Carbon Fiber - Achieving Glossy Finish w/o GelCoat

[RKT]

I am trying to piece together the process of vacuum bagging a CF part from
several sources and comments. I am trying to achieve a glossy finish on the
mold side of the finished part.

I though that the gloss that I saw on a purchased part was achieved from
GelCoat. The manufacturer tells me no - not GelCoat. He tells me that my
mold (aluminum) must have a 'mirror-like' finish and that I can get that
easily by having it Nickel plated.

But I'm not certain if that approach is compatible with my perception of the
process:

1. Nickel plate the mold.
2. Wax the mold several times.
3. Apply resin to both sides of the CF fabric.
4. Remove execess resin.
5. Apply CF to mold.
6. Apply peel-ply.
7. Apply breather.
8. Apply vacuum bag, seal.
9. Apply vacuum (18mm Hg) and slight heat to accel the cure (~110F)
10. Remove piece.
11. Buff or solvent (to remove wax?)
12. Buff to gloss?

What is confusing to me is why a mirror finish of the mold is 'absolutely
required' to achieve gloss(acc. to source) if I am applying and buffing the
release wax. He says 'the wax is going to transfer to the part'. I certainly
believe him, but 'im not getting how the gloss is 'applied' in the process.

I have done this process using water soluble release w/o plating the mold
and get a VERY dry-looking, matte finish on the mold side. The finished part
is indeed very light - so I thought I was removing TOO much resin to achieve
the gloss.

I have a lot to learn. Can someone help me make sense of this process so I
will have confidence that Nickel plating the mold is magically (and
counter-intuitively to me) going to yield this high-gloss finish?

[Richard Riley]

On Wed, 3 Mar 2004 21:54:50 -0500, "RKT" > wrote:

:I am trying to piece together the process of vacuum bagging a CF part from
:several sources and comments. I am trying to achieve a glossy finish on the
:mold side of the finished part.
:
:I though that the gloss that I saw on a purchased part was achieved from
:GelCoat. The manufacturer tells me no - not GelCoat. He tells me that my
:mold (aluminum) must have a 'mirror-like' finish and that I can get that
:easily by having it Nickel plated.
:
:But I'm not certain if that approach is compatible with my perception of the
:process:
:
:1. Nickel plate the mold.
:2. Wax the mold several times.
:3. Apply resin to both sides of the CF fabric.
:4. Remove execess resin.
:5. Apply CF to mold.
:6. Apply peel-ply.
:7. Apply breather.
:8. Apply vacuum bag, seal.
:9. Apply vacuum (18mm Hg) and slight heat to accel the cure (~110F)
:10. Remove piece.
:11. Buff or solvent (to remove wax?)
:12. Buff to gloss?
:
:What is confusing to me is why a mirror finish of the mold is 'absolutely
:required' to achieve gloss(acc. to source) if I am applying and buffing the
:release wax. He says 'the wax is going to transfer to the part'. I certainly
:believe him, but 'im not getting how the gloss is 'applied' in the process.
:
:I have done this process using water soluble release w/o plating the mold
:and get a VERY dry-looking, matte finish on the mold side. The finished part
:is indeed very light - so I thought I was removing TOO much resin to achieve
:the gloss.
:
:I have a lot to learn. Can someone help me make sense of this process so I
:will have confidence that Nickel plating the mold is magically (and
:counter-intuitively to me) going to yield this high-gloss finish?

The only way I've gotten it is with clear gel-coat. I suppose nickel
might work, if the resin you're using (polyester, epoxy, vinyl ester,
whatever) wets nickel and doesn't bead up on it.

But it's going to bead up on wax, anyway. So I *think* you're still
going to get pinholes.

Get a piece of adhesive backed nickel foil from McMaster-Carr - they
have it 15" wide, .004" for about $30 a foot. Lay up on it the way
you describe, see if it works. Just a thought.

[jp]

Richard Riley wrote:

> On Wed, 3 Mar 2004 21:54:50 -0500, "RKT" > wrote:
>
> :I am trying to piece together the process of vacuum bagging a CF part
> :from several sources and comments. I am trying to achieve a glossy finish
> :on the mold side of the finished part.
> :
> :I though that the gloss that I saw on a purchased part was achieved from
> :GelCoat. The manufacturer tells me no - not GelCoat. He tells me that my
> :mold (aluminum) must have a 'mirror-like' finish and that I can get that
> :easily by having it Nickel plated.
> :
> :But I'm not certain if that approach is compatible with my perception of
> :the process:
> :
> :1. Nickel plate the mold.
> :2. Wax the mold several times.
> :3. Apply resin to both sides of the CF fabric.
> :4. Remove execess resin.
> :5. Apply CF to mold.
> :6. Apply peel-ply.
> :7. Apply breather.
> :8. Apply vacuum bag, seal.
> :9. Apply vacuum (18mm Hg) and slight heat to accel the cure (~110F)
> :10. Remove piece.
> :11. Buff or solvent (to remove wax?)
> :12. Buff to gloss?
> :
> :What is confusing to me is why a mirror finish of the mold is 'absolutely
> :required' to achieve gloss(acc. to source) if I am applying and buffing
> :the release wax. He says 'the wax is going to transfer to the part'. I
> :certainly believe him, but 'im not getting how the gloss is 'applied' in
> :the process.
> :
> :I have done this process using water soluble release w/o plating the mold
> :and get a VERY dry-looking, matte finish on the mold side. The finished
> :part is indeed very light - so I thought I was removing TOO much resin to
> :achieve the gloss.
> :
> :I have a lot to learn. Can someone help me make sense of this process so
> :I will have confidence that Nickel plating the mold is magically (and
> :counter-intuitively to me) going to yield this high-gloss finish?
>
> The only way I've gotten it is with clear gel-coat. I suppose nickel
> might work, if the resin you're using (polyester, epoxy, vinyl ester,
> whatever) wets nickel and doesn't bead up on it.
>
> But it's going to bead up on wax, anyway. So I *think* you're still
> going to get pinholes.
>
> Get a piece of adhesive backed nickel foil from McMaster-Carr - they
> have it 15" wide, .004" for about $30 a foot. Lay up on it the way
> you describe, see if it works. Just a thought.

Man I hope that's $.30 a foot not $30 a foot.

[Craig]

Plating and polishing significantly reduces the amount of variations
in the surface of the mold. Take a look at the mold you have now under
a magnifying glass.....the higher the power the better and compare
that surface with one that has been plated and polished. The
difference will amaze you. You can simply polish out an aluminum mold,
but the surface will start to corrode almost imediately and will not
tolerate being touched by anything that is hard without damage.

HTH...

Craig C.

[Craig]

Plating and polishing significantly reduces the amount of variations
in the surface of the mold. Take a look at the mold you have now under
a magnifying glass.....the higher the power the better and compare
that surface with one that has been plated and polished. The
difference will amaze you. You can simply polish out an aluminum mold,
but the surface will start to corrode almost imediately and will not
tolerate being touched by anything that is hard without damage.

HTH...

Craig C.

[RKT]

"Richard Riley" > wrote in message
...
> On Wed, 3 Mar 2004 21:54:50 -0500, "RKT" > wrote:
>
> :I am trying to piece together the process of vacuum bagging a CF part
from
> :several sources and comments. I am trying to achieve a glossy finish on
the
> :mold side of the finished part.
> :
> :I though that the gloss that I saw on a purchased part was achieved from
> :GelCoat. The manufacturer tells me no - not GelCoat. He tells me that my
> :mold (aluminum) must have a 'mirror-like' finish and that I can get that
> :easily by having it Nickel plated.
> :
> :But I'm not certain if that approach is compatible with my perception of
the
> :process:
> :
> :1. Nickel plate the mold.
> :2. Wax the mold several times.
> :3. Apply resin to both sides of the CF fabric.
> :4. Remove execess resin.
> :5. Apply CF to mold.
> :6. Apply peel-ply.
> :7. Apply breather.
> :8. Apply vacuum bag, seal.
> :9. Apply vacuum (18mm Hg) and slight heat to accel the cure (~110F)
> :10. Remove piece.
> :11. Buff or solvent (to remove wax?)
> :12. Buff to gloss?
> :
> :What is confusing to me is why a mirror finish of the mold is 'absolutely
> :required' to achieve gloss(acc. to source) if I am applying and buffing
the
> :release wax. He says 'the wax is going to transfer to the part'. I
certainly
> :believe him, but 'im not getting how the gloss is 'applied' in the
process.
> :
> :I have done this process using water soluble release w/o plating the mold
> :and get a VERY dry-looking, matte finish on the mold side. The finished
part
> :is indeed very light - so I thought I was removing TOO much resin to
achieve
> :the gloss.
> :
> :I have a lot to learn. Can someone help me make sense of this process so
I
> :will have confidence that Nickel plating the mold is magically (and
> :counter-intuitively to me) going to yield this high-gloss finish?
>
> The only way I've gotten it is with clear gel-coat. I suppose nickel
> might work, if the resin you're using (polyester, epoxy, vinyl ester,
> whatever) wets nickel and doesn't bead up on it.
>
> But it's going to bead up on wax, anyway. So I *think* you're still
> going to get pinholes.
>
> Get a piece of adhesive backed nickel foil from McMaster-Carr - they
> have it 15" wide, .004" for about $30 a foot. Lay up on it the way
> you describe, see if it works. Just a thought.
>

Good idea. Will try. Thank you.

[Scott Gettings]

RKT wrote:

> "Richard Riley" > wrote in message
> ...
> > On Wed, 3 Mar 2004 21:54:50 -0500, "RKT" > wrote:
> >
> > :I am trying to piece together the process of vacuum bagging a CF part
> from
> > :several sources and comments. I am trying to achieve a glossy finish on
> the
> > :mold side of the finished part.
> > :
> > :I though that the gloss that I saw on a purchased part was achieved from
> > :GelCoat. The manufacturer tells me no - not GelCoat. He tells me that my
> > :mold (aluminum) must have a 'mirror-like' finish and that I can get that
> > :easily by having it Nickel plated.
> > :
> > :But I'm not certain if that approach is compatible with my perception of
> the
> > :process:
> > :
> > :1. Nickel plate the mold.
> > :2. Wax the mold several times.
> > :3. Apply resin to both sides of the CF fabric.
> > :4. Remove execess resin.
> > :5. Apply CF to mold.
> > :6. Apply peel-ply.
> > :7. Apply breather.
> > :8. Apply vacuum bag, seal.
> > :9. Apply vacuum (18mm Hg) and slight heat to accel the cure (~110F)
> > :10. Remove piece.
> > :11. Buff or solvent (to remove wax?)
> > :12. Buff to gloss?
> > :
> > :What is confusing to me is why a mirror finish of the mold is 'absolutely
> > :required' to achieve gloss(acc. to source) if I am applying and buffing
> the
> > :release wax. He says 'the wax is going to transfer to the part'. I
> certainly
> > :believe him, but 'im not getting how the gloss is 'applied' in the
> process.
> > :
> > :I have done this process using water soluble release w/o plating the mold
> > :and get a VERY dry-looking, matte finish on the mold side. The finished
> part
> > :is indeed very light - so I thought I was removing TOO much resin to
> achieve
> > :the gloss.
> > :
> > :I have a lot to learn. Can someone help me make sense of this process so
> I
> > :will have confidence that Nickel plating the mold is magically (and
> > :counter-intuitively to me) going to yield this high-gloss finish?
> >
> > The only way I've gotten it is with clear gel-coat. I suppose nickel
> > might work, if the resin you're using (polyester, epoxy, vinyl ester,
> > whatever) wets nickel and doesn't bead up on it.
> >
> > But it's going to bead up on wax, anyway. So I *think* you're still
> > going to get pinholes.
> >
> > Get a piece of adhesive backed nickel foil from McMaster-Carr - they
> > have it 15" wide, .004" for about $30 a foot. Lay up on it the way
> > you describe, see if it works. Just a thought.
> >
>
> Good idea. Will try. Thank you.

In my experience, the mold transfers everything to the product. So your
initial plug has to be basically perfect, although you can remove a few tiny
"high" spots in your mold that were low spots in the plug. A good, hard
molding gel coat helps a lot. You need to be at 2000 grit and buffed out to
be really smooth. I can't comment on nickel plating a mold, but you can get
very, very smooth with molding gel coats on complex surfaces. For flat
surfaces, or 2-D curves there are many more options.

Using wax then PVA release agent will usually transfer some surface
imperfections to a product. After a few releases, you should be able to use
mold release wax alone. A few good coats of wax properly applied will transfer
negligible imperfections to the product. Nothing that can't be buffed out --
as long as your resin is very hard and cured. Soft materials don't buff to a
high gloss nearly as well.

Scott Gettings

[Richard Riley]

On Mon, 08 Mar 2004 03:53:56 GMT, Scott Gettings
> wrote:

:
:In my experience, the mold transfers everything to the product. So your
:initial plug has to be basically perfect, although you can remove a few tiny
:"high" spots in your mold that were low spots in the plug.

I agree, but even with a perfect mold, (using epoxy, wet layup and
vacuum) unless I had a primer of some kind before the cloth went down,
I'd end up with pinholes between the fiber bundles. Think of a tick
tack toe grid, with the outside rows representing fibers. There would
be a pinhole in the center square. It happened even when I tried a
layup on a piece of plate glass.

:A good, hard
:molding gel coat helps a lot.

Absolutely. And as good a plug as you can create, to take the mold
off of. We used epoxy gel coat only.

:You need to be at 2000 grit and buffed out to
:be really smooth. I can't comment on nickel plating a mold, but you can get
:very, very smooth with molding gel coats on complex surfaces. For flat
:surfaces, or 2-D curves there are many more options.
:
:Using wax then PVA release agent will usually transfer some surface
:imperfections to a product. After a few releases, you should be able to use
:mold release wax alone. A few good coats of wax properly applied will transfer
:negligible imperfections to the product. Nothing that can't be buffed out --
:as long as your resin is very hard and cured. Soft materials don't buff to a
:high gloss nearly as well.

I ended up using Frekote A-700NC, it's silicone based, non
transfering. Very good stuff.