how do you curve MDF?

[antonmiller 8]

I know you have to put slits in the wood, but how do you know how deep and so on, is there some type of formula? I know i read it on here some where, but i just cant find it....

Thanks,

[patented17 21]

I think I've only seen one actual formula somewhere. I would just advise trial and error on some scrap wood amigo.

[patented17 21]

Can search on google under the term "kerfing".

http://stusshed.word...n-the-tablesaw/

Edited September 14, 2009 by patented17

[sandsnip3r 0]

how do you curve MDF?

With my mind...

[jcarter1885 995]

Can search on google under the term "kerfing".

http://stusshed.word...n-the-tablesaw/

Appreciate ya for the post this helped me out since recently I have been curious on how to do it and was given told how but not really explained like this with pictures and hints to go buy. I got scrap wood so now I can go trial and error, I love this website.

[Godsmack 361]

Try slits 1/2 the way through the woodand every 1/4 to 1/2 inch. You can also heat it with steam to help it become more flexable.

These are not guarenteed tips, just things I recall having read before and they may be incorrect. I have never done this before so dont take the previous statement as the word of god.

J

[topgun 262]

It all depends on how much you want to bend it. Trial and error is the way to go.

[bigrank916 72]

Try slits 1/2 the way through the woodand every 1/4 to 1/2 inch. You can also heat it with steam to help it become more flexable.

These are not guarenteed tips, just things I recall having read before and they may be incorrect. I have never done this before so dont take the previous statement as the word of god.

J

I'll take it as the word of God...smack.

Do you think one of those clothes steamers might work for that?

Edited September 18, 2009 by bigrank916

[Godsmack 361]

Try slits 1/2 the way through the woodand every 1/4 to 1/2 inch. You can also heat it with steam to help it become more flexable.

These are not guarenteed tips, just things I recall having read before and they may be incorrect. I have never done this before so dont take the previous statement as the word of god.

J

I'll take it as the word of God...smack.

Do you think one of those clothes steamers might work for that?

LOL

And it is possible......Not 100% sure how much steam you exactly need, as it will change depending on the thickness of wood.

J

[NB50 206]

You need to cut damn near all the way through the MDF to get it to bend without breaking. The best way is to test on scraps to set the blade height. As for how many cuts to make that depends on how much flare you want. There is a semi tutorial somewhere on here of someone doing a full circle, gives you the math he used and you can then cut it down and figure what you need.

Here is one that I did awhile ago maybe you can see that you need to almost cut all the way through the wood.

[bigrank916 72]

That box is beautiful man. Im gonna try this shit and I will succeed. Probably not.

[Godsmack 361]

Thank you Bromo.............I could of sworn someone on here had done that before.

J

[NB50 206]

I used tutorial from ROE but I don't think it is up there still. But I know one is floating around here that will help.

[REVpuggie 23]

I know it lookt really sweat to have a kerfed port like that and I know thumper does it like that , but I was wondering if noone has questionmarks on how much less structural strength a port like that will give ? at least put a 45 in place to protect it from inbox pressure

[patented17 21]

Most people, usually fiberglass to give it some strength.

[Kanaworm$ 292]

Trial and error is the best way! I have found that 5/8" has worked the best as far as depth. Depending on radius of the port anywhere from 1/4" to 1/2" spacing. I'm no master by any means but it worked. I am using a 1 1/2" roundover bit currently. It works awesome and can take a good amount of material in one pass! Link is below....

http://www.mlcswoodworking.com/shopsite_sc/store/html/smarthtml/pages/bt_round_over.html

[pipes 1]

When I kerfed a port for my box I did some math to figure out how much wood I needed to remove..... I think that's what you're asking for when you mention a "formula"?

Say, for example.. you want the curve to bend 90 degrees (a right angle) with a 4 inch radius. You can find the distance from the start of the bend to the end of the bend by figuring out the circumference of a circle with a radius of 4 and taking 1/4 of that (90 degrees) seeing your first cut would be the beginning of the bend and last cut the end of the bend. Then, if you find the circumference of a circle with a radius of 3 and 1/4 inches (4 inch radius minus the 3/4 of an inch thickness of MDF) you can find how much material you need to remove by finding the difference in the two lengths.

Circumference = 2*pi*r = 2*3.14159*4 = approximately 25.13 inches... a quarter of which is 25.13*.25 = 6.28 or about 6 and 1/4 inches. This is the distance from the start of your curve to the end on the outside of the board. So, your last cut will be just a bit further than 6 and 1/4 inches away from your first.

Now find the inside

2*pi*r = 2*3.14159*3.25 = about 20.42 so a quarter of that (90 degrees of the circle) is 5.11 so just under 5 and 1/8 inches. This is the distance from the start of your curve to the end on the INSIDE of the board.

So, the amount of wood you need to remove, is the difference between the outside distance and the inside.. or 6 and 1/4 minus 5 and 1/8, which is 1 and 1/8 inch. If your saw blade removes 1/8 of an inch of wood with each pass.. then you'd need to make 9 cuts in the wood over that 6 and 1/4 distance. Considering that a cut starts, and ends, the distance, you're looking at a cut every 3/4 of an inch approximately.

Now, while this theoretically removes enough wood for your bend to reach your desired radius, a cut every 3/4 of an inch will likely leave you with a bend that looks like a bunch of flat spots. There's little harm in doing more cuts (arguably) but cuts closer together will provide a smoother looking curve as the flat part in between each cut begins to show less and less to the eye.

Anyways.... this is the general idea I think you were looking for. It only takes about a minute if you know your desired radius to figure out a starting point and then decide if you can remove that much material safely. (if you have to make so many cuts for a real tight radius that you remove most of the wood it kind of defeats the purpose and you'd have to go with a bigger radius which may change your overall design)