Welding Help

[Jethack737]

Hi guys,
I’ve built my ribs and now thinking of building a fuselage. I know nothing about welding. Is this oxyacetylene welded, tig, or mig? If I take a welding class, which form of welding should I learn for welding the fuselage? Thanks!

[Tom H]

Jet, in my opinion, oxy/acet is the most versatile.  It is relatively simple, needs no electricity, portable.  It can weld steel, aluminum, supply heat for bending and brazing.  It has been used for steel fuselage welding for nearly 100 years.

Tig is great.  Equipment is more expensive, needs electricity.  And, for fuselage welding, I have found that the required welding helmet makes some joints hard to see and get at.

Mig can and has been used.  But, is the last choice for me for thin tubing welding.  I would not recommend it for a beginner.

If you learn oxy/acet, you may find that the other methods may come easier for you.

Tom H

[Jethack737]

Thanks for the reply Tom!

[Dan_]

This will put yer head on straight...  Don't give this info to non airplane builders.  It's like throwing your pearls before swine.

https://www.eaglersnest.com/forum/index.php?topic=241.msg1225#msg1225

[okdonn]

I agree with Tom with one exception. I find it helpful (easier) to tack tubing together with a bit of MIG, then finish welding with oxy/acet. I've never used TIG, grew up using gas and ma very happy with the results.

[Chuck in Indiana]

I'm with Tom, too. Gas is much more forgiving than TIG. I, personally, wouldn't use MIG unless it was just a tack.
What I like to do is continue building the wings after I get the ribs done. Wings are the hard part. Once they are done, you can put them in racks or hang them out of the way so you can build something to sit in and make airplane noises. Making airplane noises is the fun part..and.. you have the hard part done.

[pappyadkins]

Like I've stated in my videos... I choose Tig... If I was to do it again, wish I went Gas...  Nothing wrong with Tig, BUT, ARGON ain't cheap!!! I didn't think about that before I started... I'd bet Gas welding would be a lot cheaper...  I wanted to learn something new & thought I might someday weld aluminum fuel tank (right now, I'm thinking NOT) lol (I just finished my fuse).... Either way I've got a tutorial video that I put together, it's from an OLD set of videos; but very informative if you want to take a look... I thought it was very helpful & so have many viewers... < >. Good Luck & HAVE FUN!!!!!!

[TUNDRAbilly]

, personally, wouldn't use MIG unless it was just a tack, well, I'm australia mig welding airframe is allowed   welder since 84,  I wouldn't have a problem migwelding migweldinh  with proper weld balance for heat distribution to prevent warplanes, its all good,but if not 100% confident in your weld quality,  better off gas or buying g a couple cases of beer, for a bud to weld it,mig welds can look good, but are not  remember its your ass haging out the wind

[Brock]

Not wanting to start a new thread, I hope it's ok that I ask this related question.

I'm in the same boat as Jethack except I already own a TIG and have some expirence.  Seeing what I'm welding was (it's been awhile) always the hardest part.

So my Question:  Since I own a TIG welder, and don't care to buy an oxy rig.  What works well for heating and bending tubing?  Is propane enough.

[Dan_]

Is propane enough.

Propane should be enough.  You want to do the bends gradually. 

It should be plenty for pre-heating the clusters before tig welding them as well. 

I doubt it being enough for post weld normalizing.  Leonard always says wave good by to each weld the the oxy-torch...

[Chuck in Indiana]

I've been convinced that as long as you use ER80S D2 filler rod with TIG, post weld annealing is no longer needed in the sizes of material we use in aircraft. (shrug)

[Dan_]

I wouldn't call it annealing, I would call it giving the mixed molecules time to get acquainted and settle in a way that doesn't cause a crystallization.

When I see a sharp color change about 3/4" from the bead, I get nervous.  The cold tubing further away is "sucking" the heat from the joint.  With the Oxy process, you can give the surrounding tubing enough heat to slow the suck down enough to ensure no embrittlement.

It has been my experience that the higher the tensile number of the filler the LESS elasticity is present.  But again the problem is almost never at the bead, but some distance away where the crystalline structure can form.

Not trying to revive the welding wars, just anteing up 2 cents... 

[Brock]

I've been convinced that as long as you use ER80S D2 filler rod...

Hmmm I just purchased 10 lbs of ER70S, so is ER80S now the recommended filler?
Thanks All for your input.  I'm very tempted to purchase a Mecco Midget and some regulators after reading the discussion here.  Searching a seller now.

[Dan_]

Budd Davisson wrote an article on it here...  With the size of the Oxy bead deposit compared to the thickness of the tubing RG 45 is arguably the best filler period.  RG 60 if you must.  Again a good long wave good bye with the torch to slow the color change will go a long way to prevent stress in the joint...
Also look up "balancing the gases" in the search here on the site.

[Brock]

Dan it seems that artical is saying RG 60 for oxy but 312SS for Tig (I'm using TIG, or at least for now that is the plan).  The ER70S which I picked up was recommend by one of the welders that worked on assemblies for Vans RV.  What was most interesting in this read was the issue of pre-heating and slowly cooling after a weld.  Not sure yet haw that works with TIG unless I'm keeping some sort of gas torch handy.

BTW I used MAP/Pro today to bend some tubing.  Easlily heated it cherry red.