Monday, November 16, 2009

My Welding Cart

Having finished up my welding table, the next step was to have something to actually put my welder on rather than having it sit on the floor. So, I built the following which is based on a plan from "Welding Complete" from Creative Publishing International (available from Amazon here). However, I needed to modify the original plan to make it a bit wider so my plasma cutter would have a place to stay.

Here is the drawing- which omits the wheels which were just purchased from the local home center:

I won't bother going through all the build since it was basically the same as the welding table, but one thing I forgot to get a picture of was the correct way to align the upright components for welding, which is like this:

Use a carpenter's square to ensure the uprights are at a perfect 90 degrees before welding! I missed this crucial step with one of the legs on my welding table and it will be ever so slightly out of square forever now. Welding is definitely a measure THREE times, cut once, measure TWO MORE TIMES then weld type of process.

Here is the whole frame before painting. The hooks are to hang cables off of, but I am a bit worried I will be catching my knees on them.

Finally, a good thick coat of tractor green paint covers a multitude of sins! Actually, we have a pool pump in the same garage as the welding gear and occasionally small amounts of chlorine gas seep out and rust steel instantly, so I really need to paint everything to preserve it. I also put the rubber matting on the help protect the finish and provide some extra electrical insulation.

Here is the whole team! Note that the welding cart is extra wide so the plasma cutter can go beside it.

Next up... Bringing some order to my chaotic garage and workshop, which is hardly a project worth blogging about! I will be welding up some shelves and cabinets as part of the process and I will post that later. I also promise to get back to the Arduino soon. I have another Ethernet shield I haven't yet got assembled and I really want to look at networking two Arduinos together and having them do something halfway useful!

Thursday, November 5, 2009

Welding Table Construction

In honour of Monty Python's 40th Anniversary... And now for something completely different!

I believe way back in the original start of the blog, I explained that I also did a lot of machining including designing & building steam engines a few years ago. I had always meant to take a welding course, and on a whim I decided to finally do that this fall. So, the last few Saturdays I have been struggling out of bed at 6:30 AM to get into to weld with a huge stick welder (Shielded Metal Arc Welding - SWAM) process. Naturally, I have gotten totally obsessed and decided to get a welder for myself!

Originally, I wanted to get a 240 VAC stick welder, but my friendly neighborhood electrician told me the garage wiring just wasn't up to it, and this is hardly something I want to do inside the house! After some research, I settled on a Lincoln Electric MIG-Pak 140 unit which runs off of regular 120 VAC (similar to this) that does Metal Inert Gas arc welding (aka GMAW - Gas-shielded Metal Arc Welding). Fortuitously, it went on a good sale and I picked up a bottle of C02/Argon shielding gas, a leather welders coat and an auto-darkening welding helmet and I was set!

The technique and setup for the MIG welding is quite different from the big Hobart industrial units I am using in class, but MIG welding is pretty easy to at least pick up the basics of. The good thing with getting used to using the big welder in class is it gives you a very healthy respect for all the safety precautions and you get all the good theory on how everything is supposed to work and the various types of welds as well as the good advice of an experienced instructor.

So, after fooling around with my welder to get a feel for how it performs with various thicknesses of metal and so on, I decided the first traditional project for a starting welder is to build a metal welding table. I need the extra surface space in the shop and I definitely need a metal surface table for arc welding.

Step 1 - I worked up a design to get the rough dimensions and the shopping list for the metal store:

This used 1 1/2 inch square tubing for the legs, 1 1/2 angle iron for the frame and 3/16 thick sheet for the table top.

Step 2 - I bought the table top already cut to size and then cut down the frame and leg pieces from the ten foot lengths I bought. Here are the parts laid out before welding:

Step 2 - First I welded the frame that supports the top. The parts were cut mitered and then I put them on some firebricks on the top itself - on the assumption that the top is more level that the old floor of my garage!

Step 3 - With the top frame done, then I welded the plates for the caster wheels to the bottom of the legs:

Not too bad MIG welds considering I am just starting out!

Step 4 - I welded the leg assemblies to the frame assemblies. I wish I had captured the proper way of lining up the legs perfectly perpendicular to the frame! I actually messed up the first leg and it went on slightly out of true, but the other three legs went on perfectly. You will see later that it's not too bad and the one leg being slightly out won't be too big an impact. Once the legs are welded onto the frame, I needed to grind down the welds on the top of the frame so it would mate properly to the table top:

Step 5 - The frame and leg assembly was welded to the top. Here I use an intermittent rather than a continuous weld:

Step 6 - Roll it out of the shop and paint it! The slats are 1 1/2 inch wide 1/8 thick strapping I added to make a shelf for storing stock and other bits & pieces. Can you tell which leg is slightly out of alignment?

Here it is with good double coat of primer:

Finally, it got a good heavy coat of Tremclad basic green glossy paint so it looks like a tractor!

A nice substantial first welding project and something very useful for the shop! Next up will be a cart to put the welder on and my new plasma cutter which I should get next week.

Some day, I will combine the Arduino, welding and maching stuff into one project, promise!