Scaffolder Jimmy Robertson of Kirkcaldy, who works from the firm’s Methil yard, attended the rally with his wife Lee and young son Caleb.
The 43-year-old said the turnout at the rally had been “emotional” and “heartening”
He added: “We’re not getting any pay, we’re working right now, we’re fulfilling the contract and we’re working as normal. And for a thing like this to happen, it raises the spirits.
“It makes me feel that we are going to come to a solution”.
BiFab employees have been working without pay since Monday after hearing the firm was facing critical cash flow problems.
Gary Wain of Dunfermline, also a scaffolder, took part as well. The 56-year-old has been a member of the GMB union for 40 years and depends on his job to support his two children.