How to make Mold for GT Fender/Hood Vents?

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#1

:confused: Would anybody be able to produce a picture, image, or something visual of a mold or process that will allow me to understand how I can reproduce GT/ALMS/DTM style vents? The INDIVIDUAL FINS in the ducts are the items in question. Are they bonded individually? That seems like it would be a pain. Could I replicate this without any secondary bonding process? Any ideas or pictures of the process or an actual mold?

There are a couple of different styles in the pictures posted, and I am more concerned with photos 1-4. Any help is greatly appreciated!

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#2

pics 1&4

They are a single piece assy. (panel) I make them with c/f & Kevlar(single ply on lower surface.
at my level the best results, I fuse them.
I lay up each vane and trim every opening. very time consuming.
I made spares every season ALMS P1 car. (2006-2012) Last week I did a set for an Elan DP02

#3

I can see em, and would also like to see a mold for such a vent.

#4

I can’t find pic’s of just the mold.
Here are some I did long time ago

this one came out of the same mold. I used primer for surface coat because I installed them in a Trans-Am car c/f hood

it’s a simple VE mold taken from a LOLA B0610 louver

#5

Very cool, Tom, thanks for sharing.
You must be busy this year with the expanded classes in imsa. Lots of carbon fiber parts flying at Sebring!

#6

Thanks Tom, this awesome info is exactly what I was looking. Those vents look badass…good job! The layer of Kevlar is a good tip and probably will apply to other projects that I have stored in my endless list of future projects. I kind of figured something of this nature would be very time consuming…either bonding or cutting/trimming. However, infusing them never occurred to me. Is infusion your method of choice for race car body panels?

Stealth, was it a hex on the race this year? lol

#7

I found these on my phone
DP02

the trick is to avoid the void. I use a tackifier to glue down the plies.
I ran two plies of P/W down the sides on this one, and 1 ply of 2x2 on mold face with 3 plies P/W 1 ply Kevlar. It ties in pretty good and have had no failures. Infusion is one of my favorite methods. especially on large parts. Stretchlon on the top, but I have had trouble with the greenflow cutting thru and leaking.



I have no oven, I do all this from home in my garage. Most of my work now is vintage & club racing, I don’t go with the teams much anymore, I’m to old

#8

Great parts, Tom, nice to see you doing that in a home garage.
I assume you aren’t having any warping issues with these large parts in the sun even without an oven. Are you doing any other type of post cure? Is typical low viscosity epoxy stable enough without post cure or are you using something special?
Glad to see you aren’t killing yourself on the circuit, I was thinking you were still doing parts for DP class from some of the pics I saw.

Yes, there was a hex on the Sebring race this year! Only Porsches finishing in GT , my beloved C7 zo6 didn’t make it!

#9

I was wondering about the post cure as well, as I plan on oven curing all of my parts. Apparently, Tom has found a method to make it work.

And OH, that C7.R is so brutal, yet so sexy. Have any idea how I can find out who is manufacturing that body? As a matter of fact, the 4th picture I posted is a picture of the C7.R

How those vanes are incorporated into that mold, I do not know. The only process that I can think of was something that I saw an engineering company did when I was out in Salt Lake City, UT. They made wings, without a core, in one process.

Imagine the vanes in the picture is of the inside of a wing (turned almost vertical). Got it? Well, they had a closed mold for the wings and would have several LONG aluminum extrusions in the shape of the cavity in between the vanes. The [outside] of the wing was layed up in an open ‘closed mold.’ The aluminum blocks were mold released, wrapped with prepreg, and fitted into place in the open ‘closed mold.’ The mold was then closed incorporating both sides of the wing skin as well as these prepreg wrapped aluminum cavity fillers. The part was cured, the mold was opened, and the wing was released (still incorporating the aluminum extrusions). These long aluminum extrusions were then banged out until they were free. Low and behold…one wing, no core, but with these vanes keeping it structurally adequate. It was pretty neat to watch this happen in one process.

#10

Ah yes Corvette, the one car I have never worked on. I have confidence the will be up on the curve. Danny Binks a friend of mine (crew chief for Pratt& Miller) has a lot of pressure on him. I will see his mom & dad soon and see what’s up.

Post cure done in the sun. I live in the San Fernando Valley and temps in the summer get to 3 digits. I let them age in the mold a while. I have had the tail in the pic’s running for some time now. It took 3rd. in the SCCA Runoffs 2012. and no trouble.

I’m using PTM&W 2712 and love the stuff.

to tell the truth. I had no clue how to infuse. I read up on it (most here at CC) and went down to Airtech and talked with a rep.
I would like to kidnap Herman and bleed him for all he knows:)

For real high end composite work http://www.debotech.com/
My friend Michael Scully used them for the USA Olympic 2 man Bobsled.

Michael is also a customer of mine. he raced this for some time (track record holder at Laguna Seca)

as for working in the Gee-Raj, I need more room. No website, no business card, my customer base is word of mouth.

#11

Awesome stuff once again Tom! I’m going to bet your reputation was in place long before the Interwebs.
Cutting each of those vent openings looks to be tedious as heck. Whats your tools of choice doing that?

#12

So I clicked on debotech.com and this company is literally 20 miles away from my condo :amazed:! There are a few composite shops in my area, as it is home to many many NASCAR racers/teams, but I had never known of this shop. Apparently, they have made a big splash with the Olympic bobsleds this year. This guy’s (Hans Debot) website is pretty interesting as well. He started out in his own garage and now owns multiple autoclaves. Dude made all of the carbon fiber vents for the hoods on the Camaro ZL1. I simply cannot believe it…:eek:

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Maybe I’ll go down the road and ask Hans…

Good stuff Tom. Thanks a million for your valuable input!

Also, check out thisthread

#13

Awesome thread. I have similar vents (14) on my clamshell hood. My vents were apart of the hood mold. Looks like everything was thoroghly answered. I second the points on using infusion and spray tack to hold the fabric down in the compex shapes. For my vents i make them with the holes closed. I then cut them out with a dremel. As to how the louvers are made in the last picture, they are either molded in the part from the start or added later. If we could see the underside of the vents or more pictures we could determine how it was constructed. Good luck with the build.

#14

I did a repair on a bugati hood that had louvers in it, the louvers were removable meaning that they were molded separate then attached to the hood. The hood had some cracks that I fixed and then the shop I worked at sanded the hood and painted it with clear to a high gloss finish. It had a matte finish before we started. It was all done with pre-preg.

#15

the pencil grinder @ bottom with a burr