I have completed my leather cockpit coaming, after much frustration and consternation. I finally came up with a very nice looking result, and I believe much easier method than what others have done. Basically the procedure is, to take the correct lenth pipe insulation (Home Depot)(sections glued together) and using spray adhesive (3M Foamfast 74 from Grainger), glue leather to pipe insulation, install grommets, and lace onto airplane.
Leather is marked along edge
to make a glued hem on two
Spray on adhesive and then fold up hems on both long edges.
Next, punch holes and install
grommets. I used
size 00 (black oxide finish)
Next, mask-off grommeted edges and far ends of leather, and suspend foam with copper pipe, to facilitate spraying of glue.
After spraying glue on leather and foam,
wait for tack, then carefully drop foam
down on to the center of leather, rolling
in each direction to get nice wrinkle-free roll.
Let this dry for about 1/2 hour
Next, split polyethelene tubing and apply to raw edge of aluminum. I used a few pieces of safety wire to hold it on, covered by black duct tape.
I did a trial fit at this point so I could get
a final length and sew it into the circle
Now locate and drill 3/16 holes for lacing.
A slight bit of wrinkling is evident in the curves
, but it is very uniform and goes good with
my "distressed" leather. I used round leather
lacing cord I bought on line from Leather Cord USA.
Lacing, about 1/2 way done.
Originally my coaming metal
stopped at the pilot back rest,
but I added a piece to get more
of a true "pit" look.
The width of the cut pieces is 6-1/2". Then spray glue a 1" wide strip on each long edge, wait for tack, and fold-up to make a 1/2" hem. I elected to glue these hems instead of sewing them, because a lock-stitched seam will not stretch as much, and you need that. Find center of overall length, mark-out hole patterns from center. Punch holes, but not all the way out to the end. Now install grommets in the holes that are punched. Mask off grommeted edges, and also about the last 4 inches of the far ends. Insert 1/2" copper pipe into pipe insulation, spray glue both the leather and pipe insulation (avoid same last 4 inches). Wait for tack, and CAREFULLY lay pipe insulation down in exact center-line of leather. Roll pipe insulation back and forth to "pick-up" and stick to the leather. Press all areas by hand to make sure good you have good contact. After it dries do trial fit on airplane and determine exact location of last sewn seam. I noticed mine shrunk just a bit during the gluing process, so it is best to leave both ends a little long until this point. I actually had to glue an additional extension onto my pipe insulation to make it come out right. Now cut to finish length and sew into loop. This is the reason you don't want to initially glue all the way to the end. You will need these last few inches loose in order to get it under the sewing machine to finish-sew. Now that you have made that last sewn seam, you can go back and lay-out those last few holes that you did not punch. You may have to "fudge" the hole spacing to get it to look uniform and finished. Install those last few grommets. Now you can glue the remainder of the "sausage" together near the last sewn seam. This is trick with this contact cement, because as you know, the glue must be applied to both surfaces and allowed to tack-up, before mating. You may have to use a brush to apply, and insert pencils or sticks in between the leather/foam, and then remove after tack and carefully lay together. Tricky because yu only get one chance at positioning. Make sure you get glue on all the surfaces otherwise you will end up with a bulge or wrinkle. I got a little of this, but oh well. (Now you know one of the flaws).
One more thing. On all of the sewn seams, go back and sew down the "wings" flat to either side, so excess seam leather lays flat and does not form a bulge.
Hope this helps. Let me know if you need more.
Poplar Grove, IL.