Plasma cutter for metal plate wall

I work on a nuclear fusion experiment that has a radiation shield, created of interlayed plates of mild steel with a hard skin. altogether 3 sheets, each 1 inch wide are placed vertically in close contact. To make room for diagnostics, we have to cut holes in the wall... some say 12 by 12 inches wide (or larger). At the moment we use a magnetic drilling rig with a 2 inch bit and cut a series of holes around the pieces of wall we want to cut out. Needless to say this can take days, even with cobalt bits; and bad sections of steel with slag in the middle of them can stop us dead.

I've been trying to come up with a better way to make these holes. a thermal lance would probably create too much debris and possibly effect equipment placed a few feet from the cut. Searching the web, I've been reading up on plasma cutters, but no one (the welding firms I`ve called included) seems able to answer a few queried. so any help would be appreciated.

from what i gather, i am able to get plasma cutters able to cut up to an inch thick (I don`t mind 'sever cuts' even). Does anyone know would it be possible to cut through the first plate of the wall, remove the material, them cut through the next plate in (i guess the hole int he next plate cannot be as big as you need room to put the head of the cutter in position). I am worried that in effect there is no in line exit for the air from the plasma cutter, effectively it would be just hitting the next plate then probably reflecting back towards the user. Is this a problem? will it cut? does anyone have a better idea?

many many thanks for the time,

Simon

Bill

Reports to be 80 percent cheaper to use than acy.
Only problem is that there is no importer in the US so shipping from china makes it rough.

The close stacking of the plates is a problem as well. In using my 45 amp plasma cutter, I've fount that if the plasma beam cannot emerge cleanly from the back side of the plate, the material does tend to blow back towards the torch or "bunch up" at the bottom of the cut. (The 1/16 inch wide x 1 inch thick section of steel the beam is trying to remove doesn't just "vanish", it has to have some place to go.) Oftentimes the melted material re-solidifies, leaving the cut-out portion still joined.

You can use the plasma cutter in "gouge" mode, blowing the material away at a 45 degree angle, but this makes for a rough and messy cut, and I picture it as fairly impractical for a "laboratory" setting.

Thick steel like this is usually cut with an oxygen/acetylene torch. Flame cutting works on thick sections because it is literally burning the steel (reacting the iron atoms with oxygen), and the material really does "disappear".

An acetylene torch works by reacting the iron in the steel with the excess oxygen supplied by the torch. Fe + 02 => Fe2O4. The iron literally burns once it gets hot enough. The heat of oxidation is sufficient to keep it that hot -- that's why you can turn off the acetylene once you get the process started.

Metals with low energies of oxidation can possibly be melted by an acetylene torch, but they cannot be cut. This applies to almost everything except iron and steel.