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Foam cutting tips?

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#1 Cathexis

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Posted 06 August 2014 - 09:44 AM

Greetings All,

 

The foam I'm taking about is what usually sold as "solid foam." The stuff you pack your

accessories into for storage. But what I'm trying to figure out is how to cut a curve so

that you can *lay* an eyepiece or other object down on the foam. So not a plug you push

the eyepiece into, but rather a custom-shaped "scoop" that holds it laying lengthwise. I've

tried to google this but, "how to cut curves,etc." searches end up with jig-saw like cuts of

foam board. Imagine you want to custom cut solid foam to lay all your precious Tele Vues

on their sides in the foam - that's what I'm trying to get ideas on.

 

TIA,

 

Cathexis



#2 Starman1

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Posted 06 August 2014 - 10:33 AM

You could lay the eyepiece down on the foam, outline it with a Sharpie on the foam, then, cutting just inside that line, use a steak knife to cut the foam.

The bottom of the cutout would be squared, of course.

If you really want the socket for the eyepiece to be rounded on the bottom, matching the eyepiece, then you will have to find a material that is putty

consistency into which you can push the eyepiece and which hardens thereafter.

Must simpler to just simply cut around the edge of the eyepiece.



#3 BarryBrown

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Posted 06 August 2014 - 10:34 AM

Cut out a plug all the way through the foam. Remove the plug.

 

Shape the plug the way you want. For eyepieces, it doesn't need to be fancy. Just a straight cut will do it.

 

Insert the shaped plug back into the hole.

 

To keep everything snug, make the hole slightly smaller than the object being put into it. But don't worry too much. You really only want to keep eyepieces from banging around and hitting each other. With no moving parts, they are actually very sturdy. I regularly pack $6,000 of photographic lenses into a shoulder bag with less padding than my eyepiece case.



#4 BoldAxis1967

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Posted 06 August 2014 - 02:02 PM

I have used the method described by Starrman 1 and found the Sharpie trace, cut on the inside of the trace with a knife to be easy, relatively quick and provide a good fit. 

 

Once, I tried a hot foam cutter. I do not and would not recommend it.

 

L.



#5 mclewis1

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Posted 06 August 2014 - 03:12 PM

For shaping foam for various accessories I've found that box cutter/utility knife blades work very well. I usually buy a 10 pack of the wider (1+") and one with the narrower (1/2" I think). I hand hold the narrower blades (carefully), and I've found the big ones work well for longer straight cuts and the narrower ones can even cut a reasonable curve (although the inside cut for 1.25" eyepieces is a bit tough).

 

The idea is to always use a fresh "virgin" blade for cutting foam. Work slowly and with short strokes and you can end up professional looking custom foam inserts in your storage boxes.


Edited by mclewis1, 07 August 2014 - 02:05 PM.


#6 Geo.

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Posted 06 August 2014 - 03:58 PM

Hot knives are intended for polystyrene foams. I don't know what the case foams are but they may be a vinyl and could produce hydrogen chloride fumes. You definitely don't want to be using heat around isocyanurates like polyurethane, hydrogen cyanide is lethal.



#7 BoldAxis1967

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Posted 06 August 2014 - 04:06 PM

 "Hot knives are intended for polystyrene foams. I don't know what the case foams are but they may be a vinyl and could produce hydrogen chloride fumes. You definitely don't want to be using heat around isocyanurates like polyurethane, hydrogen cyanide is lethal." Geo

 

Geo: You are correct. I was doing this outside and with a special mask.  After a few minutes I realized that this was not the way to go.

 

L.



#8 Cathexis

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Posted 06 August 2014 - 04:15 PM

All replies have been very helpful.

 

I thank each of you,

 

Cathexis



#9 JMKarian

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Posted 06 August 2014 - 04:16 PM

Having cut my share of foams for camera lenses:

 

1. Outline desired cut with a fine sharpie and / or mark corners with toothpicks. Good quality higher density  foam is the best.  

2. Place foam in freezer for a few hours. Keep dry.

3. Use a sharp,  serrated, thin knife blade

4. Consider doing only two holes at a time before re-freezing. 



#10 CharlesW

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Posted 06 August 2014 - 05:26 PM

You might also consider taking your foam and case to a person that does custom car upholstery. They cut foam eight days a week and could probably do your whole job in 15 minutes. 



#11 Pinbout

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Posted 06 August 2014 - 05:33 PM

I like electric knives. White artist tape helps keep the lines straight.

 

Telescope Eyepiece Case: http://youtu.be/_Cz4OdwrhF4



#12 skfboiler1

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Posted 06 August 2014 - 06:04 PM

I found more Youtube videos using electric knives.  That looks like the way to do it efficiently.  The pick an pluck foam that came with my case is not holding up.  I'm glad this topic was brought as I am thinking about replacing it with solid foam.



#13 cadfour

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Posted 06 August 2014 - 09:25 PM

geez...did you all cut the foam??  (ok i had to let the 13 year old in me out...sorry)



#14 Chuck Hards

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Posted 06 August 2014 - 09:47 PM

Steak knives are for cutting steak.  Use a long blade craft knife, similar to an X-Acto, only about 2 or 3 inches long.  Or a long box-cutter blade of similar length.  The sharper the blade, the cleaner the cut. 

 

Coincidentally, I just posted this in the Classics forum tonight, a new foam insert for an eyepiece case to hold old eyepieces and accessories.

 

http://www.cloudynig...eces/?p=6150727

 

I cut the insert from a piece of closed-cell foam on the table saw (this is not 'foam rubber' or packing foam, it is a bit stiffer and doesn't absorb water).

 

I then drilled eyepiece holes on the drill press, using a Forstner bit and a platform "jig" to hold the foam.  Different size bits for different size eyepieces.

 

Here you can see the wood platform, under the foam.  It is screwed to the drill press table.  On the back is a fence glued and stapled to the platform, which allows the foam to slide sideways after each hole is drilled, keeping them all lined up straight.  The platform is repositioned after each row of holes is drilled.

FoamFabrication003_zpsd0206277.jpg

 

FoamFabrication002_zps2e0270cb.jpg

 

The finished case, with a square opening for miscellaneous items.   
EverythingElsecase_zps9296e403.jpg



#15 RTLR 12

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Posted 07 August 2014 - 04:26 AM

I use an electric knife to cut open cell foam. I make a template (2-one for the top and one for the bottom) and use it as a guide to cut odd shapes. I use a sharpened cookie cutter to cut round holes for eyepieces. I use various or muliple  thicknesses of foam to fit the object and use a solid bottom piece underneath it. When I'm done I make a cover piece of thin rubberized foam for the top. This helps to keep the foam stable and hold it's shape and it will last longer. You can see it here in my CG-5 case. I buy my foam from Foam Factory.

 

 http://www.foambymai...aging-foam.html

 

Stan

 

 

Attached Files


Edited by RTLR 12, 07 August 2014 - 04:35 AM.


#16 Geo.

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Posted 11 August 2014 - 09:08 AM

I've found that neat holes can be made quickly with bimetallic hole saws. These are pretty aggressive so I run them in reverse.

 

A case like Chuck's is going to take a bit of work at the gym to handle :lol:



#17 Chuck Hards

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Posted 11 August 2014 - 09:52 AM

 

 

A case like Chuck's is going to take a bit of work at the gym to handle :lol:

 

 

I was definitely surprised when I closed the lid and lifted it.  All those eyepieces do add up!








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