Thursday, 3 November 2011

In the spotlight: Subaru auxiliary lighting

Continuing toward the goal of giving sunburns to roadside moose, it’s time to add the spotlights to the Subaru.




The first thing I did was to decide how I wanted to arrange my lights. I had three 100-watt spotlights to play with (I had somehow collected these over the years and never mounted them on anything). I drilled some holes in a piece of wood and tried a few combinations:



I was torn between three in a row, like in the top left, or a triangular arrangement like the bottom picture. Practicality won out and I decided for three in a row. This would keep the lights a bit safer from flying rocks and should give more effective lighting.

After deciding where I wanted the lights, I needed to decide how I wanted them there. I wanted it set up to be easily removable, and I didn’t want to drill any new holes in my bumper. I wanted the mount to be fairly stable so the lights wouldn’t bounce over bumps. Mounting the lights on some bent aluminum helped me imagine where to attach things:



Wanting the lights as close to flush with the grille as I could get them, it seemed obvious that the mounting points would have to go around the bumper and down to the licence plate mounting loction, with some additional bracing under the grille.

I wanted as much of the mount as possible to be aluminum for weight savings and corrosion resistance, but not having the ability to weld aluminum meant I had to compromise for the lower portion of the mount that would curve around the bumper.

I had some narrow solid steel rod in my scrap collection and decided to use that for the curved portion. My metal bending setup is pretty crude; a portable torch, and two lengths of pipe to use as handles. Heat the bar where it is to be bent, slide the other pipes over the ends, and bend until the bend angle is achieved. This wouldn’t work on hollow metal. Note the bent piece between the two bigger pipes:



A couple of small brackets for the bottom bolts plus a quick spot weld to the newly-bent piece:



That was the easy part. The first weld didn’t much matter, but to make the other one look close to identical would take some effort. Normally, I would bolt up the brackets and spot weld them actually on the car, so I could visually confirm that it looked even, but welding in close proximity to plastic tends to result in melted plastic.

This is where a building a jig to hold the parts evenly while welding would come in handy, but I didn’t want to take the time to do that. I instead laid the welded piece on a chunk of wood and carefully took measurements from an arbitrary centre point, then marked mirrored points to lay out the unwelded pieces. It took a few attempts: spot welding then taking the parts back to the car to see what they look like, bending and tweaking, until I had something I liked.



Walrus Subaru will eat your baby seals!

I then cut some small pieces of angle steel to weld to the “tusks” and drilled some holes in them which would serve as attachment points for the bent aluminum of the light bar. These were bolted to the light bar in preparation for attaching to the tusks. This would be the bridge between the aluminum upper half and the steel lower half. Sorry, no pics of these before welding! To get everything nice and even I would be forced to weld these on the car, so I took precautions to prevent burning my bumper:



You can also see my centreline marking on the green tape, and the magnetic angle finder used to align the bar with the horizontal axis of the car. For the record, the aluminum tape was a terrible idea. I still ended up with a couple of small burn marks on the bumper, and removing the tape afterwards involved picking off tape one dime-sized piece at a time! A few layers of duct tape would have been better and easier.

The light bar was held up and spot welded, then removed for final welding. A bit of grinding to remove sharp edges and extra metal, and this is what I had at this point:



From here, it was a matter of fabricating some bracing from above the bumper. I cut some strips of aluminum from scraps in my bin and found an attachment point on the back of the bumper beam:



My bracket bending setup is even more rudimentary than my bar bending setup:



Measure, mark the bend point, heat it a little with a torch (not too much!), put it in the vise, smack it with a hammer until it’s bent and hope it doesn’t shear.

A few bends to get up and over the bumper:



Plus a couple more small bends (not shown) to gain a half-inch of height.

Everything gets the usual coat of brushed-on semi-gloss black Tremclad:



And some stick-on velcro (fuzzy side only) serves as abrasion resistance for the braces that run over the bumper and under the grille:



This is also a good picture to point out the riv-nuts that I used on the upper braces. They go on like rivets with a special adapter for a riveter, and they're threaded like a nut. They’re a bit pricey, but should make attaching and dismounting the light bar much easier.

Test fitting everything together:



Because I used bent aluminum, rather than more-rigid and more-suitable angle aluminum, the middle light tended to bounce more than I liked. The solution was a little more aluminum in the form of some bent triangular gussets:



Which were riveted onto the light bar:



…making things just a little more rigid.

Attaching the light bar is now a matter of four bolts and about one minute. The upper mounts will stay on the car and are reasonably inconspicuous without the light bar.



The next part of this project is to add some electricity and finally some light. Stay tuned!

Cost breakdown:

$25 - two 100w spotlights from Princess Auto, impulsively bought years ago while on sale

$free - single 100w spotlight, found years ago in a box of free parts

$free - steel and aluminum from my pile o’ scraps

$17 - package of assorted riv-nuts from Princess Auto (my favourite store)

$3 - sticky velcro

==$45

Incidental supplies:

paint and brushes

tape

nuts/bolts from my bolt bucket

rivets

No comments:

Post a Comment