I have made a Mold out of Silicone to cast my own foam cores for carbon fiber grips. My 1st attempts at this are definitely not acceptable. I will be picking up a paint mixer tomorrow to try it again. I had large air bubbles in the foam when I cut it open (for inspection) as well as resin visible instead of the cream colored foam. I attribute this to not being properly mixed. I will fix that issue tomorrow. However, I was expecting the foam to be - shall I say "tighter" and similar to the CFX foam cores that I have purchased. Has anyone that makes these cores themselves found a material that resembles the CFX cores?
The material I just tried was Alumilite 610 - 6 lb density.

Jon Hood



Edited 2 time(s). Last edit at 04/20/2019 07:31PM by Jon Hood.

The original article on the technique specified US Composites 8lb density foam. It seems to work well under a wide variety of conditions.

Air bubbles and voids can also be the result of over-mixing which tends to create bubbles.

Captive molds may not release bubbles as well as open type container-molds as specified in the original article.

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I responded to a similar post a few weeks ago. I do not see the point of going through the hassle, mess and time of casting a foam core to eventually be skinned with CF or other fabric! Unless the mold is absolutely perfect and of a simple, straight taper, sanding will be required anyway. Why not eliminate the hassle, mess and time required to cast the core and simply start with a foam block specifically designed for composite sandwich construction? Divinycell is available from Aircraft Spruce and Specialty in different densities, thicknesses and sheet sizes. Shaping and sanding is ultra-easy and quick. Even their 3lb/cu ft sheets are probably more dent-resistant than home-made 6lb/ cu ft pour foams! You will find the cost per grip will be less than $3.00 each. Make your life easy and check it out.

Mark Talmo
FISHING IS NOT AN ESCAPE FROM LIFE BUT RATHER A DEEPER IMMERSION INTO IT!!! BUILDING YOUR OWN SIMPLY ENHANCES THE EXPERIENCE.

The foam in the CFX grips was explained to me, without telling me exactly what it was, as a foam made in a nitrogen rich environment to reduce the chance of bubbles. It produces a foam according to them that is as tough as approximately 18 lb foam with a weight of around 6 lb foam.

hi Spencer..so instead of 80% nitrogen rich bubbles they are 100% nitrogen rich bubbles..lol.

Tom,
I have ordered (Rod maker)10-6 and 11-1 (have already received - waiting on the prior) this issue so I will be better educated with this foam core technique soon.
As far as my mold - I have air vents to release the air as much as possible, and have read that applying back pressure to the foam will actually reduce air bubbles. I will update this post when I cast a few today.

Spencer,
Thanks for the information - now I won't be wondering why the @#$%& my foam cores are different than the ones we buy!

Mark,
Yes, I seem to remember you responding to my post a few weeks ago. I am sure what you are talking about will work and may be the easiest, greatest way to do what I am doing. I will definitely look into it. But for now - I am interested in forming and casting the cores. The first ones I make will be just straight cylinders -1.25" dia x 15" long and will have to be shaped. However, if I am satisfied with my results, I will make molds that are already shaped and will only need light sanding to remove the skin. So, while this may seem to be a hassle to you - it is not to me and I will continue to learn and experiment with this until I am successful or decide to give it up.
I guess I could make my life REAL easy as you say and just go buy a fishing rod from a tackle store, but whats the freaking fun in that !!!

Jon Hood

Temperature also plays a role. My cores come out better in warmer rather than cooler temps. There is a bit of an experimentation process to dial in on what works best for you.

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Yes, I read that as well. I am going to heat my silicone mold in the oven prior to casting the next core.

Jon Hood

As I stated above - I am back to report.

I purchased small paint mixer and adjusted the fins so it would fit all the way to the bottom of a plastic SOLO cup. I mixed full speed (approximately 1700 rpm) for 20 seconds, then immediately poured it in the bottom half of my mold, put the mandrel in place, set the top of the mold and clamped it in place.

Prior to pouring, I warmed the silicone mold to 110 F - 125 F, and put the bottles of liquid in hot tap water for about 20 min. The difference in the appearance and overall structure of the foam core is unbelievable!
The heating process was enough to continue casting the cores without reheating as it was heated again every time I cast another core from the exothermic reaction of the material. The cores are 1 5/16" diameter and 15" long. They require 1.25 oz of Part A and 1.25 oz of part B. Hope this info is helpful to anyone just trying this or thinking about it.

Jon Hood

Not sure if this applies to foam.. But with alumilite 2 part acrylic epoxy, the kind for turning on a lathe.. To get that crystal clear, no bubbles finish you have to place the cast in a vacuum chamber... I sae a video once where they did a side by side with a pressue chamber vs a vacuum chamber to see which worked better... Its surprising the ammount of bubbles that get forced to the surface.. Looks like a pot boiling over until you open the valve back up.. The vacuum chamber works better by the way... Lol

Again, this is for doing acryloc pours, not foam.. But if the goal is to get a closed cell product, i dont see why this wouldnt apply.. Worth a shot i would say

Anthony Unger Wrote:
-------------------------------------------------------
> Not sure if this applies to foam.. But with
> alumilite 2 part acrylic epoxy, the kind for
> turning on a lathe.. To get that crystal clear, no
> bubbles finish you have to place the cast in a
> vacuum chamber... I sae a video once where they
> did a side by side with a pressue chamber vs a
> vacuum chamber to see which worked better... Its
> surprising the ammount of bubbles that get forced
> to the surface.. Looks like a pot boiling over
> until you open the valve back up.. The vacuum
> chamber works better by the way... Lol
>
> Again, this is for doing acryloc pours, not foam..
> But if the goal is to get a closed cell product, i
> dont see why this wouldnt apply.. Worth a shot i
> would say

I wouldn't pour foam and put it into a pressure pot, the point of applying pressure is to reduce the size of the bubbles in the casting. With foam you want the bubbles to reduce weight and for structure, adding pressure would defeat that goal.

Vacuum wouldn’t work any way - it grows in seconds - not minutes - you would never have enough time to get it in the mold.

Jon Hood

See that... Learn something everyday