President Donald Trump's severe tariffs against virtually all U.S. trading partners are set to take effect on Wednesday at 12:01 a.m. ET. Among his sweeping new trade moves is a hefty 104% tariff rate on China. Trump has described the tariffs as reciprocal, saying the steep toll will correct a grievance he's held for 35 years: that the U.S. is being ripped off by trade imbalances. The president has claimed the tariffs will prompt countries to try to negotiate a deal with the U.S., boosting the economy, while the immediate fallout from his tariffs announcement has seen major losses in the stock market. Trump doubles down on tariffs plan: 'I know what the hell I'm doing' During his remarks at the National Republican Congressional Committee dinner in Washington, D.C., on Tuesday, President Donald Trump touted his tariffs plan, doubling down and telling GOP congressional members, I know what the hell I'm doing. Trump's comments come as concerns grow about the impact the tariffs will have on the economy and stock market. With his reciprocal tariffs set to go into effect at 12:01 a.m. ET on Wednesday, the president again said that the US has been ripped off and that he’s putting an end to it. Many countries have they've ripped us off left and right. But now it's our turn to do the ripping, he said. Trump claimed that countries have been calling him wanting to make a deal in the lead up to the sweeping tariffs. I'm telling you, these countries are calling us up, kissing my a**. They are They are dying to make a deal, he said. Impact of tariffs: Maryland contractor says suppliers have already raised prices President Donald Trump's sweeping tariff policies are already impacting home building. ABC News spoke with Scott Saling, a second-generation contractor in Potomac, Maryland. Saling said nearly every material used to build his home comes from overseas or is constructed from materials imported from other countries from the HVAC to the railings, the sheetrock, the metal brackets and the lumber too. You've got steel, tile wood, all sourced from Canada and China, Saling said. Already, Saling said his suppliers have started raising prices anywhere from 5% to 20% on supplies amid the tariff threats. Increases on roofing and lumber materials and metal. It's already here, he said, adding he has no choice but to pass the costs off to his customers. 'Made in America' is making a comeback, says pro-tariff lawmaker Rep. Marlin Stutzman of Indiana joined ABC News Live on Tuesday to react to the latest on President Donald Trump’s tariff plans and the impact he thinks they will have. Made in America is on a comeback. We all talk about buying made in America, and instead, what's happened over the last several decades is that a lot of these manufactured goods are made elsewhere, whether it's Mexico or China, the Republican congressman told anchor Linsey Davis. Despite the roller coaster stock market reactions to Trump's trade action, Stutzman believes the tariffs will make the country financially stronger in the long run. I would rather see President Trump doing what he's doing and setting the stage for our country to be strong economically because we have a debt crisis coming at us, Stutzman said. Trump's sweeping tariffs are set to go into effect at 12:01 a.m. on Wednesday. Trump claims multiple countries will fly to US to negotiate During a photo op with coal miners where he signed an executive order related to the coal industry, Trump touched on tariffs and claimed multiple countries would be flying to the U.S. to strike a tailored deal. These are tailored, highly tailored deals. Right now, Japan is flying here to make a deal. South Korea is flying here to make a deal. And others are flying here, he said. The tariffs don't go into effect until midnight, but Trump claimed without evidence that the U.S. was already bringing in $2 billion a day through the tariffs. Our problem is you can’t see that many that fast. But we don't have to because ... the money is pouring in at a level that we've never seen before. And, it's going to be great for us, the president claimed without giving more details. 'Whose throat do I get to choke if this proves to be wrong?' Republican senator says over tariffs Republican Sen. Thom Tillis, who grilled the president's top trade negotiator on Capitol Hill on Tuesday, expressed deep frustration with the tariffs as he entered the Senate Finance Committee. Of course, it concerns me. I mean my god, it's a stability issue. Businesses hate uncertainty. We've got a lot of uncertainty, he told ABC News. When the hearing got underway, Tillis drove home that point. Whose throat do I get to choke if this proves to be wrong? Tillis said. Other Republicans are standing by the president but admit they don't know what the president's next move is. Sen. John Kennedy, R-La., told ABC News the president is absolutely correct that foreign countries have trade barriers, but he also acknowledged he doesn't know what the president's game plan is. Whether this will have a happy ending or a sad ending depends in large part what President Trump does next, Kennedy said. Trump's 104% tariff rate on China to go into effect early Wednesday White House press secretary Karoline Leavitt confirmed on Tuesday that Trump's threatened additional 50% tariff on China will go into effect early Wednesday, bringing the total tariff rate against Beijing to 104%. They will be going into effect at 12:01 a.m., she said. It was a mistake for China to retaliate. The president, when America is punched, he punches back harder, Leavitt said. She added Trump believes China wants to make a deal but doesn't know where to start. How long will tariff negotiations take? WH says they're moving at 'Trump speed' White House press secretary Karoline Leavitt was asked during Tuesday's briefing if President Trump is operating on any specific timeline for when he wants to complete negotiations on tariffs. Well, we always move at Trump speed here at the White House, which is incredibly fast, she responded. Leavitt added, the president likes to get things done, but he's very much focused on ensuring that these deals are good for the American worker, they are good for American manufacturing, and again, that they tackle these crippling deficits with these countries. They will be tailor-made deals, Leavitt said, with Trump directing his entire trade team to be involved in the effort. European, Asian stocks partly rebound, but analysts warn further volatility is likely Stocks in Europe and Asia partially rebounded Tuesday, buoyed by signals from the White House that it is open to talks on tariffs with countries. The UK’s FTSE, Germany’s DAX and the pan-European Stoxx 600 closed at 2.5% or above. In Asia, Japan’s Nikkei jumped over 6%, while China’s Shanghai Composite index closed at 1.4%. However, analysts warn further volatility is likely, with Trump’s higher-rate tariffs due to go into effect Wednesday and the EU also preparing to impose its own retaliatory tariffs. The EU reportedly plans to impose import duties of up to 25% on a range of US goods, including diamonds, motorbikes, luxury boats, domestic appliances, tobacco, poultry and many other agricultural products.