We figure it the same as shorthood, 60-65 an hour per man, and estimate 50 per day (8hrs) in consumables per man (gas, rod, wire, fuel, ware/tare, ect).  If you have been in the welding field long enough, you can almost look at the task at hand and estimate it within an hour or two.

Yep, that's a good point that I forgot to mention, the F@*%$ factor.  We add 10% to the hours, and 15% to the consumables estimation.  We also add 20% to the material cost.  That's just the cost of handling, and money.  This gives you a little room to negotiate if the contractor demands a lower price.  If you have good material suppliers, you should be able to get 30 day terms.  Since you need material the fist day, and if the job you're on takes 2 weeks to complete, that means your material bill needs to be paid in 2 weeks.  Since your customer will pay you in 30 days from the completion date that means your material bill will have to come out of your cash reserve.  Along with that your helper won't wait to be paid for 30 days so that money also comes from the cash reserve. 
As you can see, this is the demise of many small businesses.  We call it the cash flow circle, and you are the start of the circle and from that point forward you are paying out until that circle comes all the way around again and is completed, then you get paid.  Managing expenses as the circle revolves around will make or break you.  Also, having many circles going at once will help you ensure money going out is less than money coming in.

now, i like that....F#%^$ Factor...thats goood...damn good.