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Fin mold help

Discussion in 'Fish Taxidermy' started by joe54, Apr 24, 2015.

  1. joe54

    joe54 Member

    Hello everyone, I was hoping someone could help me out. I been attempting to mold some fins. I got the molds made. I tried this with 2 separate methods. The bondo mold method. And also with mold max 30. I been using smooth cast 325 in the molds to make the fins. I been working on a tail and I just can't seem to get the tail to come out of the mold in decent condition..... It either rips up completely... Or comes out with small slivers missing.... Keep in mind I coated both types of molds with vaseline first.... I've attempted it several times and let it cure for different time periods such as a few hours up to 5 hours.... But the time doesn't seem to have an effect. But I'm getting very flustered because I can't get a 'whole fin' out without it being destroyed or damaged. Can someone please help me? I'd appreciate it so much!

    FORTMEEKS New Member

    I've been having the same issue. I've tried IE3025 and fin magic. The IE3025 either kicks before I get it poured or it runs everywhere and I just get strands. I'd appreciate the help too! :)

  3. JL

    JL Taxidermist for 64 years

    Seems to me your problem is you are missing some coverage with mold release. I would apply paste wax first and buff it, then melt the Vaseline and apply it liberally with a brush, but not enough to lose your details. Might try PVC ( polyvinyl alcohol ) as the first coat on the mold. As for a leaky mold, apply a coating of straight Vaseline around the outer border of the mold to act as a seal. A thin string of clay would do the same. Good luck, JL
  4. Jimmy Lawrence

    Jimmy Lawrence Well-Known Member

    Why the heck are you putting vaseline in your molds????????

    I would say it's probably a mixing/measuring issue more than anything. Mix each material both before and after you combine A&B. Sometimes you'll get a bad batch of Fin Magic but the 3025& 325 are usually good. Mixing/measuring is more than likely your issue.
  5. Is the troublesome tail fin mold a silicone glove mold or a two-part bondo mold? For fin molds I don't mess with wax or vaseline or pva (polyvinyl alcohol) any more. You shouldn't need any mold release with the mold max, but mold release will extend the life of the mold and make demolding easier. All I use now for mold release is mann's ease release (usually dick blick has some good deals on it). With the silicone molds, I just give it a shot and let it sit for a few minutes before casting. With the bondo mold, I spray the entire inside surface(s), brush with a paint brush, spray again, and allow to sit. Works flawlessly everytime, takes 30 seconds, and causes no loss of detail.

    The issue you are describing sounds to me like you're either clamping a bondo mold too tightly and too close to the void to be cast. Or if it's a glove mold, you're just not getting the silicone down where it needs to go, remedied by a pressure pot. It the absence of a pressure pot, you could careful split the mold further (beyond the end of the fin) with a Popsicle stick. Then when it is cast, you just trim the edge up. Step away from it and return after a few days with fresh eyes and look it over again. I'm sure there's a way to use the mold; you just have to figure it out.
  6. JHardman

    JHardman Active Member

    I can't speak to the mold max or smooth cast, but I do all of my molding with bondo. I do also use fin Magic for casting fins but have had good success with bondo molds and casts. it sounds like to me you are clamping too close to the fin or clamping too hard. Instead of vaseline try using some of the other products mentioned for mold release. I personally use turtlewax car wax on my molds 2 coats. The first one coat everything very thoroughly and polish to a nice sheen. The second coat I do not typically polish as much. The "Yellow Perch and question for comp judge thread" fish and fins were using this method.
  7. boarhunter67

    boarhunter67 Well-Known Member

    For silicone type molds I use synlube as a release. I sometimes have to add a small chunk of cured resin to hold the mold open to the correct width. I grind this off with a dremmel afterward.
  8. Frank E. Kotula

    Frank E. Kotula master, judge, instructor

    ok I use just about nothing else bondo molds for all my fins and that's includes competition ones too. Two reasons your having issues on the tail. One if it's ripping then the plastic is not set yet so wait another 10 min before you demold and if it's in slivers then your clamping too tight.

    I will wax my mold twice and buff with carnauba wax, then use a mixture of Vaseline and paint thinner mix and then brush it on the mold. Let that sit over night and by morning the mold is ready for the plastic.
    I use binder clips for clamping my molds. Now there are time where I can't get it all the way down, resolved by taking duck tape and going over my keys with this and then using Vaseline on the tape reclap and do a pour. This will take care of that problem.

    Also the Vaseline mix is on thin not a heavy coat. I can sometimes get 5 pours before I have apply it again.

    I have shown this method many time in my seminars and never had in issue ( murphy's law yet)

    Jim Vaseline and paint thinner is a great mold release for the plastic.
    silverwings and Jkostella like this.
  9. JHardman

    JHardman Active Member

    Mr. Kotula

    Thank you for the info! This why I enjoy this site so much, some of the best in the industry are glad to help out!
  10. boarhunter67

    boarhunter67 Well-Known Member

    Frank, I usually use straight resin for my fins. What type of plastic do you use?
  11. Frank E. Kotula

    Frank E. Kotula master, judge, instructor

    I've been using 3025 innovative polymer. You can get it now at Rick Kranes angler artistry web site.