My Maggie Mugs Clone

Moderator: Mike Everman

heada
Posts: 118
Joined: Tue Nov 21, 2006 4:34 am
Antipspambot question: 0
Location: Indianapolis

Post by heada » Fri Nov 02, 2007 6:08 am

Most razing rods that I've worked with melt in the 1000 to 1300 degree F range (550 to 700 degrees C). Propane has a max burn temp of just under 2400 degree C Most propane torches will not get maximum burn temp and will get to about 1800 to 1900 degrees C Obviously you don't need Oxy-Acet to get beyond the melting point of the brazing rods. For comparison, mapp gas has a max burn temp of just over 2900 degrees C and oxy-acet has a max burn temp of 3500 degrees C Type 304 stainless steel has a melting point of 1350 degrees C to 1450 degrees C (depending on thickness and other items) Again, propane can burn hot enough to melt your ramjet so it really wont matter what you run it on. Just use what you have access to and are the most familiar with.

For a good brazing rod, check out McMaster-Carr part number 7674A4 It is 5.2 feet of nickel/silver brazing coil for $20 Or part number 76935A11 which is flux-coated 18" rods (8 of them for $58)

-Aaron

Bobthemonkey
Posts: 25
Joined: Sat Sep 15, 2007 4:45 pm
Antipspambot question: 0
Location: Madison Wisconsin

Post by Bobthemonkey » Tue Nov 06, 2007 11:42 pm

Thanks for the feedback everybody!
Sorry I have not replied sooner, I have been pretty busy but I figured out
how to hold togeather the CC and diffuser with a single braze insted of
two whitch would have not worked anyway. I had to reduce the diameter
so that the flameholder would not fall into the CC and would rest on the
lip easly. I did this by cutting the vertical part of the mug that I had
epoxied to before into small strips and bending them over with the help of
a propane torch. I found that I could heat the stainless to a glowing red
hot in just 15 seconds! I have one of those trigger type torches that bosts
a high efficency swirl flame. All I know is that I will probably not need
MAPP gas at all as I can melt a peice of brass pipe to near liquid in about
30 seconds. I tried soddering as I understnd it is a bit like brazing and I
could not get it to flow into the slit I had made in the side of a pipe, it all
just slid off the sides and splatted on the floor. Am I using too much flux?
Not enough? I have no idea.

-Bob
Attachments
Braze2.jpg
My idea
Braze2.jpg (18.1 KiB) Viewed 5297 times
Never take life seriously. Nobody gets out alive anyway.

larry cottrill
Posts: 4140
Joined: Sun Oct 05, 2003 1:17 am
Antipspambot question: 0
Location: Mingo, Iowa USA
Contact:

Post by larry cottrill » Wed Nov 07, 2007 12:52 pm

Bobthemonkey wrote:I tried soddering as I understnd it is a bit like brazing and I
could not get it to flow into the slit I had made in the side of a pipe, it all
just slid off the sides and splatted on the floor. Am I using too much flux?
Not enough? I have no idea.
Bob -

Soft soldering stainless is practically hopeless - I say "practically" because expert metalworkers that have resources to do some special things CAN do it, but it is way different from say, sweating together two pieces of copper plumbing pipe. Silver soldering with an acid flux is actually easier (though the temperature has to be so high you might as well go ahead and do brazing).

I am not an expert on brazing, though my dad was - it was actually his favorite way of joining metal, especially if the full strength of welding wasn't needed. One thing I do know is that it can be difficult if you're trying to fill a significant gap, i.e. it works best like soldering, where the material will suddenly flow by capillary action into a small space. One difficulty is that brazing rod (usually some kind of bronze) doesn't have a very wide plastic state - it transitions from solid to flowing liquid quite suddenly. So, when you're trying to build it up in a heap to close a gap, it will tend to "run out" onto one side or the other. I'm not saying it can't be done, just that you'll have to have a cool hand on the torch and a good eye for when your heat is "just enough". I have no experience with the modern brazing alloys (like silver brazing), so maybe this isn't such a problem with those. We need to hear from someone who's really using the stuff!

All that being said, years ago I have seen beautiful small scupltures of horses and such, made by building up ("modeling") from ordinary brazing rod, then cleaned and polished and coated with clear lacquer. So I know with practice, it can be done.

L Cottrill

Irvine.J
Posts: 1063
Joined: Mon Jun 05, 2006 4:28 pm
Antipspambot question: 0
Location: Brisbane, Australia
Contact:

Post by Irvine.J » Wed Nov 07, 2007 1:27 pm

Spot on larry, normal solder will not work, especially on stainless. You need an acid flux like you said, and some proper silver braze (silver solder) rods. They can be from 2% up to 45%, it just gets easier the higher you go. There are techniques I use for filling large gaps, it is basically a process of letting it get hot, start the melting, then getting a big blob and basically as its starts to cool "swishing" to use your coined term larry, (or simply manipulating it into place, then just slowly keep heating it to add more or move it more. The advantage of using a good silver braze is the bottom might be solid, but you can heat it just right so only the top melts and get a few seconds to move it around. In some cases, i will start by adding the braze, then litterally lying the filler rod across the join. You need proper braze, and a grainy liquid flux, its also good to score the metal with some sandpaper or grinder in the area to be joined, it will grip a lot better when not trying to join to a perfectly smooth surface.
James
James- Image KEEPING IT REAL SINCE 1982
http://pulseairdefence.com
[url=callto://project42labs]Image[/url]

Bobthemonkey
Posts: 25
Joined: Sat Sep 15, 2007 4:45 pm
Antipspambot question: 0
Location: Madison Wisconsin

Post by Bobthemonkey » Sun Nov 11, 2007 7:25 pm

Well I was actually just trying to soder a peice of aluminum pipe with a
small cut in the side of it.
I recently went to a large "Trash and Treasure" sale (mostly trash) and
found a pair of diffusers for 10 cents and they happen to be just the right
size that I could use one of them to replace the old diffuser.
I have no idea what their intended use was but they appear to be stainless.
They are a lot shorter than my old diffuser and I was wondering if they might still work well enough.
I have not gotten any brazing rods yet but I was wondering, would brass work?
I just ask because I know that I can get those easly.

Replies are greatly appreciated!

-Bob
Attachments
Diffuser003small.jpg
the diffusers
Diffuser003small.jpg (94.44 KiB) Viewed 5218 times
diffuser ad2.jpg
diffuser ad2.jpg (65.61 KiB) Viewed 5220 times
Never take life seriously. Nobody gets out alive anyway.

tufty
Posts: 845
Joined: Wed Dec 24, 2003 12:12 pm
Antipspambot question: 0
Location: France
Contact:

Post by tufty » Mon Nov 12, 2007 11:16 am

Bobthemonkey wrote:Well I was actually just trying to soder a peice of aluminum pipe with a small cut in the side of it.
You can't solder aluminium with normal solder. Don't even bother trying, it won't work.

There are specialist aluminium soldering / brazing rods available, but even so, they are completely useless for anything you're going to put near anywhere near the sort of heat a ramjet is going to generate. That's been my experience, anyway.
Bobthemonkey wrote:I have not gotten any brazing rods yet but I was wondering, would brass work?
I just ask because I know that I can get those easly.
No, standard brass rods will not work. For stainless, you *need* relatively high silver content brazing rods. Anything else will either simply flow off the stainless and form a pretty-looking puddle on your workbench, or crack off when it cools.

Brazing and soldering of any metals is not simply a case of "melt some old crap up and seal the joint with it". That only covers the technique of getting the filler in place, making it actually stick has a chemistry element involved as well; that's why there's such a dizzying array of solders and braze compounds available. Once you throw the chemical behaviour of metails like alu or stainless into the mix, it's really tricky. In short, you need the right rods for the job.

Simon

Bobthemonkey
Posts: 25
Joined: Sat Sep 15, 2007 4:45 pm
Antipspambot question: 0
Location: Madison Wisconsin

Post by Bobthemonkey » Tue Nov 20, 2007 1:37 am

Thanks for the replies!
I am still waiting to get some brazing rods so I havent really progressed at all with the design.
I was wondering about the aluminum supports, will the braze attach them?
also, the brass connections and fittings for fuel, how do I attach those?

Any suggestions ANYONE?

-Bob
Never take life seriously. Nobody gets out alive anyway.

Bobthemonkey
Posts: 25
Joined: Sat Sep 15, 2007 4:45 pm
Antipspambot question: 0
Location: Madison Wisconsin

Post by Bobthemonkey » Sun Nov 25, 2007 7:21 pm

Guys, I really need to know weather or not the braze will hold the aluminum strus on because if they wont then I will need make new supports and I sort of want to finish this projact before I get 2 feet of snow.

-bob
Never take life seriously. Nobody gets out alive anyway.

heada
Posts: 118
Joined: Tue Nov 21, 2006 4:34 am
Antipspambot question: 0
Location: Indianapolis

Post by heada » Mon Nov 26, 2007 1:02 am

Welding or brazing aluminum is very difficult. If you can swap the aluminum for steel, I would. If you can't, then get some scrap aluminum and practice brazing it. If you use the silver braze that you have to use for the stainless then it should have a higher melting point than the aluminum and the braze should be stronger than the strut itself. If you have a tig welder, that is the best way to weld aluminum (mig can do it, but tig is easier)

-Aaron

Bobthemonkey
Posts: 25
Joined: Sat Sep 15, 2007 4:45 pm
Antipspambot question: 0
Location: Madison Wisconsin

Post by Bobthemonkey » Tue Dec 11, 2007 12:12 am

Thanks for the replies!
I hve not yet been able to find any silver brazing rods at local home improvement stores so I have not progressed at all. what I really need to know is weather the diffusers I found will work better or worse than the one that I used before. I just dont want to braze the wrong thing on and then have to take it off again if I found that the other one works better.

-Bob
Never take life seriously. Nobody gets out alive anyway.

larry cottrill
Posts: 4140
Joined: Sun Oct 05, 2003 1:17 am
Antipspambot question: 0
Location: Mingo, Iowa USA
Contact:

Post by larry cottrill » Tue Dec 11, 2007 2:16 pm

Bob -

You will probably get the bowl shape to work, but it is far from ideal. What you really want to find is some kind of smoothly curved funnel shape - something where the air enters a cylinder and it then broadens out as you move downstream. Either that, or find a simple cone and just flare the front end a little for smooth entrance. (The original Maggie Muggs pattern is pretty far from the ideal.) Find some specialty shop that deals in nothing but kitchen gadgets - or, a piece cut out of some SS pitcher or some such from a big Wal-Mart or Target store.

Good luck!

L Cottrill

Irvine.J
Posts: 1063
Joined: Mon Jun 05, 2006 4:28 pm
Antipspambot question: 0
Location: Brisbane, Australia
Contact:

Post by Irvine.J » Tue Dec 11, 2007 2:25 pm

Hi bob, at the local hardware/homewares place today I saw some EXCELLENT shapes of stainless steel citronella oil burners! Just little things with a wick, to keep mosquito's away and stuff. One of them was a 45mm diameter crazy FLARE and I said out loud... MY GOD, IF THAT ISN'T THE BEST FLARED INTAKE I"VE EVER SEEN. After which came immediate reprimand from my girlfriend..."you and your stupid rockets!"
In recourse, i had to say "They are jets honey"....it was the wrong thing to say....

Moral of the story is KEEP YOUR EYES PEELED!

Larry I sent you a couple of emails, just wondering if you got them.
Talk to you soon.
James.
James- Image KEEPING IT REAL SINCE 1982
http://pulseairdefence.com
[url=callto://project42labs]Image[/url]

Mike Everman
Posts: 4930
Joined: Fri Oct 31, 2003 7:25 am
Antipspambot question: 0
Location: santa barbara, CA
Contact:

Post by Mike Everman » Tue Dec 11, 2007 2:55 pm

Wives and girlfriends will never understand the two states of matter for us now, that which is useful for jets, and that which is not. ;-)
Mike
__________________________
Follow my technical science blog at: http://mikeeverman.com/
Get alerts for the above on twitter at: http://twitter.com/mikeeverman

Mark
Posts: 10752
Joined: Sat Oct 11, 2003 10:14 pm

Common ground

Post by Mark » Tue Dec 11, 2007 3:53 pm

"Wives and girlfriends will never understand the two states of matter for us now, that which is useful for jets, and that which is not. ;-)"

Here's something I'd like to make run as a jam jar or snorkeler of some sort, (wanting to be artistic and all), and "wives and girlfriends" would at least take notice and identify with it.
Wouldn't it be fun to be looking at some model wearing these, the best of both worlds? ha
It's pretty bad when you start to see everything as a potential jam jar. Some of you might be thinking a potential ramjet and that's OK too. I understand, these babies look fast. How many foot pounds? ha

http://butlersheetmetal.com/tinbasherbl ... _heels.jpg
Presentation is Everything

larry cottrill
Posts: 4140
Joined: Sun Oct 05, 2003 1:17 am
Antipspambot question: 0
Location: Mingo, Iowa USA
Contact:

Post by larry cottrill » Wed Dec 12, 2007 1:56 pm

Yes, at least in indutrialized nations, decent stainless parts are available almost anywhere you shop, once your mind is permanently altered to see every shiny metal thing as a jet part - or possibly, a piece of jet art.
Irvine.J wrote:Larry I sent you a couple of emails, just wondering if you got them.
Talk to you soon.
James.
No, never got anything. Might be due to the occasional "suds clog" of my overburdened email account here at my day job. Please try again.

L Cottrill

Post Reply