Any experience with 12x18 random floor sanders?

[NM_Shooter]

Another project I need to take care of is staining of a newly resurfaced deck. 

I replaced 1000 ft^2 of redwood on a deck, and the redwood is completely unfinished and new.  A few months ago, the guys at the paint shop told me to let it dry out and season for a couple of months before I stain it. 

So... time to sand and stain.

I am renting a 12x18 sander, and have purchased a dozen sheets of 100grit paper for it.  Redwood being soft, and the fact that I am only trying to open the top grain and remove milling marks.  I'm hoping that I can do 100 square feet with one sheet.  If not I am in trouble 

I'm going to blow the dust off with a leaf blower and then commence staining.  I bought 6 gallons of red label Penofin.  Going to apply with stain pads, wipe dry, and let dry.  I'll follow up with a second coat if I have enough stain left over. 

BTW, I am bringing a metal paint can to store the wipe rags.  I hear that penofin oil stain will self combust. 

Questions :

1)  Is 12 sheets enough sand paper for 1000 sq ft of redwood?
2)  Any tips on getting the stain down?
3)  Any need to stain the under side of the deck or in-between boards?  (The deck is well above a walk-out basement)
4)  Is there a way to clean the staining pads so they can be reused?

Thanks!

-f-

[Redoverfarm]

Frank I am not familiar with that brand of stain.  On mine I used Cabots semi-transp oil based stain.  I went with them because they have a mildew/algae inhibitor as well as UV protector.  On the installation I used a paint sprayer gun like you would use in a auto body shop.  I back brushed the stain as I went along to even everything out.  Couldn't tell you about the underneath portion only that it seems like a good idea to protect both sides but mine was impossible  ( no clearance) .  I like spraying the finish on in that I was able to get some stain between the boards on the edges.  As for sanding I never have sanded a deck.  I did however sand the handrail which had weathered and felt rough followed by some stain.

Within 24 hours the stain was dry. 

Most manufacturers caution against spontaneous combustion in regards to oil stains (petroleum products).  I believe that is if you leave them wadded up.  I lay mine out flat and allow to dry.

Good luck.