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JAF's +221-Haynes/Custom-Miata
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Author:  horizenjob [ September 30, 2012, 11:34 am ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
The SouthWest Speed pedals look nice, are you happy with them?

I don't see much use for carbon once you are using honeycomb for a sandwich. You can get stiffness so rapidly with thickness of the sandwich.

Do you think you'll get a weight saving over aluminum skin? Are you going to do something like test panels and dropping a weight on them? I think it's difficult to figure out something like damage resistance. I've seen aluminum boats take a pretty good dent in the bottom when dropped on a rock and still be water tight. Fiberglass won't dent but it might be able to spring back from a pretty good impact.

Kevlar can be pretty attractive in a layup. It won't heat up like carbon if the sun gets to it also.
Author:  jaf [ September 30, 2012, 12:23 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
horizenjob wrote:
The SouthWest Speed pedals look nice, are you happy with them?

I don't see much use for carbon once you are using honeycomb for a sandwich. You can get stiffness so rapidly with thickness of the sandwich.

Do you think you'll get a weight saving over aluminum skin? Are you going to do something like test panels and dropping a weight on them? I think it's difficult to figure out something like damage resistance. I've seen aluminum boats take a pretty good dent in the bottom when dropped on a rock and still be water tight. Fiberglass won't dent but it might be able to spring back from a pretty good impact.

Kevlar can be pretty attractive in a layup. It won't heat up like carbon if the sun gets to it also.


So far I like the pedals, although I've yet to push any fluid with them yet. Price was right and it was easy to get all of the fittings from one website to plumb everthing.

Agree with the carbon vs. core assessment. I keep reminding myself this is a LOW-cost. Composites are't the low cost option but I already have most of the knowledge, tools, and consumables required.........plus I enjoy doing it. I'm planning on only using carbon for the visual pieces (dash, firewall, fenders), which are pretty much the only pieces that won't have core in them.

Assuming you use .032 or greater aluminum....then you bet there will be a weight saving. The only panel that has to do any "work", other than skinning the chassis, is the portion of the floor under the occupants which will mainly be kevlar, glass and core.

Right now I have Style 220 Glass, Style 7781 Glass, Style 220 Kevlar, a one off Hexcel experimental 7.3oz/yd Glass/Kevlar hybrid, 3K twill Carbon, 6K twill Carbon. The core is .300" 3/16-3.0 Nomex. Still playing with epoxys but it looks like it will be Aeropoxy 2032 for laminating, and ES6279 for bonding core to face sheets. Vacuum bag wet layup with be fabrication method.
Author:  jaf [ May 2, 2013, 8:09 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
First few composite pieces complete.

Firewall layed up on "L-shaped" mold then trimmed to make vertical plate scuttle section, and horizontal chassis section that carried the return flange to stiffen it. Laminate consisted of one layer of carbon, two layers of kevlar/glass hybrid, and one layer of 220 glass.

The steering shaft fairing was layed up over a cardboard tube that I cut into shape. A few layers of glass and then one layer of carbon.

The kick panel is a honeycomb core pillowed sandwich panel with one layer of 220 glass and one layer of kevlar/glass hybrid on either side of the core.
Attachment:
Firewall.jpg

Attachment:
Pass. Kick Panel.jpg
Author:  cwhite [ May 3, 2013, 9:25 am ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
I'm impressed, this is one of the nicest build I've seen yet. Time to cover mine up and hide it. :oops:
Author:  jaf [ September 29, 2013, 7:55 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
More composite goodness. Dash, center console, and rear bulkhead are complete less a bunch of coats of clear. Side panels are in-work. Then it's finally onto the actual body panels and the floor.
Attachment:
bulkhead-dash-console.jpg

Attachment:
side-panels.jpg
Author:  Lonnie-S [ September 30, 2013, 9:09 am ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
Is the plastic in the last photo of the side panels just for protection or are you doing some kind of vacuum bag technique?

Cheers,
Author:  jaf [ September 30, 2013, 5:02 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
Lonnie-S wrote:
Is the plastic in the last photo of the side panels just for protection or are you doing some kind of vacuum bag technique?

Cheers,


Yes........I'm vacuum bagging the honeycomb core pieces down to the outer moldline. Next step is to vacuum bag the inner moldline plys down.
Author:  hedtrip [ October 8, 2013, 10:59 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
That firewall is just plain sexy. It doesn't look like you've done much updating lately I'd hate to such a good build goto waste.
Author:  jaf [ October 16, 2013, 6:49 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
And still more composites.......transmission side panels, and the half completed floor. I think I'll skin the side panels with a layer of carbon instead of painting them black. I'm also planning on using carbon for the portion of the floor under my legs. Then I'll be properly bathed in carbon.
Attachment:
sidepanels.jpg

Attachment:
floor.jpg
Author:  ngpmike [ October 17, 2013, 7:12 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
Very impressive build! I was wondering if I could see it first hand? What part of Missouri are you in? I'm in Gainesville, South Central Mo.
Author:  jaf [ November 11, 2013, 10:27 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
Rear panel flat as a board and properly curved in all the right places, and the floor both completed less final trim. Onto the side panels once another gallon of resin comes in.
Attachment:
Rear Panel and Floor.jpg
Author:  mjalaly [ March 21, 2014, 10:02 am ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
jaf wrote:
Rear panel flat as a board and properly curved in all the right places, and the floor both completed less final trim. Onto the side panels once another gallon of resin comes in.
Attachment:
Rear Panel and Floor.jpg


What process are you using to make your curved molds?
Author:  jaf [ March 22, 2014, 4:56 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
mjalaly wrote:
What process are you using to make your curved molds?


If you look closely you'll see the black sharpie lines on the rear panel at the tangency points. I tapered the core to end exactly 0.25" back from those lines so the "coreless" laminate (2-layers each of 220 f/g and a Kevlar/glass hybrid) just bends around the corner. I layed up the panel flat and let it cure until the resin was at "handling strength". Then unbag, rough trim, and just clamp it down to the chassis while the epoxy resin continued to cure.

If work with your epoxy long enough you know what I'm talking about assuming you are just room temperature curing everything. When you first unbag your part the resin is still a little flexible. Over the next few days depending on the temperature, it will continue to harden (cross-link) until it becomes rock hard.

I wouldn't recommend this process for a carbon laminate due to it's stiffness but for Kevlar and/or glass it works great for the ~5" radius I had to bend around. I have a little bit of "spring-back" but nothing you can't take back out with finger pressure.
Author:  Tongboy [ March 25, 2014, 1:20 am ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
I just wanted to comment on how beautiful your composite work is, probably the best I've seen on here - that inner scuttle/steering column looks perfect as do all of those other pieces!
Author:  jaf [ May 8, 2014, 7:31 pm ]
Post subject:  Re: JAF's +221-Haynes/Custom-Miata
Progress is slow but I'm still moving forward. Just waiting for more resin to do the other rear fender. If anyone has a weight of a similar sized rear fender I'd love to compare. I'm 11" wide (flange-to-flange), approx. 62" long, with a 28.5" diameter and it's 2.4lbs untrimmed. I think after final trim I could be under 2lbs.

Pics to enjoy.
The black "framing" in the side panels is a layer of carbon directly over where the chassis tubing sits.
The transmission tunnel panels are still pretty nasty on the outer surface because I let the resin bleed through the laminate when I skinned it. Nothing a little sanding and a few clear coats won't fix.
Attachment:
Rear Fender Untrimmed.jpg

Attachment:
Sidepanels rough trim.jpg

Attachment:
Driver Tunnel Panels.jpg

Attachment:
Pass Tunnel Panel.jpg
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