Etched Champion is a must in my opinion. That protection makes it insanely hard to get rid of.

Also, instead of Galvanic Blast, why not try Ensoul Artifact? I reckon you might get a bit more bang for your buck with a T2 5/5 flying Ornithopter than with a burn spell.

The problem with Etched Champion is that it's a three drop, and what I should take out for it.

Yeah... This build is very Blood Moon weak. What sort and what should I take out for it?

I'm new to the modern format and affinity and all of your comments have been very helpful for me.

Also, what coloured spells would you recommend taking out?

What cards do you recommend for sideboarding?

I personally wouldn't play Springleaf Drum. It seems a bit disjointed in the deck. I'll tell you what though, I don't know what you personally would be willing to take out for Etched Champion, but he is the main peanut in this deck and makes it so much more durable since it has the ability to stick around. Remember that you ought to be able to cast him turn 2 in 90% of cases with Mox Opal despite his 3cmc. PERSONALLY I wouldn't play 4 of each Steel Overseer or Signal Pest. They assist you to win by boosting your other creatures, but that won't help much if they can't stick around. That's just me however.

You could cut some of your colored spells to make room for at least one Etched Champion in the main. Having more than 6 colored spells puts too much strain on your manabase.

Ensoul Artifact is good because it can make Darksteel Citadel an indestructible 5/5. However, it opens you up for a lot of 2-for-1s since they can just bolt your Vault Skirge in response to it and you will lose both.

I don't think Dragon's Claw is good in the sideboard because the burn match up is actually good. I would recommend replacing it with Thoughtseize because its great against a lot of the deck in the field.

I'm not sure if the 3-drop numbers are correct. Running a total of 4 Champions and 3 Masters can be a strain. 4 Overseers and 3 Memnites also seem a bit much since they are essentially support cards. I'd consider playing around with the numbers and including 2 Ensoul Artifacts, just to try. Some lists throw in a one-of Thoughtcast for measure. The problem I have with Memnite is that it has no evasion and thus doesn't really carry the hat well.

As for the sideboard, I've had luck running Spell Pierce as a one-of but your results may vary. Wear / Tear is also nice against Stony Silence.

Etched Champion is a card I have found to be very important, as its steady clock and synergy with other cards is incredibly powerful. Master of Etherium usually brings in game wins just because making itself and all the other artifacts huge is great, though I could cut one. I agree with Spell Pierce, but I'm not sure whether Wear / Tear is better than or more effective than Ancient Grudge, and I have other cards for dealing with answers and artifact hate in the sideboard.

Herman have you ever even played affinity or even know what it does? You are very wrong on many of these things. First off, Springleaf Drum is a necessity. So is Galvanic Blast. Yes Etched Champion is great but only if you run 2 or 3. It just costs too much. Also while I think Ensoul Artifact is awesome and I run it in my affinity many people are taking it out just because it gets killed right off the bat to removal.

Also HPJJ I strongly recommend you not putting Chief Engineer in there as it taps your artifacts making them useless. Plus all your artifacts don't cost much anyways.

Take out the Welding Jar and one Memnite for 2 Galvanic Blasts. Although I would recommend running 3 or 4.

And I see you didnt listen to Herman which is good.

I did a playtest and it was fine. Maybe u need some more of Thoughtcast, the card draw is pretty nice since ur hand is pretty low on mana cost. My personal recommendation is Vapor Snag to boost ur aggro.I play an aggro artifact UR myself but unfortunately without the Springleaf Drum which i should change i think. Maybe u could even play some Lightning Bolt too.

i play an affinity deck, and having too many etched champions is a huge downfall. Keep them in the sideboard for games against decks like grixis delver do your entire board state isn't destroyed, but sometimes, they just end up being 2/2's for 3. I also highly recomend a 4th Glimmervoid, the mana coloring is essential so you can always pull off galvanic blast and thoughtcast. add a second thoughtcast too, and a 4th steel overseer. it helps itself too when it taps, and its another way too give ornithopters utility, and just all in all makes your huge army of tiny creatures bigger. affinity is different fro other decks because usually each card is its own good card, especially in agro. but this deck is very different in that you need to have a lot of small things work together, its why the deck always struggles in games 2 and 3, because people sideboard in removal which gets rid of the stuff that makes our creatures not have 0 power. 4 galvanic blasts is too many. u need more artifacts so that you can rely on mox opal to come through and to make master of etherium bigger (which i dont see and u need at least 3 of, its one of the running factors of the deck, almost as important as arcbound ravager.)2-3 galvanic blasts will do the job. That should be it! just remember, a lot of people think this deck is just playing creatures and tapping them but there is a whole world of thought too it, like when to sacrifice artifacts to arcbound ravager, whether to put cranial plating on inkmoth or blinkmoth for infect or regular, etc. it gets crazy complicated and u just need time with the deck to learn it. also you might want to try a tezzeret agent of bolas, i just recently added one and took out a signal pest, and it has worked phenomally! good luck!

wizardofwizdom, 4 Etched Champion and 3-4 Galvanic Blast in the mainboard is actually pretty good in the current meta. With a meta filled with Grixis and Jund running Kolaghan's Command, Etched Champion basically turns into a True-Name Nemesis. Personally, I like a 2-2 split of Etched Champion and Master of Etherium. However, Master of Etherium is very vulnerable to Path to Exile and especially Kolaghan's Command.

3-4 Galvanic Blast is fantastic against all the Twin variants because it's one of the only ways to interact with the combo in Game 1 aside from Spellskite. Also, when not against Twin, Galvanic Blast is still a great removal spell that hits a lot of creatures and can still be used as a 4 damage burn spell to the face.

Moving the 2 Spellskite to the mainboard really helps your bad matchups and frees up 2 sideboard slots for some extra tech. It turns Kolaghan's Command into a 1-for-1 instead of a 2-for-1, steals Splinter Twin, and eats up 90% of the relevant removal spells against Affinity. You can cut down to 2 Memnite and 3 Steel Overseer because, while Overseer can just steal games, it dies to a swift breeze and ends up being a 2 mana 1/1 lightning rod.

I really recommend 1 Dismember in the sideboard and cutting a Torpor Orb. Dismember is great against those pesky 5/5s like Siege Rhino, Tarmogoyf and Tasigur, the Golden Fang while adding more interaction against Twin because you can cast it for 1 colorless mana in case your colored sources are unavailable. It's just a great removal spell in general.

You can also try Ghirapur AEther Grid in the sideboard. It was used by some Affinity decks in the most recent World Championships to get around Stony Silence by turning your useless artifacts into some extra damage. It also kills pesky 1/1 flying tokens and Grim Lavamancer. Tapping 2 artifacts then sacrificing them to Arcbound Ravager is also a pretty neat interaction; especially after blocks. The idea seems good on paper but I haven't really tested it yet.

Enjoy the wall of text

Wall of text enjoyed!

you should play a basic mountain instead of an island

Shrapnel Blast maybe 1? Maybe just in side board?Etched Champion 3 at most.

If you look at this link, which is probably one of the best metagame sites, http://www.mtggoldfish.com/archetype/modern-affinity-8972#paper 95% of decks have 4x Etched Champion it is very good in the current meta.