Smooth-On OOMOO 25 Tin-Cure Silicone Rubber Mold Making Kit

I've been buying and using this product for years. It tears easily and it's prone to have bubbles. Once you get the hang of it, it makes a great mold for a flat object. It, also, make a great mold for a 3-d object that you only want to use a few times.

I used this material to make a silicone mold for a musket part that I wanted to have cast out of steel. To do this I had to make a wax master. I used Solid Edge CAD software to design the master, and then used it to scale the part up 3% to account for shrinkage of the steel. After filling and sanding the master smooth, I was able to pour a silicone mold around it. I used vegetable oil as a mold release agent. The silicone worked very very nice because I was not able to easily make a two-part mold for this part, and this part has undercuts that would make it hard to remove from a rigid mold. But due to the flexible nature of the silicone, once the wax solidified I could stretch the opening enough for the part to be pulled out, and then it returned to its original shape for more pouring. Being 2 parts equal volume to mix, it's very easy to mix this "by eye" without measuring. I had enough silicone to make 3 molds as seen in the picture. Few problems with bubbles, and the material conforms closely to the master and picks up all details. Sets up fast enough that you can use your mold the same day you cast it. I used a palm vibratory sander to vibrate the mold casing while the silicone was still liquid to help shake out any bubbles. Because I did not scale up the first master enough to account for shrinkage of both the steel and the wax, I am having to do this over again with a larger master. But I am buying this product again for round two! This was my first ever attempt at making a silicone mold and casting wax in it. I highly recommend this product.

This stuff is freaking AWESOME! Was super skeptical since I've never done mold casting like this before. I've done fiberglass and carbon fiber, but those are pretty straight forward. And especially since I was doing it on a coated surface that I couldn't find any information on whethe or not it would stick to it. So, this stuff can beapplied over a Plasti-Dip sprayed item without it sticking to it or anything, so it worked perfect for what I needed! Making shroud extenders for a projector retrofit, and needed to make a reverse of the vacuum form piece I already made. Sprayed it with Plasti Dip as a spot evener, and this stuff didn't stick to it or even tried to pull it of. Sweet! I was worried I would get the mix ratio wrong, or mess up a step, but it's really not hard, but this stuff is a chore to mix by hand. Oh! BE SURE once you've poured A and B together and mixed that you pour into a second cup, and remix and scrape the sides and get every bit you can because the different parts WILL stick to whatever you're mixing in. When I scraped out cup #1 into cup #2 there were still parts of blue and green not mixed all the way, so it's a definite MUST. A++, 5 stars, 100% what ever, I'm impressed , and have just have to buy more for the 2nd headlight.(wasn't sure how much I was going to need, so just ordered the one) Going to also be buying their smooth cast 300 for the actual cast piece once these puppies are all set up

This produces an excellent silicone mold and reproduces fine detail, however it has a very limited shelf life prior to use. The batch received had thickened up more than my earlier use of the product, although still usable and produced an excellent mold. The mold casting is extremely floppy flexible and needs to be used in conjunction with a properly keyed mother mold (reinforced plaster of paris--suggestion: if you mix some Elmers/Titebond wood glue into the plaster when mixing it becomes very hard and strong)

It was easy to use and mix. The cure time is super fast! It's thicker than other silicones I've used, and this is the first time I was able to cast a mold without the silicone leaking. The mold came out really nice! It's firm, yet flexible, and easy to demold. The orange cone on the left is plastic that I used to make the mold, it came right out with no issues. And the pink and blue cone on the right is resin that I poured into the mold just a few hours after making it. It came out nice and shiny! The bottom of the cone is slightly warped, but that's because I was so anxious to see the finished product, I demolded it early. Over all, this is a great product!

Part A in my first order was solidified when I opened the seal so they replaced the whole product. When I got the replacement shipment I opened the seals to make sure the product was still liquid and it was. I closed both bottles and stored them for a few months. Decided to make a mold and found part A was clumpy and drying. Stirring wasn’t possible because there was hardly any liquid left, the product was lumpy, sticky, impossible to ‘pour’ out of the bottle. I’m very disappointed and wish I could return it but it is outside of the window. I would say don’t buy unless you plan to use it soon after you buy it. This has the shortest shelf life I’ve encountered in mold making products.

Creates excellent results if you read and follow the instructions. You need to mix individual chems to compensate for any settling. Then mix the 2 chems and mix till color is even. Pour into a properly prepared molding box/container with objects to mold. Use Release 200 spray as instructed, for best results. Two different batches came out perfect. You must learn to pour silicone from about 12" into the lowest point of the mold to avoid bubbles also. My results were amazing after a 75 min cure. The better/smoother the 3d prints, the better your results.

Found out that resin 3d prints do not like platinum cure silicone. People recommended the tin cure. I was on a time crunch and rolled the dice with this product. I got a good batch with no leaks delivered next day. This stuff is thick. Use a a flat screwdriver to mix the parts well before you mix them together. I broke off a wooden stir stick in one of the compounds. Make sure you stir the compounds together extremely well. Otherwise they won't set right. Next day it was solid and perfect. It did stick to my glass base plate so use a scraper for that. Overall very good buy for resin 3d printer parts.

I never go wrong with smooth-on products, great quality and easy to use. This is my first experience using Oomo 25 and O was very pleased with the results, and fast set up time! As it is a tin-cure silicone, it is ideal for avoiding most things that usually cause silicone inhibition.

Product arrived earlier than expected, however when I opened the package, one of the silicone liquid has spilled as there was a cut on the ‘sealed’ bottle plus the cap was not secured tightly.

This product literally arrived unusable. Part A was fully cured in the container to the point that I could turn it upside down and nothing came out. Huge disappointment as this was needed for an upcoming project. Basically garbage as part A needs to be mixed with part B to actually make the silicone usable.

Used to create a mould for repairing an MDF cabinet door. Worked well. Got a tiny bubble in one spot, but I guess that was my bad.

They tell you to use it quickly... But not specific. Two weeks in and it was already drying out.