Aluminum Sliders?

I didn't think of that. I also asked if it were possible to heat treat sliders or if they were too large? Also, knowing this about aluminum sliders makes me a bit uneasy about aluminum bumpers that are not heat treated... Is that not the same concept as a poorly built steel bumper? Shouldn't it be a concern if you spend time and effort to make a strong bumper for your efforts not to be wasted?

I think someone previously mentioned rubber gaskets. It seems easily avoidable, what do the offroad vendors do about aluminum bumpers, then? Don't they bolt straight to steel?

 

If you bolted them on with stainless steel then you'd be fine.

 

First. See post 28 But seriously, I think your advice to use stainless is wrong. Stainless is father away from aluminum than carbon on the anodic chart so will cause corrosion at a faster rate. The way to join aluminum to steel is with steel fasteners ofthe correct strength and nonmetallic isolation..

 

This is irrelevant.

The point is that aluminum in contact with steel creates a battery. Stainless steel is convenient to use because it sits between the steel and the aluminum, preventing a circuit from being formed. Also, it will corrode more slowly than your frame, this is sort of irrelevant except for knowing that the bolts you use to hold the aluminum armor on will outlast the life of your frame.

 

Stainless bolts basically welded themselves to my aluminum headache rack

I ended up isolating the two with some peel and stick on the washers and bolt heads and surgical tubing on the through bolts , after I had to cut them off that is

 

You get a gold star!

 

This is wrong.

Edit - And here is why. Stainless is well toward the cathodic end of the scale and aluminum is well toward the anodic end of the scale. Carbon steel is fairly close to aluminum on the anodic end of the scale. In the presence of road salts and moisture the aluminum will corrode MUCH faster around a stainess bolt than it will in contact with a carbon steel bolt. And the surfaces where aluminum is in contact with carbon will also corrode but at a slower rate than the aluminum/stainless interface. So the correct answer is to isolate the carbon steel and aluminum mating surfaces with either a coating or other barrier that won't easily wear as the metals get dirty and vibrate, expand, contract, and etc. And use dielectric washers, and even a sleeve if possible, at the carbon steel fasteners.

 

It would be totally possible to heat treat sliders, they would just need to be taken to a heat treat shop with a big enough oven. The one in that picture I posted holds about a dozen mountain bike frames at a time so sliders would fit in it with ease.

Please don't let my concern about heat treat on sliders steer you away from aluminum bumpers. It's a bit of an apples and oranges comparison. I think that for the right application aluminum bumpers are great. I love the lighter weight but any vendor on here will tell you aluminum bumpers are a compromise between weight and strength with lighter weight being the primary goal. If you want a super strong bumper to beat the hell out of steel would be a better choice.

I plan on welding up an aluminum bumper for my truck and also getting aluminum skids because it's my daily driver and I don't want to kill the gas mileage by weighing it down with a ton of armor. But I also wheel it like a daily driver, being my only vehicle I can't afford to push it super hard breaking things so aluminum will be fine for my application. I'm more interested in the improved approach angles than smashing the bumper into rocks all the time. I'm actually a big fan of some of the aluminum products that vendors here are producing. It's just a matter of choosing the correct material for your application and goals.

 

Great news!! I understand, sliders are a lever, bumpers are not. But as for aluminum bumpers being weaker, I had assumed that anytime you make an aluminum bumper, it would be made with thicker plate/tubing to compensate, but STILL being much lighter than steel (Just not 3 times, perhaps 2 times?) Is this how it works? Or are there other properties that keep aluminum from being a "win-win" situation? Even if not, I am with you. I want an aluminum armor bumper for better clearance, minimal if any bumping, and weight savings. Also, don't tell anyone, but because they look awesome to me.

Decorative winch?

 

Titanium sparks, yes steel does as well, but titanium really throws off sparks. I'm talking embers. I've lit off a puddle of alcohol by dragging titanium tubing across concrete. (Navy boredom, hydraulic tubing also makes great blow guns with foam earplugs and thumb tacs.)


As far as corrosion goes, you all know it takes an anode, cathode, AND an electrolyte. You can't do anything on the anode or cathode (well, maybe a boat zinc on the aluminum), however you can try to control the electrolyte.
The proper way to attach the dissimilar metals is to install the fasteners "wet".
In aviation we'll put sealant in the holes when riveting, however the proper method for bolts is to apply it under the bolt head, not on the threads as that can give false torque readings, then "cap-seal" the nut on the other side with sealant.

 

...and since I'm handing out info, a "Fay" seal is when you sandwich two faces with sealant in between. To do this properly you spread sealant over the surface, drag a squeegee across that has a jagged edge on it so that you're left with uniform lines of sealant that when pressed down provides the correct coverage with no voids.

QA (Quality Assurance), then comes by to check your work and looks for the proper "squeeze out" all the way around the patch, part, whatever it was you fay sealed.

 

There are several Titanium alloys. I would be willing to be some of them would not spark excessively, though I personally have not worked with the material. It's a moot point anyways. No one is going to spend 4-5 times the money for Titanium armour on a steel truck.

Besides, Tungsten Carbide (if you could even work with it) would be the obvious choice for sliders since you'd need to be climbing diamonds to scratch it lol. I wouldn't even want to know the cost of that, nor the weight.

When I armour up I plan on going all steel. Every person I talked to running aluminum armour, other than just the bumper, complained of gouging and hanging up on there skid plates up in the rockies where I like to go. I'd like to avoid that problem.

As for the corrosion part you're right. Ford attaches the aluminum panels on the F150 in a similar manner. Basically they use a permanent adhesive to isolate the panel from the truck. They tested the idea over 5 years using real trucks on the road, that they didn't tell the owners were partially aluminum, doing normal every day work and there were no issues. Too bad Ford wouldn't just sell the adhesive they are using. If they did then slider/bumper/armour corrosion problem solved. You could still use bolts for strength in the way OZ-T described but isolate the aluminum with the adhesive and gain even a stronger connection. Damn proprietary technology.

 

It's not proprietary, aviation has been doing it for decades. Everyone just puts their own name on a process to avoid being sued.

Hell, you can use Toyota's FIP (Form in place) gasket for oil pans. Basically just RTV with their name on it.

 

Yeah I know what you mean but every mix has slightly, or sometimes vastly, different properties depending on what loads, tolerances, and forces it needs to cope will. I'd assume the same stuff that affixes the aluminum body panels to our F150 would work exceptionally well with an aluminum skid plate to a steel truck.

 

Holy thread revival batman. To stir the pot, I since have setup a set of hdpe skids on my new truck. Alum is old news!

 

Thinking about what I said, and I think it's been hinted at before, wheat would really work well would be aluminum sliders with a half tube of tungsten carbide bonded to the bottom of the slider. Play to the strength of both metals. I bet you it would only cost $5K a side .

Getting back to why this thread was revised, I see no reason why with those open source bolt on brackets you couldn't take the plans to a welding shop, have them measure your truck, and fabricate up something aluminum for maybe double the price of steel. You'd have all the disadvantages of the aluminum but if you need to save the weight you would get some protection and still be far lighter than a steel setup.

 

I think we ought to consult an Aussie member - either all these laws of science are suspended there - or the common Ford and Holden Utes with "aluminium" flat beds and bull bars must be dropping scrap all over the roads. Dying like flies for all to see. Everyone lives within about 30-35 klicks of the sea there, plenty of salt air to go around......... In all of the times I worked over there, none of the fitters or riggers ever bitched about corrosion of attachment hardware for their shiny roo bars and hoops.

 

I think a Hawaiian member would be better.

 

Also with all of this talk about steel fasteners corroding into place on aluminum stuff makes me think of aluminum framed motocross bikes. There are tons of steel bolts that go into the Al frame. Simply applying anti-seize before installing the bolt is all that I have ever found necessary to keep them from corroding in place.

 

Only in the presence of an electrolyte such as salt water. Who ever heard of anyone getting salt on the bottom of their truck? ;-)