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Building a custom foam insert

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#1 Hilmi

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Posted 05 February 2013 - 04:45 AM

OK, I have been considering building my own custom foam insert to make a transportation box for my G11 mount head. So I figured the cheapest way to do it would be to build a mold out of construction foam. I figure that if I put a tough plastic bag nested within another bag, then pump the foam into the bag while it is hanging over the mount so that it drapes over it and let it cure. The idea being that the foam would expand in the bag and conform in shape to the shape of the mount. I would wait for this to cure then shape the sides so that they would squarely fit inside a small suitcase.

Has anybody tried this before? Do you see any possible problems? Would the double bag be enough security against leaks while the foam cures?

#2 zippeee

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Posted 05 February 2013 - 09:07 AM

There are actual products made for this. They work very well, we use this type of material to pack precision items at our machine shop.

Check it out: Flashpac

#3 Hilmi

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Posted 05 February 2013 - 10:00 AM

I'll need to check if it is locally available. If not, I will still have to use my improvised method

#4 csrlice12

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Posted 05 February 2013 - 11:19 AM

Problem is that once your mount is surrounded by foam, you have to be able to "cut" the foam into the top/bottom pieces, and if the mount has any undercuts or areas where the foam can "wrap" around something, it would be hard to get off. Once off, however, excess foam can be removed. If you have access, put the mount into a bag and remove most of the air with a vacumme cleaner (or other suction device like a food wrapper) and seal the bag. This should prevent any foam from getting into the mount. Don't completly vacumme seal it though, as, if the bag punctures during the procedure, it'll suck the liquified foam into the bag/mount. Just seal it enough for the bag to conform to the shape of the mount. I'd also allow time for the foam to completely cure and outgas before actually using it. Not that outgassing would hurt the mount, more for the benefit of the foam to completely set up.

#5 neotesla

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Posted 05 February 2013 - 12:21 PM

The one thing that may not be good about the foam is that when it does set, it tends to get a bit brittle, and will crumble under weight over time. One telescope I have came packed that way, and I hesitate to use the box, because the plastic coating over the foam has torn, and the disintegrating foam gets everywhere when disturbed.

#6 Hilmi

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Posted 05 February 2013 - 01:02 PM

Its OK. I finally managed to get a case with pluck foam that was big enough to fit my mount and all mount accessories and was available locally at prices that didn't involve selling body parts to fund. Now to figure out how to pluck the foam in a way that sort of molds around the mount head. Never done this before.

#7 csrlice12

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Posted 05 February 2013 - 01:10 PM

Zilladude's off the wall idea # 372 for today: open the case, place a board capable of supporting the mount across the case; lay it on the board (you may need someone to help hold it) as it would lay in the case; take a long marker and "trace" the outline of the mount; then pluck out the foam with your fingers (you can make ititial cuts with a knife).

#8 Hilmi

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Posted 05 February 2013 - 02:05 PM

Doesnt the pluck foam need to confirm to the shape of the bits that stick out sideways like the motors for example? i.e. I can see how its done if you wanted the entire depth of the foam with the same profile, but if I wanted parts of the foam at the bottom hollowed out more than others to sort of have a form fitting hole. How would I do that? Or am I just over complicating this?

#9 csrlice12

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Posted 05 February 2013 - 02:29 PM

Just use your fingers to pluck out deeper in those areas, also, don't know how you planned the case, but you may need to do the same thing to the lid, unless the case is deep enough and has Egg Crate or foam in the lid.

#10 Pinbout

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Posted 05 February 2013 - 02:42 PM

but if I wanted parts of the foam at the bottom hollowed out more than others to sort of have a form fitting hole. How would I do that?



an electric knife can do a lot.

#11 Hilmi

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Posted 05 February 2013 - 11:57 PM

Just use your fingers to pluck out deeper in those areas, also, don't know how you planned the case, but you may need to do the same thing to the lid, unless the case is deep enough and has Egg Crate or foam in the lid.


Ohh, its plenty deep enough. I accidentally purchased a size too big. I think I might be able to fit most of the mount in there upright! And the cover does have that egg carton pattern foam. I'm thinking this case is big enough for the mount head, counter weights, counter weight shaft , Gemini 2 unit, hand controller, cables and my 2 year old son.

I don't know what I was thinking when I bought one this large. I just looked at this one and the next one down in size and this was the same price as the smaller one and I went for the bigger thinking I was getting better value for money.

#12 Brent Campbell

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Posted 06 February 2013 - 07:13 AM

Check out the company www.mycasebuilder.com. I did a review of my eyepiece case that I built with their service. It comes out awesome! Easy to do. I tried cutting various foams and nothing worked.

#13 Hilmi

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Posted 06 February 2013 - 09:11 AM

Thanks Brent, I did know about about that site, but I decided that to get an exact mold of the mount designed would be too complicated.

Anyway, for now I have the pluck foam case and that will have to do.

#14 EFT

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Posted 06 February 2013 - 09:35 AM

Thanks Brent, I did know about about that site, but I decided that to get an exact mold of the mount designed would be too complicated.

Anyway, for now I have the pluck foam case and that will have to do.


Hilmi,

I would try something like Instapak rather than the construction foam. I would be very worried about getting the expanding construction foam on anything and it makes a terrible mess. Just search for "expanding foam packing material" and you will find it online. Many pack-and-ship places also have it.






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