General welding questions that dont fit in TIG, MIG, Stick, or Certification etc.
completenoob
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hi everyone :)

i'm a guitar builder and am thinking of picking up welding to create truss rods for my guitars. A truss rod is a device that is built into the neck of a guitar under the fretboard to counteract string tension and control/remove up- and back-bow of the neck. Here is a simplified diagram of the principle: Image.

It's a pretty simple device and the problem i have is that i need specific lengths and adjustment screws and i'm tired having to adapt my builds to what is available on the market. Being able to make my own truss rods to MY specs would be awesome .. and of course more economical.

One of the most promising materials i've tried so far is Titanium on steel since the titanium truss rods weigh only half as much as the steel ones (which is important for the balance of the final instrument), but unfortunately there is only one variant available on the market as of today (made in Japan i think) and once again i can't find it with the right length and adjustment screw. The other reason i would like to make my own titanium truss rods is the price, these retail for around 45€/USD a piece which is a lot considering the base material cost of less than 5€. I've asked around here where i live if someone could make custom rods for me but welders are either not interested in such a small job or are asking for a lot of money (which i understand but just isn't workable for me).

I've been reading up and watching youtube about welding to get a basic understanding but am overwhelmed by the amount of information and different options.

So i was wondering if some of you could help me identify what kind of welding would be most apropriate to do these tiny welds.

There are two different welds: the weld connecting the flat steel bar to the threaded block holding the rod and the weld (possibly a braze ?) connecting the adjustment screw to the threaded rod:
Image
Image

I think on the titanium truss rod the flat bar and the threaded block is actually steel. I'm not sure about the grade of titanium either, someone said somewhere on the web it was grade 2.

So the questions i'm asking myself at this point are:

1. Is it realistic for someone who has absolutely no experience/knowledge about welding to undertake such an enterprise ?

2. Is it even a good idea/safe to try to learn welding on my own (there are only lengthy and expensive courses for welding in my area and i don't really want to weld anything else than those tiny dot welds and connect an adjustment screw to the threaded rod) ?

3. What kind of welding technique(s) are most apropriate for welding titanium to steel ?

4. Would a cheap-ish welding machine be adequate for this or does titanium welding require 'proper' gear ?

5. If titanium welding for me isn't realistic then what kind of welding technique would i need to make the traditional steel rods ?


Many thx in advance for your help :oops:

PS: i've used many different steel truss rods from various manufacturers and sometimes the welds look a bit shoddy to my untrained eye. Can you tell from the pictures above if these are quality welds ?
BugHunter
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You're looking for a small TIG welder.

1. Yes
2. Yes
3. Never done it but I'd be surprised if 309 filler used for steel to stainless, would not work fine.
4. Trick question... Gonna get lots of answers I bet. I say this would not require anything special, and a machine from any mfgr would do the trick. No need for big amps or many features.
5. You would still TIG them. But, don't be afraid of Ti. You need good gas coverage, perhaps even a nice little "well" to do them in so you have a box full of gas to work in, but really it's not a big problem for such an easy part.

On your first day I could have you making welds that look nicer than any except that first one on the Ti. That was actually a nice job. The others I'd be embarrassed to say I did.
tweake
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yes i think its quite realistic to teach your self how to weld.
the catch is it takes a whole lot longer than having someone teach you.

no idea about titanium to steel.

a small dc tig machine is all you need. the plus is they have stick mode.
learn to weld with stick. then onto tig steel, then to titanium. start with the basics first.

you will probably spend more on the fixturing and setup than the actual welding side of things.
tweak it until it breaks
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"3. What kind of welding technique(s) are most apropriate for welding titanium to steel ?"

Not possible using "normal", commercially available methods. They can be bonded together using other means, just not welding.
Image
cj737
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    Thu Sep 29, 2016 8:59 am

I don’t think you can weld Ti to carbon steel. ;)
BugHunter
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I don't know guys, I seem to recall a video some time ago where they welded some material on to the titanium and then was able to weld to it. Sort of an indirect method.

I don't know if it would work in this application, but I'm not sure he has to do any welding of titanium to carbon steel here anyway. The only part there that's titanium is the truss and the threaded blocks. Looks to me like they are both titanium. Then somebody just did a fusion weld on those two parts after they assembled them on the threaded rod.
BugHunter
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To the op, you might find that the majority of the cost in that titanium Gizmo is in the cutting, Drilling and tapping of the parts. Be prepared for some sticker shock when you see what Taps cost for doing that stuff. And you need those in both right-hand and left-hand.
Spartan
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Can material A be welded to material B? If you look for answers on this, you will often only come across answers applicable to structural/code work. There's a very good reason for that, but it should also be taken for what it is.

I would argue that what this guy is doing is closer to ornamental work (even though it does seem the assembly will take a bit of stress, it is in no way critical, and there is zero chance of a person getting hurt because of it). So my answer to "Can material A be welded to material B?" Try it and find out. Weld it and then try to break it. Let it sit for several weeks, and then try to break it again. If it still holds up, then it's good enough for ornamental. Will it hold up for 20 years? I dunno... Only one way to find out. Just my two cents.
completenoob
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    Mon Jan 18, 2021 7:06 am

hey everyone, many thanks for all your replies, it's really great to be able to rely on all your experience ;)

great to hear that i'm not completely delusional and getting pretty excited now to be able to take this project on. ALso wanted to say that i am still a bit paranoid muckin about with high voltage and molten metal and while i certainly don't have the budget to go for state of the art equipment i'll go about this as carefully as possible and that adequate protective gear and anything else i need to make this as safe as possible will be at the top of my shopping list.

a couple of thoughts from your comments:
closer to ornamental work (even though it does seem the assembly will take a bit of stress, it is in no way critical, and there is zero chance of a person getting hurt because of it)
most definitely the welds won't have to withstand a lot of stress, the bends in the first image i posted are very extreme and no guitar neck will have to be bowed that much. at the most the deflection in the middle of the rod will be one or two millimeters and also be encased from all sides in hardwood so definitely no risk of injury. I might also shrinkwrap them in plastic to prevent rattling and deformation at the looser points like this which might minimize the stress on the welds a bit:

Image

It's rare to see a trussrod fail and the most common failure point is the weld where the adjustment nut/screw/spokewheel is welded to the threaded rod. And that is mostly due to user manipulation error: overtightening.
you might find that the majority of the cost in that titanium Gizmo is in the cutting, Drilling and tapping of the parts. Be prepared for some sticker shock when you see what Taps cost for doing that stuff. And you need those in both right-hand and left-hand.
i was kinda hoping to do the threading and tapping myself but haven't looked into if that's even possible to do by hand in titanium. I do a fair bit of threading and tapping in brass and aluminium but haven't tried steel yet, but at least i got the technique down already :lol:
I don't know if it would work in this application, but I'm not sure he has to do any welding of titanium to carbon steel here anyway. The only part there that's titanium is the truss and the threaded blocks. Looks to me like they are both titanium. Then somebody just did a fusion weld on those two parts after they assembled them on the threaded rod.
I have little info on the composition of the titanium/steel trussrod in my picture, it only says titanium/steel but i'm not sure if it's the threaded rod that's titanium or the square bar and tapped blocks, or if they both are and only the adjustment screw is steel.
I don’t think you can weld Ti to carbon steel.
Not possible using "normal", commercially available methods. They can be bonded together using other means, just not welding.
so that probably means that the square bar and tapped blocks are either both Ti or both steel :)
the catch is it takes a whole lot longer than having someone teach you.
a small dc tig machine is all you need. the plus is they have stick mode.
learn to weld with stick. then onto tig steel, then to titanium. start with the basics first.
sure i'm fully prepared for this taking some time until i'm able to do finished usable truss rods, i'm a patient man :lol:
On your first day I could have you making welds that look nicer than any except that first one on the Ti. That was actually a nice job. The others I'd be embarrassed to say I did.
ha, i knew it .. and you haven't seen the half of it. i had some which had such bulky welds on them that they wouldn't even fit into the slot and when i tried to file them down a bit they came apart. all these are are sold under a variety of brands/suppliers with huge markups but like many guitar parts most come out of china, probably the same factory.
completenoob
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one more thing i'm wondering is about the electrical side of welding. i read somewhere that welders can take a toll on the elctrical circuit and i have my workshop in the cellar of a hundred year old industrial building converted to residential apartments. there is no high voltage circuit and the welder would be plugged in to a 'normal' electrical outlet.

this is what i found somewhere on the web where someone was asking if it's ok to weld in an apartment (which of course i don't want to do but i'll be using the same electrical circuit than the apartments in the building)
There will be mains voltage drops that ruin peoples’ TV viewing and perhaps might affect PC operation; freezers will all switch on due to the voltage drop triggering unregulated thermostats, which will then put more load on the building supply and drop the voltage more; and the RFI (radio frequency interference) will add to the problems.

You’ll get lynched, especially if you weld in the evenings.
:lol:

my neighbors are pretty cool and supportive of my trade so i'll doubt it'll come to the lynching part but best to avoid problems that will affect them.
cj737
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Both Ti, or both steel, yup.

Welding inside your environment won't be an issue. Modern machines are self-grounded for their work, and as long as a competent electrician provides the service, you will be plenty fine.

Ti is an alloy. It is much harder than steel and usually requires carbide tooling to cut and tap. This is where the difficulty arises and costs increase. You aren't going to be drilling holes with a handheld DeWalt and a Home Depot bit.

The weight of those parts, if important, should be done in Ti.

Someone mentioned it, but really full and long gas coverage is super important with Ti. It is very reactive to heat and oxidizes badly when you weld it if you don't "shield" it. You could make a small argon chamber out of sheet aluminum and plumb in a separate gas line (this thing only needs to be large enough to put your parts in so you can weld it) then weld. Argon is much heavier than O2, so "purging" from bottom up, you would create a super clean weld.

Here's an example, and it doesn't need to be this large or complicated, but you can use it to understand the point https://www.youtube.com/watch?v=-uoxKZtqXrA
BugHunter
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https://www.mmsonline.com/articles/tips ... ium-alloys

There's a good article which points out a lot of the problems with tapping titanium. Don't be scared off because they talked about automated equipment, you may take note they had a comment in there about using manual equipment also. In your case you would need a milling machine that you can reverse the spindle (or see below). I have an XLO Mill which I would use if I were to do something like this.

They talk about Emuge taps. They are worth their weight in gold , and you will believe it when you see what they cost. I have never used them in titanium but I have used them in both stainless steels and hardened pH stainless. I've done low volume work in hardened pH stainless by hand in a milling machine with just a spring Center and a tap wrench. The spring Center just keeps the Tap lined up with the whole that was just drilled, and done properly, the tap feels like nothing you've ever run before. (edit) I hate v-text on tablets...

If I were to do the job you're thinking about in titanium, I would do my drilling a couple drill sizes larger than I was supposed to. For instance if you were tapping a 10-32 which calls for a number 21 drill, I might use a 20 or even a 19. It takes a tremendous amount of load off the tap when you open the hole up some.
Last edited by BugHunter on Sat Jan 23, 2021 4:13 pm, edited 1 time in total.
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yeap, 10-32 Ti Emuge tap is $37 from MSC. Pricey!
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completenoob
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https://www.mmsonline.com/articles/tips ... ium-alloys

There's a good article which points out a lot of the problems with tapping titanium. Don't be scared off because they talked about automated equipment, you may take note they had a comment in there about using manual equipment also. In your case you would need a milling machine that you can reverse the spindle (or see below). I have an XLO Mill which I would use if I were to do something like this.
Ti is an alloy. It is much harder than steel and usually requires carbide tooling to cut and tap. This is where the difficulty arises and costs increase. You aren't going to be drilling holes with a handheld DeWalt and a Home Depot bit.
Ti is an alloy. It is much harder than steel and usually requires carbide tooling to cut and tap. This is where the difficulty arises and costs increase. You aren't going to be drilling holes with a handheld DeWalt and a Home Depot bit.
Emuge
that's all super helpfull.

i do have a 3-axis CNC and i'm used to using quality HSM and Carbide bits depending on use/material. I usually buy from Hoffman tools https://www.hoffmann-group.com/ who have really good professional tools (been through a lot of other vendors and settled for them in the end. They do have drill and mill bitts and thread mills and taps, some rated for Ti as well. I will give them a call to ask for advice. The price of the bits doesn't scare me too much (to a certain extent) since i have learned that quality bits last much longer and give a cleaner finish. I usually use DLC coated bits if available (Diamond Like Coating), they are awesome and last forever. Unfortunately i have a fixed size metric collar (6mm) which limits the available options of mill/thread bits a lot

I usually drill or bore my pilot holes with the CNCX and then tap by hand, i haven't tried thread milling yet but think i will look into that now. Unfortunately my spindle is a bit weak and i'm not sure my spindle speed is fast enough. I have however managed to cut/drill harder materials by using tiny cutting depths and maybe i can get awa with it on Steel and titanium as well. I think i can revers my spindle as well with a couple of tricks for the reverse threads, will have to look into that.
Someone mentioned it, but really full and long gas coverage is super important with Ti. It is very reactive to heat and oxidizes badly when you weld it if you don't "shield" it. You could make a small argon chamber out of sheet aluminum and plumb in a separate gas line (this thing only needs to be large enough to put your parts in so you can weld it) then weld. Argon is much heavier than O2, so "purging" from bottom up, you would create a super clean weld.

Here's an example, and it doesn't need to be this large or complicated, but you can use it to understand the point https://www.youtube.com/watch?v=-uoxKZtqXrA
yes that is definitely something i'll have to look into since i came across the oxidation issue a lot while youtiubing Ti welding.
Poland308
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I have more questions than answers

Josh
completenoob
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hey many many thanks for that link, especially because there is a link at the end of the page for Welding Titanium: A designers and users handbook, and that is absolutely amazing and the most complete and detailed info on Ti welding i've found so far:

https://www.twi-global.com/pdfs/pdfs-pu ... weldti.pdf

it confirms that welding Ti to steel is difficult, that brazing doesn't seem to be feasable since it requires to be done in a vacuum but also confirms that TIG welding is the way to go. I've only read through it diagonally so far and will have to go over it in depth before i move on i think.

At some point it also talks about color of the weld and weld quality and it looks like some of the welds on the titanium truss rod are contaminated and thus a bit poor. Coming back to that picture i posted of the Ti truss rod above, can anyone tell from the picture what kind of technique was used to make tose round weld spots (instead of a molten weld line like on the steel rod) ? Was that done with a TIG and a filler stick or some other technique ?
BugHunter
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Looks to me like they used a TIG welder with no filler Rod. Typically called a fusion weld when you do not use filler and you just knit the two parts together.
alexweeks1996
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Hi, I found this interesting, especially since I used to be a pretty good guitar player lol. I would say that titanium can only be Welded to titanium, but I imagine that isn't 100% true anymore. Just know that if you are talking about joining titanium to anything but titanium, you are getting into some NASA level complexities, as this is a task beyond any conventional joining methods. I'm not sure if it's even possible, but it might have been done with something like friction-stir-welding, which is a process developed by NASA and is actually proprietary according to my understanding. If you're joining titanium to to titanium, then you can certainly do that exceptionally well by using the TIG welding-, aka Gas Tungsten Arc welding- process. You'll want a large cup and a good diffuser, which you can get with a Furick BBW or MK-14 and a good gas lens. For drilling and tapping, I don't have any experience with that, but I know that especially with 6Al-4V titanium, it has a sort of memory, meaning the hole wants to close up right behind the drill bit. It might be unique to that particular Alloy, but either way, you just want to be aware and approach titanium cautiously, using best practices. That means flooding with argon, purging when necessary, and using plenty of coolant and slower feeds & speeds when machining. With that in mind, it isn't like welding on diamonds or anything, it's done all the time and I've had great success welding titanium in my make-shift basement shop area lol. I just make sure it's very clean and covered with argon. I'd recommend getting 2 argon bottles if you can.
Gdarc21
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yup braze it! if it breaks........... put a fender sticker on it :lol: :shock: :?
i know i know.......too far :lol:
braze should work nicely.
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