Need Recommendations for a Tool to Cut & Sand Foam

[vemnox]

Hey everyone,
I'm looking for advice on what tool I can use to cut 1/4" and 1/8" hard foam with? I need one that can make pretty precise cuts. Would a Xacto knife be best?

Also, what is good for sanding the edges of the foam? Just regular sandpaper or some kind of sanding tool?

Here's the type of foam I'm talking about:

 

[vemnox]

Just a little bump to see if I can get some help.

I used a Xacto knife to cut my 1/8" foam last night and, boy, was it a challenge. The edges came out really rough and the cuts feel imprecise, particularly on the curved edges. I tried sanding with 100 grade sandpaper and, while it helped, it still didn't get the smoothness I'd like to see.

With that said, is there a special tool that's good for small, precise cuts onto foamcore and how can I achieve smoother edges?

Thanks!

 

[drakeprimeone]

You may what to look into using one of those hot wire knives. I use them to cut pretty precise foam cut outs in pelican cases. They can be bought our even made

 

[vemnox]

Not a bad idea; thanks!

 

[Rhett J Martin]

I usually use a FRESH blade, and go slowly, stopping to either swap the blade out, or give it a few swipes in my trusty fishhook sharpener (a trick I picked up on the Fine Scale Modeler site). If I have to sand an edge down, or correct a curve cut, etc. the sanding wheels on my Dremel work fine on a super slow setting.

The hot knives work great, but for foam only!! Foamcore has paper on the outside of the foam, and the knife will grab and burn up the foam inside.

Blue home insulation works great, and is expanded polyurethane in most cases, so it sands and cuts like a dream. Takes clay and Apoxie Sculpt well too.

Best of luck!

 

[Jango72]

When making scale terrain pieces out of 1" and 2" thick pink insulation foam, I used a scrollsaw to cut out the rough shapes as it makes perfect cuts in the foam and cuts it easily ( like a hot knife through butter ). For shaping, try rough cutting the foam with a serated knife ( old bread knife works well ) or a retractable x-acto knife, then smooth it all out with 220grit sandpaper... I used 400grit sandpaper for the final smoothing.

 

[NormanF]

I have been using green floral foam, specifically "Desert Foam". This is not the super soft stuff. Very easy to shape. Actually it is on the border of being too easy to shape. I cut it with a regular hand saw and shape it with coarse sandpaper or even my hands. It is urethane so I can put polyester resin (fiberglass) directly on it without it melting like EPS does. I am doing this from my phone so I cannot add a link to it, but if you look for my mini-nuke thread you can see what I am talking about.

Sent from my Etch-A-Sketch