Risk of oxidization leaving a lager in a bucket primary?

My father-in-law and I brew together & he wanted to try a lager (I'm pretty much an ale guy!!!), so on 5-8-10 we brewed a boston lager clone. Did not get a lot of air lock activity, but after scouring the threads, I overcame my NOOB fears and trusted the yeasty beasties...thank you all!!! I just took a hydrometer reading and we nailed our target gravity at 1.012:rockin:
My concern is that there is too much head space in a 6.5 gal primary bucket and the yeast have finished their job so no more C02 will be produced to protect the beer. We don't have a 5 gal carboy to rack to for a secondary--we have just used another bucket in the past. FIL is not convinced we need one or that oxidization is even a concern. We did a diacetyl rest for the last 48 hrs and now back to the fridge to get it back to the high 50's. Again, I have scoured the threads and still can't come to any satisfying conclusions. So...
1) How long can I leave a lager in the primary bucket once the lid has been removed, CO2 released, & fermentation is complete?
2) How big a problem is oxidization? Can't imagine there is any difference between racking off the trub into another bucket and leaving it in the primary at this point.
3) Is there a cheaper way to protect the beer from oxidization than buying a 5 gal carboy?
4) If I can't lager in a carboy, should I just bottle and let it condition there?

Any and all advice is appreciated...Y'all have helped maintain my sanity and have been a motherlode of info as we have set off on this grand brewing experiment!

If I were you, I'd just bottle it and then lager in the bottles. I know that freaks some people out, but there really is not much difference from bulk conditioning, just maybe a little more bottle sediment. Obviously let them carb up at room temperature first.

1)2-6 months
2) not
3) it's okay
4) lager first

If you are very, very worried, toss 1 oz of cane sugar in the bucket and reform the CO2 blanket.

You could get yourself a cornelius keg and lager in that. The bonus is that you already have a start on the equipment for when you start kegging.

uwjester has a good idea. Kegs are compact, light-proof, air-tight and relatively cheap.

I use kegs, they are perfect.

I wouldn't do secondary of any kind in a bucket...I did it once and it was horrible. I suppose I cannot be certain it was the buckets fault, but it was by no means airtight and I wouldn't trust a bucket at all.

Bottle it and lager in bottles or get a corny keg.

Adventures in homebrewing is selling sets of four for $80.

http://www.homebrewing.org/Set-of-4-Soda-Kegs-5-gallon-Cornelius-keg-_p_1549.html

Thank you all for the advice, but if I could afford to run out and buy cornies, I would go buy a 5 gal. carboy. I bottle, I enjoy bottling (gasp!!!), and will keep bottling for the forseeable future. My questions are concerning what I should do with the equipment I have and how big an issue oxidization will be if I use a bucket...

david_42 said:

Kegs are compact, light-proof, air-tight and relatively cheap.

Click to expand...

They also have built-in handles and dip tubes, they hold pressure, and you can serve from them. They are quite useful even if you continue to bottle:
https://www.homebrewtalk.com/f13/priming-keg-bottle-conditioning-92692/

There are a couple of issues (to me) with lagering in the bucket. One is the headspace, which I think is a concern after a month or so. Secondly, I didn't see if you racked the beer or not. If you did, I don't think I'd worry but if not, I'd get the beer off of the yeast cake ASAP. I like to rack my lagers right after the diacetyl rest, to get it off of the yeast cake. So, my thought is that there are two strikes against you- the yeast cake and the headspace. I'd get a carboy, and rack and then lager.

Thanks Yooper, I don't have a carboy yet but just racked to another bucket to get it off the yeast. Cest la vie!!! It is a little tough brewing by committee...my FIL & I are both NOOBs, both hardheaded, and both want the best beer possible under the circumstances. Alas, we don't always agree on what is best...he keeps buyin buckets & I'm broke!!! But every single batch we have brewed is the best beer we have ever had