I once tried a deck like this, but it was when I first started so it wasn't too good but I did pull off the combo sometimes of infinite mana into any X spell(my favorite was Brain Geyser lol).
I think you should run Tinker. Every part of your combo( Staff, Metal Worker, Goblin Cannon) is an artifact. And if you ran Tinker, if you wanted to you could run an alternate win condition of Tinker-Darksteel Colossus. The only problem is your only blue source is Tolarian Academy and it's restricted.
It might not be worth adding enough blue sources for only Tinker. But if you were going to power it(maybe at a tournament) then it would be easier with Lotus Petal(well this isn't power but just saying this would probably be one), Black Lotus, Mox Sapphire.
Power Artifact would also be useful. If on your staff then you only need 2 artifacts in your hand for Metal Worker to combo off on the Staff. Or, it also makes it so Grim Monolith can create infinite mana and combo off on the Staff.
Adding blue starts to take away artifacts from the deck, and you really need them in order to go off.
Also, I think Wastelands could really hurt this deck because you don't have a single basic land. But maybe not if you manage to get some mana artifacts out quick. Also, even though you have good disruption, if a card hits play that hates artifacts there's not much you have to get rid of it.
Wastelands and Strip Mines shouldn't really hurt. You only really need to resolve Metal Worker to win, and Goblin Welder as back up. All of that can be done with a single land drop and/or with use of Simian Spirit Guide. Also Blood Moon helps against Wastes and Strips. As for hate on artifacts: Null rod will rock this deck, that is why Chalice for zero Turn 1 is important if you can combo off Turn 2, and you can also Chalice for 2 on Turn 1. As for Energy Flux, that is nothing. Often the only artifact you will have in play is Metal Worker at the beginning of your turn, and he can pay for himself. This usually slows you a turn.
I'm interested, how many turns on average does it take this deck to combo off?
The deck usually comboes off turn 2 or 3 without disruption, but it requires muligans often.
Would you mind going in depth about the day's matchups?
I didn't find Voltaic Construcs until Sunday Morning at Gencon, so I played this in the Sunday Vintage.
The bye was pretty easy in the first round. I was kind of worried he might pull out some tricks, but I managed to beat the bye.
Round 2 I played against Roland Chang.
Two games in a row he had amazing hands. He won the die and openned with Mox, Mana Crypt, Sol Ring, Trinisphere. I had a turn 2 win in hand, but the Trinisphere kept me unable to play anything. My hand was Ancient Tomb, City of Traitors, Mana Crypt, Metal Worker, Staff of Domination, Voltaic Construct, Planar Portal. I drew a 2nd Metal Worker and dropped Ancient Tomb and passed the turn. He played wasteland, wasted my land and then played Crucible of Worlds. There was a lot of Pass go for awhile, and I had to start discarding. I held on to the City of Traitors, so I could draw Simian Spirit Guide. I saw no SSG or Workshop in 10 turns and once he had an active Welder I conceeded and we went to the next game.
Game 2 I make a mistake, and kept a hand with 3 City of Traitors, Great Furnace, 2x Metal Worker, Staff of Domination. I thought I only had 2 City of Traitors and that the other one was an artifact, but that is what happens when you don't sleep at Gencon. I play City of Traitors and pass the turn. He Strips my City and plays Mox, another mana accel or 2 and drops Trinisphere. I draw a City of Traitors and play it, yea all 4 of them. He plays wasteland and wastes my land. I play another City and pass. Roland rips Crucible, plays it and wastes again. I sit on my last city and once again never see a Mishra or SSG.
He admits to having two really good hands. I could have played around them if I could have just seen Mishra's Workshop or a Simian Spirit Guide. We play a game 3 for fun because he wants to see what my deck does since I didn't do anything for 2 games. I proceed to drop Mishra -> Metal Worker -> win turn 2 with Voltaic Construct and Planar Portal.
Round 3 I play against a guy I played the day prior. I cann't remember his name, but he was a nice guy, and we had lots of fun playing both days.
Game 1 I go first and gamble that he doesn't have a Force of Will. He doesn't and I drop Chalice for zero then Mishra -> Worker and I pass the turn. I know I win turn two unless he bounces the Worker as I am holding Staff of Domination, Voltaic Construct, Sphere of Resistance, Trinisphere. I could have gone with 1st turn Trinisphere, but if he dropped a wasteland I could be screwed. He plays a land and passes the turn. I draw another Staff of Domination. I tap Metal Worker and reveal my entire hand. He brainstorms in response, and just asks me to show me the win condition. I drop Trinisphere and then Staff of Domination and draw untill I hit Planar Portal then play Portal fetching Goblin Cannon, and we go to the next game.
Game 2 is much more drawn out, but it is one sided. I don't remember the specifics, but I remember he kept having to use Merchant Scroll for Force of Will and Bounce. I resolve an early Metal Worker and I eventually gain enough card advantage through Planar Portal activation every turn. He has to counter Voltaic Construct every turn or I win. I have Metal Worker (2 Staff of Domination in Hand), Mishra's Workshop, Ancient Tomb, City of Traitors, and Great Furnace all providing me 12 mana each turn so that I can Search with Planar Portal, cast Voltaic Construct, and untap Metal Worker should he resolve. I finally draw an artifact right before I run out of Constructs, and that allows me to cast Goblin Welder. Metal Worker gets bounced. I cast him on my turn and he gets countered. I cast Construct and a Staff with 3 Artifacts still in hand. He's run out of counters. At the end of his turn I weld Metal Worker in and go off on my turn. All of his resources were used to prevent me from going off, and I outlasted them. I did take a lot of damage from Ancient Tomb, but I still comboed off.
Round 4, the last round of Gencon. I was playing against Flash.
This all gets a little fuzzy, I was magiced out and making mistakes left and right. Game 1 I force him to rip his hand apart with Force of Will removing Flash. He has to Force two early spells and rebuild his hand from there. He also uses Pact of Negation twice and pays for it both times. One turn it taps him out completely, but he plays a land and passes. He casts another Pact of Negation uses his one blue mana to Mystical for Demonic Tutor. He again pays for pact, but doesn't have another land and passes the turn. I drop Blood Moon taking away his black and green mana. He brainstorms on his 1st main phase. He takes about 3 minutes looking at his hand and deciding which cards to put back. He knows I will go off on my turn as I have an active Goblin Welder now and Voltaic Construct on the board, as well as a Metal Worker and Staff of Domination in my grave. He finally resolves Brainstorm, and then thinks for a few minutes and finally casts flash. I remark how it must have sucked having the Brainstorm reveal more Slivers. I knew he had gotten stuck with one Sliver in hand, and it meant that he could not win because if I played properly I had 2 blockers. The Blood Moon kept him off green so he could not cast the last Sliver. He searches for 3 Virulent Slivers and a Heart Sliver and swings. I weld out an artifact for Metal Worker, and pay two to untap the Construct, as he had been beating down for a few turns. I block two of the Virulent Slivers and take 2 damage and get 6 poisen counters. I take my turn and go off.
Game 2 I make another gamble that actually costs me the game. I drop Ancient Tomb and cast Caltrops, to which I get pointed to the "3" in the casting cost. I remark about oh yea that's right, my friend and I were stating how it sucks that it costs three. Since I have 2 in my pool, I cast Mana Vault. I go to play the Caltrops, but decide to gamble and go with Metal Worker instead. Bad Gamble, he wins on his turn, but this game actually sets up the next game.
Game 3 my opponent sides out all of his Enchantment hate thinking I am not running Leyline of the Void because of the Caltrops. I open game two with double Leyline of the Void, and my opponent's face shows how screwed he was. We battle back and forth I beat down with Metal Worker and a Voltaic Construct, until my opponent plays a Elvish Spirit Guide and then returns the beats as I can't give up my combo pieces. I don't draw any thing and what I do draw gets countered. Finally I get something to land, I think it was a Goblin Welder. We go to time, and I have things bounced. He is playing not to lose as he can not win. on Turn 5 I go off, and actually do not win. LOL I don't play it safe, and only have a single defense grid with a Trinisphere and he has 3 mana available. I didn't recall that Trinisphere is applied last. I could have played more Defense Grids as I had Staff drawing most of my deck, but I didn't. He Force of Wills my Goblin Cannon. I look puzzled and angry at myself for not playing more defense grids, and taking the short cut instead. What I don't realize is that I could just pay 3 mana and use the staff to untap the Welder and bring the Goblin Cannon Back into play and win, but being completely tired and all magiced out I look at the die representing turn 5, think about how I should have played the additional grids and ask him if he would like to conceed. He says no. The judge says ok it is a draw. I say it is stupid for one of us not to conceed. if we draw we both get nothing, if one person conceeds at least someone gets prize, so I conceed the game, and ultimately the match. I deserve to lose for playing so horribly anyways. My opponent is cool and splits the prize packs he gets with me. After the match the on-lookers asked why I didn't untap the welder. I remarked because Voltaic Construct can only untap artifact creatures. They say, no with the staff. I laugh and say because that would make sense, I was to tired to realize that as I was actually untapping Metal Worker with the Construct each time not the Staff so that was what my mind was locked into.
Should have been 3-1, but ended 2-2.
EDIT: I had Gorila Shaman in the deck, but when throwing the deck together at the last minute could not find them so they did not go in. They would be the removal, and there was two of them planned main.
