There are a few things that I immediately noticed. You have a big seam showing on the bottom of the back piece, try to clone that out and avoid the butterfly effect you have going right above that seam with the rust.
The caution sign is really damaged but all the metal surrounding that sign looks undamaged and clean. Try messing with your spec map too to try and get some better highlights along the edges of your metal.
Your normal map is screwed up (the line btween the plates/grills and the rest of the thing are not straight). Try baking your normal map on a subdivised version of the low poly without smooth UV's.
I'm not sure it doesn't say "furnace" to me. Maybe add some temperature gauges, some heating elements, red glow from the coils inside, right now it looks like some primitives with a flame warning on it. Throw some handles on them panels...they'd be hot to touch, right? It looks more like a water heater then a furnace. Throw some heat and burn marks on that baby, make us be able to tell that thing is getting hot. Right now we see some indescriminate rust and clean gray areas. Throw some colors around your rivets if those are rivets so they don't look like raised bumps.
Come on man, good start but push this baby!!! Make us feel that heat.
Wow, thanks for the feedback guys ill be making all of those changes in a few days ill most definitly be reposting to get more critique...thanks for the quick responses:)
This is looking good. I think you should make the round screws look like its not a bump in the metal. I would add a bit darker outlines to them, and change the colour a bit. It kinda looks like itsa bulge on the metal. Hope that makes sense.
EDIT: lol i just read dekards post, he said, but anyways:
Replies
The caution sign is really damaged but all the metal surrounding that sign looks undamaged and clean. Try messing with your spec map too to try and get some better highlights along the edges of your metal.
Check this 'webage of awe' for the know-how: http://wiki.polycount.net/Normal_Map
Come on man, good start but push this baby!!! Make us feel that heat.
EDIT: lol i just read dekards post, he said, but anyways: