aluminum instead of brass???

[BiLLy bOb]

was wondering if a person can use aluminum instead of brass to build a frame for a tttt? ive played around with brass before and never had much luck soldering it. aluminum im pretty good with figure i can get a BIG chunk and just mill it down to what i want. was curious why a body couldnt it instead of brass? is there a reason inparticular? my lhs is 70 miles away so mailorder is how i do most of my *goody getting*. was also curious if anybody had a source for gears here in the states for making gear boxes?
BiLLy bOb

I'm sorry, I don't have an answer to your question. I noticed you started two threads with the exact same thing minus the last sentence of this post. I deleted the other. You are able to edit your posts, please do so in the future if you want to change something.

[BiLLy bOb]

thank you, im slowly learing computers.
BB

[Fred]

Originally Posted by BiLLy bOb

was wondering if a person can use aluminum instead of brass to build a frame for a tttt? ....

BiLLy bOb,

you mention that you are not too successful soldering brass. Solderabilty depends on the specific alloy. I have some brass in my scrap box (salvaged from old clocks) that does not solder too well. Most of today's brass solders well if it machines well. Well, soldering aluminum is quite a different animal...

Alternatively, you could use a solid piece of brass and mill the entire frame from it (as you are suggesting to do with aluminum). Have you tried modern cements? (In my experience, e.g. Loctite 601 works quite well on brass).

Sure, aluminum would work, your frame would probably be lighter; but depending on the specific alloy you may have to use more "beef" than with brass to end up with equivalent strength.

Brass can double as a bearing surface (acceptable friction when paired with a hard, e.g. steel shaft). Aluminum does not have that property.

Let us know how things work out for you,

Fred

(In lieu of a real introduction: active in the micro airplane world, lots of experience with homemade IR r/c, microcontrollers, fairly new to 1:87 cars; I live in Germany)

[BiLLy bOb]

Fred,

Alternatively, you could use a solid piece of brass and mill the entire frame from it (as you are suggesting to do with aluminum).

Thats exactly what i had in mind. Milling down a chunk of aluminum for the frame. I *was* favoring aluminum because almost everything I purchase I have to have mailed to me (closest hobby shop is 130 kilometers for me). Aluminum is much cheaper for me at this time. I have thought about the advantage of brass acting as a bushing and thought that i could install brass where the bushings would be needed.

Have you tried modern cements? (In my experience, e.g. Loctite 601 works quite well on brass).

My big brother does a lot of fiberglass and carbon fiber assembly. The adhesives used with that stuff is simply AMAZING. Thank you, I have not thought about just gluing together a frame. I'm glad you brought up the point about different alloys of brass too. I did not even think about it. I guess i will get some brass the next time i am at the hobby shop and see if i have any better luck with it.
Thank you for bringing up points that I hadn't thought of.
BiLLy bOb

[Fred]

Originally Posted by BiLLy bOb

...I guess i will get some brass the next time i am at the hobby shop and see if i have any better luck with it. ...

Hi BiLLy bOb,

make sure you buy "free machining /cutting brass " (DIN EN 17660 / MS58 or similar). How powerful is your soldering iron? Some folks love acid flux for soldering brass frames; I am quite happy with resin flux. You may want to add (resin) flux if you believe there is not enough in the core of whatever solder you use. Depending on your preference, use liberal pre-tinning.

Remember that brass conducts heat very well. Preheating the frame (e.g. on an electric range or hotplate) works wonders. There is another downside to the superb heat conductivity of brass: Not only does the heat dissappear from the spot you want to solder, but this heat can melt the solder in a nearby finished joint. You may want to cool nearby completed joints with some wet kitchen paper.

I have never tried cement for building an entire frame, although I use cement quite often for other joints (e.g. for attaching a motor -- Stabilit Express is just great for that purpose).

Good luck,

Fred

[BiLLy bOb]

My iron is a 60w stick unit. Not a gun type. My brother has a adjustable watt unit for his electrical work. I might try the glue, between me and my brother we can experiment until I go to the hobby shop again. The fiberglass glue I mentioned is amazingly strong. My brother was making a custom console for a 1972 Buick and dropped some onto a cement building block (approx 7 kilo's). 20 Minutes later he had to move a piece of railroad iron (approximately 70 or so Kilo's) placed it ontop of the cement block and never thought about it. 3 weeks later he needed the RR iron for anvil and went to move it. It is now 3 years later and the cement block is STILL FIRMLY BONDED to the iron. So i might give that a try. Tonite i got into my train collection and got out a few vehicles and grabbed some of my indoor airplane stuff i have. Unfortunately a *hitec hs55* is the smallest servo I currently have. Do you use servos of this size or smaller ones? I tell ya, after looking at what im trying to accomplish, this is a VERY intimidating thing to attempt.
BiLLy bOb

[Fred]

Originally Posted by BiLLy bOb

...Unfortunately a *hitec hs55* is the smallest servo I currently have. Do you use servos of this size or smaller ones? ...

BiLLy bOb,

I am new to this forum and not sure if changing the topic within a thread is acceptable here... The HS55 servo is what I use in a slope soarer; but I have not used any commercial servos in 1:87 models (I am working on DIY stepper motor servos). Most people trim the cases of their servos to make them fit. Have a look at http://freenet-homepage.de/andreasrackel/hobby.htm (under "Modelle 1:87") and http://ig.micromotor.org/LKW/lkw.html (this is the address of a frame under http://ig.micromotor.org -- you can click on the individual models and see a lot of detail) for examples. The pictures will help, even if you do not read German.

Good luck with your "cemented frame" experiment!

Regards,

Fred