Author Topic: Metal workers--Plasma cutting (Read 1514 times)

Al_Smith · « **Reply #20 on:** November 10, 2011, 07:27:49 am »

When you talk metal prep it can get rather involved .First you have to have it clean,all the mill slag off etc .Slag would require sand blasting .Then acid prep it with "triple etch " or some other product .Give it a good shot of red oxide primer then shoot it with paint .On galvanized acid prep it then a coat of zink oxide followed by red oxide then paint .

I personally use Rustolium brand myself ,it's never failed me yet but that's just a personal preference .

mometal77 · « **Reply #21 on:** November 10, 2011, 11:17:30 am »

Plasma cutters are a great way to cut steel when you do not know if it is Ar400 or T1 steel. And comes out of a scrap yard. And you could mess up you ironworker shear not knowing what it is. The history of plasma cutters are just like the invention of leaf blowers. Invented by 2 guys in a shop and they went wrong by trying to get their invention out there as the story goes. There are stories and ideas online where you can build your own online machine. Thermal Dynamics i think makes the best machine out there.

http://www.plasma-cutter.com/ Just an idea for information.

Plasma cutters have come a long way from just having a transformer and weight in at a few hundred ibs of copper and not being able to cut more than a few gauges of metal. I have heard of plasma cutting machines that could cut 6 ft thick and rubber walls/thicknesses of nuclear subs. I cannot wait for the technology to come out we're all you need is a ''small'' box and consumables that never need changing and are reliable. But then again companies would go bankrupt if not selling merchandise that lasts. Kinda like that pizza in back to the future 3 or chicken in the fifth element.

Safety:
If you ever cut stainless steel use a respirator and cover yourself from Uv hazards. When I worked for Haskell Corp. 3 journeymen sheetmetalworkers went to the ER over no masks were used. And never work in a confined space when using them.

http://www.metalwebnews.org is a great site if you have ideas or projects.

Al_Smith · « **Reply #22 on:** November 10, 2011, 01:36:31 pm »

Well yeah T1 is some tough stuff .I haven't seen any in years myself .That which was was cut on a flame cutter .Big buckets for Michigan front end loaders and Madsen asphault plant dust collecters back in the day .Lawdy though that day was 40 some years ago when my hair was all one color which it's soon to be again although somewhat lighter than the coal black in the days of my youth .

mometal77 · « **Reply #23 on:** November 11, 2011, 09:43:45 am »

T1 is some tough stuff. Repairing buckets at the quarry. I would use old broken drilling rod. Or it makes good stuff when material goes from a conveyor into a shaker. We're I am you never know what you will find at the recyclers. A friend of mine ran into a nice sheet of Titanium and they thought it was stainless. If you have ever welded titanium with a tig welder it omits a white light. Kinda neat stuff I just cannot believe with the way the economy is going locally here i have got some great findings on tig rod 3/16 to stainless steel rod and i was just in the other day and it looked like someone recycled their whole shop. I scored on some brand new welding lead at 2.50 ib

DouginUtah · « **Reply #24 on:** November 30, 2011, 11:57:45 pm »

Yet another question.

I have spindles with a 6" long 1.25" shaft. I bought 1 1/4" Schedule 80 pipe for the axle. It is 1.278" ID, but it has a ridge (seam) from the manufacturing process which prevents the shaft from going into the pipe. I can't think of a way to get rid of the ridge.

Also, when the ridge is removed, the fit will be sloppy (0.03"). How would you recommend overcoming that and how would you weld the two together--pipe to the inserted shaft. I'm thinking of drilling some holes in the pipe and filling the holes with the weld. Any better ideas?

isawlogs · « **Reply #25 on:** December 01, 2011, 12:20:58 am »

Doug , use an axe file , it comes with a nice handle to remove the ridge, I really don't think that .03 " is that big of a deal , file till its a tight fit , both spindles will have the same offset that is neglectable. ( Unless you are a purest then .. shime to your hearts content

Or ... Give the pipe a whack with a hammer a quarter turn from the ridge .. that would be my shimming

)
Once fitted tight , tack weld the end of the spindle to the end of the pipe. Now put the wheels on and check the distance between the rims, if it is same, put a full weld on the spindle & pipe.

To prep , I only ever use a hand held grinder with a sanding disc the type that has many over lapping leaves of sandpaper attached to a plastic disc. For preping the spindle I would use a grinding disc to remove any oils/rust or paint but only where I would be welding.

scsmith42 · « **Reply #26 on:** December 01, 2011, 07:38:28 am »

Doug, Marcel is providing some great advice.

When I have built trailer axles in the past, I would use either a round file to remove the burr inside the axle tube, or more commonly a die grinder with a carbide bit in the end.

To weld the stub axle to the tube, I would do a combination of drilling a few 3/4" holes through the tube and then filling them with weld after the stub was inserted, and then full weld the end of the tube to the stub axle.

Personally, I prefer that my axle's be as precise as possible, and in order to make sure that the centerline of the tube and the stub axles were true I would use one of two techniques. If the fit between the two is relatively close, let's say within .050, then I will take a center punch and make a series of deep punch marks on each end of the stub axle, making 3 - 4 rows all of the way around the axle. When you make a punch mark a rim of displaced metal is raised up from the punch, and this serves to take up the clearance between the axle and the tube.

If the clearance is too great to be taken up with the punch method, then I will tape a piece of shim metal around the stub axle at each end, close enought to the ends so that the stub is centered but far enough so that the melting tape does not contaminate my weld.

DouginUtah · « **Reply #27 on:** December 19, 2011, 03:57:42 pm »

It's been a couple of months since I started this and I have now built two trailers.

One is a 5x10 (somewhat unconventional--actually 5'-4") and the last one is a 4x8 with a 3/4" birch plywood deck--which I bought at Home Depot for half price ($13) with an Ace 50% off coupon.

So, I learned a few things:
I said a Sharpie doesn't work. I was wrong. If the metal is clean and you use a fresh Sharpie it works fine. My first Sharpie was old and partially dried out.

I plasma cutter is really good at cutting a bead when you make a mistake. I put the tongue on with the frame upside down and then put the shackles pointing down. Had to remove the tongue and put it on the other side. Of course that meant that the turn signal wires (running in the tubes) were switched so I had to switch the brown and yellow wires in the tongue.

I used Purple Power to clean the metal. (Intended to buy Simple Green but PP claimed to be a degreaser on the label.)

Utah has a requirement that any trailer over 750 lbs. has to be registered. I made sure these trailers were under that, and will never again build a trailer that has to be licensed which precludes building a dual-axle trailer.