SeaDek Milling

I recently ran some test cuts on a piece of SeaDek. It’s 2-ply EVA foam 3mm each ply (6mm overall). I tried a 1/8th 2 flute spiral upcut end mill, a 1/32nd 6 degree tapered 2 flute upcut endmill and a 1/2in 90 degree v-bit, all at different speeds and different feeds. My best results came from the v-bit at 50 IPM and roughly 22k rpm. Speed didn’t seem to make a difference at all.

There is really no info out there about feed/speed for cutting EVA, like there is for other materials. I can look up on KING Plastics website their exact bit/feed/speed recommendations for milling Starboard, but it seems like SeaDek and other marine flooring companies have kept this all hush hush. Maybe I’m looking in the wrong place.

The material is expensive so doing test after test is not very cost effective and was hoping to get some advice. I ordered a high speed steel straight flute foam bit to see how that works, and carbide v or shaping tools seem to work well.

I think on my next test I will ramp up my feed and slow my speed. Anyone have any experience with this product?

Best bits?
Best Feed rate?
Best speed?

Roughing pass with 1/8th in endmill 30 IPM variable speed (didn’t seem to matter 16k-27k)

Foam seems torn not sliced.

I tried my 1/32nd bit and finished the “D” with the 1/2" v-bit Still at 30 IPM settled around 22k rpm

Best results are from solely the v-bit at 50 IPM 22k rpm “EUCES”

The holes in the center of the playing cards is from me scraping the left behind glue. I managed to mill down through the first layer and not take the glue with is on some spots. My table isn’t perfectly level.

I am happy with the end result. this will be going on my boat, but I would love to get better and be able to hook up my buddies with a helm pad or eventually do my whole boat so I can save about $1500-$2000


I have never used this actual material but I routinely use 1 1/2" sign foam and have used divinycell ranging from 3/4" to 2" , various H ratings. You need a very sharp bit. Your bit is just dull enough to tear the edge. Set your depth of cut vs your per pass setting so the last pass is .002 so it cleans up without having to hog out material.
Contact the distributors ans ask for samples, most of the time they are free and you can do your testing on them.

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Thank you for the tips. I use easel as my software and I’ll have to figure out how to set up the last pass as you say. I will try it as soon as I get some more material and post my results.

If you look at the recommended or custom feedrates you will see the depth per pass… EX : If I am milling out 1/4" deep I will set my depth per pass at .06" instead of .062" giving me .001" final pass… or my depth per pass at .12" rather than .125" giving a .01" final pass…

Not sure if Im explaining well enough…

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Makes total sense. Thanks

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Seems like anyone who lives near water could make a killing selling custom carves with this stuff.


Yes they could. First the material is about $15/sqft retail and fabricators charge $18/sqft to mill. My plan is to customize helm pads until I do my whole boat and see how much work it will be for me.

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I am cutting the same stuff only my material is from china . Two color EVA foam similar to SeaDek but much cheaper . Ive been using carbide ball nose cutters two flute and carbide two flute centre cutting end mills . This leaves a good finish . You have to be careful and hold the material secure or it will vibrate and create lines . My machine is now a 4ft x 7 ft just for cutting EVA . Ive also built a vacuum hold down into the material surface .This helps stop vibration in the material .

You made your XCarve 4’x7’ or are you running a different machine. I had good luck with a high speed steel foam cutting bit and making my last pass .001. Easel made me update my driver and now my xcarve isn’t running properly. I reflashed GRBL to no avail. Haven’t done much troubleshooting beyond that.

No I’m running an x carve that has been expanded to that size. Simply because the Chinese material is that size. I built the machine that size to cut up to that size as I use it to make my own personal boat stuff.

I might add though I am a machinist by trade. I tried various cutters because they were readily available due to my chosen profession. I find high speed steel or none indexable carbide cutters work best. Reason being they are sharpe edge cutters. If you look. At an indexable cuter under microscope it actually has rounded.