President Donald Trump visited the $147-million border wall replacement project in Otay Mesa, California, on Wednesday, and called it "amazing."

While no new border wall has been built while Trump has been in office, the 14-mile stretch of 18- to 30-foot steel wall that replaced a decaying section on the US-Mexico border fence was completed in August.

Trump took out one of his signature Sharpies and signed a slat, saying, "You can fry an egg on that wall," because it's designed to absorb heat.

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President Donald Trump took time from his two-day fundraising trip to California to visit his beloved border wall in Otay Mesa.

He was so taken with the project that he signed one of the slats with a Sharpie.

President Donald Trump signs his name as he tours a section of the southern border wall, Wednesday, Sept. 18, 2019, in Otay Mesa, Calif. AP Photo/Evan Vucci

"You can fry an egg on that wall," Trump told the reporters and officials gathered at the fence, because it's designed to absorb heat.

The section of wall Trump visited Wednesday was a $147-million replacement project stretching 14 miles. His administration hasn't completed any new wall construction since he took office, but has replaced about 60 miles total.

Trump said he thinks they can build close to 500 miles of wall next year "depending on terrain conditions." About 650 miles of the nearly 2,000-mile border is currently covered with barriers.

Read more: A journey along the entire 1,933-mile US-Mexico border shows the monumental task of securing it

The Otay Mesa section is 18- to 30- feet high, made of steel, concrete, and rebar.

"If you think you're gonna cut it with a blowtorch that doesn't work because you hit concrete," Trump said, adding: "It's pretty amazing."

President Donald Trump gestures during his visit to a section of the U.S.-Mexico border wall in Otay Mesa, California, on September 18, 2019. REUTERS/Tom Brenner

Trump said they had "20 mountain climbers" try and climb the wall, and this design was the hardest to climb, according to the White House pool report.

A border patrol agent told Trump: "This is the wall the agents asked for."

Speaking to reporters on Air Force One on the way back to Washington Wednesday night, Trump said he signed just his name after border patrol agents asked him to.

"I autographed one of the bollards," he said. "There are a lot of bollards. That's a lot of bollards."