nailing cornice boards

[gene]

When I make a cornice board I glue and brad nail the face board, two sides (returns) and a top board (dust cover).

I saw a video where the boards were covered with lining first and then they were glued and brad nailed together.

Do you think putting on the lining first makes for a less strong joint?

Do you think it would be better to use staples (1 1/2" for example) instead of the brad nails?

Thanks for your thoughts.

gene

[MinUph]

I build quite a few conices and use 1 1/4 - 1 1/2 staples and glue. I find the staples do a better job than brads or finishing nails. If you caver any wood with lining the glue joint wouls suffer. You basicly gluing linning to linning except wgat bleeds through ontp the wood. Bad idea these.

[gene]

Paul, I appreciate your comments.

I tested 3 groups of butt joints using 9/16 OSB.

'1 1/4" brad nails and glue'

'OSB covered with lining and then 1 1/4" brad nails and glue'

'1 1/4" brad nails only'

The lining, even though it was a very thin and cheap lining, kept the glue from having any impact. The 'OSB covered with lining and then 1 1/4"brad nails and glue', took the same amount of weight to break the joint as "1 1/4" brad nails only".

I have read online that 1 1/4" staples will hold the same as 1 1/4" brad nails. And I read that staples give more holding strength. The bottom line is that the glue is the main force to hold the wood together.

I recently made 3 cornice boards with this lining technique shown in the video. I really like how that looks and it seems much easier than my old technique of finishing off the back with lining last and covering the staples with gimp. I did use a lot of extra brad nails.

I think if I continue to use this technique shown on the video I will cut the lining near the edge of the board so some glue can catch bare wood.

gene

[SteveA]

the brad ring nails would increase the holding power of the two joints
SA

[gene]

Steve, I couldn't find "brad ring nails". What are you referring to? Are these used in a pneumatic gun?

gene

[MinUph]

  Watching Youtube videos don't always bring out the best in me or any trade for that matter. Either do some writeups. What is mentioned above about staples holding the same as brad nails and then they hold better is a good example. Staples have 2 nails side by side and these are generally coated. How someone could think they would hold the same as on nail is beyond me. But who am I?

  Also gluing fabric covered wood to another piece of wood covered or not will no make a glue joint. It will just fail. Why try I ask?

  So in closing. Building anything out of wood is a challenge. Glue will fasten two pieces of wood together if the joint is good, clean and prepared properly. Wood to wood and virgin wood is alway the best. In no previous glue on the joint. I use staples to hold it all together as it helps the glue joint. Screws would by far be best but on a cornice it is not needed. Once the unit is up it won't get stressed. Some will build them without glue and they would be fine.

  Have fun building and making sawdust. It is my favorite thing to do actually.

[65Buick]

I don't know if you guys watch 'this old house'. obviously these guys get to play with a whole lot more tools than we do.

If you watch this video: https://www.thisoldhouse.com/watch/ask-toh-generator-wood-floor
at the 20 minute mark Tom uses this 'domino' joiner which actually looks kind of like a super biscuit.

If you built a cornice board with this I would imagine it would probably be over-engineered, but some pretty fun tools!!

[gene]

I use OSB (Oriented Strand Board) for my cornice boards and I don't think any type of biscuit joiner would work due to the fact that this board is nothing more than chips of wood with the grains all going in one direction held together with glue.

gene

[SteveA]

I don't remember where I bought these nails but when I see them I buy them in all the colors and both sizes.  I first started using these nails when wood paneling was popular because color on the heads.  Now I use them for better holding strength - color doesn't matter as much -

[byhammerandhand]

I remember way back in the '70s, when I was just getting started in woodworking, I read an article that said ring- or spiral-shank nails have vastly superior holding power to regular nails.   Recently, I have read that cc (cement coated) nails don't really add much.  But I can tell you after pulling apart lots of recent furniture joints that failed, staples and pneumatic brads don't have a lot of holding power in a stress situation.  But I've never seen a scientific test that says this type has x withdrawal force required and this other one has y.  Some people think that if you put the nails in at opposing angles, that increases the resistance.  Again, no numbers given.

Not sure about OSB, but a good side-grain to side-grain glue joint is generally stronger than the surrounding wood.   Found this out years ago too when I tried to break apart a joint and it split the wood and not the joint.

I did a presentation last year on joint strength and one of things I came away with is there are different kinds of stress on a joint, commonly
- Shear
- Cleavage
- Tension
- Compression
- Racking

Also important is sudden vs. gradual failure.  If you have a chair joint that fails, you want it to gradually loosen and not just dump the occupant on the floor one day.

Wood (and engineered wood products) are orthotropic or anisotropic, so a lot of this depends upon direction of grain lines in the orientation of the joint and which way the fastener goes.

(Once a geek, always a geek)