Ipe expansion/contraction for bench slats

[dan lemkin]

Hi,

I am making a ipe bench / "pool chest" for outdoor storage of my kids toys. Kinda standard design... like this:

http://www.ipefurniture.com/shop/form.asp?pid=207&catid=&listid=5

I made up this little sample of the slats, by quartering a 1x4, and running a 1/8" roundover. I planed them to 1/4" and rabbeted a matching groove on my test ?aprons

Questions?
1) Should I glue or pin the slats, or let them float in the rabbets. I was going to make the upper rabbet 1" to permit sliding in replacement slat later if necessary
2) For a 4' wide bench, will there be enough lateral expansion, that I need to rabbet a 1/4" groove in the legs to prevent bowing of the slats. Is there an easier, more elegant solution
3) Should I brace the slats by screwing in a horizontal support board into each slat from the inside? (Will be hard, as the slats are only 1/4" thick)

Thanks for any advice you can offer...

[Joe Chritz]

Shrinkulator answers nearly all that.

http://www.woodbin.com/calcs/shrinkulator.htm

Looks like a 4" wide slat from low humidity to average in your area will move .05".

A 4' wide panel would move like crazy. Wood moves by a percentage so a 4' panel would move to 4.05 feet or well over 1/2 wider at average humidity from low. The slats keep that from being an issue as each one moves a much smaller amount.

Definitely don't glue them in solid. Either a dab of glue in the center or a pin or you could opt for something flexible like silicone to hold them and still allow movement.

Ipe is pretty strong, I doubt a support is needed but 1/4 is thin. I haven't used any so I don't really know about a support.

Joe