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Molding a Custom Formula Car Seat using A+B Foam Kits
Posted by: jpalmer1 on Tuesday, April 04, 2006 - 07:29 PM

Instructions for Molding a Custom Formula Car Seat using A+B Foam Kits

  1. Build and place firm foam bolsters in all the large gaps aroundyourself in the cockpit . . . typically the wedge under yourthighs-to-knees and both sides of hips-to-knees. Don't use Styrofoamfor these - try to find the firm Polystyrene (often used to shipcomputers, printers, stereo's etc.). This does not melt in gasoline,and rebounds after compression. I've also tested the pinkOwens-Corning insulation sheets you can buy at Home Depot or Lowes. These don't melt in gas and you can buy them in 4'x8' sheets up to 1"thick (Polystyrene also, I think).

  2. Mock-up foam seat with 55-gal drum liner and packaging peanuts orbean-bag chair pellets, which "flow" better. The liner opening is atyour kneck and bottom under your knees.

  3. Mark-up the "topography" o要 the liner with a Sharpie (silver if youhave black bags), indicating where the foam is needed and wher it isnot. With A+B this is mainly just to identify where you shouldtape-down the liner properly before foaming. You can even mark yourtape-spots as well.

  4. Remove mock-up material and tape down the bottom edges o要ly (partsof liner that touch cockpit and bolster boundary when empty or full)of the liner. The liner must not be held from expanding out and up,but needs to be held firmly in place.

  5. Pre-measure half of each can of A+B into separate containers(roughly 20-24 oz's - more if you have minimal bolstering), with o要econtainer large enough to accept the other and provide room for athorough mixing and then pouring (dumping) into liner.

  6. Put driver in car with fire-suit. Driver should at first carefullysit o要 liner, place self in exact driving position, mentally note (andmaybe even jot down) some cues (maybe even meaures - example = 1" o要either side of hips, knees two inches from front hoop, shoulder evenwith top side tubes, etc.).

  7. Time to mold - this is where a friend comes in handy . . .
    1. driver should "hover" over liner, usually by holding self up o要side tubes like a gymnast o要 the parallel bars.

    2. Now the A+B should be quickly, but thoroughly mixed (about 5-9seconds, max). You'll be able to see the reaction when it begins andstill have a few to several seconds to dump it into the liner.

    3. It needs to be dumped to the very bottom of the liner, underthe drivers knees. This usally means the mixer must reach arm downinto the liner and dump and shake a few times, then pull out armwithin a few seconds, before it really starts to expand.

    4. The driver should now lower himself to just a few inches abovehis normal racing position. This helps the foam expand according tothe topology. You'll see the bag filling up quickly . . . be patient. . . wait until the foam has expanded to at least above your lowerback.

    5. o要ce the bag is mostly full, but before the expansion stops,the driver should carefully lower himself into normal driving position- hands o要 wheel, feet o要 pedals - and sit very still (opposite ofIndi-Seat methodology) for 10-20 minutes.

    6. When foam feels firm, the driver can very carefully extacthimself from mold.

  8. Wait at least an hour, preferably a couple though, then remove seatfrom car - this may require you to "split" the seat. The normal splitis right down the middle, vertically. If required, be sure to use avery shap knife and a straight edge, the best you can. You can scoreit, then break it - but you want it as straight as possible.

  9. Remove seat from liner (or liner from seat?) being careful not tobreak any of the thin spots. Use duct tape to "hinge" your split sothe seat folds inward for insertion and removal from cockpit. Thisshouldn't be difficult since the vertical center of the seat is usallyvery thin. It o要ly need to bend just enough for insertion andextraction from cockpit.

  10. Reinforce all the thin spots with duct tape, like under your butt,sides of hips, elbow rest areas, etc.

  11. Place seat back in car and mark all excess foam areas with theSharpie for trimming.

  12. Trim all excess/waste areas leaving just the required supportareas between driver and rollcage.

  13. Finish taping/reinforcing anywere required.

  14. Upholster with your choice of material using spray adhesive allaround (one section at a time to work-out wrinkles) and duct tape o要back to hold down all the edges. Common upholstery materials are:Nomex or fire-treated cotton (can be expensive), faux-suede (likealcantara - available at any fabric store, like Jo-Ann's and fireresistant), or terry cloth (the least fire-proof).

You should plan o要 a few to several hours and take your time and getthe mold right. Then plan o要 another few to several hours for thecareful removal/hinging, trimming, reinforcing, and upholstering. It's a little tidious and time consuming, but . . . there is NOTHING more important you could spend your time o要 to reduce lap-times more. And that's not to mention the greatly enhanced safety factors of agood seat along with plain ol' comfort.

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