TESTING

It is important that welds be AT LEAST as strong as the joined metal.  In order to test that, the coupons are put into a vice and stressed until the joint fails.

OR NOT!!  The test successfully demonstrates that the weld joint is as strong as the steel. A little more practice so that the welds look pretty, and practice adding filler rod, and I will feel like I can start tackling the fittings.

One of my advisers pointed out that I need to be as comfortable as possible with my arms supported in order to produce nice even welds.  That advice helped quite a bit, though I am still working on ways to keep my arms supported while being able to move the torch along the weld.

SUCCESS!!

After burning, literally, through a bunch of sheet metal, I have gotten some decent welds.  Not perfect. Not things of beauty.  But good penetration and decent looking ridges.

All during my practice if I got a decent puddle, I promptly burned a hole in the coupon.  I either burned holes in a lot of metal, or had very poor welds with no penetration.

Today, there was breakthrough.  The furthest set of coupons was the first set that had good welds. However, if you look close, you can see that I had some blowouts while doing the tack welds at each end.  The weld itself is pretty consistent and has good penetration WITH NO HOLES!.

The middle set is another good weld.  Plus I managed to tack both ends while blowing a hole in only one end.

In the closest set of coupons I used a bit of RG-45 rod while doing the tacks.  NO HOLES!  And, a pretty good looking weld.  Not quite as good as I want to be before I start welding up fittings, but certainly a workable weld.

Getting here has been quite frustrating, but I am elated at the moment.

Now for a bit more practice!

Metal Work

Re-acquiring my welding skills is proving to be more difficult than I thought.  I figured a few practice welds and I would be back in the groove.  It is not working out that way.  I am making progress, but not as fast as I would like.

Here is the welding setup:

This view shows the tanks.  Well, almost.  The shorter acetylene tank is to the left of the oxygen tank. The stack of boxes in the background is waiting to be flattened and put in the recycle bin.


I had been struggling with cutting the practice coupons.  I tried putting a metal cutting wheel on my trim saw.  That did not work so well.  I think the trim saw simply turns to fast.  I found that the hack saw with a really fine tooth blade works pretty well. I also have a variable speed jig saw.  I put a fine tooth hack saw blade in that, and it works OK, too.  But it really isn't any faster, or any less effort, than the plain ole hack saw.




And then I ran across a tip on the EAA site relating to turning a table saw into a cut-off saw.

So I mounted the cut-off wheel in my ancient Craftsman (actually Rockwell) table saw. This works extremely well.  The board clamped to the miter gauge makes it easier to slit sheet steel.  As an aside, they don't make tools like this old table saw anymore.  At least, not at prices us mere mortals can afford.  It isn't very big.  The  table is 16" X 24".  I have a 5HP motor mounted on it.  The thing is very solid and makes nice cuts.  It takes two strong people to lift it, despite it being rather small. The tilt arbor has no detectable run-out and the gears on the adjustments are smooth with no backlash. Pretty amazing.

Speaking of things that work extremely well:

The little tool mounted in my vice is a simple press brake manufactured (in Canada) by Veritas Tools and marketed by Garrett-Wade.  It is held in the jaws by the tabs on top and strong magnets.

Simply slide in the stock and tighten down on the vice.  This is a piece of 16 gauge and required practically no effort at all.

The finished bend is great.  I was worried that without any adjustments the little brake would produce inappropriate bend radii.  As the photo shows, not at all.  This simple, high quality tool produces very nice bends.  The specs say it can bend up to 1/8".  I'm not sure I am ready to try that in my vice.  But the brake ought to work fine bending small parts out of .090 chrome-moly. And what's to loose for under thirty bucks!

Relearning Welding Session 1

I got the chance to do a bit welding practice last night.  I was hoping that it would be like riding a bicycle.  Not quite.

I managed to create pretty good, though not even puddles.  But the penetration was not good.  I think the material I am using for practice is too thick for the tip I am using.  So I will be getting some thinner material in the next day or two.

A note on the blog...if you are not familiar with the blog format, the latest post is always on top.  Don't neglect to go to "Older Posts" see earlier history. 

Rib Completion

I thank all you faithful readers for your patience while it looked like nothing much was happening.  Between some health issues and dealing with my aging parents not much got done in February.  But the project is back underway!

The ribs are done, done, done!  The final step was getting them varnished.  My EAA tech adviser showed up and we spent a delightful afternoon dip-varnishing the ribs.

They have now been moved up to the hangar.

Here is our hero (Me!  :)  ) with the ribs hanging to dry.  I have enjoyed fabricating the ribs, but I am glad that phase is over and it is time to move on to the next phase.

Which is...fabricating the metal fittings needed to build the wings.  I have acquired welding equipment and will have the welding corner set up very soon.  Then I will need to spend some time re-learning how to weld. 

Though I have received some pressure to consider TIG welding, I am passing on that for the moment.  Not only are good TIG welders expensive, I would have to completely re-wire my shop (garage) space to accommodate a TIG unit with an acceptable duty cycle. There are nice TIG welders that can operate on 110 volts, but their duty cycle is very short.  That would be frustrating when I get to building the fuselage.  In order to get an acceptable duty cycle I would need to purchase something other than a bottom-of-the-line welder ($$$$) and bring 220 volt power into the shop (more $$$$$).

So, at least for the time being, I am sticking with oxy-acetylene.  I have a Victor medium-duty torch for heavier (by aircraft standards) welding, such as cluster welds.  The Victor has a cutting attachment, which I needed.  I also have a Harris "airline" torch for working on the lighter gauge material. There is no cutting attachment available for the Harris torch.  I acquired the Harris torch on eBay for a very reasonable price and it will be ideal for working with the light gauge steel used in aircraft construction  However, the hose and tips had to be special ordered.  They are on their way.

I started off with the idea that I would order the "downstream" accessories for the Harris (hose, tips, tanks, etc.) ala carte.  In view of the need for a cutting torch, it proved less expensive to purchase a complete Victor "kit" and purchase the tips and hose for the Harris separately.  In pulling together the ala carte idea, the cost rapidly ran up to $500.  I was able to purchase a Victor kit that included the torch, cutting attachment, suitable tips, regulators, hose, goggles, and striker for under $300. 

Of course, by time I added tanks, a cart (you have to have a means of securing the tanks upright), acetylene, oxygen and the governor's share the whole bill took a major bite out $1,000.

The table you see in earlier photos is being converted to a welding bench by adding fire brick to the top.  I am also modifying my trim saw into a cut-off saw by replacing the wood cutting blade with an abrasive cut-off disk.  It should work fine and saves the cost of a cut-off saw.

I have a small supply of mild steel which I will cut into "coupons" on which to practice welding.  I will post the joys and sorrows of that task.