Cutting MDF

[InfoH]

Hi all,

Just a question around the best way to cut MDF

I am getting a sheet 2440x1220x19mm and need to cut a portion out for a curve in a desk I am making

what would be the best way to cut the MDF so that it doesnt chip and ruin the finished edge?

 

[woodguy7]

For straight cuts i use the Festool track saw. don't think you will get a better cut. For curved work i would cut bigger with a jigsaw & trim to final shape with a router with bearing guide straight cutter running on a template.

Woodguy

 

[PeterBassett]

And how does he cut the template?

Info, cut it out with a jig saw and smooth it out, if needed, with sand paper.

 

[mailee]

I would cut it out with a router circle guide, assuming it doesn't matter if a screw is inserted in the centre. :wink:

 

[InfoH]

thanks for the advice everyone

I think i'll cut it down most of the way and then do it with sanding paper to finish it

think thats the only way of making sure it doesnt chip

 

[PeterBassett]

Chip? Is this normal MDF or is it a veneered board?

 

[InfoH]

sorry its venerred MDF

 

[Carlow52]

If u intend facing the cut edge unless the sanding is square to the surface it will be tougher to get right.

Needless to say sanding MDF needs a good facemask, even out doors

 

[jasonB]

It far easier to sand a thin say 4-6mm template and then use a router than it is to try and accurately sand the 19mm edge. When routing always run teh router down the grain even if it means comming from both ends, this is where a multitrim bit with both top & bottom bearings comes into its own as you don't need to reposition the template.

Jason

 

[InfoH]

sorry if i'm asking a silly question but what is the difference between using a router with a template compared to just following a line drawn on the MDF?

 

[JoinerySolutions]

If you make a template of the shape you want in say 6mm mdf sanding to the correct shape will be easier and quicker. Then use this template with a bearing guided router bit to copy it onto the veneered board. Veneered board will require little or no sanding and the finish will spot on.
Great if you have several of the same to do too!

Rob.

 

[wobblycogs]

I've been watching David Marks shows quite a bit lately (at least some of which can be viewed online - the starred ones I think - from here http://www.djmarks.com/woodworks.asp). He makes a template out of MDF just about every other show so if you want a visual guide check a couple of the videos out. Normally for the template it's: draw line, cut close with a jigsaw / bandsaw, file with a pattern makers rasp and then smooth with sand paper. To make the piece: double stick template on final piece, cut on bandsaw, flush cut with router.

 

[jasonB]

sorry if i'm asking a silly question but what is the difference between using a router with a template compared to just following a line drawn on the MDF?

With the best will in the world you won't be able to follow a line.

Jason

 

[joiner_sim]

Another vote for rough cutting the curve with a jigsaw/bandsaw and then finishing it off with a template clamped to the mdf and routing away. Try using mask & shield tape on the edge that will be cut to further protect the veneer from chipping away.

 

[Paul Chapman]

I would also use a router. If you don't want to use a template with a bearing-guided cutter, it would be easy enough to make a tramel bar from MDF and use a straight bit, like this

I made this tramel adjustable so that it was easy to set the exact diameter

If the curve is only gentle, the centre point for the tramel doesn't have to be on the workpiece. Just make the tramel bar longer and have the centre point further away.

For best results always take very shallow cuts rather than trying to do it in one cut.

Cheers :wink:

Paul

 

[InfoH]

All,

Please could you give me more detail on exacally what to use to cut it?

I have spoke to my Dad who has a Router but has not had much experience with using it.

we had a look over the attachments the router has and we cant work out which one would be used to cut the desk

can the router also cut the curve or would that require a jig?

If you can also attach pictures of any equipment please as it'll help,

Many Thanks!

 

[Chems]

A picture speaks a thousand words, so a video must speak a million, does this help:

http://www.youtube.com/watch?v=-61bH15tJmw


Where abouts are you, a forum member might be nearby to help you.

 

[Jonzjob]

InfoH, is this going to be a concave or convex cut out of the desk top?

If it's a concave cut then you could still use a router by screwing an extension from the MDF and mounting the centre of the circle jig at the centre of the radius.

I had to cut 8 X 5 foot diameter 22mm thick MDF table tops. I made my circle circle jig and screwed the pivot point in the middle of the board. Then I used a top bearing cutter, but I only cut a slot about 1/4" deep. Then I cut round the middle-ish of the slot with a jig saw and then used the top bearing cutter to finish the cut full depth. The bearing followed the router cut slot with absolutely no problems and The Bear if Rodborough had 8 new 5' table tops!

Cutting a slot and rough cutting the shape with my jig saw made it a lot easier than having to cut the complete thing with the router because there was less material to remove.

 

[jams]

Just an addendum on MDF finished edges, wood glue provides a reasonable finish to cut MDF . Sand , paint it on, then use fine grade sand paper (or wet and dry) to flatten ,paint again and sand (finer) finish.

James