An Alternative to Welding ?

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http://www.youtube.com/v/oWmydudM41c?version=3&hl=en_GBAn incredible display of the strength of some glues .....A good guess is better than a bad measurement
Reply:I don't know if it's the same adhesive, probably not, but they make one for auto body panels. From what I've been told, using both spot welds and adhesive along a seam , destructive testing showed failures at the spot welds but not at the adhered seams. They do make some good stuff, but it comes at a price.
Reply:When they measure the cylinder, it looks to me like a 3" diameter. That means that surface area is about 7 square inches, and 8.1 metric tons is a hair under 9 tons. That gives a strength of just over 2.5ksi, which is exceeded by even the weakest welds. In comparison, to support 9 tons with 60ksi steel - which isn't particularly strong - you would need a surface area of .3in^2, which is the area of a round rod of diameter .62".Yes, it's cool, but it's nowhere *near* as strong as welds.
Reply:I hear what you saying slotard,5 Points though,Gluing reduces the skill level needed.Very difficult to get 7 square inches of weld (in that application)Cheaper , not just labour but Capital Investment of plant.*Guessing* should be a very constant strength from one "weld" to another.No heat if used near something else like live wires.True glues will never replace welding but in certain applications they are becoming a viable alternative.A good guess is better than a bad measurement
Reply:Just an FYI (in case you're ever in a facility). Having spent the majority of the last 23 years working in their plants all over the country, as a contractor, never say "gluing" around a chemical engineer in the adhesives division. Got my azz handed to me on that one. "Glue is made of animal products - adhesives are not".Kinda of like saying velcro......... they make hook and loop. I got reminded of that too.Either way, regardless of the manufacturer, the advances in chemical engineering have made significant strides in all aspects of life, including the welding industry with the alloy compounding of filler materials to fabricate/repair and machines to do the fusion.Course I'm "justa" dumb old mechanic and don't know 'nuthin.
Reply:3m vhb is amazing stuff... I think their newer stuff has over 100lb/sq in" strength. It is actually stronger than the base medal in certain cases, and is a better fit for some applications.The one off the top of my head is enclosed trailer walls. Instead of riveting or welding the panels, they can just get taped. I use it fairly often for thin aluminum sheeting on a few applications, and wouldn't do it any other way. I made a buddy a small carry-all style toolbox. Built the frame, then skinned it. I riveted it, but it wasn't as strong and flexed more than I would like. I drilled all the rivets off, 3m vhb'd each cross member, then riveted it back, and it was like i skinned it with 1/8" thick sheet.Miller: 200dx, Bobcat 225, Passport, Powermax 45, Milwaukee: Dry Saw, MagDrill, grinders
Reply:Originally Posted by JohnR3m vhb is amazing stuff... I think their newer stuff has over 100lb/sq in" strength. It is actually stronger than the base medal in certain cases, and is a better fit for some applications.
Reply:Yup. They make good "stuff". If you look closely at the video, You will notice the the joints were machined absolutely flat. Makes a big difference in bonding with that type of adhesive. Saw cuts probably wouldn't have given the same results.
Reply:A while back, I made a wing for my race car with $25 worth of aluminum and about $75 worth of 3M structural adhesives.  It's pretty remarkable stuff -- not as useful as a good weld, in my opinion, but MUCH simpler to do.  You do have to be careful about what kind of stresses the bond is exposed to -- the forklift test only produced a force in one direction.  But my wing has continued to hold together for over six years, now.  Some parts of it have suffered from metal fatigue, which I had to repair, but the adhesive has not failed at all.  And an automotive wing is subject to a lot of vibration and spike loads as it generates somewhere in the neighborhood of 400 pounds of downforce, all with 6 pounds of aluminum and no fasteners holding it together -- only the adhesive.Jack OlsenMy garage website
Reply:Originally Posted by mjbI use it to attach lights to glass display cases.  I have not had a light come off yet.I did make the mistake of using it to attach a temporary display to a melamine cabinet.  It ripped the laminate off of the wood when I tried to remove it.
Reply:The Aston Martin factory has replaced some conventional aluminum welding with adhesive technology.http://weldingweb.com/vbb/showthread.php?t=52432------------------------------------------------------------------------(been around for a while)Lotus Bonds with AluminumBy Kermit Whitfield, Senior Associate Editor Kermit's Bio Write KermitIf aluminum-intensive cars are ever to become more than an occasional curiosity, automakers may have to give up their weld shops. At least that's the conclusion you could draw after talking with the people at Lotus Engineering (Hethel, England). Lotus has been building cars with aluminum chassis for many years, but none of them are welded: they are held together with screws and adhesives. When Lotus first introduced the method on the low-volume Elise in 1996, company leaders were worried about market acceptance for what is essentially a glued-together car, but the technique proved so successful (over 23,000 cars produced with no reported failures) that it has become the basis of a new higher volume venture that may help to bring aluminum-intensive vehicles more into the mainstream. The new project, which uses Lotus' Versatile Vehicle Architecture (see AD&P February 2004, "Lotus' Versatile Venture"), tweaks the lessons learned on the Elise for volume production, but remains true to the fundamental concept: to get the most out of aluminum structures you must design for the material, not treat it like a steel substitute.Bond, Adhesive Bond. First and foremost, that means not welding it. Why? "The yield strength of aluminum goes down by half once its welded," explains Richard Rackham, vehicle architect at Lotus. So, getting the same strength in a welded aluminum chassis as in a bonded unit requires doubling the amount of material used; since aluminum is usually chosen for its light weight, that dilutes its key benefit. Another big disadvantage of welding aluminum is that stresses are localized along a point or a line, which can lead to material fatigue. Stresses are distributed over a wide part-mating when bonding is used. To gain the full merits of using adhesive, Lotus had to come up with ways to optimize its properties. For example, after determining that the optimum bond gap between parts is 0.2 mm, the question became how to maintain that gap uniformly over the bonded surface. The answer: Lotus designed tiny protrusions, or "pips" on the parts that held them exactly 0.2 mm apart.Aluminum bonding methodsThe shape of things to come? Lotus is bringing the aluminum bonding methods it pioneered with the Elise chassis to higher volume production. The first of the new vehicles are scheduled to be produced at the end of 2005.To fabricate the main chassis components Lotus chose a process well-suited to aluminum: extrusion. Chassis supplier Norsk Hydro ASA (Oslo, Norway) extrudes the closed-box parts out of 6000 series aluminum and bonds them to folded sheets of recycled 3000 series. Rackham says that one reason extrusions were chosen is because they can be inexpensively produced (he estimates the cost of a die at about $5,000), which helps to offset the higher material costs of aluminum. Another is that they can be formed into complex shapes that serve multiple purposes and help keep parts count down. The proof: the entire Elise chassis consists of only 27 different extrusions.Higher Volume. The challenge Lotus now faces is translating the aluminum production methods for an essentially hand-made $40,000 sports car to affordable vehicles that can be mass-produced. It's current initiative, which is being conducted for an unnamed automaker, looks to build sub-$30,000 vehicles in the 40,000 to 50,000 annual unit range. To do that, Lotus is making some changes. According to Kerry Osborne, principal engineer, the hand-applied flow drill screws that are currently used to knit the Elise chassis together are being replaced by self-piercing rivets which can be shot more quickly, though they require application tools that generate at least five tons of pressure. But perhaps the biggest change is in the bonding. Realizing that no mass-production operation can afford the Elise's 50-minute curing time (nor would it wish to incur the expense of multiple ovens), Lotus is replacing the heat-cured single part epoxy adhesive used on the sports car, which required temperatures of 180ºC, with one that will cure in the lower heat of the paint oven. (Both adhesives are sourced from Dow Automotive [Auburn Hills, MI].) The savings in process time garnered by these changes could be enough to peak the interest of volume automakers and get them to consider bonded aluminum chassis as a viable alternative for niche vehicle production.Last edited by TxDoc; 10-04-2012 at 02:20 AM.TxDoc's Photos Lincoln SP175 PlusLincoln Power Mig 256Lincoln 250 LX Spool Gun Lincoln Precision Tig 225 Hypertherm 600 KMG 2x72 Belt GrinderBaldor 812RE Grinder
Reply:I use structural adhesives in the body shop, my employer has demanded it because of how much time it saves and as a reply I have come back with a combination of spot welds with resistance welding with common resistance welder on steel panels the  cost of resistance welding equipment costs still has not dropped to the point of doing a panel with properly sized spot welds hence the combination.With structural adhesives alone I have seen vehicles come back a year later panels separated, if any stress is placed upon box panels glued on without additional welding.A benifit is corrosion inhibition with structural adhesives.In most cases use depends upon personal comfort using it alone.Either way corrosion inhibitors and substrate prep has to be done properly.
Reply:That means that surface area is about 7 square inches