Welding help

[thetractorfan]

I don't have a welder nor can I afford one. I have heard of a method that uses a torch, flux and brazing rods. Heat up the metal, apply flux and brazing rods. Would this method be strong enough for RC models? Thanks for any help!

[modelman]

Brazing works really good if done properly and is almost as strong as a weld but does not penetrate the metal. It takes some practice but unfortunately a propane torch or even a mapp gas torch is not hot enough except on very small pcs.. You will need something like a jewelers torch with oxygen-acetylene or oxygen-propane combination. I have a jewelers torch with oxygen-propane and it works really good. However, if you are looking for something cheap you are out of luck. There is nothing cheap about scratch building a model (materials or equipment) so sounds like you need to start saving your money. Good Luck

[bigford]

try muggy weld

[thetractorfan]

Originally Posted by modelman

Brazing works really good if done properly and is almost as strong as a weld but does not penetrate the metal. It takes some practice but unfortunately a propane torch or even a mapp gas torch is not hot enough except on very small pcs.. You will need something like a jewelers torch with oxygen-acetylene or oxygen-propane combination. I have a jewelers torch with oxygen-propane and it works really good. However, if you are looking for something cheap you are out of luck. There is nothing cheap about scratch building a model (materials or equipment) so sounds like you need to start saving your money. Good Luck

Thanks! Like a true craftsman, I don`t settle for cheap. I will be sure to take your advice!

[thetractorfan]

Originally Posted by bigford

try muggy weld

I have heard about muggy weld. It seems like a very convenient way to weld. I am probably going to use their products because, from what I have seen, they can work on a variety of metals. And, their products work for the 2 metals I plan to use: brass and aluminum. Thanks for the suggestion!

[Blender]

I've had good luck with a butane torch, flux and solder. Usually plain electrical solder, but sometimes silver solder. Brass and thin steel only.

[RobotArms24]

Originally Posted by modelman

Brazing works really good if done properly and is almost as strong as a weld but does not penetrate the metal. It takes some practice but unfortunately a propane torch or even a mapp gas torch is not hot enough except on very small pcs.. You will need something like a jewelers torch with oxygen-acetylene or oxygen-propane combination. I have a jewelers torch with oxygen-propane and it works really good. However, if you are looking for something cheap you are out of luck. There is nothing cheap about scratch building a model (materials or equipment) so sounds like you need to start saving your money. Good Luck

Oxy Acetylene braze welding can be too hot for some metals. Mind you, there are tons of different brazing alloys available. I braze weld 8-12 hours a day with a silver alloy, and I can tell you, it will cook the aluminum before melting the braze wire.

I have heard good things about durafix, it is an aluminum brazing alloy that melts at about 700 degrees Fahrenheit and can be used with propane. It also doesn't require any flux. I don't think it works for brass though.

The muggy weld stuff looks promising too, but I have no experience with it.

I would recommend staying away from oxy-acetylene if you can. Propane burns at 3000F and oxy-aceteylene is in the 5000F range. It is easy to overheat your work with oxy-acetylene.

[dozerbuilder]

Tractorfan, maybe assess your situation a little more before you set out to build a model. Firstly, don't let me put you off starting. Obviously you are considering a scratch build RC in metal, not a Bruder repower. You are going to need more than a welder.

One needs to assess what you want to do; do you want to learn the various trades involved in building the detailed working models you see here at RT&C such as CAD drawings, 2D DXF drawings, welding, milling, precision lathe work, etc etc, all essentially skilled trades in their own right or; do you want to end up with a specific model of a particular machine or; do you want to build something to occupy your time; or do you want a small machine shop and build models. As others have mentioned, it's an expensive hobby building a detailed working model like you see here on RT&C.

And if you have to buy all the CAD software, welding and bending and cutting equipment and machine tools, its even more expensive. And then you need to learn how to use all that equipment. And the CAD side is a steep learning curve (at least for me anyhow). Don't give up yet.

I went through all this myself building my 1st dozer. I was pricing welders, small lathes, a milling machine, 3D printer and so on an I don't even know how to use those. That was thousands of $$ worth of equipment that I had yet to learn how to use before I even started. All I got was a headache and all I wanted was a decent working RC dozer. I didn't want a workshop. The end result for me was when I asked myself the 2 questions; am I a model builder or do I want a particular model? It was the latter and I built this dozer:
http://www.rctruckandconstruction.com/showthread.php?t=11337"
So before you get too bogged down buying expensive equipment, consider what I did. Jobbing out the things you can't do or don't have the tools or knowledge to do. That's what I did. The only machine tool I own is a small drill press that cost $60.00 and a big grab kit of all the drill sizes from the smallest micro up to 12mm. And of course other small hand tools like torx drivers and allen keys, pliers, drivers, files etc etc.

Learning basic CAD to create your drawings is very handy. Find a outfit that can do all your laser cuts from your drawings. Find a small job shop that does welding,bending and sheet metal work from the laser cuts. Find a small job shop engineering outfit that does small lathe work, turning, milling, etc etc. Some shops won't touch small stuff, others are happy to do it. Sometimes home handymen are glad to be paid for making something constructive on their home machine tools and they are very good at it. Advertise for that in your local paper. There'll be guys who want to do it.

My point is you don't have to buy all these machines and tools. Job the your work out. Save yourself a bundle and concentrate your $$ on your model/s instead of an elaborate workshop and the learning curve. And getting tradesmen to do the job-shop work ended up in a top-notch job for me anyhow and was very quick. I'd get complex engineering work back in a few days ready to move on to the next stage. Even so, a decent size RC metal dozer in sat 1:12th or 1:16th is going to cost several thousand plus all up. The hydraulics or actuators and ESC's are going to be 1K.

Get good at one thing and let tradesmen do the trades. For example I found I could do the drawings. So I concentrated on that and got good at it IMHO. But I can't precision weld for peanuts. I had a lot of fun doing the build and I'm doing another soon, probably a Komatsu D475-5 or a Fiat -Allis FD50 in 1:16th. I'm glad I never bought all the machines and tools to build it, I have the dozer I wanted and no unused workshop and tools left over. Hope that helps.