Friday, February 8, 2013

Interior Floor & Trunk Priming

The last couple of weeks have been very productive in the shop!  The trunk floor and interior floor prep is complete and all of the SEM Rust Shield paint is nicely cured and with an extra pair of capable hands to help, the entire interior and exterior floor and trunk area is scuffed.

The main focus on this round of work was to get the interior areas that we recently coated with the Rust Shield primed along with the door sills and B-posts.  This would pretty much get all of the remaining bare metal surfaces in the interior locked down in preparation for seam sealing.
As with any coating application, the first task was to vacuum all of the loose dust and clag out of the car and swab every surface thoroughly with grease and wax remover until the surfaces were clean and the solvent had flashed off.  Then a few fresh tack cloths were used to scrub away the last reaming particles of debris before setting off to mix up a batch of primer/sealer.

As many of the followers of my blog have become accustomed to, I am a HUGE fan of the PPG line of products and swear by the entire system.  Just follow the instructions to the letter and apply good equipment and spraying techniques and this stuff just works.  Bare metal, original paint, EDP, or any combination of these is easily handled by the PPG DPLF line of primer/sealers.  This was once again proven by shooting the SEM coated surfaces with two coats of DP40LF primer mixed as a sealer by adding about 15-20% DT870 reducer by volume.  While there, I chose to touch up a few of the thinner spots that were created when scuffing the previously primed floor surfaces.
After a few days of letting the fresh primer flash off, I was very pleased to see the Rust Shield and the DP40LF had played exceptionally nice together, showing absolutely no signs of crazing or lifting on any surface.  This is a significant different between the Zero Rust product and the SEM Rust Shield in that the Zero Rust had a slight tendency to craze and lift at the edges of the thinner films. 

I suspect the primary reason for the Rust Shield’s advantage is that I used the recommended hardener which definitely made a huge different in the final coating durability.  Zero Rust had no such hardener either available or recommended.  The one distinct DIS-advantage to the Rust Shield is it is an absolute B*TCH to spray smoothly and by the time it is thinned enough to spray it has a very annoying tendency to sag or run………at least in my limited experience.  Zero Rust was a clear leader in this category, so take that for what it’s worth…….
Getting back on topic, Ted and I jumped on scuffing the fresh primer after a few days to make the job immensely easier.  One thing to note about PPG DPLF primers is that it gets HARD after about a week of solid cure time and it is a miserable pain to sand by hand in that state.  So, if you know you will not be going straight to a finish coat right away, it’s best to scuff it when it’s still relatively “soft” and then it can be left indefinitely in the “scuffed state” until you are ready to re-prime it and begin the wet-on-wet application of finish coats.

So at the end of this part of the adventure, we now have the interior and exterior floor and trunk surfaces in primer and all of the surfaces scuffed.  Next on the menu is fitting the new stainless steel fuel tank, spot priming the areas that need it and then begins the process of seam sealing the interior and exterior floor areas in preparation for exterior floor painting and the application of U-POL Raptor urethane spray bed liner material on the entire lower surfaces of the car and wheel tubs.
Lot’s more exciting stuff to come in the next several weeks and the spring and summer should be interesting!

Like color-matched luggage, young Ted fits in the trunk area like he was made to be in there!  Here he is finishing up the wipe-down of the interior with wax and grease remover before the priming fun begins!

After a brief bit of strategic planning, we decided to tackle priming of the rear wheel tubs first along with some small spot prime areas that got a bit thin when we scuffed the exterior floor.

Looking toward the right rear corner, you can see how well the PPG epoxy primer covered the areas that were previously coated in SEM Rust Shield.

Still tacky in this shot, the driver door sill and B-pillar look quite nice in fresh primer.

Some of the detail in the left rear trunk.  After upgrading my spray guns to the 3M PPS cup system, getting into tight spots has never been easier.  The gun works in any position so you can shoot just about any surface in a position that you can manage without ever worrying about spilling a drop!  Money well spent!

Another shot of the left rear trunk floor primer fresh out of the gun.

And finally, the passenger door sill and B-pillar with a fresh coat of primer.  Nice!

Tuesday, February 5, 2013

Trimming Rear Fender Lips

You know you’ve “made it” in the Mustang hobby when you get your new NPD parts catalog in the mail early.  After the past few years’ worth of investment in the NPD product line, I was kinda expecting an autographed copy…….but alas……no joy (just kidding).
On the cover of the new catalog, a beautiful cream-colored fastback is shown from the left rear ¾ view with emphasis on the rear wheel opening (to my eye anyway).  Taking nothing away from how nice the car is, this photo reminded me of a detailing trick I use in this area that is decidedly against the “concours bible”, however it makes for a nicer presentation of almost any car nonetheless:  Wheel lip trimming.
Basically, the rear wheel lips on almost all classic Mustangs are the model of variability.  Mass production techniques being what they were, you can often spot huge variances in the fender lip width from car-to-car and even from one side to the other on the same car.  Coupled with the “normal” alignment doodads and lumps-n-bumps, this bugs me considerably and is especially noticeable on lighter colored cars, like the one on the NPD catalog cover (made ya look!).
Since my Boss 302 will be a shade of “Screamin” white, the fender lips will be very obvious and any inconsistencies easy to detect.  As such, I thought it would be a good idea to document how I trim the rear fender lips to be nice and even on their exposed edges and offer a few hints on how it’s done and what to be aware of if you choose to do this to your car.
The most important rule in making this simple modification is to remember to stay outside the spot weld line, toward the lip edge and do not cut through the spot welds.  This weakens the joint and makes sealing the lip areas quite a bit more difficult.  Generally speaking this means the lip width will rarely get narrower than about ¾” on most cars.  Fortunately, this seems to allow plenty of room to clean them up, but careful measurement is still in order to make absolutely sure to clear the spot welds.
Once the appropriate lip width is established, I simply use a machinist’s square set to that width and trace along the lip to mark the cut line I need to follow with the cutoff wheel.  Then it is a relatively simple matter of carefully trimming off the lip to the line and finishing the edges with a body file, an angle grinder and/or sand paper.
For the investment of about an hour, I was able to tidy up both rear fender lips and they are now ready to be finished off nice and smooth as the body work phase approaches.  It’s simple and easy and makes quite a difference to the eye when finished.  So there ya go!  A quick tip to correct an often overlooked detail.
Ragged fender lips are a peeve of mine.  With a little work, I was able to clean up the inner lips and even the width so they present much better than when they were produced.

This poor photo shows the cleaned up edge of the passenger side rear fender lip.  Lots of bodywork yet to be done in this area, but you can clearly see how much cleaner a consistent inner edge and even width makes this area look.

Driver side rear lip is also nice and tidy.  Most times, very little material removal is actually required to get the fender lips looking nice.

The passenger side rear edges also look nice following a little trimming.  You can also see that I stayed clear of the spot welds to avoid any compromise to the strength of this critical joint.