I would like to make a mold of a brass plaque (8 x 10 inches) embedded in the ground at a public park. I will use this mold to create a 'positive' to use for casting an aluminum copy of the plaque. I am limited to about 10 hours for the mold creation process. Will Quickest cure sufficiently in 10 hours?
Post by carol - Alumilite Corp on Sept 18, 2018 11:02:18 GMT -5
You will have to make sure the Brass Plaque is good and clean, no dirt, particles, or anything else on the plaque that could prohibit the cure of the Amazing Mold Putty which is a platinum base silicone (see website). QuickSet silicone is a tin cure with out the inhibitions of Platinum cures. However, I can not give you a 100% positive it will cure in 10 hours. We usually tell people to allow 24 hour cures times for the liquid silicone as temperature and humidity can vary cure times. The plus with the QuickSet is being tin it does not have the inhibition issues that Platinum cure silicone's (Amazing Mold Putty) could potentially have. Did you have a plan for an encasement/mold box around this plaque, the silicone is viscous and would need to be contained.
I am assuming you have permission to make a mold of this plaque.
I had not looked at the Amazing Mold Putty. It looks like this is what I should use. The plaque looks to be brass with the relief anodized or painted black. The plaque was installed by the city in 2003 and honors our late son. It is set into a concrete pad. I plan to use heavy cardboard to contain the mold material if needed and to contain the plaster of paris backing. Do you know of any issues with using this product on a plaque such as this?
I 'm going to add to what Carol said in that the mold box should be something sturdier than cardboard due to the lateral force that will be created with the mold material you choose to use. My suggestion to you would be to construct the mold box out of 1"x wood...Pine would work fine or if your more adventurous metal...something that 2 halves or 4 quarters can be bolted together. With the wood use deck screws that can be screwed into and out of with a cordless drill.
Since the plaque is set into a concrete pad, you can seal the mold box bottom to the concrete pad with a sealant like RTV silicone....the type like you would use to seal a window which is available at any home improvement store. Once you are thru making a mold of the plaque, the silicone can easily be pealed off of the concrete pad returning it to its original condition.
With that far of a distance, I'd be sure to have all the tools needed plus extra. I'd bring both the Amazing Mold putty and a liquid mold material - use the putty first as it cures faster. And make sure you have more than enough of both to make the mold, you might need more than two packages (or several) of the Amazing Mold putty depending on the plaque size and depth. I'd also bring the silicone caulking to secure the box and a heat gun. Heat helps to cure liquid silicone faster. A hair dryer would work in a pinch to help along the cure but a heat gun might be better.
I wonder if the city kept the original mold used to cast the plaque? If they did, they might be willing to let you borrow it for a few hours. Then you could pour the liquid silicone in the original mold and make a mold of that to cast in once you get home. It's worth asking about if you know who to ask. As you would be asking to do the casting yourself instead of asking for a copy, they might not have a problem with it considering it's for your son. If you make a mold of the plaque, you might need to stay with it to ensure no one disturbs it but if you use their mold you might be working in a room where there's less chance of it being disturbed. It's worth asking about - it never hurts to ask.