Carve breaks raised letters in mdf

I am carving a raised letter sign, and I am breaking letters, using the skinny Jenny on mdf, this has happened on various carves, doing something wrong.

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This is just the way MDF is made. A solid wood would turn out much different.

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I’m really trying to find a way to make MDF work on these kind of sign due to the price of other Woods was hoping perhaps I’ll feed them speed change might help a little more or so or should I just toss the whole MDF hope out the window

Have you tried a font that is a little broader so that they don’t break out so easy??? You can use the program WORDMARK,IT in a browser. You Then enter a word or phrase and it will show that using all your fonts. Then you can pick a different one.

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That sounds like a real good alternative my pastor really likes this font I’ll see if I can find a font that was satisfying him or perhaps even just Whiting name that part of the letter y thank you for your help

MDF can be challenging, but there are a few things you could try. First use a down cut bit to reduce the cutting forces trying to lift the parts. Use multiple passes combined with a contour cut around the letters first and a downcut bit will pack some of the chips (dust) into the contour cut helping to stabilize the material. Then follow that up with your clearing operation for the remainder of the pocket but set it up to stay slightly away from the letters themselves that you cut around with the initial contour cut, don’t try to cut them twice.

You can also try using a 15 or 30 degree bit and make the letters tapered, that can make them more resilient to breaking off.


Wow right on I’ve been trying to learn more about MDF you have any ideas how I could repair that why actually there’s two wise that broke off the same

Have you tried stabilizing the MDF with something like shellac?

A few options to come to mind for me

  1. Different material… maybe extruded PVC
  2. Set up a separate set of tool paths that clear and cut out around those delicate parts first while there’s material to support with smaller step over and shallower cuts. This also helps you ‘fail’ faster if it is going to fail so you don’t loose time on a full cut.

You can always level them off and glue in replacement and working on those letters alone can help you sort out how to cut one that won’t break. When you get a consistent unbroken tool path, you can save it and add it to future projects with the same letter/size.

GL. I hope you share your solution.


Thanks a lot
Yes today I’m going to use your advice
Ok be cutting some replacement letters to glue in
Using method you explained of a more delicate methodof removing material around this delicate areas I’ll update
Once again thanks

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My solution for fixing the carve that had broken letters was to carve out some more of the same letters that were broken chisel out the broken ones and glue them in now I cut out or I router it out six more letters Y’s

were three of them got broken I’m going to try pocketing around letters and then pocketing again the rest to see if that works MDF is easy to break I thank you for all your help


Nice. Did you change up your cut on all 6 or just settle in on the first set that worked?

Yes sir I did as you advised to do use a different bit do a cutout first and then clear out around it where the dust help stabilize it as on your number two and instruction I really appreciate your help thank you

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An east Coast Plywood supplier, Russel Plywood sells an MDF skinned, 9 ply plywood product in 1/2", 3/4"and 1" thickness. A lot more expensive then MDF but will get the job done. Do a search in your area for wholesale plywood merchants and see if there are any close.

Amen thank you I’m trying to investigate now