Little advice with smal parts.

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#1

Hello,

I made my first small part (Iphone case. first i did it by hand layup. I had a good vac-bag and after i repaired a few holes it was still at 0,85 bar vac. Only when the part was cured it looks very dry (see Photo’s) whas the vac to high?

After a layer of clearcoat it looks okee for the first one i think :slight_smile:

Today I triad to make the part whit infusion but for suds a smal part the infusion was ready by 30 min. I think did the infision -mesh wrong.

The layup whas:
3 layers carbon 204 gr/m2
1 layer glas 163 gr/m2
1 layer peelply
A little infusionmesh
a vacuum bag

I hope some wane could give me some advice.

After clearcoat on the outside…

Gr Henk

#2

And here are the pics from the infusion.

Gr Henk

#3

You will have no radio reception with a carbon case;)

Your layup was wrong for an infusion, take a look at the MTI thread and our video for infusion.
For vacuumbagging a wet layup reduce your Vacuum to about 650mbar abs, but that depends to the viscosity of the resin.

#4

Thanks,

I already noticed the radio had a bad reception, for the layup you mean from the center of the part till the edge around?

Gr Henk

#5

I think these small parts are perfect for press moulding. Is this a cover for a case, or a replacement cover for the one supplied?

Make a 2 piece mould, pour in a blob of resin (can be thickish), add the fiber, perhaps add some more resin (all in the middle) then close the mould, and add pressure. (sturdy moulds can be clamped with bench clamps). This should do the job.

I feel infusion is a bit complicated for such small parts.

#6

Hey Herman,

I thought about a 2-piece mold, and i think when this cover is a good one I will tray to make the 2e mold.

Thanks for the advice.

Gr Henk

#7

+1, it can be infused but a little too much work involved for a Iphone 4 case…a press mould will work better. In order to complete a unit with as little re-work (sanding & clear) I would spend some more time working on the mould and ensure it is as smooth as glass. It is important especially in a press mould.

#8

This may be a stupid question…

But are you guys serious that a carbon fiber case will give the phone bad reception? I am trying to make a couple cases now but don’t want to waste my time if thats the case :slight_smile:

Also, I am curious about how he is doing how mold. I made a mold of an iPhone case but the case has to grip the phone so when I pulled the first part out it broke the edge of the mold. It looks to me like he is infusing on a plug? is that possible?

I am also interested in how a press mold would work and how to make one.

#9

Carbon fiber will most certainly block radio frequencies.

#10

How badly does it block? Is it not worth making phone cases?

#11

Carbon fiber is conductive and will act like a Faraday cage. Jobs acknowledged in his bio that the original iphone metal case was chosen for looks alone in spite of his design team telling him it will cause bad reception. Use black glass instead. It will like carbon but is RF-neutral.

#12

HP-textiles sells black glass, looks a lot like CF, except the gloss.

#13

The black glas that looks like carbon will not work! It is Aluminium coated before coulored black to get the carbon look and also acts as an Farraday cage;)

#14

Do a Kevlar case, will not block RF. But won’t give you that “look factor” although ti will provide awesome abrasion resistance to the phone, hahah.

#15

I was planning on trying Kevlar. I have never used it before, only carbon fiber. I thought Kevlar was just a synthetic version of carbon fiber. Doesn’t it look the same?

Does anyone have any picture examples of a part made of Kevlar?

#16

Completely different fiber.

#17

But can’t you get it in a black/carbon look?

#18

You can get a hybrid fabric, in carbon/kevlar, but that won’t work well for you a cell phone application where you need clear RF transmittance.

#19

OK, I have seen the hybrid material but have never used any. I guess if nobody offers a carbon fiber look Kevlar than its not work making phone cases (if thats the looks your going for).

#20

Here is an option… I am not sure if you can get anything like it in the states though.

http://www.easycomposites.co.uk/Products/Kevlar-Aramid-Others/Black-Diolen-200g-1200mm.aspx