Custom Extended Swim Platform

Discussion in 'Boatbuilding' started by tpenfield, Jan 8, 2019.

  1. tpenfield
    Joined: Dec 2016
    Posts: 81
    Likes: 1, Points: 8, Legacy Rep: 10
    Location: Cape Cod, MA

    tpenfield Junior Member

    I'll be back at it, working on the main platform mold this weekend. It seems that I am only getting a few days a month to work on the platform, but with warmer weather a couple of months off, I need to get things moving along.

    I'm going to run a test of the TBC inhibitor to see what approach (MCP catalyst or TBC inhibitor) seems best , then move onto the platform mold. The lower temps in the northeast USA will make for an interesting time, as I try to maintain reasonable curing temperatures in the workspace (my garage).

    Saturday will be 2 coats of tooling gelcoat.

    Sunday will be infusion set-up and the actual infusion. I'll let the infusion sit for a week, then add some stiffeners by hand layup. After all is cured, I'll pull the mold from the plug.
     
  2. gonzo
    Joined: Aug 2002
    Posts: 13,247
    Likes: 319, Points: 93, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    You can eliminate the struts by bracing the platform from above. The aluminum pipes can be made to do double duty as handrails.
     
  3. tpenfield
    Joined: Dec 2016
    Posts: 81
    Likes: 1, Points: 8, Legacy Rep: 10
    Location: Cape Cod, MA

    tpenfield Junior Member

    TBC inhibitor test update . . .

    I did a resin 'pot life' test on MEKP activated poly resin w/ 300 ppm TBC inhibitor, in similar fashion to the other tests that I did a couple of weeks ago.

    The TBC inhibited resin started to gel at about 75 minutes and reached a temperature of 150 F at 120 minutes.

    So, in summary

    0.75 fl oz of resin for each sample starting temperature 55-57 F

    2% MEKP gel @ 30 minutes, peak temperature 140+ F

    2% MCP gel at 70 minutes, peak temperature 75 F

    2% MEKP inhibited by TBC @ 300 ppm gel at 75 minutes, peak temperature 150 F

    It looks like the TBC inhibited resin really kicks into gear after the 70 minute open time, where as the MCP activated resin had a similar open time, but did not generate nearly as much heat as the TBC/MEKP combination.

    I'm not sure what is best . . . a slow low temperature cure . . . or a presumably faster and high temperature cure. :confused:
     
  4. ondarvr
    Joined: Dec 2005
    Posts: 1,854
    Likes: 103, Points: 63, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    If you have a thin laminate the higher exotherm isn’t an issue. Add a foam core, plus more glass, and the exotherm can become higher than desired, this is where MCP comes into play.

    You will get more shrink with the higher exotherm, this may lead to the fabric printing through.

    But if ambient temps are low, the higher exotherm will allow for quicker de-molding of the part.
     
    fallguy likes this.
  5. tpenfield
    Joined: Dec 2016
    Posts: 81
    Likes: 1, Points: 8, Legacy Rep: 10
    Location: Cape Cod, MA

    tpenfield Junior Member

    Yes, that is what I was thinking . . . thin laminate, colder than ideal temperatures, might be a bit of shrinkage, but the other factors may offset.

    I won't de-mold for a week or 2, so speed is not a concern.
     
  6. tpenfield
    Joined: Dec 2016
    Posts: 81
    Likes: 1, Points: 8, Legacy Rep: 10
    Location: Cape Cod, MA

    tpenfield Junior Member

    Here are the resin test samples . . .

    IMG_2263.jpg
     
  7. tpenfield
    Joined: Dec 2016
    Posts: 81
    Likes: 1, Points: 8, Legacy Rep: 10
    Location: Cape Cod, MA

    tpenfield Junior Member

    Tooling gelcoat on the platform plug. . . .

    It seems to be curing OK.

    IMG_2266.jpg

    Getting ready for infusion tomorrow . . .
     

  8. tpenfield
    Joined: Dec 2016
    Posts: 81
    Likes: 1, Points: 8, Legacy Rep: 10
    Location: Cape Cod, MA

    tpenfield Junior Member

    Quick Update . . .

    I had trouble getting a perfect seal for the vacuum. So, rather than risk it, I am doing some re-engineering on the bagging material.

    I'll take another run at it within the next couple of weeks.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.