For those of you that have made foam cores, here is a question? If you are making a 12 in foam core who many cc's for parts a and b do you use? I have only try this once and used 10 cc each and it seems like that was not enough. Just trying to save some time and product from waste. If any one would care to expand on this topic. thanks again for all your help.

Hi Brad - I'll chime in here not claiming any expertise but have pour a few cores.

I used ounces as my unit of measurement, not CCs. Most measuring cups are graduated in oz. I started with 2oz of water then poured that into a dixie cup and made a mark. Made cups for part A and B. Mix them together and pour and at room temperature (72 degrees) that resulted in about a twelve inch core, for me. Your results may vary.

But wait, there's more!

That didn't seem like enough core for that amount of fluid and knowing that this stuff is sensitive to temperature I got out an electric space heater and placed the PVC directly of the heater, for a while maybe five to ten minutes. With the same amount fluid the core expanded to eighteen inches. Let me say with a fair deal of pride, I haven't put any foam on the ceiling due to an exothermic explosion.

My final offer, if you call within the next thirty minutes I'll include this next tidbit of information.

Using a thirty inch (heated) PVC mold I used three oz. of fluid that gave me a twenty eight inch core. Of course I then I just cut of whatever length of core that I need.

At first I was skeptical if the foam was some how changed due to the heating but have now formed most of the cores and they work great.

Hope this helps.

Mike

I'm real happy with the cores I'm producing now and have pretty much narrowed it down to two molds to cover all my needs.

12 1/2" long (fits perfectly on Lamar mandrels) by 1 1/4 diam. and 1 3/4 diam.

I use 23ml each part for the 1 1/4" and 32ml each for the 1 3/4". Which works out darn close (within 1ml) doing the math too.

For smaller molds Scott Parsons is right on about weighing it out on a digi scale with the 1.15:1 ratio but for the size mold I'm using the 1:1 seems to work just fine and since the B has a thicker consistency and leaves a little more residual left behind on the pour I figure I end up real close to the correct ratio anyways.

I also like to work with it around 80 degrees.

Hope this helps.

Thanks for the resposes. It really helps out alot. Do you think that it would be easier to pour say a 25-36 in core and cut to length rather than pour 3 12.5 in cores at one time. My thinking is that because of the time issue that pouring one verse 3 at one time would be better..

I would not pour 36 inches. Even with mold release, the inside of th pvc is not totally perfect and A 12 inch core takes some effort to remove. I believe it would be very difficult to get 20+ inches out of the mould. Just MHO.



Edited 1 time(s). Last edit at 04/22/2008 11:28PM by Bill Lane.

I can only speak for myself but I started pouring with much longer lengths and just found to many inconsistencies.

Like turning a real nice piece and then oops an air pocket. Trash that one.

Also I just couldn't come up with an easy way to get the cores out of longer molds. Broke a serious bead trying a bunch of different ways too. Maybe someone else has figured out a better way.

And the longer the center rod is the more likely it bends a little, or a lot if you pour staight down one side only, since the liquid that will stick to the sides starts expanding. With the shorter length I've got them pretty much concentric right out of the mold.

I just find that 12 1/2" is enough for both the rear and fore grips in most applications. And I've only built a couple of rods that would call for anything longer than that as a single section.

I just pour one at a time every 40 minutes while I'm actually doing other things and before I realized it, last count I had more than 200 on hand.

I think that anyhting over about 15",s would create more problems than it's worth.

Mike (Southgate, MI)
If I don't want to, I don't have to and nobody can make me (except my wife) cuz I'm RETIRED!!

I don't know but maybe it's because I heated the inch and a half Schedule 40 (thick wall PVC) that I got a consistent twenty eight inch core. Temperature seems to be a critical issue. We won't see eighty degrees around here for more than a month so that's why I thought I'd use the space heater to preheat the tube.

The only time I had trouble pulling the core is when I forgot to put Stoner on the wax paper that covers the end plug.

I build mostly salmon/steelhead casting rods. We like 12 - 14 inch grips and make fore grips or fly grips with the remainder.

I'm not adverse to going to Plan B but until I experience the air pockets or some other problem this seems to work for me.

My next endeavor will be to flock the cores but I sure like the sleeves.

Thanks

Mike

Per the information in the article, once you move much past 15 to 18 inches in length, trying to get the core out of the mold/pipe can become a real chore.

Also mentioned in the article - if you come up short, that is, if the foam doesn't expand to the length you needed, just mix up more and pour in on top of what you have now. It will bond tenaciously, effectively forming a one piece core. There is no weak spot where the two cores join with each other.

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