Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

What to use for cutting Foam board?

4930 views
18 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    October 2004
  • From: Blair, Nebraska
  • 205 posts
Posted by Boiler-man on Sunday, February 9, 2020 9:39 AM

If you are going to use a table or circular saw put the blade in backwords as it will creat less of a mess.

Boilerman
  • Member since
    July 2007
  • From: Yorkton, Sk, Cnd
  • 441 posts
Posted by wvg_ca on Sunday, February 9, 2020 6:34 AM

a hot knife can do an excellent job, especially with a fence that holds the foam steady,  and there's no cleanup with a vacumn cleaner, lol  ...

that's what I used to do a 15 x 16 layout, worked well ..

  • Member since
    July 2006
  • From: Central Vermont
  • 4,565 posts
Posted by cowman on Saturday, February 8, 2020 7:53 PM

Since your gate has a curved end, hhow about attavhing a strip of 1/8 masonitr?  If you had it attached at each end and one or two places around the curve, I would think it would holld it.x shape.

Good luck ,

Richard

  • Member since
    January 2005
  • From: New Milford, Ct
  • 3,232 posts
Posted by GMTRacing on Saturday, February 8, 2020 2:37 PM

I would cut the foam with a hot knife or bread knife slightly oversize. Bond the foam to the wood securely and then sand to final fit with a bondo file and drywall sanding block (hopefully outside as it will be messy). Expect issues over time with the track walking on the foam if you do not figure out a way to secure the track to the plywood base. I have made 3-4 swing gates in the past and with the seasonal movement of the wood and wear on the hinges, it has always moved enough to make drama when trying to run trains through the cuts in the track. I finally made a liftout located with metal to metal pins and so far it works well. In any event good luck and let us know how it turns out.   

  • Member since
    November 2015
  • 723 posts
Posted by UNCLEBUTCH on Saturday, February 8, 2020 2:10 PM

E-L man tom

I failed to mention that the non-hinged side of the joint between the plywood and the foam is an arc, not a straight edge. This makes the cut more difficult. I thought of doing a rough cut, slightly outside the arc, say, 1/4" or so, then rasping it off so that it matches, but I can visualize some imperfections/nicks that willcause gaps. I don't have a band saw, but have a friend and model railroader who does. I thought of having him cut it on that.

 

Cut your blank to fit first, then cut the curve.

I don't think a few nicks would mater. You may still need to add somekind of end piece to protect it

  • Member since
    July 2006
  • From: North Dakota
  • 9,592 posts
Posted by BroadwayLion on Saturday, February 8, 2020 10:23 AM

Cutting 2" Foam? ???

Busting it over my knee seems to work good enough for me.

Some of this stuff is fiberglass roofing insulation with tar paper on each side. I get this stuf at the nearest dumpster were a roofing crew is working. I but it over my knee to make it fit in the car, and to carry it upstairs. There I can cut it with a jig saw because both sides are clad with tar paper.

I suppose you could ask a roofing supply company where you can buy the stuff, but a roofer's establishment may just give you scraps that otherwise qwould have been tossed.

 

ROAR

 

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

  • Member since
    July 2006
  • From: Boise, Idaho
  • 1,036 posts
Posted by E-L man tom on Saturday, February 8, 2020 10:00 AM

I failed to mention that the non-hinged side of the joint between the plywood and the foam is an arc, not a straight edge. This makes the cut more difficult. I thought of doing a rough cut, slightly outside the arc, say, 1/4" or so, then rasping it off so that it matches, but I can visualize some imperfections/nicks that willcause gaps. I don't have a band saw, but have a friend and model railroader who does. I thought of having him cut it on that.

Tom Modeling the free-lanced Toledo Erie Central switching layout.
  • Member since
    January 2004
  • From: Canada, eh?
  • 13,375 posts
Posted by doctorwayne on Friday, February 7, 2020 11:44 PM

I agree with Ed's suggestion, but would go further and make the whole shebang outa wood, as it's a more solid surface on which to securely attach the track.  You don't want it squirmin' around every time you open or close the gate.

Fer cuttin' yer foam, I use either a machete or a chainsaw, but the wife won't let me do it in the kitchen no more.  Now the neighbours is bellowin' about the mess in their yard...it's enough to make ya wanna git a hobby. Smile, Wink & Grin

Wayne

  • Member since
    March 2017
  • 8,173 posts
Posted by Track fiddler on Friday, February 7, 2020 11:10 PM

Put a fine-tooth blade on your table saw or a side guide on your circle saw or measure from the blade to the side of your fence on your circle saw and clamp a straightedge on your foam and rip it.

Circle saws can be a bit dangerous on foam though.  I'm sure a jig saw along a straightedge would work fine.

 

 

TF

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Friday, February 7, 2020 10:58 PM

Clamp a 1x4 to the foam and use a hot wire, perfectly straight.

  • Member since
    March 2017
  • 8,173 posts
Posted by Track fiddler on Friday, February 7, 2020 9:54 PM

I free handed my whole cookie cutter cutout with a full size one to one plan using Owens Corning pink extruded foam and a fine toothed jigsaw blade to cut it out.

That was a quite a while ago in my beginning phases but it worked great.

I deleted the 3 O-Clock one going to the right after l changed my mind and added some after thoughts later in the game.

Nothing is over a 2% grade or under an 18 inch radius curve visible.  16 inch that will be hidden.

 

N Scale

 

 

TF

 

 

  • Member since
    November 2015
  • 723 posts
Posted by UNCLEBUTCH on Friday, February 7, 2020 9:40 PM

The first thing that comes to mind;  Why are you useing foam for a gate when the rest is plywood?.

 IMO it would be a pretty good trick to get any kind of a square cut with a hand held knifeor hot wire.

 My first choice would be some kind of power tool. Skil saw,table saw ect. where both items are somewhat stable. Next would be a hand saw . Hold a 2X4 on top of foam and use it as a guide to keep saw square with top.

Other then that ,Ed has a good idea.  You could glue/caulk a thin piese of something on the end to help protect it.

  • Member since
    May 2010
  • From: SE. WI.
  • 8,253 posts
Posted by mbinsewi on Friday, February 7, 2020 8:33 PM

I also like Ed's suggestion.  I used a long kitchen knive, with a serated blade, like a long steak knive.  I was cutting 2" foam.  It worked great for carving and shaping.

Anyway you deal with cutting foam is not clean, keep a shop vac handy.

Mike.

  • Member since
    July 2006
  • From: Central Vermont
  • 4,565 posts
Posted by cowman on Friday, February 7, 2020 6:59 PM

Planning a tip-up gate, hadn't gotten as far as thinking of the mating edge yet.  Another agreement with Ed's solid edge and fill.

Good luck,

Richard

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
Posted by RR_Mel on Friday, February 7, 2020 6:55 PM

A good sharp kitchen knife worked good for me on 1½” foam.  It was a 8” stake knife, be careful, can’t glue fingers on.
 
 
 
Mel
 
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
  • 18,255 posts
Posted by SeeYou190 on Friday, February 7, 2020 6:47 PM

You need a perfectly steady hand to get a square edge with a hot wire cutter. Even with the Hot Wire Foam Factory's miter box, perfect was near impossible.

.

I like Ed's suggestion of making the edges with plywood and filling the gate with foam.

.

-Kevin

.

Living the dream.

  • Member since
    December 2015
  • From: Shenandoah Valley
  • 9,094 posts
Posted by BigDaddy on Friday, February 7, 2020 6:43 PM

You can score and snap foam, but in my experience 2" won't snap perfectly square.  

I've not tried an electric carving knife (kitchen type) but I have used a big French knife (don't tell my wife)  The  kind that is 10" long and 2" wide at the hilt.

Hot Wire has a foam tool that look like a giant skewer.  I wonder how that would work against a straight edge, either metal or a piece of lumber?

Henry

COB Potomac & Northern

Shenandoah Valley

  • Member since
    August 2003
  • From: Collinwood, Ohio, USA
  • 16,367 posts
Posted by gmpullman on Friday, February 7, 2020 6:33 PM

E-L man tom
The top of the swing gate is 2 inch thick foam insulation board

I would suggest making the mating edge of the swing gate a nice, clean piece of wood, then mate the foam board up to it. This would prevent nicks and dings from misaligning the track and you can better secure the track ends to the moving part of the swing gate.

My 2 Cents Cheers, Ed

  • Member since
    July 2006
  • From: Boise, Idaho
  • 1,036 posts
What to use for cutting Foam board?
Posted by E-L man tom on Friday, February 7, 2020 6:29 PM

I'm installing a swing gate on my layout. The benchwork top is 1/2 inch birch plywood. The top of the swing gate is 2 inch thick foam insulation board (the pink stuff). the cut on the foam board has to be exact, so as not to leave a large gap between the foam and the plywood. What kind of tool would be best for cutting the foam board so I can get a clean, smooth cut?

Tom Modeling the free-lanced Toledo Erie Central switching layout.

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!