Author Topic: Belly pan skin  (Read 4960 times)

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Offline Clay Pitkin

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Belly pan skin
« on: August 28, 2012, 06:39:09 PM »
What is the best material to be used for a belly pan?

Also, what is the best method for securing it to the bottom of car? ie: removing it and re-attaching it, etc.

Also, I was going to use sheet metal, but I can only find it in 10' lenthgs, the car is 12 feet long. How do I join two sections?

TIA
Clay
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Offline Glen

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Re: Belly pan skin
« Reply #1 on: August 28, 2012, 06:55:39 PM »
What kind of car? how wide is the frame etc. A two piece belly pan is not difficult to fab. Dzus fasteners are the most common. Sheet metal screws are a nono.
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Offline dw230

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Re: Belly pan skin
« Reply #2 on: August 28, 2012, 07:06:49 PM »
Use captive Dzus fastners. You don't want them falling out on the track. If you lose a fastner or two bad things can happen when the under car air tries to rip the pan off the car.

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Offline Bob Drury

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Re: Belly pan skin
« Reply #3 on: August 28, 2012, 09:34:43 PM »
  Clay, on my step pan (classic fuel altered coupe) after I install the hardware, I use RTV silicone over the top of the fasterner, just in case.
  Four or five years ago it was so rough on the courses that people were breaking suspension pieces, and unless every thing is kept in place by Bonneville Loctite, it can and will depart the vehicle, and probably ruin someone elses tire or tires.           Bob
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Offline Clay Pitkin

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Re: Belly pan skin
« Reply #4 on: August 29, 2012, 04:59:35 PM »
What kind of car? how wide is the frame etc. A two piece belly pan is not difficult to fab. Dzus fasteners are the most common. Sheet metal screws are a nono.

The car is a 1996 Geo Metro Hatchback.

As far as width not sure, I am not with the car right now, as far as length its about 12' long.

TIA
Clay
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Offline kiwi belly tank

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Re: Belly pan skin
« Reply #5 on: August 29, 2012, 06:39:31 PM »
Aluminum comes in 4x12 sheets, should be big enough for ya.
  Sid.

Offline Clay Pitkin

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Re: Belly pan skin
« Reply #6 on: August 29, 2012, 06:44:39 PM »
Ok sooper!  :-)

What thickness would you go with?

Also, how do you keep it from coorision?

TIA
Clay
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Offline Jonny Hotnuts

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Re: Belly pan skin
« Reply #7 on: August 30, 2012, 12:19:04 AM »
Clay, too thin and you will need a significant amount of bracing or run the risk of having the skin ripple in dirty air and need more retention fasteners. Too think and its overkill, expensive and harder to do bends, compound or other.

If I was going to do an aluminum pan I would run, 1/32-1/16"; thats just a personal choice . painting and powder can slow the oxidation on the aluminum but eventually it will find its way in. I just did a 4'X32"X1/32" section of 308 stainless for the belly pan under my engine. Stainless is much more ridged and you can get away with thinner material and has better corrosion properties (OK, its heavier....but it would add weight really low).
Stainless in a pain in the tail but also is another consideration.

If the belly pan is flat I would give plastic a serious consideration for part or whole. A sheet of 1/16"-3/16" lexan or other polycarb would never rust and because it is clear, you could SEE salt lodged on top of the pan, tools-screws that were dropped and it would be neat to have. ABS sheet would also be a cool choice and comes in really nice colors.

Good luck and see you all soon!!!!

~JH




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Offline Bob Drury

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Re: Belly pan skin
« Reply #8 on: August 31, 2012, 11:59:06 AM »
  Actually Clay, aluminum comes in 3' and 4' widths and 8', 10' and 12' lengths.
  It is not sold in thickness by tape measture standards or gauge, rather sold as measurements in thousandths.
  You will probably want to use .090 or .120 minimum for a pan whereas for lets say inner door panels .063 would suffice.
  Hotnutz is so cheap he buys his as scrap beer cans and uses a steam roller (boy that shows my age) to crush them to the size and thickness his bad eye proclaims perfect...........
  By the way you will want a 5052 or simillar alluminum which can be easily bent without cracking.                      Bob
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Offline bearingburner

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Re: Belly pan skin
« Reply #9 on: August 31, 2012, 08:54:27 PM »
You have to think about taking pan down and putting it back up. 12 ft long panel of any gauge will be hard to handle. Think about smaller pieces with a step joint on the trailing edge of the leading piece. The step would be down and the trailing piece would slide into the step.

Offline Dr Goggles

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Re: Belly pan skin
« Reply #10 on: August 31, 2012, 09:16:52 PM »
If you have access to a hoist and also a laser level( or a dumpy) they may be useful. With the car on a hoist work out where you want to attach the pan, attach temporary "posts" which can be marked. Using the laser level you can get a map of how long the attachment points need to be, OR how much you need to contour the pan in order to attach it.
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Offline kiwi belly tank

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Re: Belly pan skin
« Reply #11 on: September 01, 2012, 02:47:52 PM »
Jeez mate, it's a Geo Metro, put it on two Harbor Freight engine stands & turn it over. Put a join in the panel at the back of the engine if you need to get in there. & yep, 5052 is the stuff to use. The thickness will depend on how much support you have for it to retain shape.
  Sid.

Offline manta22

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Re: Belly pan skin
« Reply #12 on: September 01, 2012, 05:44:54 PM »
Clay;

The key questions are how much unsupported length you will have and is it necessary to bend it or is the belly pan flat?

If it is flat, Alclad 2024-T3 is what I'd use; it's very strong and the Alclad coating gives it good corrosion resistance but a coat of zinc chromate on both sides will be even better. If you need to bend the panel, then half- hard 5052 is good.

If you have some stringers, etc., you can get away with pretty thin stuff-- 0.049" or 0.063" but if it is not well supported then something like 0.120 or more might be needed. Weight isn't a big consideration in LSR but thick aluminum gets expensive.

Aluminum isn't the only choice-- there is mild steel, stainless steel, or (choke) titanium.

Regards, Neil  Tucson, AZ
Regards, Neil  Tucson, AZ