Most Important Project of My Life

[Thomas Ghesquiere]

I'm back on this forum after a one year break. I retired and moved from Fort Worth, TX to Satellite Beach, FL. My parish in Fort Worth is in construction on a new church building with seating for 750 people. It is looking wonderful and they are hoping to bless the building in April '09. The pastor asked me to do some research to find Honduran mahogany beams for the cross. We are talking about a 12'x10"x8" vertical beam and the horizontal beam is 8'x10"x8". I talked to one wood distributor and he advised that instead of solid beams I should laminate 1" wood boards (8) to get the thickness I need. He told me even if I could find 8" x 10" beam material it would be subject to warping unless it was kiln dried absolutely right and the cost would be prohibitive. When I communicated this information to our pastor he asked if I would be willing to come back to Fort Worth to assemble the beams and make the cross. (Most Important Project of My Life). A sculpture of the body of Christ is being carved and will be integrated onto the cross I will build. The cross will be done in a distressed finish. Honduras mahogany is desired because of our mission connection with Honduras.
Do you guys agree that layering up boards is the right answer?
I was thinking of using dowels in addition to glue to keep it all together. What do you recommend to keep the indoor mounted cross strong and true for many years? Any other suggestions are greatly appreciated.
Thanks, Tom

[John Keeton]

I vote for cabinet grade veneered plywood. Much more stable, lot less cost, easier to get structural integrity, and easier to affix some sort of fixation of the final piece. With the appropriate plan and construction method, I doubt anyone would be able to tell the difference.

[Jim Becker]

Laying up something of this size to create a solid beam of mahogany is going to be 1) very, very, VERY expensive and 2) very, very heavy. An alternate construction would be to carefully build the components as "hollow", using mitered edge joints to mask the fact that it's a construction, rather than solid. You would then be able to do any mild distressing you desire, just taking a little care with the edges. Because such an item is going to be at some distance from those who view it, you have some breathing room when it comes to "perfection", too.

[Thomas Ghesquiere]

Jim, I agree with your suggestion. I was also considering building a 'box' cross that would be hollow inside. I sure appreciate the suggestions, you can appreciate how important this project is to me.

[Ted Shrader]

Thomas -

I agree with the other suggestions that you built a hollow form to save weight. Something that large will be very heavy. I recommend solid sides and front and use available materials for bracing inside. That way you will be able to use the Honduras mahogany for most of the construction. The addition of the sculpture on the front allows you to make a fairly simple cross and distress the finish as desired.


A little background on my experience with this: . . .
I made a cross, much much smaller (78" x 56" x 2"), using solid oak for our church. An oak tree had been planted as a memorial to a girl that had died some thirty five years previously. The tree had to be removed to allow room for an expansion to the church. The family understood the need for the expansion and was very pleased with the idea of using the wood from the tree to continue the memorial in the sanctuary.

The solid oak cross, much smaller than the one you intend to build, is pretty heavy. (Don't have an exact weight.) It was mounted using a french cleat lag bolted to rear wall of the church. That allows the cross to stand out from the wall about 1½" giving a nice shadow line.

Thomas, you are correct about the importance of this particular task. Since you will be involved from the beginning and have sufficient time to plan, you will be able to construct a suitable piece - both in appearance and in stable construction.

PM me if you need further details.

Regards,
Ted

[Lucas Bittick]

Unless it is balsa wood, any 8' beam is going to be heavy! I am always surprised at how heavy wood gets with seemingly small increases in size. Even if mahogany wood were not expensive and subject to warping, I think Jim's suggestion of laminated plywood is prudent just based on weight/safety. Not to mention, it probably would be more durable in the long run.

Don't forget to post pics of the project-- I am curious to see how it turns out.

[Ron Bontz]

I was just curious if there is any reason you could not use lock miter corners to hide the end grains on a box beam with 1" thick squares used inside to fasten the beams mechanically as well as the sculpture? Lots of wood clamps on this one.:) Good luck.

[Ron Bontz]

Sorry. I missed part of the replies.:o

[Ron Jones near Indy]

Mr. Becker nailed this one! Excellent advice.

[Peter Quinn]

I would go one step further and not use any solid wood at all, nor mahogany plywood. I would build the cross assembly as a torsion box of sorts, then carefully skin each face with 1/8"-3/16" honduran mahogany veneer. Solid wood construction for a non load bearing application is if nothing else a shameful waste of a scarce resource. With a plywood core you can accommodate attachment points with blocking and control your wood movement. I would start with the ends of each cross member, glue up oversized and flush trim, then glue up the sides, then the faces front and back. Time consuming but simple.

One problem with a hollow solid wood box construction will be the four ends, two on each cross member. How will you fill these ends to accommodate wood movement in both directions? A floating panel attached like a box lid would work, and could be coved for decoration and to hide any minor gaps as the wood moves. Otherwise a thick saw veneer solves these construction issues assuming you have the capacity to produce the veneer or have access to the equipment to do so within your community.

I have made hundreds of small crosses for my church's retreat program (6"X10") using a half lap in solid wood. I imagine this would be possible to recreate using 16/6 material or similar laminations, I just can't see the point to create a monolithic cross as a display piece.

[Rick Potter]

Since the mission ties are in Honduras, could someone there possibly ship you some local wood? That would make it even more appropriate.

Rick Potter

[Clisby Clark]

I built a smaller cross for our church a few years back from oak and mahogany. It looks really good and I'm very proud of it, but I sometimes wonder if I should've not made a pretty cross and instead made a cross of rugged construction like Jesus was actually crucified on. I still may make an old rugged cross to hang across from the nice one-just to remember what it was really used for.

[Steve Jenkins]

Where are you going to build it? Do you need a place to work? I'm a ways from Ft. Worth but if you need shop space it might be worth the drive. I'm just east of Mckinney.

[jeremy levine]

I have a thought , box in or veneer a Parallam beam. You are dealing with some large spans and weights a parallam ( mirco lam or glue lam ) beam might be the way to go vertically ,and a pure box horizontally with all the weight on the vertical.

[Lee Schierer]

I agree with the hollow concept. I like the mitered or locked miter corner ideas. A solid wood cross of that size will weigh between 350-600 pounds depending upon the grade of wood, plust he weight of your carved image. Make sure your structure for supporting the cross will hold that much weight. You'll also need a crane to lift it in place. You might be able to leave the back open to lighten the weight and make attachement of the image easier.

[Ed Bamba]

We have a huge cross with a carved (I think) figure of Jesus attached to it. It hangs from the ceiling behind the altar. I really never looked close enough to see how it is made. If I get a chance this Sunday, I'll try to get a closer look.

How is the cross going to be displayed? That may come into play when it comes to how it will be made. To me, it needs to be stout enough so it will hold together for the entire time it is being displayed. You may want to ask if there is an insurance liability if it isn't at least designed by a certified engineer. I know it sounds paranoid, but it may be a concern that hasn't been brought up yet.

Would like to see the finished product; I sometimes wonder what it would be like to have something I made, displayed in our church.

Ed

[John Keeton]

Some really good ideas are developing. When I first posted about using veneered ply I missed the part about wanting a distressed finish. The box idea has flourished in the discussion.

Would it be feasible to build the structure from ply substrate, with all of the necessary blocking, etc. Then do an overlay (1/2" thick?) with solid mahogany that had been distressed? The overlay would be a hollow cross, with solid end blocks. It could actually be built in sections and half lapped or shiplapped at the intersection.

The overlay could be attached to the "box form" from the interior with screws, allowing for movement in elongated holes. Would take some thought, but might provide the structural integrity needed, and yet give the appearance of solid, distressed mahogany.

Just brainstorming.

[Thomas Ghesquiere]

Thanks for all the suggestions. I got an estimate of 500 lbs for a solid wood cross, not going that route. I believe going with the box concept I can get the cross weight down to around 200 lbs and the sculpture of Christ would be an additional 200 lbs. Thanks for the offer of a semi local shop to do the project; a friend has a shop and spare bedroom very close to the construction site. I'm still open to more detail.

Thanks,
Tom