Wednesday, August 12, 2015

Raptor Liner: Fuel Tank & Rear Valence Treatment

In between new shop general contracting duties, I managed to sneak in a few hours of work on the Boss project this week.  I have been working on a few details at the rear of the car and the time finally came to finish the bottom surfaces of the fuel tank and rear valence to match the rest of the lower surfaces of the car.

Some followers of this blog may recall that I am a HUGE fan of U-Pol Raptor bed liner and protective coating material to finish the underside of my project cars.  This incredibly durable, waterproof, semi-flexible and easy to apply sprayable coating is an awesome choice for a very clean, custom appearance on the bottom of the car and it is very easy to maintain and keep looking fresh for years to come.  Truth is:  There is practically no limit to the applications you can dream up for the stuff, but in this case, we keep it pretty simple.
A few months back, I prepped and primed the bottom of the stainless fuel tank in preparation for the Raptor liner application.  Since then, I have been working on the fit and finish of the rear valence and with that work now complete and the entire valence primed in PPG epoxy, the time had come to finish the bottom exposed surfaces of each part in Raptor.

Like just about any paint prep, Raptor requires a moderate “tooth” on the surface to ensure optimum adhesion of the product.  To achieve this, I scuffed all of the surfaces with a red Scotch Brite pad and wiped everything down with prep solvent to ensure the surfaces were absolutely clean.  Then, a few run downs with a fresh tack cloth and it was off to masking.
After the masking work was complete, it was time to suit-up and apply the Raptor coating to the tank and valence.  To match the texture that was applied to the rest of the floor, the “triggered” air pressure at the applicator “Schutz” gun was set to 45psi.  Once that was set, the process is very simple:  mix the catalyst with the product according to the instructions, shake for 2 minutes and shoot!

To ensure the texture was a perfect match, it was critical to maintain a shooting distance of about 16-18 inches.  I find this provides a medium-fine texture with a non-directional finish that looks great.  The first coat will generally provide about 75% coverage and acts as a very solid ground coat that needs to be left to flash off for one hour before the second finish coat.  By alternating the spray direction between coats, the finish is absolutely non-directional and coverage is 100% on all surfaces.
After letting the second coat flash for one hour, I carefully remove the masking being very careful to avoid dragging the tacky Raptor material on to clean surfaces.  The benefit of removing the masking when the Raptor is still a bit tacky is that the mask edges will pull very clean and sharp and the edges will “lay down” and provide a very nice finish.

With the tank and valence bottom surfaces finished, the bottom of the car is now fully finished and looks fantastic.  This finish is far more durable and easy to maintain than any factory undercoating option and the ease of maintenance is far and away easier as well.  Consider this finish option on your next project!

The top of the new stainless steel fuel tank will remain in bare metal, however the flange will be the base for the back-taping that will begin our masking work.

Here is a shot of the primed, scuffed and masked tank bottom, and the rear valence in the background.  At this point, I wiped down the parts with prep solvent and tacked them off in preparation to spray the Raptor material.

Apologies for the bad picture quality, but here is a shot of the tank right after the second coat of Raptor has been applied.  The glossy sheen is normal for the wet coating and mutes considerably during the curing process.

Here is another poor shot of the rear valence after the second coat of Raptor has been applied.  After about an hour, the masking is pulled from each part and they are left to dry overnight before any further handling.

Fully unmasked and completely dry, the tank fuel sender hole contrasts very nicely against the fresh Raptor coating.  This is now a perfect match to the rest of the underside of the car and will look seamlessly integrated under the car.


  1. It never ceases to amaze me how good that bedliner looks. Great job Sven!

    1. Thanks Grant! If you ever see a need to do something similar on your fastback, it's worth looking at this stuff!

  2. Glad to see you back at it again. That look you're going for is absolutely awesome and IMHO, looks much better than painting the underside body color. It also looks like work has taken you away from the Boss just like mine has. However, I'll be home in a week and a half from Can-eh-da and hope to get back on my fastback.

    1. Thanks Dennis! Obviously, I'm a big fan of the look of the spray bed liner coating on the bottom as well. When it's done, the look is so clean and uniform and the protection it offers is second to none!

      Work has definitely been a killer, but I guess that is a good thing. Apparently launching something like the Dodge Hellcat on the unsuspecting public was something akin to shifting the automotive world off axis a bit. LOL! The new shop is now conspiring to do much the same!

      Hope all is well with you and we'll see some new updates on your project very soon!

  3. Checking in Sven to see how you are getting along. Looking good! Look forward to seeing her sitting in the new shop!!!

    1. Wow! Haven't heard from you in a LONG time! Glad to hear from you and thanks as always for the compliments. Like you, I can't wait to have the new shop up and running and have the space dedicated to hot rod work! When ya coming back?