Model Railroading > Using a router on Extruded Foam panels?

Has anyone tried using a router on extruded foam board, 2"?

I need to sink an engine house base into the foam about 3/8" and it seems the best way to do it is with a router. Having said that I do not want to create a problem such as a friction-created fire, or some sort of foam snow shower in the room. I can deal with the dust issue but  am concerned that the router cannot be adequately controlled working in the foam.

Any thoughts?
Bob
 



Edited 1 time(s). Last edit at 04/21/15 05:13 by navarch2.

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I certainly wouldn't try it indoors.

KG

kgmontreal Wrote:
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> I certainly wouldn't try it indoors.
>
> KG

I agree, outdoors, and a mask for dust... Steve H...

 Get a helper and have them stick a vacuum hose near the business end of the router to assist with the dust control.  Good luck.

Shawn

cut the section out with a knife then shim the floor up to height

Ed Stewart
Jacksonville, FL

I've had really good results using an oscillating multi-tool, it's like a shaped saw blade that moves just enough to 'saw' back and forth. The result is much less debris and it doesn't throw it far, very easy to control. Not sure it can cut two inches though.

I've also used an Electricians drywall saw, once again not much debris and it doesn't get thrown around. A vacuum is a very good idea either way.

Use a hot wire foam cutter would be another way to do it. Using a router indoors is going to be a mess there isnt enough friction to cause any problems with fire but dust is another matter. No matter how you try it will be everywhere. What about doing that outside and then cutting a hole for it to fit in on the layout? I will be facing some of the same on mine when I start the scenery.

I wonder if a Roto-Zip may work better.  Smaller so it's easier to use although I'm not sure how it's RPM compare to a router.
I have one that I use for drywall and tile work and the thing is amaizing.

Doing a little search on Google it appears people say the 1/8 & 3/4 tile bit work great for cutting this foam when using the
variable speed setting at the lower 11,000 RPM.  Of course I have not tried it, but from a few different messages boards
it seems this way works good.

Kris



Edited 1 time(s). Last edit at 04/21/15 09:47 by dcmkris.

Wouldn't it be much simpler and cleaner to cut the entire foam section out and replace it at the correct height?  I think that's what Ed Stewart (calsubd) was suggesting.

Warren



Edited 1 time(s). Last edit at 04/21/15 11:14 by warrenpweiss.

I've used a router on foam board and it works great, but as stated, have someone with a vacuum handy, and the foam dust gets everywhere.  Depending on the router base, some models have an attachment to hook a vacuum hose to, otherwise have a friend help, as suggested.  The router does a good job and make a very clean and precise cut.

Ron Evans
Golden Valley, AZ

Just realized you're removing 3/8" across the whole area. Agree the Router would be only way to do that. Also agree it's gonna be a major mess.

I would have removed the whole chunk and then built it back up as a sub-assembly, ergo the saw ideas. I do have a Walther's roll dump to build and install so I'm curious how it works out.

I actually have allot of experience with 2" form. My whole 2nd deck is all 2" blue board.

What I would do is cut an opening straight though slightly smaller then the 3 track pit. Then slowly make small adjustments with small cuts until the pit can be "press fitted" into the space. I would slowly drop it down until it was at the level it was needed at. I would run the tracks and get it done. Once done, I would put latex liquid nails underneath to lock it in and if that area needed abit more support, a bracket or 2 for support.

Bruce

calsubd Wrote:
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> cut the section out with a knife then shim the
> floor up to height

That was going to be my suggestion as well.  I wouldn't do what you are asking about.

Rick

You are going to create a snow shower that you will never be able to get rid of. Far better to cut all the way through the foam with a knife and then back fill with a slab of foam or wood at the desired thickness.

Ted Curphey
Ontario, OR

I'm assuming this is 2" foam glued to plywood sheet?  If so, then the router idea may not be as crazy as some fear. Sure, it's gonna make a mess. A BIG mess, but as someone suggested, have a shop vac ready and sucking before the first cut. 

Now, if it's 2" foam over girder bench work, I think the better idea is to remove the whole section down to the girders and then shim your pit to the height that you require. That will be the cleanest, most mess free solution. 

imrl Wrote:
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> I'm assuming this is 2" foam glued to plywood
> sheet?  If so, then the router idea may not be as
> crazy as some fear.

All you need to route is the perimeter.  That will support the model.  The inner area can be gouged away.  Arm yourself with a big spray can of "Static Guard" or "Cling Free."  That will let you clean up yourself and your router. 

Been there,done that. Huge mess,but was worth it. Was easier to vacuum the mess than to do the cutting I would have needed to do. Would I do it again? Under the same circumstances yes,but honestly,I'd try something less messy first if at all possible.

           Tom

I used a router at my neighbor's garage. He had a shop vac and we had it running constantly. I started with 3" foam and we removed 1" for the main line ROW since this was going to be hilly area. Worked really well and I'd do it again.

Ryan Wilkerson
Fair Oaks, CA

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Thank you for all of the great suggestions. I will either try the router with a wide suction bell on my shop-vac to control dust, or I will cut it out completely from the 2" foam (over bench farmework) and re-add foam layers to build it up to where it needs to be. I'll try both methods outside on test foam and let you know what worked best. I'll have the same thing to deal with for the rotary dumper at the steel mill, and the turntable.

Thanks again to everyone who wrote in....

Bob