In last month's story "Bubbly Like A Thunderbolt," we began this series on how to graft fiberglass to steel by following Tom Prewitt and Matt Means of Resurrection Rods in Fullerton, California, as they performed all the metalwork necessary to remove existing dents and reshape the top of the hood so that the Ford Thunderbolt-style hoodscoop from Speedway Motors would sit flat. After Tom and Matt leveled the hood surface, the next step was to place the Thunderbolt hoodscoop in place and check to see if anything else was needed for a proper fit. Sure enough, we soon discovered that the length of the flat area on a '72 F-100 hood was shorter than a Ford passenger car hood. That said, Tom established that we could obtain a perfect fit for the Thunderbolt hoodscoop by breaking its nose. Not literally-but pie-cutting the nose would allow the end of it to bend downward and adhere to the curvature of the F-100 hood. With the fitment problem solved, Tom's next concern was how to attach the fiberglass Thunderbolt scoop to the steel F-100 hood without running into all of the problems associated with a graft of this nature as done in past years.
Thanks to the leaps and bounds achieved on the technological end of the automotive adhesive industry, the solution came to Tom with a quick look at SEM's latest catalog. Listed amongst a proverbial plethora of modern innovations available from SEM, Tom read the specifications of SEM's Dual-Mix Weld-Bond adhesive and knew that he had discovered gold. Follow along and we'll see how Tom Prewitt uses SEM Products to bond Speedway Motor's Thunderbolt hoodscoop onto our '72 F-100 so it will last a lifetime of Gasser-style abuse and keep-on sticking.
A perfect fit, except for...
A perfect fit, except for a slight gap at the nose of the scoop.
This specially designed SEM...
This specially designed SEM Weld-Bond applicator has internal channeling that mixes the two-part adhesive as it's pumped into becoming a catalyzed bonding agent.
Just a sampling of SEM's technologically...
Just a sampling of SEM's technologically advanced line of innovative goodies to make a gearhead's life a lot easier.
If you've ever worked with...
If you've ever worked with fiberglass, you know that it itches like a ... what rhymes with itch? Anyways, Tom's tip for anyone that doesn't want to suffer is to coat (seal) their arms with a thick lotion.
Tom marked the point at where...
Tom marked the point at where the scoop's nose and the hood angle changed.
An angle-head disc-grinder...
An angle-head disc-grinder was used to ensure the steel was clean-free from rust, etc.
Using the same grinder, Tom...
Using the same grinder, Tom made sure the surface of the Thunderbolt hoodscoop was flat as possible to allow the scoop to fit as close as possible to the steel hood.
Using a pneumatic hacksaw,...
Using a pneumatic hacksaw, Tom made the first of three cuts needed to shape the scoop's nose.
Here's the second cut.
Before the third cut was made,...
Before the third cut was made, the rear of the scoop was held down in place with one of these pin things.
With the Thunderbolt hoodscoop...
With the Thunderbolt hoodscoop in place it was completely pinned down.
A quick double check for ...
A quick double check for alignment.
The scoop flange was glued...
The scoop flange was glued with SEM Dual-Mix...
...And then spread with a...
...And then spread with a Good Humor stick.
Tom wasn't shy with the S...
Tom wasn't shy with the SEM.
"Carefully" was the word Tom...
"Carefully" was the word Tom used here.
One by one, the pins were...
One by one, the pins were reinserted.
Front ... and then to the...
Front ... and then to the rear.
Any visible gaps were filled...
Any visible gaps were filled in with additional Dual-Mix.
A special glove was used to...
A special glove was used to spread the sticky Dual-Mix goo.
With all the pins in place...
With all the pins in place and the Dual-Mix applied, it was essential to allow the SEM Dual-Mix 24 hours to dry (cure).
Twenty-four hours later the...
Twenty-four hours later the pins were removed and the Thunderbolt scoop was ready to be molded in.
The air disc-grinder was used...
The air disc-grinder was used to grind off the white gelcoat.
Then it was used to shape...
Then it was used to shape the hoodscoop into the hood.
An orbital sander was used...
An orbital sander was used to sand the gelcoat from a smooth surface to a rough one to create a foot for the next steps to adhere to.
The entire area was prepared...
The entire area was prepared for primer.
A blue paper towel was used...
A blue paper towel was used to make a template to cut a pattern.
The pattern was cut out.....
The pattern was cut out...
...And then laid onto fiberglass...
...And then laid onto fiberglass mat and traced with a Sharpie.
Next it was cut out with a...
Next it was cut out with a pair of sharp scissors.
The fiberglass mat was fluffed...
The fiberglass mat was fluffed into place.
The resin was mixed to the...
The resin was mixed to the amount of catalyst and resin specified on the can.
Then it was applied to scoop...
Then it was applied to scoop and hood with a cheap disposable paintbrush.
Strips of fiberglass mat were...
Strips of fiberglass mat were applied over the three pie cuts to fill in the gaps.
The process of building up...
The process of building up the fiberglass continued with liberal amounts of resin applied.
It was important to spread...
It was important to spread fiberglass resin all around the base of the scoop.
It was necessary to bury the...
It was necessary to bury the texture of the fiberglass matt with a heavy build-up of resin...
...So that it could be ground...
...So that it could be ground into a relatively level surface.
This SEM product gets its...
This SEM product gets its name from carbon fiber, one of the hardest synthetic surfaces known to man.
Not mixing the SEM Carbo-Fill...
Not mixing the SEM Carbo-Fill completely with the red catalyst will leave spots that will never harden.
An evenly mixed light-pink...
An evenly mixed light-pink color indicated the Carbo-Fill was ready to apply.
Tom used a Bondo spreader...
Tom used a Bondo spreader to apply the Carbo-Fill so that it would require as little sanding as possible.
Tom started with 36-grit paper...
Tom started with 36-grit paper and then switched to 80-grit on a Dura-Block long-block.
Tom held the Dura-Block perfectly...
Tom held the Dura-Block perfectly flat to generate a lot of pink dust.
In addition to the long-block,...
In addition to the long-block, Tom used the dual-action orbital sander to work things into shape.
A round Dura-Block was used...
A round Dura-Block was used to shape the areas that needed to be rounded.
It took a lot of sanding to...
It took a lot of sanding to get this far.
That said, it was time to...
That said, it was time to apply a second coating of a more fluid body filler to help level the surface and to fill in holes and slight imperfections.
The sanding process was repeated....
The sanding process was repeated. The reward: the bodywork was becoming devoid of ripples.
The final step before shooting...
The final step before shooting primer onto the hood appeared like this.
Tom sprayed the primer on...
Tom sprayed the primer on a little at a time...
...Until he could gradually...
...Until he could gradually lay down a super-thick coating that will be blocked out in the next segment, where Tom will repaint the hood to look like new.