Partly because you are closer, but also because of the shaded lens. I don't know if this holds true for everyone (I didn't need reading glasses until I turned 40) but as I understand it brighter ambient light causes the pupils to get smaller, which (at least in me) changes how your eyes focus. I can read in bright sunlight but indoors I have to have reading glasses. The shaded lens does the opposite & actually makes it harder for me to focus on stuff close in, so I need the stronger lens.
Yup. It happens for everyone. Cameras do it too. It's called "depth of field." The depth of field is the distance, front-to-rear, in the field of view that covers all of the things that are in focus. When your pupil is larger, fewer things are in focus (naturally) so your muscles work to flex your lens ... and you get tired.
I just wish someone would figure out how to make some kind of differential welding filter so that you don't have to look at a bright spot on a dark background. Hmmm ... laser welding (and laser goggles) anyone?
Richard Johnson, EAA #395588
That is part of why I don't like to use my mig anymore. I have an auto darkening electronic welding hood, and when I was working away from home (over 10 years ago) Dad "put it away" for me, & I cant find it, and he can't remember where he put it, so I have to use my old one with the flip up lens. Can't see a dang thing, it is either blind yourself with the first arc or start blind & the first arc is 1/2 inch away from where I want it.... And I'm too cheap to buy another one, because as soon as I do we will locate it....
Well, I think I've decided on a gas welding rig.
Smith 30-100-540 Oxygen Regulator
Smith 30-15-510 Acetylene Regulator
Smith AW1A Torch Handle
Smith RA921 Grade R Hose, 12ft
AW201 Welding Tip
AW203 Welding Tip
AW205 Welding Tip
Tanks will be rented. Per this EAA article, I'm thinking a 40CF acetylene tank and 60CF oxygen tank will be suitable, but I'm open to suggestions.
Total cost, less tanks and safety gear, is about $350 before tax. I'm planning to order online from Weldfabulous, though I may get the hose and tips locally (maybe A.S.). Might save the sales tax, as I think they're out of state. Shipping estimates are cheaper than the sales tax. I have been looking into used equipment sources and I just don't think it's worth the trouble. I'm not going to find a much better price on the regulators ($136 combined), and honestly I feel it's worth it for the new equipment. The torch handle I would be willing to purchase used, but the people who have the AW1A aren't selling them, and the ones that are selling them know what they're worth. I'd like to think I might run across one for $50 or so, but I'm not holding my breath. At $103, Weldfabulous is fine. Tips and hose I might just purchase at A.S. since the price is comparable and I can divide the purchase into more manageable budgetary chunks. Plus it's an excuse to go over to A.S.
Next up is learning to actually weld, which I have a few leads on. I left a message with the local EAA chapter as well in the hopes of finding someone more in-tune with aircraft welding (or at least inspection).
Onward and upward
Congrats on your choice Tony, now you have a setup that will allow you to weld all the materials you will need to build your plane. Cylinder size looks good to me, should be able to weld 2 or 3 fuselages with that set. As for learning......maybe its time for a sportair welding class is CA??
-Aaron
Hmm... It doesn't look like there are ANY gas welding courses on the schedule. What's up with that?
Tony - if you have never done any welding you should expect a long learning curve & lots of practice. I have a lot of arc welding experience so I was able to pick up what was taught at the SportAir gas welding workshop with just a little practice, but it would have been more difficult if I hadn't already had that experience.
You might think about getting more hose, 12' will have you moving the cylinders a lot. I think I have 30', I can reach most everywhere in the shop but I still have to move them if I have to work on something outside the door.
Last edited by Mike Switzer; 08-12-2011 at 12:55 PM.
I've been watching the SportAir schedule for 6 months to no avail! And I obviously couldn't justify travelling to Texas or where ever the last gas welding workshop was held. I wish I had been more on the ball when I went to Oshkosh last year and would have attended some welding forums, though at the time I wasn't really in a position to make progress on the build (and had plenty of other things to occupy me that week). I've looked into the local JCs hoping for courses, but they're not really scheduled around the 9-5 worker and I'm not keen to take half days at work several times a week. I know several people who know how to weld and will be hitting them up for some instruction. I'm expecting a steep learning curve, but I really don't mind as long as I know how to judge my own weld quality. My main concern is that I'll inspect a weld and call it good, when in reality it's crap. I'm willing to put in the practice if I have a metric with which to gauge progress. I know there's a lot of talent and experience at a nearby EAA chapter, so I suspect that will be a major source of knowledge in the process.
Also, I'll go ahead and spring for the 25 foot hose per your suggestion, Mike. Makes little difference in price, and probably a lot of difference in the level of annoyance while moving around the shop.
-Tony
Just for the record, if anyone is following this thread and curious, I called up several gas suppliers in Southern California. I started with the big 2 (Airgas and Praxair), as well as Cameron Welding Supply (3 locations, all in SoCal) and one small place. Praxair was not willing to rent, but had cylinders for sale at around $400 (presumably for both, but I don't recall the capacity). Another local place, being relatively small, does not rent tanks but sells 55CF oxygen cylinders for $120 (full) and 40CF acetylene cylinders for $150 (full). Refills are $15 and $28, respectively. Airgas rents cylinders at $0.50/day, and Cameron rents at $0.35/day with a $170-$200 deposit. Unfortunately, the guy I spoke with said the smallest they rent are 130CF capacity.
We use Cameron's services where I work so I'm thinking about adding onto our weekly delivery, which may avoid the deposit as well. I'm not too hot on such large tanks though. I guess the real problem is mobility, which shouldn't be THAT big a deal if mounted to a wheeled cart and with a long enough hose. To play devil's advocate, I'm also seeing what it takes to buy the tanks outright, which is $150-$250 in 10-40CF capacities when new according to A.S., Weldfabulous, and Cameron's website. Not thrilling.
So take those numbers for what they're worth. YMMV.
-Tony
To quote Hank Hill, "Holy crap...."
I have a 145 ft^3 acetelyne & a 150 ft^3 oxygen (and a nitrogen & shurgon, approx the same size (nitrogen is for purging the O2 from the wine tanks)) & I'm paying Ernie $36/year/cyl rent. And I'm pretty sure he's an airgas dealer, but HE owns the cylinders.