In a reversal, the National Park Service said Thursday that the repair to the controversial inscription on the Martin Luther King Jr. Memorial should be finished in time for the 50th anniversary of the 1963 March on Washington.

A solution to a sandblasting problem has been found, and the shrouding and scaffolding around the memorial’s three-story-tall statue of King should be down in about a week, Park Service spokeswoman Carol Bradley Johnson said.

A standoff over using a sealant to protect the repaired sections also was resolved, with the Park Service agreeing to the sculptor’s desire to use it.

Trouble on the project cropped up late last week, when it was discovered that a contractor’s insurance would not cover sandblasting with the type of material the sculptor, Lei Yixin, wanted to use, officials said.

He wanted to use an artificial sand called “black beauty,” but the supervising contractor’s insurance did not cover its use, officials said.

Exploring the Martin Luther King Jr. memorial

A test sandblast with an alternative, crushed walnut shells, failed when oil in the shells stained the memorial’s pale granite.

In addition, the Park Service had balked at Lei’s desire to use a sealant to protect repaired areas on the memorial, as he had in sculpting the original. The Park Service generally prefers not to use sealants on its memorials, officials said.

On Monday, the Park Service had said the repair would probably not be complete in time for the King march commemorations, which begin next week.

Lei is scheduled to depart Washington on Tuesday and will not be able to return for several months.

But if all goes well, “and there’s no reason to think it won’t, it will be finished before Master Lei leaves,” Johnson said. The anniversary of King’s march is Aug. 28.

The insurance problem was circumvented by the use of self-insured Park Service historical preservation experts working under Lei’s supervision, the Park Service said.

An alternate sandblasting material made with glass beads was acquired in Allentown, Pa., on Wednesday night and has met with the approval of the sculptor.

“It’s working,” Johnson said.

And Ke Shi, Lei’s son, said that although the walnut stains are deep, they can be chiseled out.

Hundreds of thousands of people attended the Aug. 28, 1963, March on Washington and heard King deliver his soaring “I Have a Dream” speech at the Lincoln Memorial. Thousands are expected to attend the anniversary events in Washington.

King’s memorial is southeast of the Lincoln Memorial, on the edge of the Tidal Basin.

The offending inscription, “I was a drum major for justice, peace and righteousness,” was removed last week. It was one of two inscriptions carved on the memorial’s statue of King.

It appeared on the north face of the statue and was designed to pair with an inscription on the south face that reads, “Out of the mountain of despair, a stone of hope.” Those words will not be altered.

The inscription was a paraphrase of a quote from a sermon that King delivered two months before he was assassinated in 1968. “Yes, if you want to say that I was a drum major, say that I was a drum major for justice,” King said, speaking at Atlanta’s Ebenezer Baptist Church.

“Say that I was a drum major for peace. I was a drum major for righteousness,” King said. “And all of the other shallow things will not matter.”

The inscription aroused controversy when The Washington Post’s Rachel Manteuffel wrote an opinion piece pointing out the extent of the paraphrase.

After Manteuffel’s piece appeared, poet and author Maya Angelou said the abridgement made King sound like an “arrogant twit,” and members of King’s family also expressed their dismay.

The Interior Department originally wanted the inscription to be replaced with the full quotation from King’s speech, but it then decided to remove it altogether.