Best Rtv For Molds
2 replies to this topic
Posted 21 January 2013 - 02:56 PM
I've looked through a lot of posts but Im having trouble finding the best rtv silicone for mold making. I have used the Alumilite from the super casting kit, but that is it.
Looking for suggestions regarding best for bulk price and ease of use (no bubbles)
How much is needed to make say 5 six to eight inch musky sized lure molds
Thanks in advace for the tips fellas
Posted 21 January 2013 - 10:36 PM
This subject could open a can of worms that even bait fishermen would not want to open. LOL I'll give you my opinion, with the statement up front, this is MY opinion only.
First there are more RTV's then just silicone. But, Silicone usually does not require a mold release (easier to paint after), it has a longer shelf life (does not degrade for years on the shelf), and it comes in several different strengths or firmness. Additionally, there are more than just the pour type of Silicones; there are silicone mold putties as well. Both will do a great job for what they are intended. Obviously mold putty has no bubbles, but it does not take as much detail and the shorter working time makes it pretty hard to do a lure with much detail. Still, it is worth having around for simple lures.
Now, for the Silicone itself, I do prefer the Alumilite products, but not necessarily the one in the super casting kit. Alumilite makes the Quickset, the High Strength 2, and they make a High Strength 3.
The Quickset is the one that comes in the Super casting kit to the best of my knowledge. It sets up fast, so fast that it can leave some bubbles. Still, if you do a two part mold and pour the top first, the bubbles move away from the lure so they are not against the finished product. Turn the blank over and pour the other part and you get the second half without bubbles. If the lure is pretty simple and you do not have undercuts, the Quickset works well. This is available at Hobby Lobby and you can use a 40% discount coupon on it. (This would be good for a Big O or a Rapala Minnow style bait)
High Strength 2 is a similar product, but it is far more tear resistant and far more flexible. This is the best overall product for lure makers. It also takes longer to set up. If you follow the procedure given above, you can get molds without any bubbles at all. Because it is so flexible, it can give great detail, it is dimensionally more stable on bigger lures, and .......... well ............. I just wish Hobby Lobby carried this product.
High Strength 3 is the most flexible of the Alumilite products, and it is quite tear resistant, but not as tear resistant as the HS2. It is the best of the three for one piece molds. It will stretch to release lures so I don't need to use 2 pieces. With a proper design, you can do almost any design in this stuff, but it can tear, it may require thicker walls to make it more dimensionally stable, but it IS AVAILABLE at Hobby Lobby and the 40% off coupon.
I offer a hint that is NOT from the company. The mixing ratios for QuickSet, HS2 and HS3 are 10:1 by weight. If you add just a little less catalyst, it takes longer to set up and the bubbles can work out better. If you add a little more catalyst, it will set up faster. Don't overdo it. If you put the product in the fridge overnight to cool it, it takes longer to set up. If you warm it above room temperature, it will set up faster. You can use these hints to assist in bubble removal.
Now, what about other makers of RTV? Similar shore hardness products will give similar results. To help you figure out what you want, I am going to provide a link to the Alumilite data page. http://www.alumilite...=SiliconeRubber
With the above links, I think that you can find similar RTV products that would work for you. With the How To sections, you can get a start on how others have made lures as well. Now, one last point.
You ask how much it takes to do 5 to 8 Muskie size lure molds. That is pretty tough to answer without knowing the volume of the lures and the general size. Again, I offer a link to help, but ........ http://www.makelure.com/CalcVolume.cfm
I suspect it would take about 3 pounds. Note that Alumilite sells in one pound, 5 pounds, or 10 pounds. You can order more and if you call them they can help with suggestions. I suggest you don't buy anymore then you can use in a year, but I have had some longer and it has lasted for me.
Good luck, I hope this will get you started. Let us know how it works for you.
Posted 22 January 2013 - 06:26 PM
Thanks so much for all the info...I will digest it and get after it.