no control over burn!!

I did do a search last night but I just couldn't get the right search words I guess.
So last night I had a fire in my quad 400.
Quick set up:
Quad 400 w/ secondary burn
1 spin draft in the ash pan door
1 primary air intake above the singe door, sliding metal to metal, just adjusted and cleaned, working properly
Secondary air intake in the back
6" pipe about 15-17ft from the bottom of the fire box, straight up no 90's or any bends
outside temp around 50-52f no wind at all, very calm

After a few reloads (with no problems controlling fire or temp) I thought I would try more wood this time. Two chunks of maple and 1 16" long by 2-3" thick split. As I watched it very closely I shut the spin draft with a pipe temp on the magnet of around 350f as I have done all night, all logs were charred and burning nicely.
After a few minutes I started to close the primary down with no effect, closed a-little more no effect, the fire was still getting hotter but not fast, slow increase in temp . now the primary in fully closed and fire is still getting hotter. With a full firebox of flames. The fire settled in around 425 pipe temp and around 500f stove top. This was much hotter than I am used to so I watched it close and she just cooked away. I closed the damper down all the way with no effect. no change in flame pattern or temp.

This is such a small stove I didn't think temps of 500f stove top would be ok to run. If that is a good cruising temp I'm ok with that but shouldn't I have control over it?

But the BIG concern was I no longer had any control over the fire itself other than stuffing my fire gloves in the secondary air intake if things should have gotten out of control or putting up the screen and opening the door. Can anyone tell me what happened? Did I not do something right or just overloaded with wood? I wonder if the ash grate is leaking air? I closed it and packed it with ash before the burn.

Oh I did do the dollar bill test on all gaskets and they passed, I also sealed all potential air leaks with furnace cement from factory joints, also inspected for cracks or damage prior to first burn.

Help,
Charlie

It's a cast stove. The cracks I was referring to were factory seams from the sides and back were they are put together.
No real cracks. After the same problem last year I filled them this season thinking these seams were leaking air.

That will be done tonight. Is it possible the the secondary let's in enough
air to let it keep getting hotter after it gets going? Big enough to create a self sustaining fire.
What I mean
is should I have started closing the drafts earlier in the burning process because of the larger supply of wood?
Did I maybe reload to early. Too many coals?

Thanks everyone. I leaning on operator error at this point. I've completely reinspected the stove and found nothin to say air leak.
Tonight I will try to duplicate the scenerio with amount of fuel but start with less coals and start closing the air off sooner. I'll report my findings in the a.m.

Thanks again,
Charlie

Ok, Checked the stove for leaks, none found. Tried again with a hefty load of wood BUT this time I let the previous burn run all the way down to a small pile of coals, much smaller than last time. Raked the coal forward, packed with wood (4 smaller split, remember small stove), started up right away, got up to temp all nice and charred, closed spin draft, backed down primary to around 50% and PRESTO a nice even burn with no fooling around with. I am still going to cover the ash grate with a piece of steel though. When the stove was at 75% air it looked like a volcano in the center front. Oh the outside temp was cooler also went from 53 from the original post to 40 tonight.

Thanks for all the help, any other good info out there?
Charlie