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Making new Conform Foam seats

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Posted (edited)

After placing a few 'Want to Buy' ads for Kitfox seat covers with no response, I decided to make new seats for my Kitfox 4-1200.

Aircraft Spruce and other Aircraft supply shops sell Conform Foam for aircraft seats. Oregon Aero, arguably one of the highest regarded custom aircraft seat manufacturer, also uses this foam. Reading about all the benefits convinced me to use Conform Foam vs. the standard upholstery foam available at craft stores, etc. Conform Foam is a viseoelastic, electrometric, open cell urethane foam that breathes, molds and shapes to your body to absorb moisture and distribute your weight evenly over its entire surface. This eliminates uncomfortable 'hot spots' and pressure on your spine or tailbone to help you sit comfortably for an extended period of time. This foam also offers superior spinal protection in a hard landing or crash, ie. the more weight or pressure applied, the more resistance increases so you do not 'bottom out' like you would with standard foam.

A word of caution, the terms 'Memory Foam' and 'Temper Foam' are often used interchangeably even though they are separate products with very different characteristics. Conform Foam is not the same 'memory foam' typically sold as a mattress topper (I tried that in my KF3 seats and they bottomed out terribly). Viseoelastic foam was initially developed for the NASA space program, and the US Military has tested for it's benefits as well. For a good overview of Conform Foam and link to the US Military test whitepaper that concludes what combination of Conform Foam foam firmness and thickness provides optimum comfort and safety, check out this site: http://www.cumulus-s...g.com/e-a-r.htm

Or you can go directly to the manufacture's info:

CONFOR Foam Data Sheet

CONFOR Foam Brochure

Some good tips on seat construction here: Using Specialty Engineered Foams in Seating Design

Only problem, Conform Foam is expensive as hell. I found a couple other manufacturers supplying their own brand of viseoelastic foam, including one small supplier Dynamic Systems, Inc. that sold larger sheets of foam in different firmness and thickness at discount prices. Like Conform Foam, SunMate Foam meets FAR 25.853, FAR 25.855 and CAL 117 fire retardant specifications, and I found exactly what I needed for my project in their cheap overstock inventory. I bought (1) sheet of 32" x 37" x 1" Medium Firm, (2) sheets 16" X 18" X 1/2" Medium Soft and (1) sheet 16" X 37" X 1/2" Soft. Enough to do (2) 2" thick layered seat cushions and (2) 1" thick back cushions, all for $48 + $16.10 S&H. That's only a couple bucks more than a single 16" X 18" X 2" seat cushion from ACS at $45.75 + S&H (ouch!).

Rec'd the foam in timely fashion and was pleased to see they used some misc. pieces to support the folded foam sheets in the box during shipping. Great, I will cut these and now add side bolsters and lumbar support to my new seats! Started the project yesterday and will post progress as I go. Here's the start...

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Edited by dholly

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Posted

First thing I did was make up some templates for the seat cushions. This one for shaping the contour of the seat cushion to the curve of the seat pan at the rear. You can see it assumes the use of a 2" thick seat cushion.

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I marked the rear point on the seat pan and noted the 14-3/4"L template wasn't long enough to reach the front edge of the seat pan. A quick measure showed another 3" to the front edge, therefore, the lower seat cushions need to be at least 17-3/4" long front to back.

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Then I made up the actual full size seat cushion template. Of course, the other side is simply a mirror image.

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Took one last look at my pretty foam and a deep breath, then grabbed the electric knife...

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Posted

Short of using a commercial spray gun applied adhesive made specifically for foam, my research suggests 3M's #74 Spray Adhesive for Foam is the very best. Supposedly available at HD and Lowes but mine didn't stock it, nor did any of the small or chain crafts stores in my area. I did find another 'Super Strength' spray adhesive for foam at a True Value hardware store. I opted to try it as it was a high strength adhesive for use specifically with foam, mineral spirit (not water) clean-up, and re-positionable for an hour or so after application. Once dry, it seems to be working good though time will tell.

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I sprayed each mating surface, let get tacky for a few seconds then layered up the lower seat cushions.

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I took one of the long scrap pieces and made a crude jig to see if I could cut it into two smaller wedges for angle bolsters.

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If they don't work out, I'll try to run another piece through my band saw with the table set on angle.

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Pretty rough, but will wait to see how they shape up after sanding with the die grinder.

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Posted (edited)

Here you can see I elected to follow the taper of the seat pan for the outside edge of the seat and back cushions. Hopefully give a little more butt and hip room.

Got both seat back cushions out of the remaining 1" medium firm sheet material with -zero- waste. smile.gif

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I carved the general shapes and rough tapered the edges with the electric knife. Worked fine, but got gummed up quick when cutting through adhesive after gluing the seat cushion layers together. Quick wipe with odorless Mineral Spirits and back to business, no biggie. You can see the (3) layer build up for the lower seat cushion, 1" med firm on bottom > 1/2" med soft in the middle > 1/2" soft on top.

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Haven't decided on fabric or vinyl, colors etc., however, I do like the shape and look of these best and am leaning in this direction.

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More to come...

Edited by dholly

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Posted

damn, that is going to be one comfy seat! A friend had the seats in her Cherokee six done and WOW did that make a difference!

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Posted

I would highly suggest sculpting in some lumbar support...

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Posted

Just wondering Doug, was the wife out of town when you turned the kitchen into your workshop? LOL. Looks like you are going to have some nice seats when you get done. I may copy some of your ideas. Take care, Jim Chuk

I would highly suggest sculpting in some lumbar support...

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Posted (edited)

Hi Jim - like you I am blessed with a very patient wife, although, she did kick me out of the Living room. smile.gif

I was able to try the die grinder on one seat cushion last night and was amazed at how easy it was to sculpt the foam. You would think a rough grit would grab the foam, and it does to some extent if you don't keep the correct angle to the work piece, but it works really well.

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Then I wrapped a finer grit sandpaper around a longer scrap piece of T&G flooring for a final smoothing by hand. Easy, peasy and you can see the result below. Spent only about 10min. on this phase, with some waiting for the compressor to cycle. So far, so good!

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Larry - if you count up those extra long, square foam pieces, I have (3) 2-1/2" X 2" X 37" pieces which is enough to do side bolsters on both seat and back cushions, and (1) 1-1/2" X 2" X 37" that is destined for a lumbar support. At least, that is the plan. If I play my cards right and cut straight, that last piece should be enough to make (2) 3/4" X 4" X 18" lumbar supports which should be just about perfect. The Oregon Aero site says that a 3/4" thick lumbar support is sufficient to naturally roll your hips forward into the proper spinal position, but any thicker becomes noticeable and intrusive. Remember, it's really not there for any kind of 'support', it's there to roll the hips forward. There is a small lumbar hump molded into the seat pan which should come through a thin back cushion, and there will also be a thin 1/8"-1/4" layer of non-technical foam over the cushions I am making now which is necessary to form the pleating in the center. Hoping that works out good.

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Instead of leaving them straight alone their entire length, I plan on sculpting the seat cushion bolsters to the outside edge toward the front, idea being that it should help prevent your legs from being forced together in the rather uncomfortable 'nutcrusher' position.

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Pretty good use of materials so far, here's the total waste after cutting the seat and back cushions.

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Edited by dholly

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Posted

I'm very impressed with the shaping and finish you've achieved so far. Now you've got a sideline business to fall back on. Are you going to sew the cushions yourself too?

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Posted

Very nice Doug! I redid the pilots half of my sling seat with two layers of the Conform foam. Just glued it to the old yellow stuff and sewed it back up. Made a night and day difference from the 20 year old coach cushion foam was in there. Figured the weight penalty wasn't worth doing the entire seat since I rarely fly with a passenger and when I do it's not for very long. The only negative I've had with it is when it's cold that foam is hard as a rock until it takes the shape of your butt.

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Posted

Joey - Like you, I figure anything will be better than my old cushions! What firmness and thickness did you use? The following is copied from one of the links in the original post:

Introduction: Glider flights may require the pilot to sit for many hours in a cramped cockpit that allows little movement. Experiments were undertaken to evaluate the performance of different seat cushions in a glider simulator. Methods: Subjects were male glider pilots with a maximum height of 1.85 m (6.07 ft) who participated in simulated glider flights lasting 1.5 h. A pressure-mapping device was used to determine cushion performance. By analyzing 15 subjects we calculated the pressure threshold for comfort, above which fidgeting provided objective evidence of discomfort. To determine cushion performance relative to that threshold, 20 other pilots then sat on 5 different viscoelastic foam cushions in the simulator. Results: The time-averaged peak pressure below which no discomfort-induced fidgeting occurred was 8.8 kPa (1.28 psi). The highest peak pressure at which discomfort could be relieved by fidgeting was 11.0 kPa (1.6 psi).
Of the five cushions tested, pressure remained below the discomfort threshold for almost all subjects for only one type of cushion. Discussion: The best-performing cushion had a layered structure made up of approximately 25 mm of Confor C47 (green) foam with an overlay of approximately 13 mm of Confor C45 (blue foam).
The other types of energy-absorbing cushions tested, either with or without a softer top layer, are unlikely to provide comfortable seating solutions for most pilots. We conclude that satisfactory cushions are available for this application and that they can be objectively evaluated using this technique.

After I read that the green (firm) Conform foam is really hard in cool Wx, I changed my layers for what I hope will be a more appropriate and comfortable mix here in the northeast. Mostly what I really want though is the extremely high energy-absorption characteristics to help protect my ass (back, really) from a hard landing. When you move beyond the comfort studies, energy impact studies have shown Conform Foam dramatically reduces the likelihood of back injury if used in adequate thicknesses. At 2" thick, in the firmness layering I used, it is not quite optimum for my weight. Never the less, these cushions will offer significantly better safety characteristics than I had so $50 well spent IMHO!

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Posted

I'm very impressed with the shaping and finish you've achieved so far. Now you've got a sideline business to fall back on. Are you going to sew the cushions yourself too?

Hi Paul - the foam is not hard to cut and sculpt, easier than I expected and much better workability than the standard sofa cushion foam. Since my sewing experience is non-existent and my dear wife actually laughed out loud for several minutes when I asked if she wanted to tackle the covers, sure looks like I'll be supporting my local business community on this one. :)

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Posted

I am seriously digging those new seat cushions! After about an hour in my seat I am getting fidgety and the last flight to the lodge that took almost 4 hrs, my back was down right pissed off at me. I wonder though at -30 how long it will take for the heat from my butt to get through the snow gear and into the seat foam to soften them up so I am not sitting on a brick... I would really like better cushoining but I dont want to raise the seat height either...

:BC:

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Posted

Hi Paul - the foam is not hard to cut and sculpt, easier than I expected and much better workability than the standard sofa cushion foam. Since my sewing experience is non-existent and my dear wife actually laughed out loud for several minutes when I asked if she wanted to tackle the covers, sure looks like I'll be supporting my local business community on this one. :)/>

Doug,

Thanks for the detailed post! I'm about to tackle this myself, so I'm glad to follow your lead.

I broke my back in the military, and I have a lot of nerve issues that make my tailbone hyper sensitive. Because of that I have tried about every cushion shape and thickness to help long drives or flights. The design that helps me the most has the back center cut out so that your tailbone and spine are not holding you up, your gluts are.

So, I was wondering if you made the main cushion out of the Confor foam for heavier pilots, and then cut out the back center, then filled it with Confor foam for lighter pilots, if it would work in the same way?

My spine has been injured so long that I can't remember what body part hurts, on normal people, when sitting for long periods. However, I think it is pressure on the tailbone.

I'm with you on the sewing! I bought a special sewing machine so I could cover some seats on a different plane and after a lot of wasted time and horrible looking covers, I took them to a local professional! It is definitely an art, that takes a lot of practice!

Your seats are looking great!

Thanks again,

Ron

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Posted

Doug,

Do your seats slide forward and back in the Avid Plus?

Thanks,

Ron

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Got another hour and a half in on the seats tonight and I am real happy with the progress so far. This has taken way less time than I anticipated.

Finished sculpting the bottom of the right seat cushion and got a nice fit...

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There are a lot of curves and angles in the seat pan to mold to, another good reason for a professional to sew up the covers. smile.gif

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Here's the seat and back cushions in place, laying nice and flat.

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Time to add some bolsters. I didn't care for the results with the electric knife and jig board method so I tried using a band saw. Wowee, cuts like buttah! Very nice cuts even with a wood blade, this is the way to go.

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I cut all the scrap shipping pieces into shape for seat and back cushion bolsters, had plenty left over to make some lumbar supports. I am sooo happy the foam co. put those pieces in the box for shipping.

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I cut the bolsters and lumbar supports a bit proud and did not glue them on. I'll let the cover guy use his commercial glue to stick those on real good and do whatever finish sculpting he deems fit, ie. still need to taper the front of the seat bolsters and cut 45's where the seat and back bolsters meet. I figure it might be best to leave the cover guy as many options as possible. Will have to do a test 'sit' to find the right lumbar support placement and mark before dropping off at the cover shop.

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Posted

Ron-

If you go to http://www.oregonaero.com/, on the left side of the Home page under Products, click through all the links under Seating Systems and Portable Cushions. Lots of info on the best pain free sitting position for us non-damaged folk. The video about rolling hips forward to take pressure off the tailbone sounds like it might help you, although I see no reason why you also couldn't incorporate different foam firmnesses in you own custom cushion. Heck, that's what I did. The only downside I see to the Conform or viscoelastic foams is one might want two 'seasonal' cushions for summer and winter.

The Avid+ seat cushions are stationary, no slide rails like the Magnum or Highlander unfortunately. The seat backs, however, tilt forward and are easily re-positionable which definitely is nice. Just pull the pins and re-pin where you want it, no added weight with this system. tongue.gif

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Posted

While you are making cushions, you might consider making the pilot's about 4"thick on the seat and about 2.5 on the back. This arrangement allows pilot and passengers shoulders to offset making for a much more comfortable seating arrangement for two big guys.

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Indeed, an excellent idea, thank you. I did read that somewhere as I was formulating my plan of attack and planned on doing it. Ultimately, however, I decided to make one extra seat and one extra back cushion to use as boosters. Plain Jane and nothing fancy but, because each is a mirror of the other side, flipping them gives me the ability to use one or more on either side in any combination. The flexibility appealed to me, as does the symmetrical look of nice, even cushions when not in use.

:beerchug:

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Posted (edited)

Indeed, an excellent idea, thank you. I did read that somewhere as I was formulating my plan of attack and planned on doing it. Ultimately, however, I decided to make one extra seat and one extra back cushion to use as boosters. Plain Jane and nothing fancy but, because each is a mirror of the other side, flipping them gives me the ability to use one or more on either side in any combination. The flexibility appealed to me, as does the symmetrical look of nice, even cushions when not in use.

:beerchug:/>/>

I want to make slip-on seat covers because I hate sitting on leather - which foam would you use for an insert for a 1 inch seat pad and 1/2 inch back pad? Would you split the 1 inch into two layers of different foams?

ED in MO

Edited by Ed In Missouri

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Posted

Ed - other than refer you back to the study i linked earlier, I can't say for Conform foam. Never saw any manufacturer guide on that. On the other hand, I used the Sunmate brand viscoelastic foam and I did find guidelines on their website (I provided that link earlier as well).

SUPPORT PRESSURE SELECTION

SunMate cushions are available in 8 different degrees of pressure support: Extra-Soft, Soft, Medium-Soft, Medium, Medium-Firm, Firm, Extra-Firm and Hard. This provides a wide support range for any body weight or special weight-distribution need. The SunMate formulation can also be customized to meet special requirements.

Find out which cushion is right for you HERE.

:beerchug:

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Posted

Well I took the seats back to the upholstery shop to see if I could get a thumbs up for my efforts to date. He said it was a good start, but suggested:

1.) reducing the height of the side bolsters from 1-1/8" high to 3/4"-7/8" high.

2.) putting the seat pan back in the plane and sitting on the new cushions to find the most effective lumbar support thickness and location.

3.) adding thigh support along the front seat edge. I normally don't find this very comfortable in cars due to my rather short legs (30" inseam) but I'm glad I tried it.

So back in the shop today I cut all the side bolsters down to 7/8" and added 3/4"H x 5-1/2"W lumbar support, with the lower lumbar support edge located 1-1/2" above the seat cushion top. It was very surprising how just little movement up and down causes your seating position to go from seating bliss to immediately uncomfortable. Don't skip this step or attempt to eyeball guesstimate, well worth the time!

After sitting for nearly an hour testing out a few different configurations, I decided to add full span thigh supports. I found 7/8" high was comfortable so I shaped to match the height of the side bolsters. I found the thigh support helped hold your legs together (but not too tight!), actually more like it helped keep them from splaying too far apart. It eliminated having to make any physical effort to keep your legs together which should be much more comfy flying with a passenger. Interesting to note too, that the current Kitfox Model 7 seat is 1" thick under butt and 2" under thigh. Obviously, they like the thigh support idea as well.

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I did screw up the bolster mitres on the pilot side, cut too short... grrr... left the other side for the expert. I am down to only one of the long scrap shipping pieces left, need to figure best way to use it on the top seat cushion. Played around with the 'sunken' back cushion look, kinda like that. Will need the expert's input on fixing the goof first.

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Got to pick a covering material now. Leaning toward Ultrasuede rather than vinyl for better durability and breathability. Much easier to keep clean than fabric, and being softer, thinner than vinyl should allow the butt to mold to the foam better. So... French stitch or piping? Solid colors or patterns? Any color suggestions for a yellow plane with orange powder coated frame?

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Posted

Doug,

 

Those look really nice but I think they need to be tested before you use them.  If you want to send them up here I will fly the first 40 hours off of them for you. :lmao:

 

 

Indeed, an excellent idea, thank you. I did read that somewhere as I was formulating my plan of attack and planned on doing it. Ultimately, however, I decided to make one extra seat and one extra back cushion to use as boosters. Plain Jane and nothing fancy but, because each is a mirror of the other side, flipping them gives me the ability to use one or more on either side in any combination. The flexibility appealed to me, as does the symmetrical look of nice, even cushions when not in use.

:beerchug:

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Posted

Been a while so I better post an update. Finished everything and sent the seats off for covering. Pics show the work I did which saved a considerable amount off the do-it-all price quotes from the upholestry shops in my area. Aside from the ca$h savings, I feel like time well spent because I got the safety foam and had an opportunity to do several test sits, etc. and have confidence that they will be comfortable at least for my butt. I did add a seat wedge per the Oregon Aero design to roll hips forward, it really did make a noticable difference over just a simple back bolster. FWIW, I also put up a pic of the spray adhesive I ended up using. Very tenacious stuff, the original glue I tried was garbage in comparison.

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Posted

Looks good Doug!

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