Not getting any help from the local welding shops around here on selecting which SMITH torch to weld all the 4130 tubing on a Breezy fuselage. Any of you guys that could offer some advice from experience would be greatly appreciated. Thanks
I just looked at the Smith welding website. The only one that looks small enough is the AW1A model. It has the knobs up by where the tip connects. On the Victor style torches, the knobs are down by where the hoses conect. If you don't clock the handle and tip to turn the knobs away from your wrist, the knobs are next to your wrist and can get bumped easily.
I think that the old Smith torch that everyone talks about is no longer made. I saw one one time. It is little bitty. They or someone used to make lightweight hoses which would help on the weight and drag as you move the torch around.
You really can get along just fine with a Victor style torch if you can't find a Smith you like.
And for all you on a budget, you can buy a complete set: torch, tips, cutting attachment, hose, regulators, goggles, spark lighter, in a case for around $100 if you shop around. Yes it is probably made offshore But the el-cheapo set I have still works fine.
The Smith torch handle alone is about $150. Then you still have to buy each size tip you will need. Get a "OO", "O" "1" and "2". Most sets do not go down to the "OO" size. For real thin stuff, the "OO" makes it easier. For clusters, you will need a 1 or a 2 to get enough heat in the joint to weld it.
Then just practice, practice, practice.
Oh, the popping that sometimes happens is most likely caused by a dirty tip. Use a cleaning tool to make sure it is clean. As the gasses come out of the little hole, they cool the copper tip. Except the very end does get hot as it is used and carbon builds up inside the little hole. When the tip get hot, the hot bits of carbon try to ignite the gasses back inside the little hole insead of the flame being just outside of the hole. So it pops! And splatters the molten weld everywhere.
Yes, the AW1A is the correct one. To get started, all you need is the 201 and 203 tips. You'll need the 205, too, but not very often. You may want to pick up two 201's and drill one out to the .069 drill size. For welding tips, size matters .
For a legitimate reference, you should look at the 43.13 under welding and see the tip drill sizes for the metal thickness you will be using. Plan on between .025 and .125 thickness for the majority of the work. The Smith site should confirm their tip size to drill size.
AW1A is the standard aircraft welding set-up from Smith. That is what I use and it is a good product. However, just for giggles, look at their jewelers torch. I noticed that the tip sizes (drill sizes) are right in line with aircraft welding. It is real cheap and looks like the thing to use because its small size and the flexible hose. A lot of people like another brand of torch because of it's small size and flexible hose. This looks a lot like that one and I'll bet it is a similar product at about a quarter of the cost. I think Smith just markets that torch incorrectly by calling it a jewelers torch. I have considered buying it, but the local welding shop doesn't stock it and I want it to see before I buy.
Now that I have said that, I live less than two miles from the Smith factory, I'll go down there and see if they'll show me that torch. I'll re-post later this week if I think it is something to consider.
I bought the Harris model 15-3 set up at Oshkosh a couple of years ago. It is the same light weight small handle and tips used for the welding forums taught at Oshkosh. I have their tips 1-5 and you learn what tips work best with the different thicknesses you are welding. I did about half my fuselage with a big Victor with heavy hoses. The pain in my arm after hours of welding was intense. No pain with the Harris at all. I think the Harris and the Smith are comparable, great touches.
OK, I just got back from the Smith factory inquiring about their jewelers "Mini Torch" for aviation use. It looks like a real handy item for around the shop, but the tips are probably to dainty and short for some of the welding you'll do. The orifice ranges do fall into the sizes we use, but the tip is real small and short. The guy there didn't think there would be enough thermal mass in the tip, so it wouldn't last very long. Also, being that short may preclude you from welding things like clusters that have a lot of reflected heat. It would be great for a lot of stuff, though.
Back to the AW1A: Get the AW1A with the AW201, 203, and 205 tips. If you don't have the hose yet, look at their brazing hose: Part no. 14779-4-10. The standard 3/16" torch hose at the welding store is too heavy and stiff for airframe work.