November 2018: DIY fluid reservoirs
Disclaimer: I hold no responsibility to your personal safety. Fabrication and welding often requires heat, flames, and other things that can harm you if not properly equipped or prepared. Keep a fire extinguisher handy at all times because if you havenít set something on fire it is only a matter of time. Fabricate at your own risk.
Day late and probably a dollar short but fashionably late is my style. Just look how long my build is taking. On this monthís DIY I wanted to cover some of the basics of working with tubing/pipe that will help you progress into the more complicated points of tubing like building a manifold or a rollcage even. This DIY encompasses the ins and outs of making a simple fluid reservoir. While it could theoretically be used for housing just about any liquid, in this case they will be used for brake fluid and clutch fluid.
While the materials list can be altered to suit your own personal needs I tried to use as much as I had laying around rather than going out and buying the materials or even buying reservoirs (The Tilton reservoirs that I wanted were $30 a piece, I have the cost of argon into mine). Having a few lengths of 1.75 inch diameter stainless leftover from my exhaust I figured that would be a good starting point. I broke out the trusty harbor freight chop saw and cut three pieces to 2.5 inches. This measurement and size of the tubing fit my needs; feel free to adjust them according to your own.
While the chop saw is an excellent (and cheap) tool for making straight cuts on tube it does leave quite a bit of leftover cut material around the edges. This extra material can not only wreak havoc on your gloves but it will also contaminate your weld. The extra material can act as ďfillerĒ and make the puddle inconsistent or even add impurities. To address the leftover cut material I like to use a carbide burr on a straight die grinder. I prefer MACís mini die grinders as the cheaper ones canít keep up with the all day abuse. At a hobbyist level one of the non-tool truck brands will work chipper. In the words of my fabrication teacher Mike Streicher (he beat out Jeff Gordon for the USAC Midget championship in his own chassis, he knows his stuff) ďIf you cannot rub that piece of tubing along your nut-sack, It is not deburred enoughĒ. For the ladies reading I would suggest employing a male friend or significant other. I can guarantee if you mention taking their pants off they wonít think twice that you are about to rub a sharp piece of tubing along their private bits. Pictured is a, pardon my Mandarin, Nut-sack worthy deburred piece of tubing.
After a short trip to urgent care to stitch up your nether regions it is time to cap the tubing. The easiest way to go about cutting a perfect circle that I have found is a hole saw. Now personally I hate using hole saws. If you are not using a speed adjustable drill press it is pretty easy to overheat the saw and dull it up. At $10 and up per saw this gets rather pricy. Since the material in question was only 18 gauge tin snips were the ideal candidate for the job. I traced the tubing onto the sheet and then cut along the inside of the sharpie line; you could also scribe it with a compass and just cut along that line as well. Itís more of a preference thing than anything else. Unless you are a Savant with the snips you are going to be left with a slightly jagged circle. This is fine, I will explain how this is alleviated in the next paragraph. Now is time to tack your caps to the tubes. Finding a comfortable position to weld tubing is very difficult. I recommend trying a handful of different seating and arm rest positions before settling. I like to use a crows foot or a hammer to keep the caps secure on tubes while I am tacking. It is very easy to knock the cap off by mistake with the filler or have the MIG wire not start and arc instantly and do the same.
Ignore your jagged bits of circle and tack the cap on where it is closest to the rim of the tube. Try for at least four evenly spaced tacks but no less than two. I ran a few autogenous (without filler) beads for tacks as I have used snips a time or two before this. Using the proper filler wire and gas mix is essential to a sound weld. Since this is stainless tubing to mild caps, I used 309 wire and 100% argon for TIG welding.
Now that your cap(s) are securely tacked it is time to add the bungs and NPT fittings on each end of the cap. For an appealing look I like to center all my bungs. Now with a jagged circle it is difficult to reference an edge to properly center the circle. Assuming you placed an appropriate amount of tacks you can take the tubing and run both edges along the bench grinder or belt sander to flush the caps to the tube. Now layout a square on a piece of paper with the same leg lengths as the diameter of your chosen tube and intersect the corners to create a center point.
Place the capped tube in the center of your square aligning the edges accordingly. Take a sharpie and mark where the corners meet the intersecting lines. You can then draw a line from each corner on your tube creating the same intersecting point that you drew on the paper. Drill the holes according to what size bungs you are using and bingo you have nice centered holes.
Sometimes you donít have the luxury of stepped bungs for easy centering. A neat trick I picked up was to use the drill bit I had used to drill the initial holes to center the bung. Be very careful when doing this as it can easily destroy the heat treatment of the bit. A piece of round bar would be more ideal but unless you have access to a lathe or a large stock of round bar it is not nearly as easy as whipping open your drill index and selecting the appropriate size.
Assuming you have followed along this far all that is left is to weld out the caps and fittings and use them as you intended. If you are using stainless it is a good idea to back purge the welds or use some form of flux to prevent sugaring of the welds. This can leave debris in your system and could potentially destroy the components. As always fabricate at your own risk. I hope this DIY provides a few techniques you can utilize in your own projects and if any questions are to arise feel free to post below and I am sure one of the many great fabricators that lurk in this thread will chime in to help.
Next monthís article is still up in the air so I am going to leave it up to you guys. Would you prefer an introduction to the various types and techniques of welding or dive deeper into the tubing side of things with either some cage basics or exhaust fabrication. Cast your opinions below!