DIY Home Improvement Forum banner
1 - 11 of 11 Posts

·
Registered
Joined
·
31 Posts
Discussion Starter · #1 ·
I am building 16" shelves (3/4" MDF, 12' long) for an interior storage space. How do I ensure a seamless joint where two lengths/corners meet? I'll set them at the same height, but over time MDF can warp. Any suggestions? Thank you
 

·
Super Moderator
Joined
·
12,627 Posts
Fill the joint, sand it smooth, keep it well painted and don’t get it wet.
 

·
Registered
Joined
·
11,194 Posts
I am building 16" shelves (3/4" MDF, 12' long) for an interior storage space. How do I ensure a seamless joint where two lengths/corners meet? I'll set them at the same height, but over time MDF can warp. Any suggestions? Thank you
MDF is not a good shelf material, why don't you use a plywood?
Ron
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #4 ·
Ron6519 said:
MDF is not a good shelf material, why don't you use a plywood?
Ron
I like the finish of my MDF shelves in the pantry and would like the same in the storage area. I used plywood for heavy duty garage shelves. Plywood seems to have warps that the MDF does not have.
 

·
Registered
Joined
·
11,194 Posts
I like the finish of my MDF shelves in the pantry and would like the same in the storage area. I used plywood for heavy duty garage shelves. Plywood seems to have warps that the MDF does not have.
I was speaking of a birch plywood not a construction grade material.
Ron
 

·
Civil Engineer
Joined
·
5,832 Posts
I built a 12 foot shelf using MDO (similar to MDF, but MDF is probably better). I used a couple of biscuits to keep the edges aligned at the joint. As previously noted, a good paint job and the shelf will look fine. Mine is in a damp area (we water plants on it), and has not been a problem for 10 years. I used an exterior grade oil based paint, primed, two coats, and it has held up nicely. You can't see the joint. As noted, MDO and MDF are low cost, take paint very well, and are not subject to warpage due to moisture content changes, but are susceptible to damage if they get wet and are not well painted.
 

·
Registered
Joined
·
31 Posts
Discussion Starter · #9 ·
I built a 12 foot shelf using MDO (similar to MDF, but MDF is probably better). I used a couple of biscuits to keep the edges aligned at the joint. As previously noted, a good paint job and the shelf will look fine. Mine is in a damp area (we water plants on it), and has not been a problem for 10 years. I used an exterior grade oil based paint, primed, two coats, and it has held up nicely. You can't see the joint. As noted, MDO and MDF are low cost, take paint very well, and are not subject to warpage due to moisture content changes, but are susceptible to damage if they get wet and are not well painted.
What do you mean by 'biscuits'? I am thinking of using 14" metal brackets from Home Depot and shoring up the shelf support at the wall with a 1x3
 

·
Civil Engineer
Joined
·
5,832 Posts
Biscuits are oval shaped beech inserts that are installed using a tool called a biscuit jointer. For a project like yours, you would use the largest biscuit, which is 00 on my machine, and is about 2 inches long and 1/2 inch wide. You make a slot in the center or each board, and glue in the biscuits, then you glue the two boards together.

If you don't have access to a biscuit joiner, you can make the slots using a router and a slot cutter. Or you can use dowels, which are a little harder to get just right. Or you can insert a spline using a router to make the cut. All of these techniques are designed to maintain the vertical alignment of the two boards so you don't get a gap between them.
 
1 - 11 of 11 Posts
Top