Bearhawk Aircraft Bearhawk Tailwheels LLC Eric Newton's Builder Manuals Bearhawk Plans Bearhawk Store

Announcement

Collapse
No announcement yet.

Hoerner wing tip project.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    You might consider West 105. Its low shrink, fairly thin so it wets out pretty well, has a big customer base and you can buy it by the quart. Worth a try, if you don't like it your not out much. Everything I use is for high temp so my knowledge of room temp is limited but I have heard good things about this product.
    Gerry
    Patrol #30

    Comment


    • #17
      I used Max HTE high heat epoxy resin when I built my plenum.

      https://theepoxyexperts.com/shop/adh...-glue-casting/

      Soller Composites is a great source for carbon fiber:

      https://www.sollercomposites.com/Carbon-3K-Fabrics.html
      Rob Caldwell
      Davidson, North Carolina
      EAA Chapter 309
      BH Model B Quick Build Kit Serial # 11B-24B / 25B
      Build Log: https://bearhawk4place.blogspot.com/
      YouTube Channel: http://bearhawklife.com

      Comment


      • robcaldwell
        robcaldwell commented
        Editing a comment
        I just looked it up... I purchased a 10 yard roll (30 feet) x 50" of AS4 3K Carbon Twill from Soller Composites for $167.50. That's over 120 square feet of carbon fiber for under $200. Not a bad deal!

    • #18
      Originally posted by robcaldwell View Post
      I used Max HTE high heat epoxy resin when I built my plenum.

      https://theepoxyexperts.com/shop/adh...-glue-casting/

      Soller Composites is a great source for carbon fiber:

      https://www.sollercomposites.com/Carbon-3K-Fabrics.html
      Thanks Rob, their website has a lot of good technical info.

      Comment


      • #19
        Originally posted by quadra View Post
        I have done thousands of lamination in both glass and carbon, they are equally hazardous, but I would choose carbon; not just for the weight to strength, but because the resin choices are much better. A male plug mold will be your fastest option ( and can be carved out or disolved when you are done ) and finishing with some light filler and paint will take way less time than a set of female molds..deep draw lamination.. and vacuum autoclaving
        I would argue that carbon fiber is more hazardous then glass. Check www.osha.gov technical manual OTM section 3 chapter 1 polymer matrix for more info. In addition to the health hazards, carbon dust is electrically conductive and will play hell with your shop electrical system, computer, electrically powered tools etc. Carbon dust can be explosive under the right conditions. Anyone who has worked with carbon will have stories about micro shards in fingers. Too small to see and remove and they hurt like hell. The inherent stiffness of the fiber makes touching it hazardous. Disposing of the waste is a subject unto itself. Be carefull with this stuff, it's not to be trifled with. There is lots of info on the health hazards of carbon fiber on the web. Educate yourself on how to mitigate the risk.
        Gerry
        Patrol #30
        Last edited by geraldmorrissey; 03-25-2020, 03:44 PM.

        Comment


        • quadra
          quadra commented
          Editing a comment
          your link does not support that belief. The section you refer to rightly focuses on the hazards of the sizing, resins and the final composite and its byproducts. I do agree that dust control is important but we have plenty of those tools and computers and CNC equipment in our shop and they are still going strong, most of the dust we see is from the post processing of laminate composites - encapsulated fibre.. the real risk is the chemicals and promoters and the dust smoke and fumes created in finishing composites not the raw fibres. composite construction is not as difficult or mysterious as many people make it out to be and like any other fabrication method requires education and safe practices.

      • #20
        Remember with aircraft composites the more resin you get out (up to starvation) the stronger the laminate becomes. In fact if you make a resin rich laminate you're biting yourself twice, one with weight and the other the laminate will actually become more brittle and prone to cracking. This is the reason they use Prepreg and vacuum bagging in aircraft composites. Newer process include Resin Transfer Molding (RTM) This is actually pretty simple approach but does require a mold, either female or male. Special resins are uses that flow better and basically you lay dry fabric into the mold, vacuum bag it...but leave ports in strategic locations that you can suck the resin into (these ports can be simple hard plastic line that you clamp shut to draw the vacuum). One the bag is pulled down vacuum wise (18-21" hg) you mix your resin, drop one of the port tubes in the bucket of resin and open the valve. The resin displaces the tiny amounts of air trapped in the weave of the fabric and can't build up on the surface.

        This type of composite work is replace wet layup and vacuum bag, and is some cases prepreg work because of its simplicity and cost advantage over prepreg. The powerboat guys that make the big race boats use this technique almost exclusively now.

        remember a 1972 Corvette and a 2020 Vette are both Fiberglass...but one is RTM manufactured...and the fender on the new car is 85% lighter and 300% stronger...the floorboards in the new vetter are actually balsa core, Carbon laminate panel with a single layer of .006" "8 harness weave" fiberglass on it as its easier to paint than carbon.

        Nice door Mr. Welfed…

        I've been screwing around with wingtip drawings/tooling...but with work I haven't gotten any real Bearhawk time.

        Andy

        Comment

        Working...
        X