# Bit for Blue Dow



## Steve Ash (Mar 16, 2008)

We make pre-cast concrete countertops. In the mold-making phase we use 2 1/2" thick Blue Dow Styrofoam for our sink knockouts. In the past, we have used a band saw to cut out these forms. After tracing the pattern from the template, we cut it out leaving a little extra and then carefully sand it down to the exact shape... these are usually circles or ellipses. 

I would like to start using a router but I'm not sure which bit would give us the smoothest cut through the Styrofoam. Any suggestions on type? 

Any ideas on a jig for circles and ellipses? I see that Rockler has one that looks like it might work...


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## Hamlin (Dec 25, 2005)

Hi Steve,

If all you're cutting is styrofoam, a straight bit shouldn't be a problem. For circles and elipses, you might consider making your own.


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## bobj3 (Jan 17, 2006)

Hi Steve

The Rockler jig works very well, and it sounds like you will need a extra long router bit(s) as well. 

The links below may help..

http://www.routerforums.com/jigs-fixtures/7228-eclipse-jig-how-make-one.html

http://cgi.ebay.com/1-pc-1-2-SH-2-1...50386QQcmdZViewItemQQ_trksidZp1742.m153.l1262

http://cgi.ebay.com/1-pc-1-4-SH-3-B...50386QQcmdZViewItemQQ_trksidZp1742.m153.l1262

http://cgi.ebay.com/1-pc-1-2-SH-3-B...50386QQcmdZViewItemQQ_trksidZp1742.m153.l1262

http://cgi.ebay.com/1-pc-1-4-SH-3-B...50386QQcmdZViewItemQQ_trksidZp1742.m153.l1262


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## Steve Ash (Mar 16, 2008)

Thanks, guys. I ordered a bit via one of the links above. Much appreciated. 

Now I'll take a look at your info on the jig.


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## bobj3 (Jan 17, 2006)

You'er Welcome sea Steve

You may want to get the 3" long one also...for that price they are hard to find, I think you said you are cutting 2 1/2 deep stock... 



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Steve Ash said:


> Thanks, guys. I ordered a bit via one of the links above. Much appreciated.
> 
> Now I'll take a look at your info on the jig.


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## Dr.Zook (Sep 10, 2004)

Hey Steve, welcome to the Router Forums.


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## Steve Ash (Mar 16, 2008)

bobj3 said:


> You'er Welcome sea Steve
> 
> You may want to get the 3" long one also...for that price they are hard to find, I think you said you are cutting 2 1/2 deep stock...
> 
> ...


Definitely. I forgot bout the thickness of the Rockler ellipse jig. My router has a plunge depth of 2 3/4"... guess I'll still need the longer bit, huh?

I'll order some more bits when I get home tonight. I need a round over as well. I see you have several.

I appreciate the help.


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## Steve Ash (Mar 16, 2008)

Dr.Zook said:


> Hey Steve, welcome to the Router Forums.


Thanks Dave. Nice forum you have here... very helpful.


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## Dr.Zook (Sep 10, 2004)

Steve Ash said:


> Thanks Dave. Nice forum you have here... very helpful.


Hey Steve, it's not mine, it's ours.  I know what you mean. We do have an excellent forum with great members.


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