Frame Repair And Strengthening

It's been busy with work, etc, but made time here and there for frame repairs and strengthening.  First, I power washed it to remove 42 years worth of grime, not to mention the pounds of sand I discovered inside the frame rails.  It was an Arizona car and I figure the sand hassle was a fair trade in exchange for the excellent no-rust condition it was in having spent its life in a dry, albeit sandy, climate. It was no small endeavor to move it out of the garage and onto the driveway to power wash, but thankfully my 14 yr old son and I were up to the task.

July 19, 2014

The plan was then to media blast it in a home made tent in the garage.  I gave it a valiant effort, but the combination of fully realizing the mess it was going to make plus never getting the media blaster to work quite right forced me to wave the white flag.  I returned the media blaster and got to work with a wire wheel to do localized surface prep for welding.

The biggest hurdle with the welding was that I had never done it before, but I've never done any of this before!  I wasn't going to let that stop me, so off I went to get an affordable MIG welder and some steel to practice on.  After some research, I was ready to give it a try.  Turns out that MIG welding is not that hard to do, but doing it well is another story.  I'm sure a pro would have issue with many of my amateur welds, but after a bit of practice I was able to design and weld up this barbell rack for my basement weight room.  It is still standing!

With my first welding project completed, it was time to tackle the frame.  First job was the bottom of the front cross member.  It was caved in due to improper use as a jacking point.  As you can tell from the picture below, the area is clearly not suited for that and you would think somebody would have noticed before taking it this far!

bottom of frame front cross member

You can see in the pic my guide lines for cutting out the bad area, which I did with a cutting wheel on my angle grinder.  The spot welds were broken with a cold chisel.  Then I fashioned some vertical ribs from 3/16" steel plate and welded those in as extra support in case someone wanted to jack it here again.  Finally, a new cap was cut from the same steel plate and shaped with a BFH to get the arch needed.  After some welding and grinding, the final result came out nice enough for this amateur and should be stronger than original for sure.  Once it is powder coated it should blend in well enough and certainly leave the area looking better than it did.

   

Next on the to do list was to weld in gussets at several points in the front section of the frame.  If you plan to autocross, these are recommended in the Corvette section of the Chevy Power Book produced back in the '70's.  I discovered this document in my research some time ago and wanted to follow their recommendations in case I ever did get that urge.  Before the chassis was disassembled, I made cardboard templates for all the gussets to be sure there would be no clearance issues with components of the engine or suspension.  Then the gussets were cut from 3/16" steel plate for strength, except for boxing in the front frame horns where I used 1/8" plate for better fit.  Below are some pics of the process and finished product.  Much more time was spent grinding than welding, but that's what I got for amateur welds!

The Chevy Power Book also recommends welding in the skip welded areas on the frame rails.  From the factory, the two halves of the frame rails were skip welded together every few inches or so, presumably to save time in the manufacturing process.  Welding the skipped areas is recommended to further stiffen and strengthen the frame.  Frankly, I'm unlikely to drive the car that hard when it is complete, but I figured better safe than sorry on doing the skip welds just in case I did ever want to autocross the car.

With the skip welds recently completed, I shopped around for a local powder coater and found an outfit nearby that would pick up and deliver.  They will media blast the entire frame, do some more grinding, and then powder coat it.  I should have the frame back in a week and can then begin bolting some things back on.  Meanwhile, time to make some decisions on the suspension.  The next post will document those decisions, show off my shiny new frame, and begin the process of putting back together a rolling chassis.