In the last update repairs were made to the firewall and a coat of epoxy
primer/sealer had been applied. However, the finish wasn't quite what was wanted
- a few too many gouges and imperfections remained which really detracted from
So, picking up where the last update left off, I continued working on the firewall by
applying some lightweight body filler to the larger imperfections. Rather than using Bondo
I opted to use 3M's lightweight body
filler was used which I feel is a more workable, easier to sand product. In
total there were quite a few areas that required body filler.
Once the body filler was applied and sanded smooth there were still numerous small imperfections that needed to be filled.
To fill these I opted to use a high
build sanding primer. I looked into several products and decided on Nason
SelectPrime. Nason is Dupont's generic line and, for the price, is a decent
After taping off the firewall to avoid getting primer where it wasn't wanted, followed by a thorough cleaning, the primer was applied in three medium coats
allowing for the required flash time allowed between coats. Note I'm only trying
to smooth out the engine bay side of the firewall here.
After curing overnight the entire firewall was
first sanded with 180 grit sandpaper followed by 400 grit sandpaper. The
sanding primer really helped cover the remaining small imperfections and the
resulting finish looked very nice, even without the finish coat of paint.
For the final coat of paint I was torn between using a top coat urethane or
the same PPG DP40LF epoxy/sealer I've used on the windshield frame and for the
base coat on the firewall. Ultimately I decided on the PPG DP40 for two main
reasons. First, it provides the exact semi-gloss sheen I'm looking for. Had a urethane paint
been used I would have needed to experiment with adding flattener
to achieve the desired sheen. Secondly, I still had some of the DP40 floating
around and using what I had on hand was preferable to buying more paint.
Typically you wouldn't use an epoxy primer/sealer as a topcoat since it's
prone to chalking over time if exposed to sunlight. However, in the engine
compartment this is only a minimal concern.
So, after a final wipe down with cleaner, three finish coats of PPG DP40 were applied.
end result was much nicer than the first time around; those
additional 16 hours of filling, sanding, priming, and smoothing really made a
The last item left to be addressed on the firewall was treating the inside of
the windshield wiper tub. After removing all of the bituminous coating there
were numerous small nicks and gouges left over that were a bit unsightly.
Certainly I could have used lightweight filler in this area to smooth
things out, but the area is tight and I didn't really think the payoff would be
worth the hours and hours of extra sanding. Plus, who's really ever going to see
inside the wiper tub? In the end I selected a spray in truck bed liner product
that would provide some texture and would help mask most of the minor imperfections.
After sealing any visible seams in the wiper tub with a roofing sealant,
several coats of the bed liner product were applied. One note of caution: be sure to mask off any areas you don't want overspray
to get on, this stuff can
Overall I was very pleased with the finished product.
And here it is, the painted firewall! I would never have guessed it would
take me over 40 hours to get here, but it did. What remains on this task is
cleaning up, painting, and reinstalling all the miscellaneous clips, mounting
plates and gizmos that had to be removed from the firewall.
It will be tedious for sure, but it all needs to be done nonetheless!
Stay tuned for the next update. From here progress will focus on
reinstalling the firewall hardware, repairing the floor tub, and reattaching the firewall
to the body.