Rebound 25 mould making questions

Discussion in 'Pattern making' started by Zapins, Nov 18, 2017.

  1. Jason

    Jason Gold

    I dont think we have to worry about Zap casting resin chickens. lol
     
  2. Zapins

    Zapins Gold

    Thanks OCD for calling them. Good to know it won't delaminate with an external shell. I'll probably end up trying that walmart stuff Jason used or maybe the epoxy I have for an outer shell. I don't want the weight of a cement/pop mold. They are also brittle and if dropped shatter and are difficult to remake once you take the original wax out of the mold.

    Pretty sure I will have to retake that stupid exam I took today. Tested me on bs I've never even seen before. Most people I talked to thought the same, so there will probably be a big group of retakes next month which means I'll have to spend my only month off for the next 2 years studying. ...king hurrayyyy!!!
     
  3. Jason

    Jason Gold

  4. OCD

    OCD Silver

    The only mold release that Reynolds sells for polyester resins (all fiberglass resins) and is specifically printed on the label is the Pol-Ease 2300.

    Per label, Mann Ease Release 200 states it's good for "Silicones, Urethanes & Resins. What type of resins isn't specified.

    Zap, do you have a compressor?
    If you do buy a small cheap gravity feed (jamb) spray gun and some PVA mold Release.

    Forget the WallyWorld resin.

    Much cheaper & free shipping.
    https://www.ebay.com/itm/Polyester-...500079?hash=item33dc02c0ef:g:IncAAOSwL1ZaHONZ

    As with any "Laminating resin" it will need a wax curing additive added (incorporated with the mixed resin) prior to applying the final coat/layer,
    OR
    You can spray a couple coats of PVA over the entire resinated surface after the last coat/layer and that will lock out the air allowing the resin to fully cure without it resulting in a finished sticky surface.

    Resins and gel coats which already have the wax curing agent mixed in is "ONLY" good for the final top coat.
    Yes, waxed resin's and gel coats can be applied over each other but shouldn't be and definitely not by an amateur. No offense Zap.
    It's just NOT the proper method of doing it correctly.

    Un-waxed resins and gel coats will stay sticky allowing you to continue adding another coat / layer upon each other until the final finish coat is needed and that's when you either add the wax curing agent or a gel coat ' resin which already has it in it.
     
  5. Another reason to use epoxy resin is that epoxy will stick to cured epoxy and cured polyester where polyester won't stick to cured epoxy or cured polyester. So if you're building up the glass in layers or sections, only epoxy will adhere properly.
     
  6. Jason

    Jason Gold

    I didnt know that about waxed vs unwax resins... I used the wally world stuff on a 4thousand dollar airplane potty 2 months ago. I applied 3 or 4 layers per the instructions on the can and it cured and is not sticky... What gives? I try to do VERY little fiberglass work. Hate the stuff.
     
  7. OCD

    OCD Silver

    There's 2 types of bounding.
    Chemical and Mechanical.
    If any given resin is given the appropriate amount of time to cure out not even the original resin will chemically bond to it.
    For it to bond you, (and there are exceptions which are chemically involved and have a short time frame to do so and I'm not going into them) have to create a mechanical bond which requires substrate profiling/anchoring of the new resins to adhere to.

    There are other addictive products other than curing wax which can be added to create a (0) O2 (Oxygen) atmosphere wherefore allowing the resins or gel coats to properly cure out.
    Not going into that either. lol
     
    Last edited: Dec 8, 2017
  8. Jason

    Jason Gold

    Good enough... The walmart crap works for me. ;) I'll spread some layers on the rebound when I get a chance and report back if it acts goofy. I don't think it will, but ya never know.
     
  9. OCD

    OCD Silver

    Zap is going to need more than 0.9qt.'s for his project, that's why I scrounged up the ebay list for him.
    Plus it's half the price once all said and done.
     
  10. Jason

    Jason Gold

    This is not bad... not great, but a few good parts of this process.
     
  11. Zapins

    Zapins Gold

    No offense taken!

    I do have a compressor, a little pancake one. Might browse the horriblefreight stuff for a sprayer like you say.

    I might give the stuff I bought a go first on a trial piece first. Says it needs 3.2 hours between coats to set and 5.9 hrs to dry to the touch, 10 hrs to cure properly. So I can probably add layers every 3-4 hours until I have a thick enough exterior.

    Still waiting on my fiberglass mats to be delivered. Just drove back to CT yesterday (13.5 hr drive). Went to the pet store and bought some rare fish today and sat around relaxing before I start my new rotation tomorrow at the lab.
     
  12. Zapins

    Zapins Gold

    Found out today how to tell the date of manufacture of the rebound. Apparently the 1811 circled below is actually the date backwards in their code. So this was made in November 2018.

    20190503_194506.jpg
     
  13. Jason

    Jason Gold

    good to know. But if I bought, I'm using it anyways. Not throwing away 35 bucks.
     
  14. Zapins

    Zapins Gold

    Yeah I figured I would too but I had one left over from the eagle. Manufacturing date 03/2017. So basically I think it's a waste at this point.
     
  15. Jason

    Jason Gold

    BS... If it's UNOPENED, I'd use it.
     
  16. DavidF

    DavidF Administrator Staff Member Banner Member

    Really depends on the temperature it was stored at. Ive had my silicone last for over a year after being opened. Kept in a nice cool basement :D
    Now if only I could get my investment keep that long after being opened :rolleyes:
     
  17. DavidF

    DavidF Administrator Staff Member Banner Member

    Mix up a test batch and try it out. If its going bad it will be really thick and hard to mix...
     
  18. Zapins

    Zapins Gold

    Well I'm shocked it looks usable.

    I mixed up 50 grams of the stuff and cured it with a heat lamp. It seems to behave normally, flows well and seems stretchy when cured. Will wait until tomorrow to be absolutely sure and check on the slow curing puddle I set up of the stuff. But it looks like the sealed container lasted 2 years and 3 months from date of manufacture. I'm shocked.

    My tin based liquid silicone goes bad after 8 months or so, or at least the catalyst does. So this platinum cure rebound stuff must be better quality or I just got crazy lucky.
     
  19. Jason

    Jason Gold

    I've run 2yr old r25... UNSEALED that is. I keep it at an even 73degrees yr round. I would NOT try to use 3yr old suspendaslurry however... :oops:
    :(
     
  20. Zapins

    Zapins Gold

    Hmm crazy. You learn something every day. I'm happy. This saved me 35 bucks. Kick ass.

    This 1 tentacle and octopus head looks like it's going to take 3 boxes of rebound 25 to mold. So about a hundred bucks to mold in silicone. Then probably 45 bucks worth of fiberglass and resin. So around 150 total for the octo. Hmm pricey but hopefully worth it!
     

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