Floor pan. Aluminum vs Steel
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by quantumkev » February 18, , 5:36 pm
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I am trying to decide whether to use a steel, or aluminum floorpan, and what gauge to use.
If I go with steel I can just weld it on and be done with it. I know corrosion might be an issue using steel, but I am in Texas, so I don't have to worry about that. It will be heavier, but stronger, but if welded on, it is pretty permanent.
If I go Aluminum I have to drill and rivet a LOT of holes.... but it is then at least worst case removable.
Not sure which way to go, and I thought I would open it up for conversation.
What do you think are the pros/cons of each, what experience did you have, and what gauge did you use?
Re: Floor pan. Aluminum vs Steel
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by KB58 » February 18, , 6:52 pm
There have been a lot of threads about this...
Steel, stronger and more puncture resistant, can distort due to welding heat, and can be very heavy.
Aluminum, lighter, probably more expensive (depending upon thickness), easier to puncture, and more of a pain to attach.
Don't forget that unless the likely stitch-welded steel panel is fully sealed, driving through even one puddle is going to get water into the seam and start it rusting from the inside out. A compromise is to either fully seal the seam, or use stainless.
It really comes down to how much you care about total vehicle weight, and how concerned you are that some road debris might someday come up through the floor. I remember driving over one of those 6-ft long breaker bars on the freeway one time. I could only imagine the havoc that would cause if it got bounced up right before the next car drove over it. Too ugly to even think about... Much more likely would be a rock or piece of wood, but still. Remember, for most intents and purposes, what we're building aren't that much safer than motorcycles. You make your choices and take your chances.
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Re: Floor pan. Aluminum vs Steel
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by turbo_bird » February 18, , 8:25 pm
My car has a welded steel floor, I think 16 awg. If I build another, it will be an aluminum floor about .090" thick. That should be just as stiff as the thinner steel floor I have now, as well as lighter. I painted my steel floor, and the paint wears off pretty fast from shoes and grit, I also got a bit too much heat in it when welding it on, so that's a bit annoying. For the next one I would also make the floor pretty much cover the entire bottom of the car with small access holes for oil changes and diff/transmission access. A full under tray would make a small aerodynamic improvement, but a bigger improvement in chassis stiffness. Like KB58 mentioned on safety, I pretty much see it as a four wheeled motorcycle.
Kristian
V6 in a book frame build. Now registered.
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Re: Floor pan. Aluminum vs Steel
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by FieroReinke » February 19, , 12:33 am
I am going welded steel but still debating 16 vs 18 ga. I have sheets of both but still have alot of paneling left to do. I can either do the floor in 16 and the panel behind the seats in 18 or vice versa or buy another panel. I like the weight down low and the protection of the 16 ga floor but that will add more weight.
Build on
Chris
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Re: Floor pan. Aluminum vs Steel
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by wrightcomputing » February 19, , 7:48 am
I went with an 1/8" Aluminum diamond plate floor. It covers the entire bottom of the car. I think it weights about 55lb, which is heavier duty then most but I like my balls. I got an oil sucker and pull the oil out of the dip stick just like they use on boats.
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Re: Floor pan. Aluminum vs Steel
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by nick47 » February 19, , 9:29 am
I also went welded steel, 16 gauge, and I'm glad I did. Two years and 20K miles and rust hasn't been an issue. What I really like is how stiff and solid the chassis is. Aluminum probably would be as well, but I didn't much like the idea of rivets.
Re: Floor pan. Aluminum vs Steel
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by rx7locost » February 19, , 10:56 am
For more information, please visit steel flooring panels.
If (and that's a big
IF) a steel floor is a serious rust issue, how does the frame still not rust if aluminum flooring is used? Steel floor for me and a continuous weld all along the outer edge. Stitch welded along all inside tubes with caulking between the welds to keep out "stuff". Nothing lasts forever. I think 30 years will be enough for me.
If choosing aluminum, consider the next step which is forming the aluminum along the bottom rail/floor and how std rivets may affect that forming and riveting. It is more work to use flush rivets. It is not a problem if a steel floor is chosen and welded along the outer edge of the square tube and ground flush. Either one will work. Success has been had with both materials. Your car, your choice.
Chuck.
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Re: Floor pan. Aluminum vs Steel
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by botbasher » February 19, , 12:45 pm
I decided on the best of both worlds.
I put 12ga stainless on the vert. firewalls and forward floors of the driver & pass compartment. I did 14ga directly under the seat. I'll do the remainder of the car in .040 Alum, but also toying with using .018 stainless and welding it on.
As Wright said... I like the twins where they are and 12ga is bulletproof (.22cal) and I'll trade that weight off for the thin remaining under pan.
Rx7 hit the gorilla in the room though. Alum pan doesn't eliminate a rusting issue. It just moves it from the floor itself to the spaces between!
KS
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Re: Floor pan. Aluminum vs Steel
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by Sam_68 » February 19, , 1:44 pm
rx7locost wrote:If (and that's a big IF) a steel floor is a serious rust issue, how does the frame still not rust if aluminum flooring is used?
Because it's protected by paint/powder coat and an aluminium floor.
The big difference is that whilst an aluminium floor will not be affected by road gravel bouncing up underneath (and completely covers the steel, so protecting it), with steel such inevitable 'road rash' chips off whatever paint or rust-proofing you have applied and lets the rust take hold.
It will also usually be sealed against water ingress by Sikaflex or similar sealant/adhesive between the alloy and the steel (easy to apply a bead before riveting the floor on), whereas, as previously mentioned, a stitch-welded steel floor will trap moisture between the sheet and the tube, unless you take pains to seal it properly afterwards. This is why the sills (rocker panels, I think you guys call them?) are always amongst the first places to rust out on older cars.
Aluminium every time, for me.
Re: Floor pan. Aluminum vs Steel
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by » February 19, , 2:18 pm
absolutely no way you're protecting the internal portions of the frame rails from moisture the second you drill a hole for a rivet. powder coat the rails.. sure.. then drill through it, now you have an exposed hole that will not be 100% sealed by a rivet.
I'll be using steel, with seam sealer between the floor and rails, stitch welded every few finches.
Tucker
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Re: Floor pan. Aluminum vs Steel
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by Sam_68 » February 19, , 3:04 pm
wrote:absolutely no way you're protecting the internal portions of the frame rails from moisture the second you drill a hole for a rivet. powder coat the rails.. sure.. then drill through it, now you have an exposed hole that will not be 100% sealed by a rivet.
As I said above, it is normal practice to use a PU sealant/adhesive (eg. 'Sikaflex' or 'Tiger Seal') between the aluminium and the steel, when riveting.
This gives very effective protection where the tubes are drilled and riveted.
There are thousands of specialist sportscars running round the (salted in winter) roads of this depressingly damp island of mine, that are living testimony to the fact that this approach works.
Re: Floor pan. Aluminum vs Steel
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by horizenjob » February 19, , 3:47 pm
Aluminium every time, for me.
I think it will be more resistant to damage from rocks under the car than steel. At least the reputation for small workboats is that the aluminum will deform a great deal before it actually tears and breaks.
I've always wanted to make a rig to hold a square piece of these materials and drop a pointed weight on it, like a window sash weight. How about a harbor freight anvil mounted on a 2x2 bolted to the basement ceiling joists? You could swing against a target sandbagged against the foundation. What do you folks think would be reasonable?
This is not really trying to represent something pointed but more like a round rock the size of a softball or more that you might go over at 100 KPH.
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Re: Floor pan. Aluminum vs Steel
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by turbo_bird » February 19, , 3:52 pm
Sam_68 wrote: wrote:absolutely no way you're protecting the internal portions of the frame rails from moisture the second you drill a hole for a rivet. powder coat the rails.. sure.. then drill through it, now you have an exposed hole that will not be 100% sealed by a rivet.
As I said above, it is normal practice to use a PU sealant/adhesive (eg. 'Sikaflex' or 'Tiger Seal') between the aluminium and the steel, when riveting.
This gives very effective protection where the tubes are drilled and riveted.
There are thousands of specialist sportscars running round the (salted in winter) roads of this depressingly damp island of mine, that are living testimony to the fact that this approach works.
Not to mention that even if you weld a steel floor on to avoid drilling the frame tubes for rivets, you're still going to attach the aluminum side panel with rivets to the same exact tube. At least the holes for attaching the floor are on the bottom of the tube so water will have as much chance of running out again as getting in.
Kristian
V6 in a book frame build. Now registered.
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Re: Floor pan. Aluminum vs Steel
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by Miatav8,MstrASE,A&P,F » February 19, , 5:47 pm
Contact us to discuss your requirements of stainless steel floor tile. Our experienced sales team can help you identify the options that best suit your needs.
A sealer between the metals is good but does nothing to keep the water out. The individual rivets are dipped in waxoil (that you can make at home) or other sealant that doesn’t quickly setup.
The sides should wrap the edge of the floor. For an alloy floor, I’d seal, add rivets at the ends, then seal on the sides over the top and use rivets through the floor and the side skin overlap versus flush under the side skin overlap. For steel floor, stitched, painted, then seal the side skin overlap over the floors edge.
Horizon, here is a good article on the various hull materials: https://www.morganscloud.com//08/06 ... o-impacts/
Quote: “Mild steel (until it corrodes) can be somewhat less fracture-prone in impacts than marine aluminum, and is also harder to abrade and easier to repair in the field.”
My reverse trike I’m building is using a .050” steel floor and firewall. My GO4s use aluminum sheet, about .080” thick which I have no intention of replacing with steel. I don’t know the alloy they used and it did corrode, allowing the powder coat to flake off in sheets. I used annealed to modify the floor on the P35 to get more air to the radiator.
Aluminum is a very broad term and all the alloys corrode in one way or another at different rates. Pure aluminum does not, but it isn’t a good structural material. Alclad sheet is an alloy with a thin layer of pure aluminum on top, but it can be scratched through and would be a poor choice for a floor.
In a fire, such as an accident, there is no comparison. Steel will stay solid long after the aluminum is a puddle. Also, in an accident, you do not know if you will be conscious or physically capable of escaping the car. I am not saying everybody should have steel; just sharing some info.
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hello
i want to replace the floor pans on the bronco.
many of you have changed your floor pans in the past, asking for your advise.
some places sell 18 gauge metal floor pans. i am not sure as to how thick the metal should be.
is 18 gauge a solid metal or is thinner compared to the bronco original floor pan thickness? what about 16 gauge or 14 gauge metal?
any recommendations as to which supplier to buy floor pans from?
please advise
edmond
I think 14 gauge would be considered overly thick for most applications, but great if you want extra strength and don't mind more work forming it.
16 gauge would be considered slightly thicker than most stock panels, but perhaps
"stock-ish" for earlier sheet metal from the factories.
Don't know if EB's used that thickness on any panels or not.
18 gauge seems to be the thickness of choice for much of the aftermarket stuff.
I have heard that 18 was stock. Not sure if that was authoritative information, or just an assumption. But I'm sure someone here will know for sure.
Paul
I just can't seem to find any 14 or 16 gauge metal floor pans.
All the market is offering from what I find is 18 gauge.
So it is safe to just order the 18 gauge? Since you mentioned that the factory did come with 18 gauge metal.
The reason I asked was when I took the car to a local body shop, they were saying that it is better to put 14 gauge, but they have to fabricate it.
I would like to buy ready to go made parts and not fabricate things, it will cost me more money probably of they fabricate.
Thank you
Here's a listing for some of our pre-formed pans: http://www.wildhorses4x4.com/category/Bronco_Floor_Pans
Notice that some are listed right in the title as being 16ga parts. Those are some we have made specifically for us out of thicker material for those that want it.
Those not listed as thicker are standard made by the aftermarket companies such as Carpenter, and Dynacorn, etc.
None of them are precise fits every time for every EB unfortunately. Some fit like they were made from pieces of your exact tub, while others are not quite so perfect a match. I've had them fit perfectly, while on others you had to have a really good imagination to line up the strengthening ribs.%)
And it's not that the aftermarket stuff is so inconsistent either. Sometimes it's the factory body inconsistencies and 40+ years of abuse and flex. Which is my fall-back excuse when something doesn't fit perfectly!
But they did fit the location at least, so get the job done. Probably why they're known as "patch panels" I guess.
Good luck.
Paul
Do it right and get the stamped floors, if you can. Nothing worse than a nice restored Bronco with flat sheet metal floors poorly done.
This is true.
I thought you were making fun of me for a second there....haha
I need to re-do my old floor pan repairs.....Did them when I was about 15....sigh....and you can tell....
My bronco has flat sheet metal over the old floors. It looks like crap!!! Very poor cover up and one day I will redo mine with the stamped floor pans too.
I will more than likely replace mine when I start my EFI swap which will require the fuel tanks to be removed. Good time to work on the floor pans.