Discussion in 'Finishing Techniques' started by SteveR, May 3, 2005.

1. May 3, 2005

SteveR

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The foam in my Pietenpol's seats is about 2" thick, and I think it is just typical foam rubber. It is nowhere near firm enough in my opinion. It is too soft, and you get bad, well, pressure points on long trips. I think a much more dense, firm foam would work a lot better. Any suggestions?

2. May 3, 2005

ohioflyer

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Steve,

Try using the grey closed cell foam commonly used in kayaks. Its used for seat padding that can be easily contoured with a grinder, as well as being great as a watertite bulkhead. Google minicell foam and you'll find tons of links on how to make seats and sources.

Ed

3. May 3, 2005

Craig

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Temper Foam

I used TemperFoam in my Duce - really comfortable. It, too, is about 2" thick, but fairly stiff. Conforms to your body contour after 5-8 minutes.

4. Mar 2, 2006

ZENO

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Every time I've had seat problems to deal with I go to a local upholsterer. He does custom work of all kind but these are the guys that have the different densities of foam you need.

I've done motorcycle seats with as many as 3 different layers of foam. i.e. 1 inch of soft stuff which interfaces directly with my kiester, 1 1/2 inch of medium firm for the majority of shock absorbancy, and 1 1/2 inch of firm to guard against bottoming out.

Comfortable? Geez, you could fall asleep on it. They're stuff doesn't cause perspiration, either.

Seriously, those are the guys you want to buy from. They know what they're doing.

5. Jul 24, 2006

IanJ

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Yep, I've done a few motorcycle seats (although never in layers like that, cool idea). I've done them with 5 and 7 lb rebond (looks like carpet padding but thicker). For an airplane seat that's not sculpted, I'd aim for 4-5 lb rebond. Over 5 is pretty stiff and would be uncomfortable. The layer idea warrants a serious look: 1" of 7-10 lb rebond, 1" of 4 lb, and 1" of lightweight foam.

Be prepared to spend a bundle on it, though. Foam is a petrochemical product, and it's all gotten insanely expensive just like anything else that comes from dead dinosaurs (doesn't even have the words "aviation," "marine," or "bridal" prefixed to it, which is the usual cause for something to be 100% more expensive than it should be). I just bought an admittedly large piece for a motorcycle project, and it cost $80, which is well below retail. That same piece cost$30 three years ago.

6. Jul 25, 2006

wally

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I have been thinking of hitting some local car junk yards. I am guessing I can buy seat foam out of a few otherwise shot seats for not much money. It should be the right firmness and with a little carefull shopping, perhaps shaped to fit my backside better than a flat piece.

It may be a while but I will report back on how I do.

From working on another project, an electric carving knife will cut some types of foam really nice.
Just a suggestion.
Wally

7. Jul 25, 2006

IanJ

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Yes! When I've done motorcycle seats, the indispensible tools are:

* foam adhesive (3M or similar)
* electric carving knife
* 40 grit (yep!) sanding discs chucked in an electric drill
* scissors
* staple gun

The trick with the sanding discs is to get several of them, and grind them down so you have one mostly sharp one (removes foam fast), one very slightly sharp one (shapes slowly) and one pretty much dull one (cleans up the surface). Only useful if you're shaping the surface, though. And definitely do any sanding disc work away from finished surfaces, that disc can shoot out of control quickly if you're not used to it.

The electric carving knife will be unusable for food once you're done with it, so get a cheap one from a thrift store. Don't push it to cut too fast, it's got a happy speed and doesn't work well over that speed. Don't try to use the carving knife for anything but cutting big chunks of foam -- for any fine shaping, use a sanding disc.

8. Jul 25, 2006

Nilsen

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9. Apr 26, 2007

Nilsen

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So here's the funny thing. About a year ago I posted to this thread ... I've learned so much since then but I guess I'm more cluless than ever.:depressed

I need to put a seat cushion in my Ka-6 (getting ready for my first flight). There are 2 different foams out there. The one I would have used a year ago is this:

http://www.aircraftspruce.com/catalog/cmpages/backsaverfoam.php

But a lot of people are using this:

http://www.aircraftspruce.com/catalog/cmpages/conForFoan.php

I only need something under my butt as my parachute is going to cushion my back. I'll need to trim it to size and will cover it myself, I'm handy that way. But anybody know which of the above choices is better?

10. Apr 28, 2007

dviglierchio

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I bit the bullet and bought Oregon Aero seat cushions. Very pricey but fabulously comfortable. The bottom cushion is several layers of different foams contoured to fit your butt.
I met a fellow in Michigan this year in a wheel chair because he slammed down a plane with a crappy seat cushion that did nothing for him. He swears a good cushion would have kept him out of the chair. Your choice.....

11. Apr 30, 2007

Peter V

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Add me to the foam composite camp, with one variation - the top layer extra soft stuff should be memory foam to contour to your derriere. Makes a big difference. Look for "tempur foam"

12. Apr 30, 2007

Nilsen

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Thanks for the responses. I got the "Confor Foam (formaly Temperfoam) from aircraft spruce. http://www.aircraftspruce.com/catalog/cmpages/conForFoan.php

I first ordered the 1" foam. It felt great but the part where my behind sank in didn't leave much extra room to give before 'bottoming out'. I ordered another 2" piece because I too have heard of people crushing a vertebrae on a hard landing. I hope the 2" will give me a little bit more impact absorption and still not be too thick. I looked into the Oregon Aero Seats but I don't have much room in my cockpit for something like that.

I've got to say this foam is great, great stuff. I might have too much now but it is so nice I know I'll find places to use the extra.

The stuff I got is medium firmness. It really does contour well. I have not tried the soft stuff but what I got seems pretty comfy.

Last edited: Apr 30, 2007
13. Jun 1, 2008

WurlyBird

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Spend the extra money for your seat foam. The wrong foam, as mentioned before, will compound the compression your back takes in a crash sequence. Energy absorbing foam will reduce the Gs your back feels where as carpet padding type foams will increase it. Also, most of the foams made from 'dead dinosaurs' will produce that fantastic thick, black, noxious smoke that can incapacitate you quickly in the event of a fire. In my opinion this is not one of the parts of your plane to be stingy on.

14. Apr 23, 2009

wsimpso1

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We just finished reupholstering all four seats for our store-bought airplane . We emulated the Oregon Aero seats, using Confor Foam and the softest upholstery foam we could find. So far, all three pilots are pleased tih how they sit...

The bottom cushion is blue and pink (Rubberite Cypress Sponge Rubber Products had by far the best price, two sheet minumum) , while the backs are just pink. I built jigs to cut wedges using the electric carving knife. We covered the seating surfaces with 1/4" of the softest high quality polyfoam (Upholstery Supplies, Leather Upholstery, Naugahyde, Upholstery Foam) we could find. The sides took 1/2" polyfoam to fill out the coverings (Airtex).

Now here was the neat part. 3M Fastbond 100 is designed for gluing foam pieces together. It is a waterborne neoprene adhesive that is easily repositionable, grabs over a couple of minutes, cleans up easy, is stronger than the base foam, and rubs right off of hard surfaces and your hands. The down sides are that it takes a spray gun to apply and it can take a while to get. We ordered through RS Hughes, and it took three weeks. Their usual customers buy 5 gallon pails, 55 gallon drums, and 277 gallon totes. When I went looking for a couple quarts, well, it took awhile.

Anyway, 3M Confor Foam in blue and pink, the softest polyfoam casing, and 3M Fastbond 100 glue.

Billski

15. Apr 29, 2009

mstull

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Our bodies don't have flat surfaces. One of the goals with seat design is to distribute the load over as wide a body area as possible. Yes, that can be accomplished with thick and/or expensive padding. But shaping the seat with curved surfaces is an ultimate solution.

Theoretically, if the seat is perfectly anatomically shaped, very little padding is needed. Obviously, different size and shape pilots and passengers need different shapes. So there's a limit to how anatomical you can make a seat that has to fit universally. But for your own homebuilt, you can shape your seat more ideally.

Another advantage of shaped seats is how they keep you secured. Most modern car seats have this feature in both the seat back and bottom. That makes the vehicle or aircraft feel more sporty, like you're part of the aircraft. And you can operate the controls more precisely in bumpy conditions, without having to pull your seat belts so tight or trying to hang on to something.

I did extensive experiments as I developed my first seat. All its composite parts were made on custom, curved molds. In addition, one of the parts is made with few enough plies so it would be self-conforming to some degree, like a canvas chair.

Another construction alternative is to start with a common flat frame, and put 2" of styrofoam on it. Hog out a rough shape, then sit on it with no padding until you feel spots or areas that cause pressure. Slip your hand under your body to mark the places that need more material removed. The more you do that, the more anatomical the shape becomes.