Solid Hardwood, Engineered and Laminate Flooring - To putty cracks or not?

I have just finished nailing down unfinished red oak strip flooring. I think that we did a good job of nailing it down, but there are a few spots where the joints between boards are not as tight as I would like.

My question is, should I putty the cracks or not?

The article on this website says "Use a putty knife and wood dough to fill all the small holes and cracks." and shows a photo of someone putting putty in the crack between two boards.

http://www.doityourself.com/woodfloors/hwfsandprep.htm

I have read several other sources saying not to putty cracks between boards because the expansion/contraction of the wood will eject the putty from the crack. Which is correct?

Does the size of the crack matter?
Does it matter if the crack is at an end-joint or not? My guess would be that it is OK to putty a crack at an end joint because the wood will not expand much in that direction.

I am leaning towards putting putty in all of the cracks, and if the putty comes out in a year, my floor will be no worse than if I hadn't used the putty in the first place. Or am I missing some other reason not to use it?

Also, what is the difference between "wood dough" and wood putty? Which is best for floors?

Anyone have a brand recomendation for wood putty? I will be staining it with a light oak, water based stain made by MinWax and coating it with water based Varathan Diamond Elite polyurathane.

-David

David, I would trowel on a wood filler, like WoodWise, after the first cut with the sander. Different installers putty the floor at different stages, so you may get alot of differing opinions on this. For more info check out Don Bollinger's book, "Hardwood Floors: Laying, Sanding & Refinishing". They've got it over at Amazon.com.

Scott Stephens
http://www.stephensfloor.com