Dealt with this type of player numerous times before. Best way I've found is to let their creativity run wild, but put a cap on how many toys they can bring to any single event.

Pegging the active limit to a type of Talent of the character's spec(s) should go a long way towards minimizing power creep. Switching out his active inventions can be akin to prepping spells in D&D.

Encumbrance isn't a real limit since players like this will find amusingly creative ways around it... droid pack mules, etc.

Also, make every invention require some key components that he just can't freely scavenge. Parts that would typically be removed from junkers to be re-sold before being committed to the trash heap. Otherwise you're just handing him free gear versus the other players in the group. It makes sense the most valuable pieces of droids/ships are removed before dumping the rest of it (e.g. in our world thieves steal catalytic converters on cars because of the value of the platinum or palladium inside and those are amongst the first things pulled from a junker before it gets thrown in a yard).

As long as all of this bling also comes with consequence then it should keep the other players from feeling shortchanged. Also, from an RP angle the more this guy gets known for inventing crazy-yet-effective gear some less savory power groups may seek to enlist his services whether willing or not. Some criminal groups might not even ask nice the first time... more of an "offer you can't refuse" approach. Perhaps even eventually gaining the notice of an Imperial weapons project lead.

tl,dr: don't just make this stuff free. there should be both story elements and financial costs involved.

Thank you for the great ideas! My main fear is that his creations will begin to outshine our Combat specced players, and diminish their experience. You have brought up some good stop gaps for that I hadn't thought of.

You can also use things that aren't particularly "Qualities". For instance, the heavy blaster pistol can run out of ammo with a few threats instead of a Despair, and the augmented barrel attachment adds a Setback die to all Mechanics checks on the gun.

I'd say that a tinkered and jury-rigged (not talents) weapon should be really good in some ways and not in others. So perhaps give it both a low damage and a low crit value. For a melee weapon, since your PC isn't a weaponsmith, Inaccurate seems pretty good (especially considering something like "balanced hilt" attachment reflects good smithing and gives the Accurate quality), and let him have a rank or two in Vicious; that way, it's hard to hit with, but particularly painful when he does land a blow.

So yes, have fun with Qualities and such, but also have fun in the midst of narrative if your PC rolls a large number of threat or a despair.

I'd say that a tinkered and jury-rigged (not talents) weapon should be really good in some ways and not in others. So perhaps give it both a low damage and a low crit value. For a melee weapon, since your PC isn't a weaponsmith, Inaccurate seems pretty good (especially considering something like "balanced hilt" attachment reflects good smithing and gives the Accurate quality), and let him have a rank or two in Vicious; that way, it's hard to hit with, but particularly painful when he does land a blow.

I'd take this a bit further and say that a jury-rigged weapon should be noticeably worse in general than a standard weapon except for under specific circumstances. Remember that weapon designers frequently prototype several variations of a given weapon to try for a myriad of different outcomes; it's not likely that your player would be able to come up with a design off the top of his head that improves upon all aspects of the weapon.

Thinking about a chainsword, for example, it might have been dreamed up to deal with vehicles at Personal Engaged range. That'd be fine, because at that range a vehicle can only really move in one direction at optimum speed; anything larger than a speeder bike would have to decelerate noticeably to turn, thus leaving it open to a melee attack from a weapon designed to chew through armor and vital components.

But on a target that's on-foot, that advantage disappears, and you're left with an unwieldy weapon that's impractical for that use. It probably has twice the encumbrance of a virbosword, and you could say that it has a special quality (say, Unwieldy) that means you need to score a critical to do full, vehicle-scale damage to a non-vehicle target. That would explain its comparably low damage and high crit rating.

I don't know. I'm just coming up with this off the top of my head. My point is, unlike what Gundam teaches us, typically prototypes are actually worse than their finished models, and that should be no different for players. Obviously, because they're PCs, they have the ability to improve their gear, but something as off the rails as a chainsword should have some serious drawbacks.

On another note, you could have the chainsword be a huge improvement over the vibrosword or whatever, but dictate that it'll take him several sessions to complete it, and so he's stuck with the lower stats until then.

And I still say the chainsword is thematically inappropriate to a Star Wars setting. Sure, there's bloody dismemberment in the films, but it's tastefully done. This isn't Gears of War . Pinkies out when you lop off a hand, people. It's just manners.

Thinking about a chainsword, for example, it might have been dreamed up to deal with vehicles at Personal Engaged range. That'd be fine, because at that range a vehicle can only really move in one direction at optimum speed; anything larger than a speeder bike would have to decelerate noticeably to turn, thus leaving it open to a melee attack from a weapon designed to chew through armor and vital components.

But on a target that's on-foot, that advantage disappears, and you're left with an unwieldy weapon that's impractical for that use. It probably has twice the encumbrance of a virbosword, and you could say that it has a special quality (say, Unwieldy) that means you need to score a critical to do full, vehicle-scale damage to a non-vehicle target. That would explain its comparably low damage and high crit rating.

If you do take this route, there is a precedent for weapons having different qualities against different types of targets. There are a number of items in both Suns of Fortune and Dangerous Covenants that mix personal scale and vehicle scale effects. In Dangerous Covenants, the Golan Arms FC-1 Flechette Launcher, that gains Inaccurate 3 when firing anti-vehicle rounds against Silhouette 0-1 targets.

At the request of one of my gaming groups, I am doing a minor conversion to Edge/Age rules for use in the Warhammer 40k setting. As the chainsword is the iconic melee weapon for most human factions, I've been playtesting the following profile:

Melee, BR+3, Crit 2, Engaged, 3 HP, Enc 4, Cumbersome 3, Defensive 1*, Pierce 1, Vicious 2.

*Characters do not benefit from Defensive unless their Brawn exceeds Cumbersome.

Obviously, this represents a professionally-designed, mass-produced, and battle-tested weapon, and would be out-of-place in all but the most brutally violent societies of Star Wars, but it's a decent reference point.

Going off the tabletop stats where it's just a basic melee weapon with no AP, I don't know that I'd have Pierce on there. Maybe drop Pierce and make it Crit 3, but up it to Vicious 3.

Going off the tabletop stats where it's just a basic melee weapon with no AP, I don't know that I'd have Pierce on there. Maybe drop Pierce and make it Crit 3, but up it to Vicious 3.

Based on the 40k RPG stats. Chainswords have a Penetration of 2, where the average human soldier has Toughness 3 and Armour 4. With the average human soldier in the Edge system having Soak 4, the equivalent Pierce value would be about 1.

I would also give the Despair rolls a chance to either have his chainsaw sword kick back at him (he hit a chuck of sterner-stuff and the blade bucked back and tried to 'bite' him), or have the chain snap (and now he has a chunk of chainsaw chain whipping back at his anatomy). In effect, the thing would work, but has a chance of doing more damage to him than to his target.

This might be a bit evil, but what about not only putting himself at risk with a despair? What if a despair means that he hits a friendly player in melee range (engaged)? For example, if there's 2 allies right next to him, he might hit either himself or one of them. Might make for some fun interactions between the players?

... unless he accidently kills one of them, orcourse.

On a different tangent, is a chainsaw sword really appropriate for the setting? It's up to the group as a whole, of course, but it seems a little too brutal for Star Wars.

Probably not, but then again a chainsaw really isn't an appropriate weapon at all (despite what Hollywood would have you believe). For some players, it's really just about the option to say "groovy" after reducing a foe into bloody bits of kibble.

Just my 2 cents: a chainsaw is a horrible weapon. It was designed to cut through stiff and in moving wood, not gooey-mushy bodies and things that move. A chainsaw as a weapon is likely to get stuck, break its chain, not cut that deep, and generally be underwhelming. It would be great against a deactivated droid or a tied down victim but otherwise I would rather have an actual sword. A chainsaw would be great at intimidating and causing fear and it certainly would leave nasty wounds. It's also so heavy that it would be slow and ungainly. Compare the weight of a katana or machete to that of a a chainsaw with the same length blade.

Also an improvised weapon made from scrap certainly would be crappier then a specially produced model. As I think it was said earlier, prototypes are usually worse then the produced model.

That all being said: this is a game so we are talking movie realism here. I feel like all RP has to balance betwixt reality and fun/cool factor. I totally think a scrapper could carry a chainsaw sword, it's like a tool and weapon in one. The thing that's against the chain saw sword is that it is so iconic for WH40k. It would be like the Agent in Serenity the movie busting out an energy beam sword; sure you could explain it, but everyone would call out "light saber!" Totally a judgement call with the GM.

On a side note: lots of good thoughts in this thread :-)