Has anyone used stainless steel welding rods as launch rods (like a 36" ER308L rod). These are rods that are normally used as filler when welding, but will then work as launch rods. Since they are sold by the pound, they are about the third of the price of buy a quantity of say 304 stainless steel rounds. Any thoughts or experience to share?
Welding Rods as Launch Rods
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I use cold rolled for my LPR stuff. But they come in 6' lengths.
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Be aware you need some kinda speed over the fins before it leaves the rod. Short rods are no bueno. OR, Rocksim and thrustcurve.org can give you those numbers. Straight smoke and good chutes!
rharshberger
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I believe the OP is referring to TIG rods which are about 3' in length and not fluxed.
That is just what I am referring to, TIG welding rods stainless steel 1/8' diameter and 36" length. Still my question is has everybody used these welding rods as launch rods. The specifications of the metal seems to indicate that they should be fine, but it is an unknown use of these rod to me.
I can get a lot of 304 stainless steel rounds cold rolled 1/8 inch by 36 inch length rods for around $4.15 a rod. I can get 1/8" by 36" length stainless steel ER308L welding rod for about $2.25 each. (Sorry in my original post I said about at a third of the cost, it's more like half the cost.) But if there are any issues with the welding rods, it would not be worth the saving. I need them for the Syracuse Rocket Club that maintains and sets up a bank of 16 low power launch pads at each of their monthly launches.
rharshberger
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One type might be stiffer than another, due to the hardness of the metals.
length would be my concern.
JimByrne
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Welding rods may be a bit soft & if so will bend easy.
I use 4' 1/8" & 3/16" rods from the hardware store
For 1/4" rods I go to 6'
A little extra length gives your rocket more time to pick up speed & stabilize.
I use 4' 1/8" & 3/16" rods from the hardware store
For 1/4" rods I go to 6'
A little extra length gives your rocket more time to pick up speed & stabilize.
36 inches for a 1/8 inch rod has pretty much been a standard for low power, lightweight rockets for decades. I know some people like to go 48 inches which might be good for certain rocket designs, but it seem too much for most low power flights and can subject the launch to rod whip. If one is launching a heavier, taller rocket, they should be using a x-rail with rail buttons. So my concern is not the length of the rods, but the appropriateness and durability of the material of a 1/8" by 36" length stainless steel ER308L welding rod when used as a low power launch rod.
This might be true. Or one might be more brittle. It seems that the only way I am going to find out is to experiment. I just can't believe no one has ever tried to use welding rods as launch rods before.
I’m sure it’s been done many many times since the beginning of the hobby. There might even be a few folks over on Ye Olde Rocket Forum who would admit to it.
If the rod is long enough (3 feet) and it’s not so soft that you can’t keep it straight, it could certainly be used for low power models anyway.
But I have not done it myself. I don’t know what they cost now, but my go-to source for launch rods used to be the K&S Metals rack at the hobby shop (back when there were such things). A piece of 1/8 inch music wire from that rack was what I would use. I still have a couple of them I’ve been using since the late 1960s (well, with a 30+ year gap in there).
If the rod is long enough (3 feet) and it’s not so soft that you can’t keep it straight, it could certainly be used for low power models anyway.
But I have not done it myself. I don’t know what they cost now, but my go-to source for launch rods used to be the K&S Metals rack at the hobby shop (back when there were such things). A piece of 1/8 inch music wire from that rack was what I would use. I still have a couple of them I’ve been using since the late 1960s (well, with a 30+ year gap in there).
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rharshberger
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I know unfluxed brass brazing rods have been used...
I have one bent in half on my workbench right now, now its just used as a non-sparking stir stick as I cut pieces off.
I believe all the low power pads for the club I'm in, UROC, are using TIG rods
Seem to work most excellently!
Ken
Seem to work most excellently!
Ken
This report on do-it-yourself low cost LPR launch equipment from the NAR web site mentions using welding rods, but does not specify what type, though it is a bit dated:
https://www.nar.org/nar-products/ul...t-ground-support-equipment-for-classroom-use/I would imagine that for LPR the things mentioned in the posts above would work. I have a made a couple of the launch controllers mentioned in the article (using modern-spec components from Mouser) and they work very well as long as you use decent quality batteries.
https://www.nar.org/nar-products/ul...t-ground-support-equipment-for-classroom-use/I would imagine that for LPR the things mentioned in the posts above would work. I have a made a couple of the launch controllers mentioned in the article (using modern-spec components from Mouser) and they work very well as long as you use decent quality batteries.
Not to be pedantic, but both will be of the same stiffness, if they are 300 series stainless steel and the same diameter. One may not be as strong as the other due to heat treatment or cold rolling affecting the yield strength.
Yes, I don't know why anyone is questioning this.
I do prefer 48" for 3/16" rods, but since I have encountered plenty of 36" 3/16" rods at clubs, I now use 36" for all my sims.
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I've used both aluminum and stainless tig wire (1/8") for small rockets. They work fine. The aluminum is a little soft and easy to bend. I'd suggest stainless steel.
Been using them for yrs. My 1st homemade "pad" was a 6" piece of 2x6 with a welding rod stuck in it. Used the lid from a 3# coffee can for a blast plate. 1968. Damn........ I'm OLD........
JimByrne
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A comment on rod length---with a rocket mounted on a 48" rod, mounted in the launch stand & 4" from the bottom of the rocket to the blast plate there is 35" rod left from the bottom launch lug up. So, when considering rod length & launch speed off the rod how much usable length do you have left? If using a short rod to start with, are you going to have enough speed?
I've used my dad's brazing (brass) rods for rocket launches for decades. Just wipe with steel wool, a little silicone spray or WD40 and all is good. If they were a little corroded, steel wool and WD40, followed with a wipe and they were ready to go. More recently, I've used 3ft stainless welding rods from a welding supply store and they work fine. Only one issue: near the end, they have a size stamp (1/8") which flattens the rod slightly about an inch from the tip. It flares the rod slightly, so I had to grind down the bump on each side and smooth it with a buffer. Once I took out that bump, they work great.
Yes, it seems that it is important to emphasize effective or usable rod length, especially when referring to simulation input and results. You know the old GIGO rule...
Jumping in late and hopefully not opening a can of worms. I'd like to buy something to use as a launch rod that does not rust (or at least as little as reasonable) in 6 foot lengths, 1/8, 3/16, and 1/4 inch widths.
Not finding something at my local hardware store...
What should I order and where should I order it from?
Thank you.
Not finding something at my local hardware store...
What should I order and where should I order it from?
Thank you.
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Mine was a peanut butter jar lid. I used 2x2s with opposing notches to make a cross for the base.
Stainless steel rod. Can find at McMaster Carr.
Thank you.
OMG, I had no idea there were so many kinds of stainless steel! I’m going with multipurpose 394/394l. Not that I have any idea of what that means. I know, Google is my friend.
Also available from Online Metals. They have a facility in downtown Seattle and so things can be picked up. Be aware, though, that they use a shear or something to cut rods to length. I had to straighten the last inch of a bunch of 1/8 inch stainless launch rods I got for the club and for me some years ago.
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25 years ago or so, I bought a 30 foot long piece of 1/8" diameter stainless steal rod for my club (QCRC today) from a specialty metal supply place in the Quad Cities. I brought a small bolt cutters with me and used it to cut the very long rod into 40" pieces right there in the parking lot. It fit better in my car in 40" pieces. And because I used my tools and labor to cut it into pieces, they cost a lot less too. But like I said, 25 years ago. So I have no idea what I paid. I used a grinder on a stand when I got home, to smooth all the ends and we were good to go.
Stainless is a pain to keep straight, but they clean up after a long club launch very easily. A scotch bright pad and some windex and they clean up very nicely and easily. Then just use an old clean rag to wipe off any residue and store them for the next launch. And yes, WD-40 works fine to, just make sure to wipe it off or it can get sticky. Its probably time to order another 30 footer again as a bunch of the 40 inchers have disappeared over the years. We still have three or four of the originals left. So stainless is definitely the long term choice for longevity of service.
We've also used the stainless 36" welding rods. Other than being just 36" long, I haven't noticed any difference from the original 40" stainless rods I got all those years ago. They still clean up just as easily and you still have to work at keeping them straight.
I've used the KS wire like many others, but while these are easy to keep straight, it is almost impossible to keep them from coroding. If you get one to last a full year you're doing very well or you're not flying off that rod very much. Definitely use WD-40 for these. They take lots more scotch-bright, WD40, and what we used to call "elbow grease" to keep usable. But like I said, they are easy to keep straight.
Stainless is a pain to keep straight, but they clean up after a long club launch very easily. A scotch bright pad and some windex and they clean up very nicely and easily. Then just use an old clean rag to wipe off any residue and store them for the next launch. And yes, WD-40 works fine to, just make sure to wipe it off or it can get sticky. Its probably time to order another 30 footer again as a bunch of the 40 inchers have disappeared over the years. We still have three or four of the originals left. So stainless is definitely the long term choice for longevity of service.
We've also used the stainless 36" welding rods. Other than being just 36" long, I haven't noticed any difference from the original 40" stainless rods I got all those years ago. They still clean up just as easily and you still have to work at keeping them straight.
I've used the KS wire like many others, but while these are easy to keep straight, it is almost impossible to keep them from coroding. If you get one to last a full year you're doing very well or you're not flying off that rod very much. Definitely use WD-40 for these. They take lots more scotch-bright, WD40, and what we used to call "elbow grease" to keep usable. But like I said, they are easy to keep straight.
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