Ruling that there’s no disadvantage when making the CON save makes infinitely more sense to me. I know the general opinion is that holding the item always incurs disadvantage, but for a 2nd level spell this is a more balanced approach. It’s still good this way against heavy armor users, the difference is just that it isn’t an instant win when the DM thoughtlessly puts metal armor on a boss. Just think about how it could be used by the DM to cripple martials with low level enemies.

Codpiece.

Suggestion make the spell damage for weapon/holt object 1d8 and give 1d4 more damage if the target decides to try continue holding the object, and 1d4 more damage if he succeeds/manages to hold the weapon (cons save success) 

Note: For such saves I also allow wisdom checks instead of cons. As willpower can even make a person suicide, it is logical to assume mental resolve is as usable as physical resolve in cases where pain is involved, and often much more relevant. 

I know it is game, and the 5e's point of view. Yet it doesn't really require us to cast away logic, it will only degrade the game. You might say this is not a simulation. But you do simulate during the game, otherwise you can not fantasize at all. So let's leave the hypocrisy aside. And let's agree on the fact that if there is no logical explanation to something it simply is madness.

I am not saying this mentality should be the only option. After all there is demand for madness by consumers, yet the game survived so far due to other reasons. And people do not whine when they are limited by laws in computer games, but same people even rebel when they are limited by logic in tabletop fantasy, which is rather hypocritical. 

Please rule advocates understand this about rule. Spell descriptions statements are clear indeed. But you are also interpreting. 

When doesn't necessarily mean the instant. And the instant is not quantifiable. According to spell description and title. Spell's damage comes from heated metal. And since it requires a bonus action next turn to give damage, it is clear the damage it can give dissipates by the time turn comes to you again. However there is no statement about the heat dissipating until then. So odds are that in your turn the target receives fire damage from the wielded object, but any target hit by the object before heat dissipates might be subject to fire damage. (If you had a hint from Savras or Red Knight) you might even prepare a ready action and hit with heated sword to a target (or you might use the spell to buff your allies weapon with bonus action, use an action to make him attack with a maneuver as a reaction, make him attack with with buffed weapon, so a fitting party can prepare an elaborate ready action to use that for buffed attack if they want to, yes it is not worth the effort in most cases tho) 

Anyway logic&Rai>Raw when a rule is presented, what matters is the intention of the writer, and to misunderstand it on purpose is simply odd. Yes it would be lovely if they could phrase everything perfectly, but that is asking for a lot sometimes. And devs who out right contradict themselves and what they say is also somewhat troublesome. When you read something you are already interpreting, like the word "when". So at least let's try to understand what they mean, then understand how it should be, and present constructive criticism. I love gaming not because I don't love life. I love life as well, I love to love. For me gaming is not an escapist activity, it is fun indeed but what makes it possible is life, what makes it possible is existence of logic and physics. So trying to contradict them doesn't make sense at all. Gamers can be sane too. 

is there a distance limitation for heat metal like i could cast it and teleport to a different place on the planet or a different plane ? and i could still cast it and deal damage as a bonus action because it does not mention  i have to be on the same plane of existence like some spells do  or visual after the spell is cast 

Quote from Tomrelts01 >>

is there a distance limitation for heat metal like i could cast it and teleport to a different place on the planet or a different plane ? and i could still cast it and deal damage as a bonus action because it does not mention  i have to be on the same plane of existence like some spells do  or visual after the spell is cast 

There is a rule about this in the Player's Handbook section on spellcasting, which says:

Once a spell is cast, its effects aren’t limited by its range, unless the spell’s description says otherwise.

So, since this spell's description does not say anything about this, you can still deal that Heat Metal damage while the spell is going on, regardless of where in the world/universe/multiverse you are.

Can I use this to help an armorer or weaponsmith? If I cast summon elemental, magma mephit can cast this innately (once) and also breathe fire every minute. I figure that's a really good deal to help crank up the output at the forge for an hour. 

I'd rule it as that a warforged wouldn't count as an "object". So heat metal would not work on them. 

One of my fellow party members are trying to heat the entire ocean because "salt has sodium and sodium is metal", any rules that stop them from doing so?

Quote from KhaldoDraigo >>

... so many people are really dumb when it comes to this spell. As apparently no one commenting has ever warn armor. You are not in physical contact with it. While you maybe wearing it it does not touch any part of the skin.

If you would rule someone can cast this on a spear tip and not be effected, or on any piece of metal and be able to pick it up with let's say oven mits or armored gloves and not take damage No one wearing any heavy armor would be effected.

Further while thus is a magical effect it is not magical damage and does infact follow burn damage rules. So that brings the next point in question how does any Smith work with metal then? They wear gloves? I'll tell you right now a gambeson worn under armor is far thicker than this gloves.

What would actually happen.

You cast heat metal on friendly paladin.

He runs and grapples the enemy.

Enemy takes damage while grappled.

If you were to cast heat metal on an object someone was in physical contact with rings, necklace or them holding something metal in their bare hands then yes it takes effect

Calling people dumb for not understanding the nuances of armor because they have never worn armor is pretty dumb in itself considering this is not the middle ages and 99.999% of people in the world don't wear metal armor. Who might actually wear armor today? SCA, Ampguard, LARPers, actors, people in European ceremonies?

Really, it just comes off as you thinking that your experience with armor is something to brag about.