How to Bend MDF

How to Bend MDF

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Medium density fiberboard is a pretty great building material for a variety of purposes. With that being said, MDF or medium density fiberboard is usually straight.

However, there are ways to bend MDF so you can get a curve in it. Today, how to bend MDF the right way is exactly what we are going to talk about.

Can You Bend MDF?

OK, so MDF is not really a flexible material at all. This is a rather stiff material, so bending it can be a challenge.

As you are about to see below, the main way of bending MDF doesn’t actually involve bending it as much as cutting slits into it and removing material, and then pushing it together to create a curve.

It is technically possible to bend MDF, but it does need to be done the right way. The two main ways of bending MDF are by kerf cutting and by laminating.

However, for most purposes, kerf cutting is the way to go. Therefore, below, we are going to teach you how to bend MDF through kerf cutting.

How to Bend MDF by Kerf Cutting

Like we said, the best way to bend MDF is by kerf cutting, so this is what we are going to teach you right now.

Step 1: Prepare for the Job

You are going to need to prepare for the job first, which means getting your MDF, setting up your table saw with a very large support table, and setting the depth of the blade to around 19/32 inches.

The cuts that you will make should go around three-quarters of the way through the MDF, but not penetrate all the way through. You’re also going to want to have some safety goggles to keep your eyes safe.

Step 2: Mark the Curve and Set Up the MDF

You are now going to mark the curve that you will make. For instance, if you have a piece of MDF that is 8’ long and ¾” thick, and you want to make a 30 degree curve right in the middle, you’re going to mark this section off.

You’re going to mark off, for instance, a 3’ wide curve in the middle of the MDF. You’re now going to line up your MDF with the markings on it with your table saw and prepare to make the cuts. Once again, remember to set the blade depth to the proper level.

Step 3: Make the Cuts

You are now going to use your table saw to cut into the MDF in ¾” intervals, or if you want this curve to be smoother, at 1/2” intervals. Make sure that you cut on what is going to be the inside of the curve, and make sure that you cut from the left boundary to the right boundary of that curve.

Step 4: Bend the MDF

You are now going to lay down the MDF on a very large and flat surface, with those cuts facing up. You have to put a stop at one end of the MDF so that it cannot move or slide around.

You will then lift up the other side of the MDF and put something like a block or a board underneath it.

You now want to raise up the board so that those curve cuts begin to close in on themselves. Once you’re about halfway to your desired angle, then want to repeat this process on the other side.

Step 5: Fill the Kerf Cuts with Glue

Once you have the bend in place, you actually want to spread the MDF out again. You are now going to use white glue, carpenters glue, or even a strong polyurethane adhesive to fill up all of the cuts.

Just make sure that you don’t use too much glue, or else it might expand and actually straighten out as it dries.

Once you have the glue in place, reform that bend to the desired angle, and then clamp everything in place to make sure that the glue dries with the bend in place. Once the glue has dried, the job should be done.

Mistakes to Avoid, Tips & Tricks

Let’s just go over some quick tips and tricks to help make this job a bit easier for you:

  • The smoother you want the curve to be, but closer together those cuts should be.
  • If you are doing this for the first time, you definitely want to practice on a spare piece of MDF to make sure you can get it right.
  • If it’s easier for you, instead of clamping the board down and having the bend facing upwards, you can always support the board from both ends and create the curve by bending the MDF down.
  • Before you unclamp anything, always make sure that all of the glue has dried completely.

Summary

You should know exactly how to bend MDF via kerf cutting now. Yes, you can also go with the laminating method, although that is admittedly more difficult and less effective.