Heat Exchangers High Pressure unit with 21" Thick Bonnets Fabrication Associates has the equipment and experienced personnel to build the best heat exchanger available in the market today. Whether large or small, high or low pressure, straight or U-tube, single or multi pass we can build the unit to satisfy your needs. We have cyber-tig welding machines to weld the tube ends and digital electronically controlled tube roller motors to make sure the tube ends are all compressed the same. From forming, to machining, to fabrication, your heat exchanger can be manufactured completely at our facility without any outsourcing required. 1800 Tubes Internal - 4" Diameter Bonnet Studs Multiple Units Being Manufactured Whether low pressure or high pressure, large or small the same quality goes into every heat exchanger we build. Let us be the supplier for all your heat exchanger needs.