.

Since I plan to finish the bottom of the car with spray bed liner material, I wanted to make sure that whatever mount I came up with would allow adequate access around the entire rotisserie mount so as not to act as a mask to the spraying process.  I spent several days sketching up a design that would be strong, simple to make, and still offer maximum exposure of the entire frame areas that would need to be sand blasted and coated.  What I ended up with was a solution that only required me to drill one hole in the rotisserie frame to lower the assembly by the 4¼” I needed to gain the working room I needed.

Satisfied I had something to work with; I turned four steel bushings that would fit the shackle mounts in the frame snugly.  These were effectively a steel version of the shackle mount bushings for lack of a better description.  From there, I fabricated two mount “towers” that would mount to the spring shackle bushings on the car and the rotisserie frame “arms” at the bottom.  The 3” square tubing I used for the slip mounts allowed enough slack between the tower and frame arm that they would be self-aligning once the shackle mount was tightened.

Next, I focused my attention on getting the rotisserie frame cross pin hole relocated 4¼” up from the original location.  This position would drop the frame assembly by that amount and allow me unencumbered access to the taillight panel and valence area.  And after about 10 minutes with a handful of drill bits and my trusty hole-gun, the frame cross pin hole was relocated perfectly.

The final challenge was to decide how best to remove the rear of the car from the rotisserie frame so the new mount towers could be installed and the rotisserie frame relocated.  Again, after careful measurement, I decided to make two wooded jack stand platforms that would allow me to secure the chassis in a free state while the conversion was made.  With a little clever adjustment of the adjustable jacking posts I use to stabilize the car while doing the trunk work, I was able to get the car securely on the stands with no load on the rear rotisserie frame at all.

And about half an hour later, the rotisserie frame was lowered as required, the mounting towers were secured to the spring shackle mounts, and the car was comfortably back on the jacking posts, ready for the next phase of trunk floor and tail light panel repairs to continue.

I made two pair of these steel bushings to fit into the rear spring shackle mounting location in the rear frame rail.

Here, you can get an idea of the "before-and-after" mounting styles.  In the background is the saddle mount I used before and in the foreground, you can see the steel bushings for the new mounting location.

Here are the bushings with the grade 8 attachment hardware.  Probably overkill, but I never worry with this level of fastener.

This shot gives you an idea what the mounting towers look like.  These have yet to be drilled for the upper mounting holes, and the welds haven't been smoothed up, but they are otherwise complete.

A "side view" of the mount towers for detail.

I only had to drill one hole in the rotisserie frame to get everything positioned where I needed it.

Wooden step blocks were made to rest my jack stands on to secure the chassis while it was disconnected from the rotisserie and the new chassis mounts bolted into place.

With everything bolted back up, I mocked up the rear trunk floor enclosure to see that I had the room I needed to continue work.

Perfect!  Plenty of working room for the valence as well.

This gives you an idea how much more room is available around the mount tower to allow me to spray primer, paint and bed liner coating on the entire rear frame rail without issue.