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Graphite Powder - 2/3/2008 3:32:19 AM   
wkevinm


 

Posts: 141
Joined: 9/17/2004
From: Sherwood Park, AB, CANADA
Status: offline 		Can I use graphite powder with epoxy as my first coat in making a mold of a fuse. My purpose for this use is for the black color only. Will the graphite interfere with waxing and painting in the mold.

Kevin M
       Post #: 1

RE: Graphite Powder - 2/3/2008 5:06:25 AM   
Roguedog


 

Posts: 111
Joined: 2/12/2007
From: Riverside, CA, USA
Status: offline 		Yes you can. I went to the AMA convention in Ontario, California and the talked with the a Guy from CSTSales that actually did a tutorial on there website. http://www.cstsales.com/tutorials/fiberglass_mold.pdf
West System has a product for doing just what your asking. Although he calls this the gelgoat, it is not technically correct. I was curious about this when I stopped at the booth at the show. I thought that maybe he was adding the graphite power as a means of strengthing the the very first coat (what he called the gelcoat) to make it more durable. I also wanted to know if adding the graphite power helped aid in releaseing the plug from the mold, because graphite powder is also used as a dry lubricant. He told me that the reason he used the graphite powder was for color only. He said if the face of the mold was black it made seeing airbubbles easier during the layup process. He also used a Colloidal Silica Filler eg (Carb-o-sil) for flow control. This helped the Epoxy to stay put on the sides and not run or drip off.



< Message edited by Roguedog -- 2/3/2008 5:07:12 AM >

(in reply to wkevinm)
       Post #: 2

RE: Graphite Powder - 2/3/2008 5:27:26 AM   
wkevinm


 

Posts: 141
Joined: 9/17/2004
From: Sherwood Park, AB, CANADA
Status: offline 		Thanks for the response, in fact it was west 423 graphite power I was referring to. And thanks for clearing up the use of the term Gel Coat for epoxy. I was confused, I know and have used polyester based gel coat but have never seen an epoxy gel coat, or tooling resin.

Kevin M

(in reply to Roguedog)
       Post #: 3

RE: Graphite Powder - 2/3/2008 1:57:18 PM   
Ed Smith


 

Posts: 2834
Joined: 12/29/2001
From: Brantford, ON, CANADA
Status: offline 		Do not use polyesyer for anything. Always use epoxy.

In addition to the visibility thing when laying up parts graphit will thicken the epoxy "gelcoat". I always use graphite powder for my molds. The result is a high gloss, hard, mold surface

Ed S

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(in reply to wkevinm)
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RE: Graphite Powder - 2/3/2008 6:01:42 PM   
wkevinm


 

Posts: 141
Joined: 9/17/2004
From: Sherwood Park, AB, CANADA
Status: offline 		Thanks Ed.

BTW

Your mold is unique with the parting line at the bottom of the fuse. What are the advantages of this. I was intending on building a mold with the part line along the centerline (verticle) and build a joggle to aid in joining.

When you join, do you use tape in the aft portion of the fuse or other?


Kevin M

< Message edited by wkevinm -- 2/3/2008 6:06:12 PM >

(in reply to Ed Smith)
       Post #: 5

RE: Graphite Powder - 2/4/2008 5:41:49 PM   
Ed Smith


 

Posts: 2834
Joined: 12/29/2001
From: Brantford, ON, CANADA
Status: offline 		Hi Kevin,

I had the experience with a mold for rectangular section fuselages where the mold collapsed about 1/8" inwards along the central split line. I scrapped it.

The split line on the pictured mold is along the top of the bottom corner rad. The side, top and bottom surfaces are completely smooth with no joint lines. Fixing and filling the corner joint is very easy. I acan also fit a plate to the mold to give me a recess for the flush fitting LG.

The pictures show the molding sequence. I join the two parts in the mold while everytning is still wet.

Ed S

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RE: Graphite Powder - 2/4/2008 6:36:52 PM   
soarrich



Posts: 2372
Joined: 2/1/2002
From: Middletown, NJ, USA
Status: offline 		I had a Midwest Attacker foam ARF in the late 70's that had the fuse divided top and bottom. It made it easy to install the radio, fuel tank and motor, then you put the top on.

_____________________________

Rich Border

(in reply to Ed Smith)
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RE: Graphite Powder - 2/4/2008 7:05:03 PM   
wkevinm


 

Posts: 141
Joined: 9/17/2004
From: Sherwood Park, AB, CANADA
Status: offline
quote:

ORIGINAL: Ed Smith

Hi Kevin,

I had the experience with a mold for rectangular section fuselages where the mold collapsed about 1/8" inwards along the central split line. I scrapped it.

The split line on the pictured mold is along the top of the bottom corner rad. The side, top and bottom surfaces are completely smooth with no joint lines. Fixing and filling the corner joint is very easy. I acan also fit a plate to the mold to give me a recess for the flush fitting LG.

The pictures show the molding sequence. I join the two parts in the mold while everytning is still wet.

Ed S



Thanks Ed,

I like your approach, is seems to have many more posibilities than the centre seam on the verticle or horizontal, do you ever have issues removing the fuse from the mold, it being so deep.

Kevin M

(in reply to Ed Smith)
       Post #: 8

RE: Graphite Powder - 2/4/2008 8:04:03 PM   
Ed Smith


 

Posts: 2834
Joined: 12/29/2001
From: Brantford, ON, CANADA
Status: offline
quote:

do you ever have issues removing the fuse from the mold, it being so deep.


No, I solved that problem with the removable plate at the firewall. With the plate off and the mold parts seperated I am left with the complete fuselage in the deeper mold half. I can spring the deep mold apart at the front. The rest releases as molds do.

Ed S

(in reply to wkevinm)
       Post #: 9

RE: Graphite Powder - 2/4/2008 8:16:43 PM   
wkevinm


 

Posts: 141
Joined: 9/17/2004
From: Sherwood Park, AB, CANADA
Status: offline
Thanks for information Ed, I am sold.

I am thinking I will make the parting board from 1/4" melamine board, and make a contoured support from a tracing of the fuselage bottom.

Kevin M

(in reply to Ed Smith)
       Post #: 10

RE: Graphite Powder - 2/4/2008 9:45:17 PM   
michaeldeleo


 

Posts: 5
Joined: 1/18/2008
From: Atascadero, CA, USA
Status: offline 		Kevin,

Like other posters, I've used the West graphite powder in making several molds. The dark color does make detecting bubbles during layup easier and it makes the mold harder and stiffer than you'd get with just the epoxy and hardener.

However, I would be careful how much of it you use in the first layup coat, what some are calling "gelcoat", for the actual part as the graphite will make the epoxy brittle. I've noticed that my molds crack much easier than I would want a fuselage to, for example. Luckily, a little bit of that "black powder" goes a long way toward darkening up the epoxy.

Re parting boards... I just used 1/4" hardboard (stuff you can get in 4x8' sheets from Home Depot) on a project with good results. It's very smooth and is easy to cut and shape. I used five coats of wax and a single coat of mold release.

Hope that helps or stirs some conversation,

Mike

(in reply to wkevinm)
       Post #: 11

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