brazing/welding dilemma

I'm building a cnc machine and I just bought a whole bunch of steel vat a surplus store. I need to braze or weld them together, but I can't braze since the objects too big for my propane tank, it disipates tthe heat to fast. I can't afford an arc welder. What should I do? I don't want to use nuts and bolts because that adds wiggle to the machine and I lose all of my accuracy.

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jonjon19787 years ago
im staring the mini 3 axis milling machine as seen on here im making the manual version first then maybe adding the stepper motors and all the drivers and software but that way hi-tech for me at the mo so will be making a uprated secone version of the first with all motors and measuring tools. would love to see your CNC when complete.
guyfrom7up (author) 9 years ago
well, I've never weld before, I don't think I can drill through the eighth inch angle iron, and I don't have access to old microwaves. what's jb weld?
It"s a brand of epoxy, you"ll probably want to buy the industro size.
guyfrom7up (author)  Tool Using Animal9 years ago
hmmm... that might do it, is there a different cheap fuel than propane that gets hotter?
(A) Propylene gets within fifty to one-hundred-fifty degrees of MAPP's rating (depending on the expert being quoted), and only costs about sixty percent more than propane in refillable cylinders; this is not true for disposables.
NOTE: Your torch needs to be rated for Propylene or MAPP; otherwise, its tip may just melt if it's an air/fuel type.

(B) Many zinc based aluminum filler alloys are quite strong enough to hold steel assemblies together; they don't need much heat to work, and some will bond well to steel. Gentle hint: A clean part surface and proper flux are the keys to success here, rather than so called miracle products (unless you just feel a need to spend sixty dollars a pound for some).
MAPP gas, costs about 4x as much as propane
guyfrom7up (author) 9 years ago
totally going off my own design, this cnc machine will be able to mill a 1.5 foot by 1.5 foot by 1 foot tall material. Just to give a taste of the powerfullness, these motors are rated a 297oz/in. Hooking that up to my threads, it could mill a 60 or 70 pound object, or even more with super good accuracy. I'm using picstep, and the degrees could be as small as .1125 of a degree.
MAPP gas by it self burns hotter than propane but not hot enough for true Brazing.
MAPP gas used with an O2 bottle rig would allow you to braze thin steel with brass or silver rod. But the torch kits can be expensive.
Arc welding thin steel can be tricky without lots of practice. Flux-cored welding wire welders work better but you still have slag.
The best and easiest way for beginners to weld thin steel is with a MIG welder. MIG will also weld Cast type metals
MIG welding uses Argon as an inert gas to shield the puddle from contamination. No flux/ slag clean up required.

Use 'Argon only' bottles for Aluminumn, Stainless-Steel, or mild steel.
C25 (25% CO2/75%Argon) bottles will work for Mild Steel.

Big ARC Welders give the deepest heat penetration and are best for the thicker, stronger welds.

Do not confuse a {flux-cored Welder which uses flux-cored welding wire, eliminating any need for gas and regulators that normal MIG welders require} with MIG welding. They are similar to buzzbox arc-welding with small gauge rod but easier.
so what would you suggest for 1/8 inch angle iron?
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