Altar build

[Bombarde16]

I posted an in the design area about building a new altar for a local church. After much back and forth, the church vestry voted tonight to go ahead with the project. Here's the final design that they approved:

Working in what little spare time I have (just started my third part time job) I expect this build is going to run a few months. It would be a treat to get it done by Christmas, but at this point that's probably not going to happen. More likely, delivery is going to be in mid-February to coincide with the beginning of Lent.

I enjoy projects that are a mix of familiar techniques and new challenges. This build will include a lot of techniques that I've done elsewhere:

• Large batch operations
  
• Frame and panel
  
• Mortise and tenon
  
• Profile routing
  
• Cutting dovetails
  
• Mitered frames
  
• Prefinishing
  
  But, it'll be my first excursion into two areas:
  • Bent lamination - I gave myself an easy start, as this design involves only a single curve...and a rather gentle one at that.
    
  • Carving letters - As a preliminary build while I was waiting for the various church committees to get things together, I built a dedicated sharpening station for my grinder and waterstones. I've been lazy when it comes to my plane irons and bench chisels; but carving gouges are another fettle of knish. Appropriate, then, that the construction of an altar should begin with an "altar" to the gods of sharpness.
    

  First step is going to be a cutlist. I'm a bit of a SketchUp dork, so the model is already complete (I confess, I even modeled the dovetails) and I'll be able to pull parts and dimensions right from there.

[chicks82]

Can't wait to see progress pictures. For the bent lamination I would make a nice wide form that is wide enough to accommodate for blade kerf and one sides worth of curves. I would make the form out of MDF stacked and then cut the curve. Just remember to cut the inside and outside to allow for the material you will be adding. Then cut areas for your clamps. After that sand it up and wax it.

[HolzMechaniker]

Are you planning on doing a torsion top?

[duckkisser]

did you take inspiration from some cathedral archetecture?

[Bombarde16]

Are you planning on doing a torsion top?

Inasmuch as the dovetailed frame will have two inner, horizontal pieces...I suppose that's one step down the road to torsion box. But, no. Just frame and panel.

[Bombarde16]

did you take inspiration from some cathedral archetecture?

With several centuries behind it, the Gothic arch fairly screams "churchy" at this point, doesn't it? It's not rocket science and the geometry is quite simple. Given a rectangle (such as a window opening):

You merely draw a circle from one corner...

...and the other corner...

...and remove everything that isn't part of the arch:

The problem is that, while this works fantastic in stonework, designers of the neo-Gothic school tried to impose this shape (with all of its implicit "churchiness") on the basic woodworking concept of frame and panel construction. Thus, you see in church after church silly caprices such as this: (Arrows indicate grain direction, expansion and contraction happen at 90 degrees to this.)

...or, even worse, this:

And in both cases, the wood invariably self-destructs and splits wide open somewhere because the piece ignores basic rules of wood movement.

The arched undercarriage in this design is thus a.) a way of bringing desperately needed curves into an otherwise purely square box and b.) an attempt to reconcile the Gothic arch with basic rules of woodworking in such a way that the piece won't self-destruct.

[Bombarde16]

Day one: Harvest.

The project involves salvaging some of the church's older furnishings for lumber. Specifically, the church owns two old sedilia that are no longer used. They date to the previous church building and have been sitting derelict for years.

Scrapping something this old touched off a small storm of objections when I first ran the idea over on George Walker's blog. As deliberations proceeded, a few members of the church felt the same way. In the spirit of compromise, the Vestry decided that I would scrap only one of them (whichever was in worse shape) and salvage whatever else I needed from some discarded pews in the undercroft.

With help from the church sexton, I had the piece safely broken down in under two hours, yielding a formidable, flat-packed pile:

Casual examination: Looks like red oak mixed with ash as a secondary wood. All quickly slathered in a dark brown smudge. Competent construction (aside from the design quirkiness I mentioned in an earlier post) that looks like it was built to a price. Parts that look an inch thick are actually two half inch slabs face-glued together. Anyway, in addition to a promising pile of keepers for me, the morning yielded the following:

Thinking ahead to the day when the church might have an abundance of free time, money, and desire to fix up the other sedile...I salvaged what carvings and moldings I could. (Despite fair effort, lots of pieces just plain disintegrated, though.) These will be stored downstairs. Anyone on the list like to take on odd restoration jobs? Personally and having seen the degree of decrepitude in which this one came apart, I wouldn't touch the other one with a 10' pole. But, if you get off on that kind of stuff, make the church an offer.

With the sedile dismantled and out of the way, the church can now appreciate one of the World War I memorial plaques that had hitherto been hidden:

Next step will involve some rough stock layout. Once I have a better idea of what I intend to get out of this pile, I can start making some ballpark cuts (mostly to fit it into my car for transport back to the shop) and get a handle on how many pews will be requisitioned.

[duckkisser]

hmmm i found this inturesting please keep the info coming as it is somehting that is not wide spread wood working.

[Bombarde16]

And herewith the cut list. Going overboard on detail in SketchUp was a given because of the curves, and it helped enormously in figuring this out.

[Bombarde16]

Got in a good two hours at the church this afternoon picking through the pile and deciding what to put where. How sweet it is to have a good cut list where you can just look down a column and find things. After I had marked prospects with a sharpie, I made two or three very rough crosscuts with a reciprocating saw. More useless bits went in the trash and I stuffed all the keepers into my car for a trip back home.

Now definitively identified as Red Oak and some very promising quartersawn figure throughout.

On the surface, it looks like that one stall might yield as much as two thirds of the wood I need for the altar. I say might yield two thirds because I'm still getting to know these boards. My chief concern is that nothing in this stall was more than 3/4" thick. Boards that appear to be 1" thick are actually two 1/2" boards face-glued together. You can see a thin glue line in this scan of an edge.

For the life of me, I can't fathom why someone would do this...unless the mill had a pile of 1/2" boards that they wanted to unload. More importantly, in working with this and creating the parts I need, do I trust that those glue joints will hold? Most of them look and feel plenty solid, but the tip of one board was starting to delaminate. Color me cautiously optimistic: time will tell how these laminations will fare as I work things. Worst case scenario if I get any indication that the old glue is not trustworthy? I resaw these pieces into a pile of thin stock to make the curves.

Tomorrow brings a lot of nail pulling, some ballpark ripping at the table saw as well as a preliminary scrub with a belt sander.

[duckkisser]

if the wood had been glued together on the sedilia since the previous church building that might be a couple of generations so that prity goodim surprised it held up that well.

[Bombarde16]

Bummer. After making a few ballpark rips, the laminations aren't eliciting much in the way of confidence. Looks like the sedile will yield pretty much all of my 1/2" stock and I'm going to have to source the 3/4" and 1" stock elsewhere. The harvest continues.

[chicks82]

Thats a bummer that stuff looks beautiful.

[Bombarde16]

Thats a bummer that stuff looks beautiful.

Indeed, and it brings to mind a possible fix: a.) It looks like this red oak wants to be thin and b.) the rest of the old board that the church will let me salvage will likely be flatsawn oak or ash. I'm toying with the idea of turning these into veneers. Following that idea to its end, two problems jump to mind: Making the central frame of the top out of veneered wood would preclude doing traditional dovetails and it'd make the engraving look odd. Perhaps I switch over to miters with dovetail splines and plan to paint or gild inside the engraving.

Something to sleep on. Right now, it's time to put the cars back in the garage.

[duckkisser]

hey rob you might know from earler post how much i like inlay have you thought of instead of painting or gilding the inside that you do some kind of inlay and fill in the letters with some kind of alternative material like stone or metal. just a thought or perhaps you will get some inspiration

[Bombarde16]

hey rob you might know from earler post how much i like inlay have you thought of instead of painting or gilding the inside that you do some kind of inlay and fill in the letters with some kind of alternative material like stone or metal.

Duck,

Good thought and inlays have already crossed my mind. In this case, though, I'd like the three-dimensionality that an engraved motto would bring. If I do any inlays, it'll be on the top, perhaps some stringing. But that's staying on the back burner for now. a.) I don't want to go overboard on bling. b.) Depending on how the material selection goes, I may end up wanting to hit the finished altar with some pigment, either a stain or a dye to even things out and make it all harmonize with the existing woodwork. Time will tell.

[Bombarde16]

The harvest continues. Deep in the undercroft of the church is a pile of pews that were removed when the church was renovated twenty years ago.

I included salvage privileges to these in my proposal, knowing that the sedilia likely wouldn't yield enough to make the altar I had designed. I went in today expecting an afternoon of back-breaking work to excavate and dismantle one of these monsters, followed by more work with the saw to get it to fit into my car. What should I find? Deep in the shadows behind the pile was a stack of 3/4" boards, all 60" long and around 8"~9" wide.

Saints alive, does this save a lot of work. Including allowances for snipe and joinery, 60" is just about the perfect size for everything in this project. This'll give me all the bending laminates for the curved legs, along with the internal structural parts and a bunch of other stuff. All of them are glue-ups of flat sawn boards, most of them carelessly fed into a thicknesser with tearout everywhere. But, a small handful of usable rift sawn boards crept through. This solves the question of the inscription box for the top. One pass through the saw to rip off the flat sawn section, a single pass with the belt sander and it was into the thicknesser:

...and Bob's your parent's sibling.

Mind you, the wood from the pews isn't the same Red oak as the sedilia, I'm guessing some sort of darker Ash. Machined easily enough, but I'm guessing it'll be a bastard to carve. Maybe I should take Duck's advice and drop back for an inlay instead.

[Bombarde16]

Never too early to start playing with finishes. As much as I dislike pigment stains, the Watco walnut-colored Danish oil looks like it'll be the closest match to what's already there.

[Bombarde16]

No sooner do I sing the praises of a comprehensive cut list than does this one bite me in the backside. The internal dividers for the top frame (lacking a better word, I called them muntins) need to be 3/4" thick, not 1/2" thick. Minor hurdle. I simply sliced up the quartersawn stock I had designated for those pieces and pasted it onto a flatsawn board that's been lying about since forever. Gang all three together and clamp away:

Still on track for a grand round of thicknessing on Thursday afternoon. Hoping to get into joinery for the top this weekend.

[duckkisser]

i like the rays in that last picture i think you should keep thqat one for youself.

[Bombarde16]

First round of thicknessing done. Should be a quick job to get this all to a consistent 1/2" tomorrow or Saturday.

If all you've ever known is the overpriced, kiln-dried red oak from the home center, let me say what a joy it is to work with old, quartersawn, air-dried red oak.

[duckkisser]

rob i agree i love air dried wood has so much more color and vibrant then the farm raised stuff. like some wood with charicter rather then be perfectly strait.

[Bombarde16]

Fit the TS with a cheap 7 1/4" blade and settle in for the first step in ripping up laminates for the curved pieces. Final call will be for 12 curves, each containing 8 laminates 1/8" thick. That makes 96, plus a heavy margin for rejects, screw-ups, do-overs and the like.

Width right now is 2", the final curves will be 1 1/2" inches wide. Brings the stack of boards to a much more manageable size and the marshmallow roast quotient on this project is already off the charts.

[duckkisser]

no comment about the pumpkin? like how are you going to make use that with the alter

[Guillaume Breton]

pumpkin oil as a finish imo