a few questions regarding pouring the foam:

1) The temperature here (Colorado) is well below the 40-50 degree level described in the paragraph below. So if i pour outside, i am likely to get only 50% expansion. I assume that this will make the cured grips denser and therefore heavier?

2) How can I make sure to get good expansion when working with the foam?
The expansion process sounds really fast with this stuff, so... if i kept all the components (foam containers, pvc tubes, mixing cups, etc.) warm inside and quickly moved the stuff outside and poured, do you think i could still get good expansion?

3) US composites states that you can work in a garage with a heater, but also states that the product will "out gas carbon dioxide" and to use it in a well ventilated area. Is it safe to use in a garage?, and does it give off a odor? Our garage is underneath the kid's rooms and my wife has a nose like a bloodhound!


Thanks for any help, appreciate it!

Carrington Tate
Fort Collins, CO

This is from the us composits FAQ page:


The two things that are most important to achieving good foam expansion are as follows.
1. Temperature. If working below 80 degrees F you will notice a slight reduction in expansion. If trying to work in 40 to 50 degree weather you will be lucky to get half the ideal expansion. Try to work in a heated area, the liquids are not considered flammable so you can use a heater nearby. Also be sure to warm up the product before use to at least 80 degrees, either by storing in a heated room or by submerging the containers in a bucket or warm water. If you're already working in warm conditions these temperature precautions are probably unnecessary

You will need containers to measure and mix the foam and stir sticks to mix the two parts together. Gloves and eye protection are strongly recommended. This product will out gas carbon dioxide when expanding so for safety you should always work outdoors or in a well ventilated area. You can use a solvent such as acetone, denatured alcohol or lacquer thinner to clean up when the product is still liquid, however urethane foams will stick to virtually everything except slick plastics so you should cover-up anything you do not want the foam to damage.

They won't really be any denser and you'll have more voids. I'm not sure I'd try it in that temperature. You're getting way below what the manufacturer recommends even if you have your parts warm when you start. I'd do it inside and try to keep things above 60F.

The outgassing of CO2 is only a problem as it concerns how much oxygen you need to breathe. There is no odor to speak of, but in a small, very tight room, you might not get enough oxygen to keep you upright. But really, that's an extreme situation and not likely to be encountered in a basement or garage. A closet, perhaps, but not the type places where most rod builders work. The stuff is pretty darn safe, really.

Gloves and eye protection are recommended due to the fact that the stuff "sticks' like the devil to anything it gets on. And it's tenacious. Just don't get careless and spill it on yourself or your wife's furniture or carpet.

Within the right temperature, the stuff is really easy to work with and makes beautiful cores at little expense or trouble. I was talking with JP Timberlake just this morning and he commented on how easy it's been for him to pour his own grip cores.

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Thanks Tom, that is what i wanted to hear! Sounds like i can move operations to the basement which stays pretty mild. I sure didn't want to have to wait until spring to pour some of these cores!

Thanks
Carrington

I've pretty much used up the last of the 4lb kit I purchased about 10days ago and it's likely I will wait until the outdoor temps here in southcentral PA climb back into the 80s before ordering any more. It's probably just me and the fact that there's no way to raise the temps inside my house much above 70ºF this time of year, but I had a heck of a time getting decent cores. At first I was making sure to get the stuff mixed and poured into the PVC pipe inside of 25 sec, which didn't work out too well because Part B is quite thick at <70º and not nearly as viscious as Part A. Once I realized that the stuff wasn't going to set up inside of 45 sec at the temps I was working in and started mixing it for a full minute before pouring, things went a little better. Still the cores never did turn out completely uniform. There were far too many air pockets to be used as a base for flocking without using some sort of coating between the core and flock adhesive. For most pours, at least 1/4 of the stick was so badly formed that it ended up being tossed.

My advise to those who live where it's currently bitter cold and do not have the means to jack up the inside air temps to the upper 70s is to think hard about waiting to purchase the urethane foam kits and maybe go with preformed blocks for now. At least for me, until the temps are more suitable, my foray into the use of this new technique are going to be put on hold.

Your voids may be due to something other than temperature (although low temps don't help). Over mixing can introduce large amounts of air into the mix. And, waiting longer to pour means that the stuff is already expanding. When you do this in a long tube you may end up with areas deep in the tube that are then too thick to allow the air below to fully escape and the result is a void or air pocket left in your core.

Once you move outside the 45 second range, you won't get a good pour, regardless of temperature. Mix for more than about 20 to 25 seconds or wait too long to get the stuff in the tube and you will have voids.

Obviously, warmer is better, but voids often result from the mixing and pouring operations.

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Thanks Tom! I willingly admit that I really stirred the stuff in an attempt to get the two parts uniformly mixed. The part A was a dark, molasses color and the B a clearer epoxy resin color and I made every effort to end up with a cream like color before pouring. No doubt that I probably added a bunch of air to the mix and I'll attempt to avoid that with the next kit.

I had a chef present while I was mixing one batch. He told me that I wasn't stirring properly and showed me how the "professionals" do it. We ended up with a bunch of air pockets and voids in those cores. I went back to my regular old 20 stirring routine and things improved tremendously.

With the open pan type mold, you almost never have voids. The pipe mold originally bothered me because I worried that the stuff trying to expand only had that one slim length to do so in - what would happed if the stuff on top got too thick and the stuff underneath it was still trying to expand? What would happen to air pockets, etc.? I wasn't sure exactly what would happen and was prepared to dump if it things didn't work out well. But so far, the method I've outlined in the article seems to work very well in almost every case involving the tube mold.

Still, as more and more people give it a try we're sure to find things that don't work well. I can tell you this, even with the release agent liberally sprayed on the inside of the tube, if you try to pour cores more than 18 inches long you'll have a hard time getting them out of the tube. JP Timberlake discovered this recently and we spoke about it this morning. At 24 inches, you have to beat the stuff out of the tube. That's no good. Less than 18 inches or so, however, seems to be absolutely no problem at all.

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What about splitting the pour tube lengthwise and using hose clamps to hold it together, would that make it easier to remove from the tube? Or is the stuff so thin that it would make a huge mess with liquid running though the seam in the tube?

Speaking from a plumber’s perspective;
If using PVC and the stuff get hot as mentioned before it will push the halves apart the further you get from the clamps the worse it will be. It will most likely deform the pipe also so that at best you will only get one pour per piece.

The tubes aren't any problem, they work well. But you don't want to try and form extremely long cores with them.

A clamped together contraption would likely be forced apart as Steve mentioned, at least enough to allow expanding foam to seep out and create a mess. I'd stick with the one piece tube, but that's just me.

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Well so much for my plans of pouring 24" cores............Unless my trip to Tap Plastics comes up with a mold material. I do happen to have a bunch of PVC tubes just laying around though.....To show you just how crazy I am I was thinking about using CLEAR tubing to make the molds so I can see what was going on inside during the process....you would also be able to SEE if you got a complete coat of release agent in the tube.

Anybody tried COLORING the cores yet?

Derek L. McMaster
Rohnert Park, CA

Born to Fish, FORCED to Work

The next issue of RodMaker has plans for a multi-mold pouring station. It allows you to get the most out of each pouring session. Remember, in the long run it ends up being easier to pour two 15 inch cores than a single 24 inch core. For that matter, it's easier to pour four 15 inch cores rather than a single 24.

If you cap one end of the tube (set it on the ground) and then spray the release agent into the other end for just 3 or 4 seconds, you'll get complete coverage.


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Working on a multi-core pouring station right now as a matter of fact.

Might have to give up on the 24" cores and just try 18's......I am making the caps extra thick to hold the core properly centered while the foam expands. I am also working on a way to use a compressor to blow the cores free vs hammering them out if they get stuck.....Used to build some MAJOR potato guns back in the day........Might be interesting considering I live in a manufactured housing community.

Derek L. McMaster
Rohnert Park, CA

Born to Fish, FORCED to Work

Not sure what you mean by "caps," as one end has to remain open. If you get a good coating of the release agent in there, the cores won't get stuck. Usually it just takes a few taps on one end to get the core moving. Then you can grasp them by hand and just slide them on out.

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