RC frame welding and Repair 101

Post your tips and tricks for modification, manufacturing or substituting parts here.
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Juiced Drag Racing
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RC frame welding and Repair 101

Post by Juiced Drag Racing »

Hello all!
This is some info I felt I should share for anyone thinking about welding up a RC frame.
First about us (Tammy and I):
We have been racing 1:1 cars, karts, bikes and once a long while ago, RC cars.

We have built full race cars and champ race karts so this is my not my first in house welded frame, but one with all small tubing.
I weld, but it is not my living so I would consider myself a "expert hobbyist?"

I weld with a wire welder and use molly 4130 steel tubing. I do not have the time or money to use a tig. I have all my Tig welding done at a local shop. You will not need to Tig your frame unless you want to. A wire welded frame is very strong . (don't ask me why I know that! :) )
Welding a RC frame is similar with some noted differences.
Note: A difference of opinion in this subject is always welcome as I am only giving my experiences.

Why would you even attempt to do your own frame????
Pros:
You built it!!
You may have a different power plant that a ready built car will not hold.
Cheaper than a ready built car.
If done right, it s a very strong frame. (don't ask me again why I know that! :) )
Keeps you in the garage and out of the house, (where you should be?)
Did I mention that YOU built it?

Cons:
Is is heavier than the newer sheet metal frames.
Much more time is involved.

The differences in welding big tubing ( over 1")

Such small tubing needs more fineness to its welding than just melting holes in the stuff. Anyone can stick two pieces of metal together, it is getting the weld to be as strong as the original metal that is the trick.

This small tubing will "pull" when you make the first tack or weld. All of sudden
it is crooked. Make your tack or first weld, let it cool and then check the alignment.

Welding a bead in a straight line (because it is so small) as apposed to sweeping makes for a stronger and better looking weld.

Now that my frame is done, I need to make some changes.....

I just did this change and took some photos (now who is going to admit they did it wrong and show you a better way to fix it??)

The problem...

I made the frame several inches too long so I had some room to put all of my goodies where I wanted to and to have a chance to "balance" the car. Balance is important so you do not do wheel stands and get all of your power to the ground.

In this case I had welded the back body mount to an extension that looked UGLY. I wanted to remove it but not disturb the mount as I gotten the car body just right.

The old UGLY look.
Image

Image

There were some UGLY welds I wanted to remove so this was a double bonus.

The offending section!
Image

First cut and size up the new braces before cutting anything!!

Image

Weld up the new braces with good clean welds....

Image

Braces everywhere!!!

Image

After it as cooled and you have taken measurements to ensure nothing has moved, then cut off the old braces.

Image

Image

Then check your mounting, ground clearance, and such.

Image

Image

Then, if needed, clean up the welds, paint and go have fun!!!!!

Sound easy, doesn't it? It can be IF you take your time.

Enjoy!!!!

Ed
Juiced Drag Racing
Last edited by Juiced Drag Racing on November 24th, 2009, 2:25 am, edited 2 times in total.
M.R. Ogle

Re: RC frame welding and Repair 101

Post by M.R. Ogle »

Wow!!!

I can only imagine what a nightmare it must be to weld small-diameter tubing and not have it warp all over the place. My hat's off to you though, you've built a tube frame car pretty darn quickly, and it's looking very promising. Funny captions, too! Thanks!

Don't worry about the sheet metal cars... most of us just can't weld, although somebody up in Siberia, Michigan is cooking up... ooops, never mind, that's a secret!
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Juiced Drag Racing
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Re: RC frame welding and Repair 101

Post by Juiced Drag Racing »

Thanks Mike.

All that counts is that we are having fun!!!!!

I have a friendly bet with a guy at work that by the end of the Thanksgiving holiday, I can have a burnout photo....time will tell.

E&T

{There is a fine line between a genius and someone
that "doesn't know any better".}
M.R. Ogle

Re: RC frame welding and Repair 101

Post by M.R. Ogle »

Pour yourself a puddle of Paragon or WD40 and grab the rear bumper with one hand and a handful of throttle with the other... you'll smoke 'em!
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Juiced Drag Racing
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Re: RC frame welding and Repair 101

Post by Juiced Drag Racing »

Hee Hee.

I have some HP tricks I hope to try.

He is ole drag racer like me, not sure if holding the bumper will get me a "Win".

I need to find some good newer asphalt to do it on. I have old abrasive stuff here....

:) :)

Ed
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Juiced Drag Racing
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Re: RC frame welding and Repair 101

Post by Juiced Drag Racing »

Well now we have gone and done it.

My HP trick worked too well. It will now do burnouts all day! (and some really nice donuts too, much to my neighbors entertainment)

I may have to re balance the car. I will take it to a real track and see if she will "stick" first and go from there. I see a wheelie bar in its future.


Crazy Ed
Turbogolf
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Re: RC frame welding and Repair 101

Post by Turbogolf »

Hi Ed,

Thanks for the great tips! Quick question: what size tubing and wall thickness do you usually use for the frame? Also, what size welding wire are you using for your wire welder? Thanks in advance!
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Juiced Drag Racing
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Re: RC frame welding and Repair 101

Post by Juiced Drag Racing »

Lincoln Electric .035 Flux-cored Nr211 Mild Steel Welding Wire.

3/16" .035 supports
1 /4 ” .035 mains


Juiced
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Bryant
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Re: RC frame welding and Repair 101

Post by Bryant »

Very nice welds on small dia. tubing. Great tips Juiced.
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BeninTexas
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Re: RC frame welding and Repair 101

Post by BeninTexas »

Just Curious Amigo ???? is you Lincoln Hard wire capable, as a welding engineer and CWI i would highly suggest using .024 hard wire with a 25/75 gas mix, the NR211 your using is great however for smaller applications the cleanup is a bear to say the least not to mention you will find the hard wire gives you a more consistant bead versus the NR 211 arc become too unstable at lower voltage and amp thus creating a bigger mess, now your over all inforamtion on the welding is great it would prove HIGHLY useful for those just starting out welding and making their own chassis you should be commended for your input.

Just so you know if your Lincoln is NOT Hard wire capable let me know I think i have the internals to make it so, let me know, I have so much as far as spare parts i may have more than enought to equip yours for Hardwire if your interested

Ben
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lalacurf121
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Re: RC frame welding and Repair 101

Post by lalacurf121 »

their own chassis you should be commended for your input.
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RcBurnout
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Re: RC frame welding and Repair 101

Post by RcBurnout »

I hate to say this but tig welding small diameter chrome Molly tubing is not difficult at all. In fact it's pretty much the same as welding large diameter tube or pipe. The only difference is your weld setting. Your speed doesn't change or technique. As for these frames, yes you can mig them. And they will look like it to. But you can grind your welds in to glory. I highly recommend hard wire with a gas mix. For the weld inspector up there a couple of post ago. I wonder how you became a weld inspector as some of the requirements to become one requires at least 6000 hrs of documented welding so you should know your welding machines . Don't mess with your machine. Buy one that does the process you need it to do. And I highly recommend GTAW ON THESE FRAMES. DISCLAIMER. If your using silicon bronze as a filler metal your really not welding the 2 base metals togather. You are brazing them because the base metals are not being melted and consumed with the filler metal. If you use 70S2 as a filler metal both base metals are being melted (consumed) and the filler metal (70S2 ) is also being consumed to build strength . As for the weight of your project it will be no heavier or lighter then what..... I have no clue what that means. Just when you thought it was safe to check out QSL.
RcBurnout
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Re: RC frame welding and Repair 101

Post by RcBurnout »

3/8 inch chrome Molly tubing using GTAW Weld process with 70S2 filler metal
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RcBurnout
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Re: RC frame welding and Repair 101

Post by RcBurnout »

Some heavy pipe/tube. Same process. Different settings. Technique is the same
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RcBurnout
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Re: RC frame welding and Repair 101

Post by RcBurnout »

If you want to see Rc Frame welding and Repair 101 check out my post ANOTHER SPRINT CAR FIND in ( Projects in Process
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