making straight cuts on foamboard


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Old 09-26-16, 07:53 AM
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making straight cuts on foamboard

I have some large sheets of foamboard (like what real estate signs are made of)- The sheets are 4' x 8' but I need to cut a few inches off the 8 foot side. Is there an easy way to cut the long side straight??? When I tried with razor knife- the cut did not look very good- Any thoughts?
 
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Old 09-26-16, 08:16 AM
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Are you using a guide of any kind?
 
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Old 09-26-16, 08:28 AM
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If you are talking about foamcore..two pieces of poster board with foam in between...I use my circular saw with a straight guide. Leaves a factory clean edge. I put it on top of a piece of foam insulation board to support it during the cut.
 
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Old 09-26-16, 09:24 AM
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too thin for circular saw- it's same material as real estate signs.... bendable...yes used a 1x4 as a straightedge- the razor knife tends to "drift" when cutting... Wasn't sure if I could use 2 pieces of wood somehow to keep knife straight
 
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Old 09-26-16, 09:53 AM
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When using a straightedge as a fence you need to keep the knife pressure towards the fence. You also want to make sure that the fence is held tightly against the material being cut.
 
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Old 09-26-16, 10:20 AM
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On something that thin you could clamp a guide on each side, if that would help you.
 
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Old 09-27-16, 07:08 AM
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There's a particular blade recommended for this that works far better then a box knife. It's almost as thin as a shaving razor and just as sharp. You might find it at a good hardware store, most definitely at an art supply.
 
 

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