Disaster struck

[rufi0h]

While installing the final piece of trim on my galley hatch we broke one of the supports. The whole hatch doesn't fit right anymore. This is the third galley hatch that I have built and I am now quite annoyed and have no idea where to go with this.

I guess what I am asking is does anyone have any suggestions or advice for me. I am thinking about taking it to a machine shop and getting someone to build a aluminum frame for me. It would be a shame because I have built everything by myself so far and this is my first build ever.

Here is an album of the devastation.
http://imgur.com/a/o185u

[Rainier70]

I haven't built a TD, so take this suggestion for what it is worth with that in mind.

It looks like your curved side supports are solid wood --not plywood. If it was me I would take the curved solid wood pieces off. Trace one onto a sheet of plywood. Repeat that tracing until you have enough plywood pieces of that shape to make new supports from. Jigsaw the pieces out. Take your plywood curved pieces and glue and screw them together to make your curved supports. Probably about three or four pieces of 1/2 in plywood glued together should make some good supports that won't break as easily.

Good luck!
Cindy

[absolutsnwbrdr]

Cindy nailed it. Plywood has the grains of the different layers alternating directions, which gives it the strength needed.

[rufi0h]

Cindy nailed it. Plywood has the grains of the different layers alternating directions, which gives it the strength needed.

So the Plywood supports is going to be stronger and prevent the spring back from attaching the plywood cover to the frame?

[bobhenry]

Engineered floor system rim board was what I cut my 4 ribs out of. It is a long boring exercise and requires a couple stand by jig saw blades but they have proven to hold up in the test of time. No warp no spring back and strong enough to stand up to anything.





In this picture the 2 outboard ribs are yet to be installed. I was playing with my self leveling shelf at the time

[CarlLaFong]

All of the builds, that I have followed, use, at least four curved ribs. Also, if there is room, make the end ones as wide as you can and still clear the cabinets. In other words, instead of a bent stick, make then look more like a 1/3 moon. Much stronger. And , yes, don't use solid wood. Guaranteed to fail

[Nobody]

Yeah, I know most folks want to build (hatch included) as light as possible. I don't think the hatch is any place to skimp on strength. It cost me a little more but I bought a sheet of 3/4" cabinet grade birch plywood to cut my hatch ribs from. Those ribs are 11-plies with the grain in each ply running perpendicular to the next. That's a lot of strength to resist twisting, warping, & splitting. I also used 6 ribs rather than 4. Those 2 extra ribs added maybe 3 or 4 # of weight to the hatch but I couldn't estimate the extra strength. The cross pieces for hinge attachment (both on the hatch & the TD roof frame) are solid 1x3" (actual dimensions) oak. I made my ribs approx 1.5" in depth (height) & they're notched to fit the cross piece at the top (as is the oak cross piece). I cut the 1.5x1.5" bottom cross piece from clear spruce & it also is notched (dadoed??) to accept the rib ends. Also placed spacers between each rib at midway point between top & bottom. All joints are screwed & glued with appropriate support pieces placed to accept the 'T' bolt locking mechanism, & the surface mounted tail, turn, brake lights. My hatch is approx 51" from top to bottom thru the curve, & was covered with 2 layers of 1/8" luan (bent cross ways, with the grain). Had to add approx 3" piece at bottom but that area contains the hardware supports so it was no problem. Since I was using 4x10' 0.40" aluminum skin I had to do a little creative 'joinery' near the bottom of the hatch but that worked well & has not been a problem either with leakage or strength.

Dry fitting the rough cut ribs -


Hatch frame fitted, glued & screwed; supported at correct attitude & waiting for glue to dry -


'Finished' ribs & final 'dry fit' after glue & screw -


Ready for aluminum skin, trim, hardware, etc. -


One shot of the rig ready to roll -


Oh yeah, I had enough of the birch ply left for the 2 counter shelves, the folding table attached, & the side table-

[asianflava]

Two quick observations, you need thicker (vertically) ribs and you need more of them.

[KCStudly]

I used solid wood, but I miter cut them across the grain and butt joined them with glue and biscuits (plate joinery) so that the stress runs with the grain, not across it. Time will tell.

The way that you laid out and cut your ribs has the grain running across the short distance making the ribs very weak.

Also, with only one screw thru the rib into the cross piece, the whole assembly is much more likely to twist. Counter sunk screws can split the wood, too, if driven too far; consider investing in a Kregg pocket screw jig.

The knots don't help either, they add weakness.

So, better materials, more ribs, deeper ribs, improve fit and joint type for good solid glue joints, and remember to glue and screw.

Life is a learning curve.

[Miriam C.]

Yep, replace it with plywood laminated. If you lock the hatch in it will naturally fall into place!

[Gage]

The way you built your hatch, it will always give you trouble. Build it the way that it's been noted in the above post. You'll have no future problems. I used 3/4" Popular for my spars.

[Mary C]

I 'm not disagreeing but, you might be able to salvage some of what you have. It looks like you have possibly twisted the hinge, I was building a desk once and the support on one side broke under the weight and it would not fit after that and found that the hinge was my problem I took it off and put it on a very flat and even glass table and yep it was twisted a little out of shape. after a good 30 minutes with the hammer and pliers I finally got it straight. Sorry you had this problem. Good luck and remember this is a learning experience and keep it light and fun because it is building for fun. sounds like you have lots of people on here to help.

Mary C.

[rufi0h]

Thank you everyone for your replies. I am going to build the next ribs out of plywood and laminate them together. Now the hard part of trying to salvage my Aluminum that is stuck on there pretty well with contact cement.

[Roo Dog]

Rufi,

We were cowards and went for the welded ally frame and skin.

RD

[CarlLaFong]

Thank you everyone for your replies. I am going to build the next ribs out of plywood and laminate them together. Now the hard part of trying to salvage my Aluminum that is stuck on there pretty well with contact cement.

Peel it back a bit and pour a bit of lacquer thinner between the skin and the ply. As it loosens, spread it further apart and dab more thinner in there with a brush. It will come right off.If you have a spray gun, you can spray the thinner, outdoors, of course