I am as sure as I can be,  you are fishing in the wrong pond, if you want invader equipment you are going to have to fight invaders and stop spending gold on coffers.

You can get those things from coffers: caps and oak bark a bit more often;  gypsum, forest moss and rivets rarely.  You can also get them from Invaders - for caps and rivets hit Royal Guardsmen; for forest moss and oak bark Man-eaters; and for gypsum Centurions.  

You will very rarely get a legendary item from Invaders so gathering enough is a bit of a grind whatever you do.

Thanks for the like Blazebo,wondered with not posting if you were still playing.

If you can get non standard items as John as suggested,I am glad I qualified my answer.

I wonder if it was ever so, but it s a long time since I first bought and opened coffers and didnt get too many because gold was scarce then.

John is also right about it being a long slog to get enough materials to get legendary invader equipment, I still have none, and the reasons for wanting it have somewhat passed.

They have sometimes sold coffers in packs from the bank that give invader equipment (I bought some one time when I first started playing) ... also in the clan store you can buy coffers with centurion and barbarian materials.  But the coffers you buy with gold in the game only give standard materials not invader materials.  One can also get invader materials by farming invader lairs ... 

Yes I am still playing, as much as ever, I just have not posted a lot in the forum lately.  I did not realize one can see who likes one's posts ... lol

So I was correct about the coffers bought with gold after all. 

I had assumed TheExecutioner knew about the clan store for those 2 invaders material, and the question was specifically about coffers coming up blank.

The 'the likes' seem more of a nonsense than the badges in the old forum, and I only found out  about them myself by chance recently. I dont know if they were there at the start of this forum version, which seems to be little used compared to the old one, and so perhaps  theres not as much incentive to post.

vikings help will tell you which items are in coffers and how frequently . XYZ I am not sure why you wouldn't want legendary equipment, I don't make anything less. (You lose too much upgrading lower level equipment). And select the items that give a minmum of 30% boost.

Returned here as  a result of someone using the opening post to post a spam link.

As  to the misunderstanding about legendary items.

I had been  trying to get enough material and waiting to forge legendary equipment rather than waste the silver needed and material by using an upgrading process.

 Apart from the fact that the game is of even less appeal today,a year later .

The reason for the the passing need remains as it was then, I am not much further forward in the quest to get the legendary items in question, by the time I have all the material I will probably be hero level 70 and not need it.

If everyone can simply buy all the items they need from the store (with gold they buy from Plarium) there would be no competition and a new player can quickly get to the same level of gear as a player that has spent weeks/years playing the game.