Cutting grade in styrofoam

[Piscesman]

Does anyone have suggestions on cutting a grade into styrofoam?  Or is it always better to build up a grade (fill) and scenic around it?

[mobilman44]

Hi!  Congratulations on your first post!

I assume the grade you want is for track (as opposed to a road or path).  If so, I can't see doing it with foam.  Not saying it can't be done, but building a grade based on ply or other wood types is definitely a preferred way to go.

I'm sure others will post differently, but I stick by my recommendation.

[mbinsewi]

Welcome Piscesman.

I cut and graded mine.  Like what would be done in 1:1 scale with dozers and scrapers, I did with a knive and a surform tool, shaping the roadway, and ditch as I went.  It's messy! Keep a small shop vac at your side.

I used straight edges to keep things in line and follow a steady grade.

Mike.

[UNCLEBUTCH]

Maybe I don't understand the question. I'm pictureing glueing up a solid 5/6in chunck of foam, and then cutting the grade.

I'm sure you could,draw or snap a chauk line and then like Mike said, hack away.

or; what I did, took a long enuff piece, thats wide as you need, block it where you need it. And just fill in around. A lot less work and mess.

I used 3/4in ,3in wide and <6ft> long.Plenty of supports under it, works fine

[mbinsewi]

And that works fine!  Mine started out as a bench top, for a shelving system I made to store tupperware containers of family stuff.  The railroad came later.  I covered the top with 2" foam, and needed to drop down 1" were the hidden track is, under my city scene, etc.  It wasn't a big deal.  Nothing like 5 or 6 inches.

Your way is the more conventional, along with Mobileman's.

Mike.

[UNCLEBUTCH]

mbinsewi

needed to drop down 1" were the hidden track is

OK I see my mistake; The OP said grade, I assumed 3/5 in of hieght. Your 1in is still a grade, in that case i would just hack, er,   I mean grade it out.'' my bad'' as they say?

[BigDaddy]

Ken Patterson used one of those laser levels that project a straight line to cut a grade with a surefoam file. You would project an angle that matches the grade you want, along the area you wish to transform.

That's probably really hard to find on youtube without looking at all his What's Neat videos.  One of his buddies is Michael Coombs who is a teen age savant who remembers the dates of everything.  Maybe you could track him down on ask the question on his latest What's Neat videos.

I would guess it is more than a year old.

 

 

 

[Lonehawk]

I'm no expert when it comes to model rr applications, but as a former shop teacher, I can speak for working with the material.  The big issue I foresee would be visibility while you work.

 

While it's very doable, I'd take great care if you're talking about "trenching", where you're cutting a graded strip into the foam with level faces to either side.  It would be very easy to end up with a choppy mess that would be a royal pain to smooth and grade properly.

 

However, if  you're talking about grading along an edge, then I'd definitely second the laser-level option, if you have one.  Otherwise, a few carefully drawn lines will be all the guide you need.

 

Good luck!

[Piscesman]

Thanks everyone for your comments and suggestions!  In a nutshell it seems the idea of cutting grades in styrofoam is not advisable...which was what I thought but hoped someone had found a viable way.  In the end we decided to make our own foam risers using a homemade jig which, after some experimentation, worked pretty well.  I'll post some pics of the process for anyone that's interested.

[railandsail]

Like to see your jig,...method.

[gregc]

cardboard (cerial box, not corrugated) can be taped temporarily to the side of styrofoam block and used as a guide for a hot wire using something as cheap as the one below or something more expensive.   this means the grade has to be built up from foam that's not too wide.  Once cut, additional foam could be added to the side.   but the cardboard templates are a bit more complicated if the grade is curved, each template is different.   Multiple piece of cardboard can be taped together to make lengthy templates

[Piscesman]

Sorry about the image sizes....just getting used to this forum!  Our jig for making risers out of extruded polystyrene is made from 1x4 pine and 1/8" Masonite.  We made the inside 24" long and cut 3 1/2"-wide blocks from 2'x8' sheets of 1/2" foamboard.  Using a circular saw (or jigsaw) we cut a the slot for the saw blade in both sides at the same time to ensure uniformity.  So far, the best saw seems to be an 18 teeth/inch hacksaw blade.  Final result was two pieces of riser at approximately 2% slope (1:50).  If you need to follow a radius, you can cut slits in the riser on one edge to make it curveable.  It took some trial and error to get a feel for the cutting, but we think it was worth it.  We just glue the risers onto the baseboard to provide transition slopes between layers of foam.

 

 

[rrebell]

In future look to Woodland Scenics for their inclines, work great.

[mbinsewi]

Picesman, in order to see your pictures, you have to sign in to a Google account.

Mike.

[MisterBeasley]

I've done this a couple of times.  My suggestion is to make the entire grade a separate piece.  Cut the grade on one side of the foam, then flip it over and use the uncut edge on the other side to lay the track, thus giving you a flat surface.

Or, use a separate piece, again, and support it from below with risers so you don't have to cut at all.  I've found that's the easiest solution.

[crzink]

Our club built a "grade jig" comprised of the metal house studs our layout is built with.  The jig is two metal 2" x 4" house studs 8 feet long laid horizontally, separated by a metal base wide enough to cut (a foam plank) the width of a double track mainline.  The metal base runs from the bottom of the joists at one end at a pitch of 1%, therefore rising 0.96" over the 8 foot (96") length.  You essentially create a metal trough with a 1% gradient from one end to the other.

The bottom end of the ramp must be set so that the thickness of the foam plank puts the entire foam plank below the top of the joist, and the top end of the ramp puts the bottom of the foam plank also at the top of the other end of the joist trough.

We cut 8' long foam "planks" from 1" foam 4' x 8' sheets the width of a double track mainline.  Place the plank into the trough, and using a hot wire cutter held carefully against the top edge of the trough, slice the foam from one end to the other.  This gives us a 96" piece of foam about 3-1/2" wide, that tapers from essentially zero thickness to 1" at the other end.

If curves are needed, using the hot knife, slice very thin wedges on one side of the ramp from the outside edge inwards, past the centerline, about 2" deep, and about 3" apart.  Then do the same thing from the other outer edge, being careful to not connect to the opposite side wedges.  The ramp now will bend any direction needed. Cut to the length needed, and glue to the layout

To make a steeper grades in 1% increments, simply cut additional ramps, and glue in place on top of the original 1% ramp.  Contour as needed.  You can even make graduated grade "transition" ramps by cutting progressively shorter 1% ramp pieces and gluing then to each other.  For examle, the first 8 foot 1% ramp then gets second 1% ramp 5 feet long glued on starting at 3 feet from the zero end, then another 1% ramp 3 feet long glued on starting at 5 feet from the zero end.  This gives you a 3% grade for the last 3 feet of the total 8 foot ramp.

Best,

CRZ

TWMRC

[BroadwayLion]

The better way to do this with foam is to lay out where the track will be, and then cut out that roadbed cookie cutter fashion, and then raise the whole thing at once putting the propper suppors under it. I found this cookie cutter to work very well in plywood, there is no reason why it will not work in foam. Just be more careful with it, for it is fragile, and it will need far more support.

 

Another way to work this is to stack the layers that you want and then use a spray foam on top of this. The spray foam will hold things together nicely and will be ezsier to sand and shap, or so I would think, not having tied it yet, but do have the cans of foam waiting in my train room for my attention. Of course I was going to use that for a hillside and not a trackway, but you try what you try and then report back to us.

 

ROAR