Tooling gell need??

Tooling gell need??
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Tooling gell need?? - 5/12/2008 4:58:39 AM

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Joined: 5/10/2008
From: falmouth, ME, USA
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I've been viewing this site for a while and have found it to be very good. I recently made a Plug, Mold and Carbon Fiber Spinner cone. I found the cone came out quite hard dispite the 10 coats of partall and silicone release. Does tooling gel help this problem. I've never used the stuff. What's the differance between Tool gelocoat and normal gelcoat. The spinner came out fine but now that I'm working on a spitfire fuse and wing I want to make sure I'm using the correct stuff.
Any help here would be great!

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RE: Tooling gell need?? - 5/12/2008 12:42:48 PM

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From: Brantford, ON, CANADA
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"Tooling gel" will make little difference to how the part releases from the mold. The inside finish of the mold is very ipmortant. This finish is established by the outside finish of the plug. A high gloss finish in the mold is not just cosmetic. The higher the gloss finish the easier the release. The release wax used is of paramount importance of course. Use only top quality 'Mold Release" wax, no cheap substitutes. My polishing procedure for a new mold is to apply the wax, smooth it out and polish to a high gloss. I then let it sit for a day for the wax to harden. I repeat that about six times. I will then apply a very fine mist of PVA. and let it dry. The mold is then ready for use. The PVA will take some of the gloss off the first part but willl aid in release. Usually after the first use the mold requires only the wax and not the PVA.

The picture shows the gloss finish in a fuselage mold. It would appear from your picture that the mold does not have a gelcoat finish. When I make the mold I mix Graphite powder with some resin to make a gelcoat. This is the first coat to be applied to the plug. The graphite/resin when cured gives a hard surface to the mold.

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< Message edited by Ed Smith -- 5/12/2008 12:44:39 PM >

(in reply to sunnybreeze)

RE: Tooling gell need?? - 5/12/2008 6:14:42 PM

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From: falmouth, ME, USA
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Ed,
Thanks for the solid input. You are right on the mold I made. It's simply West epoxy 105. I used no gelcoat. I did sand the surface to 600 grit and then polished it to a high Class "A" finish. Partall (10 coats) and mold release. It still came out hard. I feel you are right and gelcoat or grafite powder are in order. I have my plug for my spitfire finished and do not want to mess it up. It's foam with cloth and epoxy sand 600 grit and again polished to a high sheen. It's flawless and super high sceen.

My question is can I use plain gelcoat from the marine store or is there something special about tooling gel. Also do I brush on the gelcoat and let it kick off or lay up the mold asap while the gelcoat is still soft? I plan to vacuum bag the mold at about 8"Hg.
Any input here would be great.
Steve

(in reply to Ed Smith)

RE: Tooling gell need?? - 5/12/2008 9:30:11 PM

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Hi Steve,

I cannot comment on marine store products. I do try to use compatible products from the same manufacturer. I use the same epoxy resin for the graphite mix, making the mold and making the parts. Once you start mixing brands who knows. I use MGS resin for everything, The graphite powder is West # 423.

I make trhe gelcoat thick enough so it brushes on to the plug smoothly but without draping. I allow it to cure so it is just tacky to the touch. My first layer of cloth is usually 1.5/2.0 oz. this will tack down on to the gelcoat. I then brush the resin through it. The important thing here is to not get any bubbles under the cloth. If there are cavities under that first layer the mold surface can break up very easily. Once this first layer has almost cured it is OK to build up the mold wall thickness.

Somewhere on this Forum are some pictures of molds and plugs for boat hulls by "Teamseacats". The finish on those is just about as perfect as it gets.

The picture shows my typical finish on plugs (Red) and a mold (Black). These were made from the plastic parts in a kit.

Ed

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(in reply to sunnybreeze)

RE: Tooling gell need?? - 5/12/2008 10:02:52 PM

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From: Enterprise, AL, USA
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quote:

ORIGINAL: Ed Smith

I cannot comment on marine store products. I do try to use compatible products from the same manufacturer. I use the same epoxy resin for the graphite mix, making the mold and making the parts. Once you start mixing brands who knows. I use MGS resin for everything, The graphite powder is West # 423.

Ed i believe that's about the most contradiction I've ever seen in a single paragraph.

.

West System is the marine store products, they make West #423 and it's made for use with their 105 resin, not that other manufactures brand MGS you're using

Oh FWIW, when making a mold i make the mold 'gel coat' with 105 resin, the 423 graphite and thicken it with 406 colloidal silica till it's about the consistency between mayonnaise and peanut butter, brush it on with an acid brush and it's slick as snot when you pull the plug.

< Message edited by KC36330 -- 5/12/2008 10:06:58 PM >

(in reply to Ed Smith)

RE: Tooling gell need?? - 5/13/2008 1:19:31 AM

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quote:

Ed i believe that's about the most contradiction I've ever seen in a single paragraph. .

West System is the marine store products, they make West #423 and it's made for use with their 105 resin, not that other manufactures brand MGS you're using

I did not intend to contradict anything. The marine store reference did not mention a West product, it was rather general. As I said I use the same resin for all of my glass work. I mix my own gelcoat with the addition of graphite powder.

In terms of quality, MGS and West Sytems epoxy are equal in all respects. However the big advantage of MGS is the selection of hardeners. MGS fast hardener will give a 20min working time. The slow hardener will give a five hour working time. The two can be mixed for a custom cure time. The slowest West hardener will give just over an hour working time. When I mold fuselages I lay up both halves and join them in the mold while still wet. It is a three hour process. Hence my reason for using MGS epoxy resin.

Ed S

(in reply to KC36330)

RE: Tooling gell need?? - 5/13/2008 1:52:16 AM

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From: falmouth, ME, USA
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Ed,
I didn't mean to start a spat with anyone! I do have to say I meant generic gelcoat from the store. I was not refering to any West system products. I have been using West for 25 years so I will stick with what I use. The Graph powder and filler will be my next step and I'm sure it will all be good. I will post pictures of my progess.

Thanks again to everyone. I still would love to have someone explain tooling gelcoat to me just so I will know!
Steve

(in reply to Ed Smith)

RE: Tooling gell need?? - 5/13/2008 3:19:26 AM

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From: Greenville, SC, USA
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Ed, I'm blushing!

"Tooling" gelcoat is a gelcoat that is specifically derived for it's color (usually orange or black), it's durability, and it's dimensional stability throughout various temperature ranges. The color is special because it makes laminations easier to see (many people prefer a black mold for this purpose). The durability is important for the repeated stresses of releasing parts. The dimensional stability is needed especially if you intend to use heat to cure your parts and not stress the mold. I would not use a West Marine off-the-shelf gelcoat for this purpose as they usually have wax (so they will cure in contact with air) and the shelf term of the gelcoat is suspect.

There are a couple of choices here - some will argue that the phrase "gelcoat" refers to a polyester based product (I argue this! ;-)) and others will argue that a gelcoat is simply your choice of products that will form the contact layer in your mold - including epoxy based products. I think of all the projects I've seen here use epoxy, thickened and colored with additives, to form the surface of their molds. I've never used epoxy for this purpose - but have seen a lot of great examples of it's use here. I use tooling gelcoat (polyester resin base) and vinylester or polyester resins for mold making. If using polyester, it's important to use a good quality resin for stability/non-warping of the mold.

Epoxy is a terrific product and though it is much more prone to mixing ratio and (low) temperature issues, it's a terrifically durable, strong, and dimensionally stable product (even most of the cheaper stuff...though don't skimp). Most of the parts that come out of my molds are laminated using epoxy - I will probably switch to epoxy molds in the future based on what I've learned here.

You can polish a mold but you are much better off if your origional plug starts off polished. Especially in the case of polyester gelcoats, the inner layers of gelcoat can be porous so you want to be sure you use the outer layer as part of the mold. if your plug is extremely shiny, you need to do very little work to your mold post molding. I presume that there are some benefits in the use of epoxy in the same respect.

If you used that much wax and PVA, I'm really surprised you had a release problem. PVA makes the molding process difficult to achieve a good finish but it is usually a very bulletproof way of releasing a part from a mold. I suspect that the PVA you put in place was not thick enough. I use first a very light fog coat to form an even grip on the waxed surface, then two thicker layers - stopping just before it starts to "look smooth". If I were using paint, I would spray on more paint to get a smooth finish - using PVA, you need to stop a little short of this point. Between each layer, I give it 15 minutes to flash off and then 30 minutes to set good before beginning to mold a part.

< Message edited by TeamSeacats -- 5/13/2008 3:22:59 AM >

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(in reply to sunnybreeze)

RE: Tooling gell need?? - 5/13/2008 4:07:42 AM

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Joined: 4/19/2006
From: Enterprise, AL, USA
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quote:

ORIGINAL: Ed Smith

In terms of quality, MGS and West Sytems epoxy are equal in all respects. However ............

I agree MGS is a good quality resin and for no other reason i like the blue tint it provides. i wasn't intending any sort of spat above, and thought that was clear with the

i attached to it, my apologies for any offense taken.

(in reply to Ed Smith)

RE: Tooling gell need?? - 5/18/2008 11:10:25 PM

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From: saint petersburg , FL, USA
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if your ever having a problem pulling a part from the mold you can soak it in water for a 1/2 hour. this always works for me and it doesnt heart the part or the mold. but you need to rewax if your going to make another part.

...mike

(in reply to KC36330)

RE: Tooling gell need?? - 5/19/2008 5:15:50 PM

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From: falmouth, ME, USA
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Mike,
Are you talking about Hot or Cold water for release?
Steve.

(in reply to maverick pro)

RE: Tooling gell need?? - 5/19/2008 8:58:00 PM

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From: saint petersburg , FL, USA
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you could use both....but ive always used cold water.

...mike

(in reply to sunnybreeze)

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