Fumed Silica Thickener (Cabosil-Type) – Quart Container

This thickener was ordered for me to use in both epoxy and a polyurethane. For epoxy it definitely seems to work better with less troubleshooting, actually no troubleshooting at all really. With polyurethane, it does take a bit longer for that to dry, and I have noticed that if not being super precise, can add a bit of cloudiness to it after the drying process is complete. That quite possibly could just be the specific product I am using, so I will not remove a star for that, but it may take a while until I get the exact measurement down that resolves this. I am confident I can, but it may take time. The fantastic thing is, that there is a ton here, so I absolutely have more than enough to test. I will not use this that often, I actually just wanted this for very particular things, so for epoxy, this will work great for that and if I cannot figure out a perfect ratio for my specific polyurethane, I will just go with that. This, if stored correctly, will last me years with how little I will use it, so in that aspect its a fantastic value. I will state however that even before opening I knew a respirator and goggles was a must. PPE should most definitely be worn with the use of this, as it is so fine it very easily gets airborne fast. It is not something you want getting into your lungs or eyes, so I do not even open this unless I am in my respirator. Once its mixed into your medium, its fine, but if working with resin, you'll likely be keeping the PPE on anyway even after adding. So not an inconvenience, but even if it were, it is definitely necessary in my opinion. Outside that, its not really a hassle to use or handle. For me, I am still in the figuring out phase of use. Epoxy was super simple to figure out, but still trying to perfect the urethane. I am giving this the full 5 stars as it does what it says, and will last me ages. I am very happy with this so far and likely would order again if ever needed.

This fumed silica weighs nothing. Maybe even less than that. The container feels empty but it's quite full. The first thing to note is the cautionary part. Although this isn't toxic, it's super fine. Finer than dust. Finer than talc. The slightest breeze will carry it away and it can be a serious irritant if you breathe it in. So use it only in a place where the air is deathly still. Don't sneeze. Don't even breathe. Okay, it's not as scary as that. But do be cautious and it's a good idea to wear a mask that can filter small particulates. Be careful around pets. So with that said, it's really cool stuff. I got it to thicken epoxy and UV resin so I can sort of mold and sculpt it and make realistic dripping and swirling effects and to build up shapes inside clear resin. The amount you use to thicken resin is small enough that it will remain transparent. If it was transparent already, that is. It works really well with UV resin because you can build up shapes layer by layer, curing them quickly in between. It's effective and fun. Even though this has a matte finish, resin remains glossy. I think the price is good for how much you get. And my interest has been piqued to thicken other materials. I am going to experiment with pigments and paint bases.

This fumed silica thickener works as seller has stated. There are several applications such as for marine repairs, woodworking, modeling ( eg a lake or river for scenery) or any place you don’t want the epoxy to run when using vertically. Works as well as name brands I have used. The amount of thickener to resin depends on the project but a little goes a long way. This thickener works with several different types of resin such as polyester, gel coat, paints or varnishes. With more applications not listed. I have not tried this with other fillers, but I can’t see why this wouldn’t work. The thicker helps create a smooth surface without runs when using other products. Although you don’t need gloves to handle the fume silica, you may want to wear them just to be safe, and you will need a mask for protection. Adding fume silica does not change the usable time of the product it has been added to. Whatever your epoxy work time is will remain the same after adding the fumed silica. This quart sized container of thickener has a moderate value of just under $14.

If you’ve never used fumed silica before, warning, it’s basically dust. I use it for 3D resin printing, especially when I’m working with low viscosity resins. When using high speed settings on the resin printer I have to use low viscosity resins, but they’re not great when I need to fill seams or smooth out tiny pits during assembly. Mixing in a little of this powder thickens the resin into a paste that stays where I put it and cures cleanly. It also works well outside of printing. Mixed with cyanoacrylate glue, it turns into a strong filler that bonds fast. I’ve used it to repair both resin and ceramic items, and the combination sets up almost instantly with a solid, sandable finish. Because the powder is so fine, you do have to be extra cautious. Exhaling can send this stuff airborne, so I always wear a mask and make sure fans and vents are off before opening the container. I’ve found that using a plastic pipette to draw out small amounts is helpful and keeps things from getting messy.