Welcome to Adobe GoLive 6

Gorilla Glue is polyurethane glue. This glue foams and fills in any gaps in the joint. Making it a sealer for the box as well as a glue. It is extremely strong, stronger than MDF itself. The clamps, screws, nails or brads you use are only needed to hold the box together until the glue sets, about 4 hours or so. The pressure is needed on the joint so the foaming action does not push the joint open. Make sure you use latex gloves when using this glue, or risk having brown hands for a few weeks.

MDF requires that the area to be glued is made moist with a sponge before you place the glue on the area to be secured. Moisten and put glue on both sides of the joint.

Notice the foam that was created. It can be removed with a sharp chisel or sanded off. It will coat the edges of all joints.

When the joint was broken, the MDF failed, not the glue joint.

MDF cuts very easily with a saw or router. I found that a saber saw would cut very quickly or slowly with a fast transition in between, beware of this when using the saber saw.

MDF is very absorbent and this must be taken into account when finishing. All cuts and holes must be sealed or filled with sheet rock compound, automotive bondo, or wood putty before you try to put a final finish on the MDF, otherwise you will get widely varying amounts of finish penetration. Bondo seems to be the recommended product to use. Water based finishes will cause MDF to raise.

When assembling the box, the joint needs to be both secured and clamped. The joint is secured so that the box can be assembled without falling apart. The joint needs to be clamped so the gaps are small and the glue can hold the box. Once the glue sets in about 4 hours, the clamps are no longer needed. The devices securing the box do not provide the strength that holds the box together, the glue does that, so the devices that secured the box can be removed or left in place.

I used 1 1/2 inch 18 gauge brads to secure the box and pipe and pony clamps while the glue set. I did not remove the brads, nor did I fill the holes since They are small and I was veneering the box. Filling the holes, no matter how small is required if you paint.

Once can use screws to both secure the box and clamp the box. This is a good method if you do not have a lot of clamps hanging around. You will need to fill the holes is the draw back. The screws can be removed once the glue has set. Removing the screws is an advantage if you want to round the corners to paint.

Any screws that you put into MDF should be pre drilled at least for the shaft. A countersink offset drill that sets the screw should be used if the screw is to remain in the MDF once the glue has set. You can remove the screw once the glue has set. All screw holes should be filled prior to finishing.