Police have found a number of handmade bombs while making an arrest over a recent firebombing on a beauty clinic.

A 29-year-old man is accused of carrying out an attack using a pipe bomb stuffed with nails in Sydney's inner-west earlier in June.

Police allegedly found large amounts of shrapnel and other bomb paraphernalia after the fire.

During raids on two properties in southwest Sydney, detectives seized two homemade pipe bombs filled with nails, an Audi SUV, electronic devices and a large amount of peptides.

The alleged fire bomber will face Bankstown Local Court on Wednesday.

"Can I say these criminals think that they're powerful, they're different people when they come into police custody," Burwood Police Area Commander Christine McDonald said.

The man was charged with possessing explosives with intent to destroy others property, damage property by fire/explosive, and two counts of possessing or attempting to possess prescribed restricted substances.

He was known to police for assault and intimidation of police officers, as well as traffic and drug matters, Superintendent McDonald said.