# Carving extruded foam



## Smokestack Lightning (Oct 31, 2010)

This is the route I am thinking of going. Anyone had any experience with this technique?
http://www.youtube.com/watch?v=S8DsSn6xznY


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## Bman (Aug 24, 2010)

I tried this technique with my current layout and it didn't work out all that well for me. I guess what turned me off the most was that I found it to be extremely messy. Maybe I'm a little bit of a neat freak but those little bits of foam where everywhere (static electricity is involved here too). I tried to build some layers with a nice edge but I'm not very artistic and for me it just didn't look right. I ended up covering it up with plaster cloth. I ended up using newspaper covered with plaster cloth to make all my hills. For the rolling hills I tried to make sure the newspaper was "wrinkle" free (in the shape of a pillow) and for the rocky areas it didn't matter as much because I covered the face in rocks made out of plaster (lightweight hydrocal). 

Don't let me discourage you from using this technique, it just didn't work out for me.


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## Nhwilliams0 (Oct 30, 2010)

I actually have all the materials for this type of carving and I am going to be starting in a few weeks. I have an army of tools at my disposal so I will be trying some other instruments out to see what works best for me. I'll keep you posted and take some photos as I go.

-Nick


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## Reckers (Oct 11, 2009)

I've used extruded foam and found it great to work with. With foam, you get dust; with Hydrocal, you get to work with wet goop. It's really a matter of what mess you want and what look you're going for----both are good materials.


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## dozer (Jan 2, 2010)

If you use a drywall saw like he does in the video, it will be very messy with rough edges but if you use a hacksaw blade with fine teeth it makes very little mess and you're left with much smoother edges. Better yet, go to Harbor freight and pick up one of their new Hot Knifes like I did (thanks to a suggestion here on the forum) and have no mess at all. There's so many different ways to approach working with extruded foam, that's what makes it so great.


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## tjcruiser (Jan 10, 2010)

Smokestack,

I went with the hand-carving method to build a small mountain/tunnel on my HO layout. Worked OK, but it was a bit messy ... little foam grit everywhere. I wanted a rough textured look (more of a granite-faced mountain theme), so manual cuts with a fine-toothed saw blade worked well, along with some local texturing via an 80-grit drum sander disk spinning in my drill.

All of that said, I'd have to think that the guys working with a hot knife are on to something. Follow up on Dozer's lead ... you might like the end result.

TJ


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## Bman (Aug 24, 2010)

If I had some of these tips when I was trying to work with foam I might have had better success!!


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## Nhwilliams0 (Oct 30, 2010)

Looks like I'm making a trip to harbor freight!


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## Smokestack Lightning (Oct 31, 2010)

Thanks for the input guys. I think I have all the supplies I need to get started. I will post pics as I go. I will make sure I keep my Shop Vac close by:laugh:


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## aionta (Apr 9, 2010)

Hey Dozer, which hot knife did you buy, does it have to be a low heat knife?

Thanks

Aaron


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## tjcruiser (Jan 10, 2010)

Gents,

Just while we're on the subject ...

There's "hot knives", which are just that ... hot blades for cutting.

Then there's also "hot wires", which are thin, taught electrical-resistance wires that are great for cutting foam, too.

TJ


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## dozer (Jan 2, 2010)

tjcruiser said:


> Gents,
> 
> Just while we're on the subject ...
> 
> ...


 Yup, very true. I used the hot wire for large cuts and the hot knife from harbor Freight on the detail stuff.


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## Smokestack Lightning (Oct 31, 2010)

dozer said:


> Yup, very true. I used the hot wire for large cuts and the hot knife from harbor Freight on the detail stuff.


Do these hot knives smell? I would rather deal with dust than horrid melting foam stench.


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## derfberger (Jul 23, 2010)

*foam*

It's the way to go.

My entire layout started with 2 in on top of 3/8 plywood.

I wanted canyons below level---no problem.

Laid my cork bed right on the foam with foam cement held with 2 in dress makers pins. Pinned the track to the foam.

if you make a mistake fill it in..with foam

I used a wire brush attached to my battery drill to make rolling hills and the rough texture left by the brush i painted which replicated grass without messing around with ground foam.

Too rough a texture cam be corrected with 100 grit sand paper

I used 40 grit paper attached to a block of wood as my rasp, cuts fast.

The foam dust is no problem, just stay on top of it with a shop vac.

the dust can also be set with spray adhesive and painted.

Only down side so far is that spray paint solvents attacks the foam.

I've tried the paper towel dipped in plaster of paris over screen wire and/or card board strips. Sets up too fast to get effects i want `


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## Reckers (Oct 11, 2009)

Spackling compound is great for filling in seams and "oops, that's too deep" errors on the pink foam.


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## RailMan (Oct 27, 2010)

dozer said:


> If you use a drywall saw like he does in the video, it will be very messy with rough edges but if you use a hacksaw blade with fine teeth it makes very little mess and you're left with much smoother edges. Better yet, go to Harbor freight and pick up one of their new Hot Knifes like I did (thanks to a suggestion here on the forum) and have no mess at all. There's so many different ways to approach working with extruded foam, that's what makes it so great.


Hmmmm...Harbor freight here I come.


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## derfberger (Jul 23, 2010)

if you can find one of those double bladed electric knives at a garage sale they are incredably fast and with a bit of practice one can carve any contour or shape


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