Building a shadow box frame...need input

[Herb G]

I need to build an air tight shadow box frame for a large Chinese fan.
Here's a link to one like it.

I need some straight grain wood that is not liable to split or warp and is not nose bleed expensive. It's probably only going to be 1/2" thick, because I am using real glass for the window in it. I want to keep the weight down as much as possible.

I am leaning towards a lighter colored wood because the background inside the box will probably be painted flat black. Maybe Chinese red lacquer if I can find any.
I haven't made up my mind on the background yet.

Anyway, I am sealing it forever with silicone once I build it & put the fan in it.
I don't want air getting to it once it's sealed up.

The finished size will be about 66" wide X 40" tall X 4" deep.

I was thinking pine or poplar, but if something is better & not too expensive
I am open to using it.
So, which wood would you recommend for this?

[MichaelMouse]

Bass. Takes clear finishes or paint like it's made for it.  Light and stable.

[K. L. McReynolds]

Maple.

Hard or soft.

[Hank Knight]

Cypress. Light, strong, straight-grained, easy to work.

[bandsaw]

Why air tight?

I'm questioning this as a long term builder of "shadow boxes"

[Herb G]

Because my fan is hand painted Chinese silk. The link was for illustration purposes only.  I don't want cooking odors or smoke or anything getting to this fan.

[bandsaw]

Is this fan historically, sentimentally, or monetarily valuable?

If so the term used is "conservation framing"

This entails reversible mounting (no glue), all internal components permanently non acidic, and a conservation grade UV blocking glass.

The parts of this unit are like woodwork - they will expand and contract at different rates which must be accounted for.

For a box this size "air tight" is probably not a good idea.

It should not be hung where cooking odors and smoke are common.

It will be 40-60 pounds when finished so I suggest building a French cleat into the back as part of the construction.

In our shop we would create an inner construction holding the fan's mounting board, a system to support the glass at an appropriate clearance for the fan, and the glass. This would be sealed but not "air tight"

The frame (wood is acidic) would then fit around this to hold it all together for hanging.

We would charge about 1500 for a piece like this in our shop.

But what do I know? Only been doing this for more than 35 years, have the credentials, have taught from Anchorage to New York.

[Paul K. Murphy]

In my view, bandsaw gives good advice. You'd be wise to follow his recommendation. Michael Mouse suggested basswood, and I agree with that too.
I think sealing the case with silicone is foolish; don't do that. Good ideas can be found in Earnest Joyce's book, "The Encyclopedia of Furnituremaking." That book has some plans and specifications for Museum cases, including cabinets to display and store moths and butterflies. That would be a good departure for you in the design process.

[Herb G]

I agree. I was given great information & lots to think about.

I will try to locate a copy of the book you mentioned.

Thanks for the replies guys.

[Cooler]

I was a picture framer for many years.  Band saw's suggestions are a beginning.

1.  conservation framing must be reversible
2.  conservation framing must do no harm

Line the frame with PH neutral mat board.  Do not mount directly to wood as it contains lignin which will damage paper and fabrics.

I would start with a molding with a rabbet about 2" deep.  First set the glass in the frame.  Then wrap the interior of the rabbet with about 1" wide x 3/16" strips of foam core board or wood to lock the glass in position.  

Attach the fan using black linen thread looping over the bamboo and piercing the mat board and tying the linen thread behind the board.  

Support the mat board with a second backing board and then use glazing points to lock it in position.

Remember:  NEVER mount any artwork directly to wood.  Never trust any finish in contact with art unless it is specifically labeled "conservation".

This is not a difficult job.   The only alien part is the tying on the fan.  You probably only need to tie the fan in three places.  Linen thread is generally PH neutral.  You can wash and dry it to be doubly sure.  But if you are tying onto the bamboo you need not worry.  The bamboo will stand up to the linen regardless.  If you can find thread that matches the mat board or the fan color then use that.  Most fabric stores will carry linen thread, which is typically much heavier than regular sewing thread.