My reloading bench is in the little utility room on the end of the carport. I've never covered my presses befor but am considering it.Would the covers cause the press to rust from not having airflow or would the be less likely to rust because the are covered?

I would make the covers out of lightweight cloth or plastic, with vents in the top.

A light coat of oil on the bare steel parts before covering will help.

I have an old Rockchucker and I keep it covered with the vinyl cover from RCBS. It has never rusted; I am in PA and your are in AR so humidity should be similar 15%-85% relative humidity range.

A heavy cotton pillow case has kept my Rock-chucker dust free for years. A light oil keeps the rust at bay. I live near the ocean and uncovered stuff tends to rust over time. I prefer the cotton to vinyl as it breaths in a humid environment, but the cover is mainly to keep it as dust free as possible, the light oil takes care of the rust side of things.
rob

An old acquaintance here in England covered his RCBS Rockchucker with the botton end of the leg of an old pair of denim jeans!

He left the foot end alone and sewed up the end where he had cut if off below the knee to make a denim bag/cover.

It worked for him!

My Lyman Orange Crusher hides under an upside down 4litre/1 US gallon motor oil container with the top cut out to just below the shoulder level. It gets an occasional spray of Wd40 on the ram & wipe over with a slightly oily rag. I don't ever prime on it & the rag is more dry than wet oily.
Steve.

I cover my press and powder measure. I have never seen any rust. Just a spray of Rem oil ever now and then.

What type of climate do you live in, Oldreloader?

Since your reloading room is in a carport, if you experience winter and rain, all exposed surfaces need to have a good oil applied every now and then. People say good things about Rem Oil and I use Breakfree as both a lubricant and protectant.

Putting a cover on will keep the dust and paint-fading sunlight off. Cloth is recommended. If you use plastic, make sure it is NOT airtight. I would suggest a breathable nylon like what Dillon makes their press covers out of. I have one on my 550B to keep dirt off (dust, random powder granules, sawdust, etc), even though my reloading room is in the basement.

I live in Magnolia AR. We have high humidities here most of the time.Hot summers and cool winters are the norm.

High humidity = rust.

I'd suggest getting a good oil like Rem Oil or Break Free and put it on all iron or steel surfaces. Then cover with a breathable cloth or nylon.