What mosfet are you uusing?

uhhhh ya forgot to mention they are 7.5A i think uh FQP7N10L

My best guess at this point is that the resistance in the mosfet is possibly higher or at least too high compared to the resistance wire.

What's the resistance of the nichome wire?

At .6 ohms you should be getting about 20 amps of current going through the wire.

First, Your power supply is not big enough for starters!
Second, For actual on off switching of loads you should have at least a 2x current rating for your Mosfets.
Third, I would still be putting a heat sink on a mosfet thats being driven the way you are running it.

tcm he's using 22 gauge wire for leads, .6 ohms for the heating element, and the FET itself is .35 ohsm. By my calculations it's 9.6 amps (this was mentioned in chat) He's losing 50% of his power to the FET and leads. he's gonna try to parallel the FETS to see if he can avoid over heating them. The leads area loss but not important.

Ah... Getting info from chat is cheating! How is anyone supposed to come up with the right answer when the questions are being loaded!

I think thats cheating! Sort of like insider trading info, only you have insider design info!

I will go and play some where else then. ..l..

So drag yer sorry behind into chat =) It's there for everyone, so don't complain about cheating

Might be in the too hard basket, but it would be great if you could log into a custom chat channel which saves chat logs to the relevant thread

Without it, chat logs containing relevant information for threads is lost forever!

Good idea gramo, but chat is often.... off topic most of the time.

I have often wondered if it would be possible to have a little indicator by the chat button that showed how many people were in the chat area at that particular moment.

Haha yea this migrated into the chat right away... I believe my main problem was concluded that I didn't know the 12v 5A supply could deliver more than 5A! Apparently the supply will drop the voltage and increase the amperage leading to my superheated mosfets. So like he said I am doubling them up and then using a relay to separate the 30 pairs into two groups of 30 giving 60 like I originally intended.

I cannot use the mosfets on the positive side (before the wire) correct? (hence using a relay instead)

Mosfets work just fine on the high side of you have a high side driver IC.

This is just one example of many high/low side driver IC's. They make running Mosfets and IGBT's on H-bridge setups very simple and reliable.