Cutting foam core with card stock face

[williams_architectural]

I need some advice on cutting 1/8", 3/16" & 1/2" foam core board. I would use gator board, however, my daughter is working on an art project using water colors and her professor instructed her to use foam core. I have lots of small to large parts to cut. The smaller parts from the 1/8" board are from 1 1/2" to 3". I was planning to use a 1/8" diameter. I've been tweaking the RPM and IPS but have problems with the edges not being clean and paper fraying. Any suggestions would greatly be appreciated.

[donek]

drag knife. I think I sound like a broken record, but it's the right tool for your job. Max thickness for now is 1/4in though. Call shopbot as they are our dealer or go to donektools.com

[Mayo]

I have not tried this but if you have scrap to test with, try coating both sides of the foamcore with clear acrylic or polyurethane spray. Or you could try clear shellac. Make sure it's totally dry before cutting. I think this would help prevent tearing and fraying.

[williams_architectural]

Well, unfortunately the coating would not allow the water color to work properly on the paper surface.

[williams_architectural]

Thanks for the tips guys. I definitely want a drag knife but I have only this weekend to finish this project.

[feinddj]

Try a compression bit. At least the fuzzies will point away from the top

[ssflyer]

Or simply a downcut, since the major concern is the top - and they're a lot less expensive!

[knight_toolworks]

drag knife. I think I sound like a broken record, but it's the right tool for your job. Max thickness for now is 1/4in though. Call shopbot as they are our dealer or go to donektools.com

nope attempted it just tore the foam but it cut the paper well.

[knight_toolworks]

Or simply a downcut, since the major concern is the top - and they're a lot less expensive!

no I never found a way to cut it cleanly. it is paper and just never cut well. I wonder if a fiberglass bit would do it? as it would more grind the edge over cut it.Really if you sand the edges you can remove the paper fuzz. not sure if I tried a 0-flute on it or not. but this may be the solution http://www.ebay.com/itm/221396883244?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

[knight_toolworks]

I have not tried this but if you have scrap to test with, try coating both sides of the foamcore with clear acrylic or polyurethane spray. Or you could try clear shellac. Make sure it's totally dry before cutting. I think this would help prevent tearing and fraying.

but then your working with gaterboard. must need paper to absorb the paint.

[Billions]

I've never cut foamcore on my Shopbot but I've cut a lot in the past with Xacto blades - still likely the best way! But it sounds like you might have a lot of pieces and this would be a slick way to do it if you figured out how.

Sometimes I have sanded edges of frayed or uneven foamcore. If your parts aren't too small and numerous, and you can access the edges with sandpaper or an emory board, maybe try that.

[donek]

nope attempted it just tore the foam but it cut the paper well.

I cut a lot of rediboard foam without any problem at all. What material were you cutting?

http://youtu.be/lzfd0jsw0Ro

[knight_toolworks]

the knife cut the paper fine but the foam did not cut it just bunched up and tore. no idea what brand it was just he cheap stuff from a sign supply.

[Burkhardt]

Can you score the paper with the drag knife and then cut through with a downcut bit? Just brainstorming.....

[knight_toolworks]

Can you score the paper with the drag knife and then cut through with a downcut bit? Just brainstorming.....

I thought about that if you could offset it right. I don't cut it very often and try to talk a customer into gaterboard.

[donek]

the knife cut the paper fine but the foam did not cut it just bunched up and tore. no idea what brand it was just he cheap stuff from a sign supply.

Given the results shown in the video I posted, there is obviously some brands that can be cut and perhaps others that don't cut as well. Can you refresh my memory on the model drag knife you have? What blade were you using?