4130 compatability

Steve. If you want to use 4130 angls, they are available from lots of different places. If you don't like the prices, use plates and weld them up yourself. You can have plate brake bent and slice out what you need. Lots of ways to get it done, don't get locked into mixing stuff like 1018 to 4130 because you are having a tough time thinking it out. Think it out CLEARLY. Go find yourself an EAA chapter and get a hold of one of their Tech Counsellors. They are really nice to work with and usually respond quite favorably to steak and beer. Proper planning of the task ensures trouble free completion.

Scott Correa

Steve, I was reading your posts on RAH newsgroup. Someone wrote that Maule uses MIG every day to weld up their airframes. I don't think they mentioned that Maule also uses CNC cut tubing that fits 'perfectly' and the tubes are in a jig. IMHO gas or TIG is the way to go for a homebuilder. You can control the puddle better and the amount of filler used to account for variations in the tubing fit-up. I just finished the tack welding of a Hatz biplane fuselage. Some of the tubes fit great but some have gaps that need careful attention to. I don't believe a MIG welder can be controlled as carefully as TIG. Just my opinion based on what I am doing right now. In fact I originally bought a MIG machine because it was cheaper than a TIG. Just couldn't turn the corners on all that tubing so I got rid of it and bought a Squarewave 175. I keep my O/A outfit on hand as well.

Ebby Hatz 598

Thanks for the heads up Ebby. I just ordered the steel to build the frame. I will tack it up and then decide whether or not to weld it myself. I have a MIG machine and will try some test pieces to see how it goes using small .023 wire. If it isn't too good I will just pay someone to come in and do it right with a TIG or torch.

Good plan.

A good welder can make short work of a completely fitted up assembly. The fittup is the time c>

Ernie, I think it was who suggested using 4130 wire for MIG welding chromoly with a MIG machine. I went to my local Airgas welding supply, the only welding supply in the area, and they had no idea wht the heck I was talking about. They told me that everyone around here uses mild steel wire.

Does anyone know of a source for buying some 4130 .023 gauge wire? I would like to at least try using both wires on some test pieces and see which is easier to work with and makes the best weldment.

Thanks!

Try ER70S-2 or -6. Both are commonly used for 4130 aircraft frames.

Steve . Use ERW70 S-6. Mild steel mig wire. what was said was that he used MIG wire to TIG weld. Real common to do that. The copper sheath on the wire wets out the tig weld really well. You will never find 023 4130 wire because it doesn't exist. TRUST YOUR WELD SUPPLY SALESMAN. I ahve real good experiences following their advice unless it is a really out there problem. MIG on 4130 isnt really out there....

Scott Correa

Thanks Guys! I did find some 4130 MIG wire on the web, but it was information only and did not list suppliers. I got the feeling it was a high dollar item and only used in specialty cases. I'll pick up some mild steel wire in town, Y'all enjoy the Holiday weekend.

Steve, I have an airframe welding shop and weld on 4130 thinwall tubing daily. I'm also an A&P with IA, so I have some background in the subject at hand. All the OEM airframes I know of are MIG welded, with Robinson the exception. The aftermarket supercub airframes are TIG welded. Post weld stress relieving is not necessary on airframes. The OEM's don't and neither does anyone I know, with Robinson the exception again. Plain ER70S-2 TIG rod is preferred over 4130. ER70S-6 wire is used by most with some ER80S-D2. I would not recommend MIG welding airframes by amateurs. I use TIG for most of my welding, although a torch works just fine and is alot cheaper. I usually tell people to do the fitup (as long as they do a good job) and let a professional finish the welding. Someone with airframe experience, not a structural steel stick welder. Wyatt Swain at TIGDEPOT.COM is knowledgable. SPORTAIR has some info online also. Sorry, I don't have time to give you the links. A Google search should turn up something. Good Luck! Scott.

Thanks Scott,

This is my current plan almost to a tee. :) I have the steel on the way now. I will fit it up and tack it together with my mig welder and .023 mmild steel wire. With the cut offs I will practice and test to destruction to see if I can do the finish welding good enough for it to be safe, then I will consider how pretty the welds look before deciding whether or not too do it myself. I did d all of the fabricating and welding of the current airframe that I am copying to a 4130 version, so maybe I can. The welds on the current airframe are not very pretty, but they are obviously very strong as the tubing has deformed, but not a single weldment has cracked. I would like for this new frame to be a little prettier. :) It's going to be a lot more work building this one, a lot more money too, and I am planning on flying it as far into the future as I can foresee. Next year I am planning a flight in it from Mexico to Canada for starters, up through Death Valley. I need it to be strong and pretty. I appreciate all of the tips from all of you guys. Between this list and the homebuilt aviaton list I have learned a lot in a short time and feel much better about this endeavour.

Hi Steve,

I have read every post to your questions. As I am sure you are aware of, some suggestions are good and some not so good, in my opinion. Here are my thoughts, for what they might be worth, but first let me tell you a little about myself. I have been in the aviation arena since 1971. I currently hold an A&P rating with IA. I am a pilot and in the last year started to learn to fly helicopter (R-22). I have worked on many types of aircraft over the years.

Steve, reading your post you have stated that you want this airframe to last, look good, and be lighter then your current design. These are all good things to want. If I were to make the decision you must make, the only welding process I would consider for this application would be TIG with O-A being second. The TIG with the right person behind it will give beautiful looking welds that are lighter, and stronger then the other technique mentioned.

Steve I enjoyed your web site and feel you are one in a million. Many people dream, very few carry their dreams into full reality as you already have.

I wish you the best in your flying adventures!

Eric D

Eric,

Thanks for the introduction and information. Yes, I realize that not all of the information gained from these sites is necessarily the way that I would proceed, but it gives me a lot to ponder. :) I can usually sort things out given enough information and a little trial and error. I do not know how to TIG, but there is a local welder here that does. I may even be able to hook up with a fellow that builds race car frames out of 4130 and get him to do the finish welding. Don't you think that it would be O.K. to tack it with the MIG and have it welded out with TIG? So many decisions. :)

I'm really glad that you and so many other folks have enjoyed the website. I have been fortunate to have such good friends and acquaintances to encourage and help me along the way during my adventures. If only my wallett were fatter I would love to do a lot more of it. Next year Mexico to Canada and who knows what will be next. I have a few things in mind, like Kentucky to Alaska, and with some sponsorship I woould love to fly the PPC from the tip of South America to the southern tip of Africa. That would be a looooooong flight. :) Some guys did it in Trikes a few years back and it is on my wish list.

It's about time I built a machine that will do what I want, and I had it in my current mild steel frame until I got into the aerobatics and competitions. I think I will quit the aerobatics, but I still need the 4130 frame for the competitions and the stuff I sometimes wander into on the cross country flights. The lighter/stronger frame is just what t he doctor ordered.