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drummerdad

Cage tubing guidance please

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Here are a few pictures of a new project Im working on. I havent started a build thread because I have a tendency to get bored or frustrated and shelve the project. This is the farthest Ive ever been on a tube chassis and Im still very happy with it. But I have a few questions for you experts. 

Obviously this is styrene. I know my gaps are a bit big, but my solution will be to use some fingernail filling powder my wife used for awhile. Ive already tried it, and it work well. So Ill address the gaps later. Ive read that the styrene is good for support on some larger scales. Im really liking the 1/16 scale. There seems to be more kits available. And now with 3d scale parts making wheels (which I am using in this build) the options are slowly opening up. Im trying to work up to my 1/8 scale Iroc Camaro, and while it will never be as epic as the ones Ive witnessed here, I would like it to be nice. But Im not sure about styrene at the 1/12 or 1/8 scale holding the weight. So I bought some brass tubing and a butane torch, and Im experimenting with that. 

The question is, how do you braise the new tube in, without the other ones falling out under the heat? Ive only started a few small tube junctions and they are falling apart when I go to add another bar close by. Im having good success holding everything with magnets, and I have seen you guys build using wood, which makes sense, but how are the other tubes not falling out on you? 

In case anyone is interested, the model is the 1/16 scale firebird from MPC, the wheels are from 3d scale parts, and the engine and trans are from 3d model specialties. Its the 1000 cid mountain motor from Sonny Leonard, the trans is an automatic 3 speed lenco, and the centrifugal is all scratch built to mimic the F3x. If you see any glaring issues, Im okay with criticism. I know some of the tubing sizes are off. 

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Posted (edited)

Here is a link to an amazing scratch built Porsche 935/78 in 1:8 scale using styrene for the chassis. I think styrene will support the model's weight unless your are using a significant amount of metal parts i.e as the basis for your engine.

The Firebird looks great!

http://www.automotiveforums.com/vbulletin/showthread.php?t=1075623

 

moby121.jpg

Edited by afx

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Thats a great build. I never thought about making a jig with legos. I have a bunch of them, but I would be afraid I would glue to it.

That guy also uses a bunch of brass inside the styrene, and to reinforce his joints. That might work. I also thought about using brass for just the base, and then switching to styrene for the upper portion. Most of the bars on the lower portion are straight and flat. I know there are some exceptions, but generally that is the case. I could use brass rod at the joints, and use brass tubing only as the base. 

And thanks for the kind words on the Firebird. I have been working on building my own chassis for a few years and this is the best I have done. Im really happy with it. 

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A soldering iron should work.

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Soldering additional parts to a model in close proximity to previously soldered parts has always been a problem.

Solder of different melting points is one solution. They are available.

Another solution is using various kinds of heat-sinks to control heat spread. A wet paste of chopped asbestos was used when I was young, though it's probably not the best solution in light of what we now know about its toxicity. Alligator clips work, or even wet paper towels.

Becoming very proficient with your soldering technique also helps, and properly tinning parts prior to soldering, then using a soldering iron or gun that has sufficient heat to make a quick job of each joint.

 

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I looked at a few videos on YouTube and they were helpful. I will try to control it with heat sinks for now. Ill also try and use an iron instead of the torch when I start going up, or close to another joint. I bought a bunch of brass, but not enough to start the big 1/8 camaro. Im going to play around and see what I come up with. I still need to get some supplies. And I might get a 1/12 model to start on, and see if switching between works, or if sticking to one or the other is better. 

I do know one thing, the brass joint is exponentially stronger when done right. I just slapped two small 1/32 rods on a plate and braised them together. No filing, no cleaning, using rosin core solder, and holy cow. It is so strong. So I coped a tube, and set it up, and tried again, and wow. I really want to try to get this down. Im getting better with the plastic, but I still have a ways to go. 

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Posted (edited)
34 minutes ago, drummerdad said:

...I do know one thing, the brass joint is exponentially stronger when done right. I just slapped two small 1/32 rods on a plate and braised them together. No filing, no cleaning, using rosin core solder, and holy cow. It is so strong. So I coped a tube, and set it up, and tried again, and wow. I really want to try to get this down. Im getting better with the plastic, but I still have a ways to go. 

Glad it's working for you. Soldering is a great technique to have in your bag of tricks.

Just a note about terminology..."braised" is a cooking term meaning lightly fried, then stewed.

When talking about joining metal, it's "brazed", but it's different from soldering. Brazing is done at a higher temperature, most often on steel or other ferrous metals, using brass as the filler material (though several other alloys can be used depending on the base metal being joined).

Brazing was widely used on European racing car tubular chassis structures at one time, as the lower temperature (lower than welding) doesn't embrittle the metal adjacent to it, but produces a very strong joint if the parts are closely fitted.

Some folks get upset with me when I try to clarify things technical. I hope you'll take the information I present in the spirit it's offered...a sincere desire to help further understanding and accuracy.

PS: Is that magnets you're using on a sheet of steel for your fixture? Very nice, if so. Great idea.

 

Edited by Ace-Garageguy

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Thank you for the terminology correction. I worry about using the wrong terms or misspelling words all the time. I wondered about that braising think. It seemed right, but I was 50/50 on the "z". 

It is magnets I am using. I have had good luck with the magnets on a flat piece of steel. I have a smaller piece, and a larger piece, both marked at .5 inches vertically and horizontally. It seems to work well, and allows me to keep things in place so the cage doesnt warp or lean. Plus its heavy, so it doesnt move around when Im working in the tight spaces and accidentally nudge something. 

Im going to get a slightly thicker and larger piece of steel and use it for the larger 1/8 models, eventually. 

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So I got a 12" x 24" piece of 14 gauge steel today at lowes. I came home and laid out a grid just like my other plates, at 1/2" centers. Ill scribe them later, Im just getting set up right now. The heavy gauge steel seems to act as a counter sink itself. Ill have to learn how to heat sink other areas in the process, but Im just getting started. Im also learning that the fish mouth of the bars is critical. I can get it to work, and Im sure I can cover up some ugly, but its important on this brass. I also tried plumbing solder, and it sucked. So I am using electrical solder, .8mm rosin core. 

I laid this out by eye, so Im not sure Ill even use it, but its straight and strong. Its a start. Its for the 1/8 scale Iroc. 

 

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Dwayne you are off to a good start with your brass frame. 

On 3/7/2020 at 9:54 AM, drummerdad said:

fingernail filling powder

I have used this in the past and it is good stuff, but it is harder than most fillers. I have found it strong even when thin also. 

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