What wax should be used for mold release?

Discussion in 'Fiberglass and Composite Boat Building' started by aaronhl, Dec 2, 2013.

  1. aaronhl
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    aaronhl Senior Member

    I tried a small test piece of wood covered with body filler and then sprayed with sandable auto paint. Then sanded to 600. I 10 coats of some liquid Turtle wax (with carnanuba) over the top of that before the tooling gel. Not sure if this will release or not. What wax do you recommend I could get at AutoZone? Also, how long should I wait to try to pop it off?
     
  2. SukiSolo
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    SukiSolo Senior Member

    Check out Meguir's Maximum mold release No 8 - carnauba wax. Also the high temperature one No 16, I think if you are curing at temperature. You may also require a mist spray of PVA Blue depends on the shape being formed. Very simple stuff can be done with a few coats of the wax only, if you are getting down to 2 degrees or less draft you will need the PVA as well.

    Your mould/ pattern prep seems a bit coarse. I would have gone down to 1000 grit and then polished out to high gloss. On patterns/bucks I epoxy coat than spray in 2k gloss black so any imperfections can be seen and sorted.

    DO NOT use beeswax with epoxy as it does not release at all well, I have been there....
     
  3. SamSam
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    SamSam Senior Member

    Johnson's Paste Wax from the grocery/hardware/discount store used to be 100% carnuba and worked well. I don't know if it still is the same.

    Scroll to the bottom of the page for 'similar threads'. Keep doing that for every thread you find. You can also search this 'Fiberglass' forum.
     
  4. richardw66
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    richardw66 Junior Member

    I followed SukiSolo into here!

    I used to do a lot of race car component forming in my youth and I myself used silicone spray as it is a proper release agent after all. Candle wax works great if you have just a simple plywood mould like for making floor plates, best applied with an old clothes iron it penetrates into the mould permanently but word of warning; it is difficult modify the mould afterwards because the pudd'n (filler/bondo) won't stick to it!
     
  5. aaronhl
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    aaronhl Senior Member

    Wow duhhh I have never seen that, thanks for that!

    I am going to try the Johnson's paste wax tomorrow. The liquid wax I used worked for the small part test. It was a flat piece about 3" x 2", just wedged it with a chisel. There was a very small area of paint that came off but was able to remove it. The Johnsons wax should work very well. I remember having that in the house years ago

    You guys are very helpful
     
  6. aaronhl
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    aaronhl Senior Member

  7. SukiSolo
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    SukiSolo Senior Member

    We don't get the Johnson's paste wax here in the UK (well I've not seen it) but any 100% carnauba would be good. I've used the silicone spray release stuff too but prefer it on silicone tooling or other moderately soft tools. It can be a bit of a pig to clean off fully, for painting and/or refinishing. Works OK, mostly.
    I do not advise candle wax as it is often beeswax based so will NOT release epoxy. OK with polyester and for the old trick of lubing draw runners!.

    If you want flat panels, one trick is to get some MFC (Melamine Faced Chipboard) and just put half a dozen coats of 100% carnauba on it, one at a time. Then laminate on top, It will spring off, no problem. I make some longish trim strips for something this way, 6' (1m 80cm) long and in tinted epoxy ie I add a couple of % gelcoat colouring/tint (note NOT gelcoat) to the epoxy. After it has cured I rip it on the circular (table) saw down to size. 2mm thick layup will bend quite a bit so part circular and curved parts can be made from an initial flat sheet 'moulding'!.

    This link should take you to a US supplier of the Meguir's

    http://www.carbonfiberglass.com/Sup...-Wax/Meguiars-Mirror-Glaze-No-8-Wax-11oz.html
     
  8. SamSam
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    SamSam Senior Member

    I never worked with epoxy so I don't know if Johnson's works with it. I'm guessing it will. I seem to remember the JPW was 100% carnuba, but the ingredients now are a mixture, but advertised as the original formula.

    I didn't use it too much before going with regular mold release waxes. Meguirers, etc.

    I was always under the impression that silicones were a very bad thing to get around molds, causing all sorts of problems with sticking, fish eyes and contamination of parts by migration while molding, which would cause problems in painting or finishing the part. It supposedly didn't just sit on the surface like wax, but penetrated and became more or less permanent. It could be there are hundreds of different silicones and only some were bad, like silicone caulking. When people had mold problems it was usually asked if a rag used with silicone had been accidentally used on the mold. Later on they came up with 'permanent' release systems that were silicone based, I think, and that's when I heard about release transfer to parts and those type problems.

    A 2x3" piece is a little small for testing release. If you had a big area and it stuck a little bit every 2 or 3 inches, that might be a big problem.

    A bunch of wax and then some PVA is pretty foolproof.

    What type of resin are you using?
     
  9. aaronhl
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    aaronhl Senior Member

    Yea I know it's a small piece, Didn't want to use too much tooling gelcoat and mess up so it's a good idea to try a bigger piece with the new wax.

    I will be using tooling gel with mek to make the mold (with epoxy and glass to strengthen). Then when I make the actual pieces from the mold it will be epoxy most likely.
     
  10. Landlubber
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    Landlubber Senior Member

    Have to agree with SukiSolo, why would you want to do it in 600.
    One would expect that you are looking for a full gloss finish on your products, so you have to get a full gloss finish on the moulds.
    Products shoul never need to be polished if the moulds are right in the first place.
    Yes, carnabu wax is very good, but so are most of the proprioritory products sold for the purpose.
     
  11. aaronhl
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    aaronhl Senior Member

    High gloss is def a great objective...for the 2% on this forum that don't have equipment to spray and barely got by in Chemistry- is it possible to use a spray paint can over the sand able primer (after sanded to 1000+) that will accept the tooling gel with wax inbetween? Can I buy this spray can at home depot?
     
  12. ondarvr
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    ondarvr Senior Member

    Typical auto paints and primers don't hold up well when used as a mold or plug surface, the gel coat tends to break them down and they wrinkle up. PVA used over it does help some, but the gel coat may still attack the primer. Some 2 part paints will hold up to gel coat, but I couldn't give you a name of one anymore, too many have changed over the years.
     
  13. Herman
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    Herman Senior Member

    Only thing that works reliably, time after time, is 2C PU paint, or a polyester based solution (gelcoat/flowcoat, sanded and polished).

    After that, a decent mold release wax. I like a semi-perm sealer on my plugs, and finish with Meguiars M87, others might like something else.
     
  14. aaronhl
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    aaronhl Senior Member

    There is an appliance epoxy paint at Home Depot, wonder if that would work. Maybe the best I would be able to get is sandable auto primer sanded to 1000+??
     

  15. ondarvr
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    ondarvr Senior Member

    One part epoxy paints are a very distant relative to true epoxies and share very few of their good properties, I wouldn't use it.
     
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