Casting Vertically

[moke]

I have been casting for while, in a 6x6 mold and cutting them apart. I like the results for the most part, but am thinking of trying Vertical casting into PVC tubes or even the clear tubes. I like the more finished look to a cylindrical blank.
I pour about 110 degrees...do you guys that pour a little colder to get it to mix or do you push it around with a dowel? I can pour it alternately of course, but how do you guys get the lengthwise color? I use Alumilte Clear Slow, mostly Mica powder, and a Cali Air Pot.
Thank You

 

[Leonardo]

I pour vertically using (mostly) clear PVC pipes. I got them from Tennessee Valley Products and my only gripe is that the ID is around .815 inches so they use a bit more resin than .75 inch molds and need a bigger collet. The interiors are much more consistent than PVC I got from Menards also, and this is reflected on the surface of the blank being smoother and more glossy. This doesn't really matter for turning them down though.

Regarding temperatures, I pour between 95-115 degrees depending on the effect I am going for. Pouring cooler will result in more color mixing which looks great in some combinations, but may turn muddy or grey in others. Also, depending on how fast you are pouring and how many blanks you are doing, you are going to get more and more color separation as you go. Pouring hot results in some very cool patterns, but it can be stressful to get the blanks in the pot in time to squash the bubbles. I've discarded a lot of blanks that I pushed to far on temperature which is always a bummer, but I have found this can usually be mitigated by trying to avoid making too many bubbles to begin with.

Regarding stirring inside the molds, I have tried a lot of different things, and found aluminum craft wire to work pretty well. You can attach one end of it to a drill and the other to a vice or pliers, hold it tight and spin it to get it straight, then use wire cutters to disconnect from the drill end. If you let it go slack it can curl back up. I think I have something like 18 or 19 gauge wire. Too thin and it doesn't do anything. Too thick and it leaves ugly trails. It also leaves marks if you bump the walls of the mold.

 

[NJturner]

I pour vertical 8" silicone molds. Depending on what I am going for, I use a combination of pour techniques (swirl, straight in, start/stop) and a thin brass rod. You kind of 'dance' with the pouring cups, sometimes multiple at a time, to develop the main color blends and then 'pull", 'push', or 'swirl' the rod to get some more cool patterns. My rod size is about 1/8 diameter and I bend the ends to get different effects - some just 90 degree angles, some with twists, each giving you different 'mixing' effects as you move the rod within the mold. Temps vary between 95 and 115 on each pour depending on how much separation I want in the final stick. You never know what you are exactly going to get, but you can reasonably copy a pour if you keep good records on temps, volumes of resin in each pouring cup, mica used, mica weight, pour 'style', etc.

Don't go by what the rod looks like on the outside - as that typically reflects what hit the mold as you were pouring, not how it blends inside.

Kevin

 

[moke]

Thank you both...I want to study these answers more....some really great ideas!

 

[KMCloonan]

I pour vertically using (mostly) clear PVC pipes. I got them from Tennessee Valley Products and my only gripe is that the ID is around .815 inches so they use a bit more resin than .75 inch molds and need a bigger collet.

I have been using the grey Schedule 80 PVC from Menards - it works great, especially if you remember to use Stoner mold release. (Don't ask me what happens if you forget to use mold release. It's not pretty.). The schedule 80 is a true 3/4" ID, so you get 3/4" rods. The main drawback is the pipe is opaque, so you can't see how full the tube is.

Earlier this week I did a search for Clear Schedule 80 PVC - there are numerous companies out there that sell it, but the several I actually looked at sell it in 10' lengths, which, if you're having it shipped, will require freight delivery, since USPS and UPS can't deliver anything longer than 5' .

I settled on the company in the link below - they cut the 10' length into two 5' pieces and shipped via UPS - shipping was only $10. (Another company quoted me $40 to ship, so $10 seems reasonable.) I ordered the pipe a couple days ago, and it should be here tomorrow.

FREE SHIPPING on Quality Industrial Liquid Handling Products

Alsco Industrial Products carries a large selection of pipe, fittings, valves, tubing, instrumentation, pumps & accessories for industrial applications in PVC, CPVC, PP, PVDF, SS, Aluminum, EPDM, FKM, Schedule 40 & 80, clear containment, from Asahi, Banjo, GF, Hayward, Kuriyama, Lasco, Nibco...

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The clear PVC is also a bit pricey, a 10' length is $34 (so $3.42 per foot), but my rationale is that these won't wear out (assuming I keep them cleaned). At least I will be able to see the resin flowing down the pipe.

 

[Leonardo]

I have been using the grey Schedule 80 PVC from Menards - it works great, especially if you remember to use Stoner mold release. (Don't ask me what happens if you forget to use mold release. It's not pretty.). The schedule 80 is a true 3/4" ID, so you get 3/4" rods. The main drawback is the pipe is opaque, so you can't see how full the tube is.

Earlier this week I did a search for Clear Schedule 80 PVC - there are numerous companies out there that sell it, but the several I actually looked at sell it in 10' lengths, which, if you're having it shipped, will require freight delivery, since USPS and UPS can't deliver anything longer than 5' .

I settled on the company in the link below - they cut the 10' length into two 5' pieces and shipped via UPS - shipping was only $10. (Another company quoted me $40 to ship, so $10 seems reasonable.) I ordered the pipe a couple days ago, and it should be here tomorrow.

FREE SHIPPING on Quality Industrial Liquid Handling Products

Alsco Industrial Products carries a large selection of pipe, fittings, valves, tubing, instrumentation, pumps & accessories for industrial applications in PVC, CPVC, PP, PVDF, SS, Aluminum, EPDM, FKM, Schedule 40 & 80, clear containment, from Asahi, Banjo, GF, Hayward, Kuriyama, Lasco, Nibco...

alscoplastics.com

The clear PVC is also a bit pricey, a 10' length is $34 (so $3.42 per foot), but my rationale is that these won't wear out (assuming I keep them cleaned). At least I will be able to see the resin flowing down the pipe.

Oh that's awesome! I didn't mention earlier but I had looked for Schedule 80 and was turned off by the high shipping. I will definitely order from there when I buy more pipes! Thank you so much for this lead! This probably doesn't matter for personal blanks, but if you are selling it might, but I accidentally scratched up one of my clear pipes on the inside trying to clear some stuck resin bits and it leaves scratches on the blank now, so I retired that piece. I think I didn't put enough mold release in that tube on that pour. Other than that, they seem to just get better with use. My Menard's Schedule 40 PVC has bumps and craters throughout unfortunately.

Seeing the resin go in the pipe is cool but it's not as helpful as you might think. I don't usually have enough working time to examine closely, but it is nice to see how full the tube is if that is relevant to your pour recipe.

 

[Displaced Canadian]

I use PVC from Home Depot. I wait until the resin is warm, put in layers, and mix with a thin wire bent into a T at the bottom. Be very careful of over mixing the colors. Once to the bottom with the wire and back up while twisting it is enough. any more it can start to look like mud. As was mentioned what the blank looks like on the outside is very different than the inside.