Gurit Ampreg vs Ampro for hand layup project?

Discussion in 'Fiberglass and Composite Boat Building' started by SwedenYachtsDaniel, Feb 9, 2020.

  1. SwedenYachtsDaniel
    Joined: May 2018
    Posts: 14
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    Location: Norway

    SwedenYachtsDaniel Junior Member

    I have been using Gurit Ampro for small repairs and installations and i works fine. Its a little thick at times when wetting out laminate. Im located in Norway so its not very warm.

    This spring/summer have a few bigger projects:
    -Im going to add a layer 450 biaxial/epoxy on my the deck after removing the teak deck and filling screw holes
    -I also might add layers of 450 biaxial in the keel area, outside and inside. So some will be upside down
    -Start building a hard dyvinycell sprayhood.

    For wetting out lot of laminat by hand, NOT using vacuum bag what Gurit product would you recomend?

    I read theis about the Ampreg 30:
    "Ampreg™ 30 has been optimised for the manufacture of large composite structures using hand layup & vacuum bagging techniques whilst offering improved health & safety through the careful selection of low toxicity raw materials.

    Can you use ampreg with out vacuum or will it be to runny?

    (Gurit is what i want to stick with for logistic reasons)

  2. fallguy
    Joined: Dec 2016
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    Location: usa

    fallguy Senior Member

    You want open time and a runnier material. A thick epoxy is a nightmare in cool temps.

    Ampro is 800cp at 20c
    Ampreg 21 slow is 705cp at 20c

    both are fairly thin...

    If you are applying epoxy you want temps above 65F. You can work as low as 55F, but wetout is awful. To help the process; wetout the substrate with 40-50% of the total need. The fabric weight and the epoxy weights will be equal.

    If you are having trouble achieving 65F; you really need to tent the job and warm things up. This will also keep condensation off both the start and end.

    Gurit's technical team is superb and they will recommend the best product.

    Trust me on the temps. In our shop, if we leave the doors open, our epoxy cools to about 64 and our usage goes up above 1:1 for the calculated rates. And I get a little mad about the fresh air idea. Try to keep your epoxy stored at 75F the day of the work. It takes quite awhile to warm.

    I would estimate you will need 10% more epoxy working below 72F, so heat the area is best. It should be tented anyway to avoid rain.
    Last edited: Feb 9, 2020
  3. SwedenYachtsDaniel
    Joined: May 2018
    Posts: 14
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    Location: Norway

    SwedenYachtsDaniel Junior Member

    Thanks fallguy for your advice. 65F is possible if i pick the right day. So the Ampro i have now is almost as thin as Ampeg. The littel work i did theis year was just below 55F and i found it tricky. It worked for small jobbs sealing old holes form instrument in the cockpit. But would not work for bigger layups.

    But from what you say i get that it is ok to use Ampreg whit out a vacuum bag..
  4. Men
    Joined: Aug 2019
    Posts: 6
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    Location: UK

    Men Junior Member

    Ampreg doesn't need vacuum but vacuum is good if you can have it.

    Ampreg can have considerably longer working times with the slow hardeners compared to Ampro, which makes it much better suited for large projects.

    It also has better properties in low temperature cures, although a higher temp post cure is recommended.

    Check the datasheets in their site, as it will say in more detail times to decide also which hardener you need

  5. SwedenYachtsDaniel
    Joined: May 2018
    Posts: 14
    Likes: 0, Points: 1
    Location: Norway

    SwedenYachtsDaniel Junior Member

    Thanks for your input. My dealer got back to me as well , and he says more ore less the same. Im going to try it out on some smaller stuff when the temp rises this spring/summer.
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