+x

 

zeda3000 - 4/13/2020 9:43:24 AM

+x

 

Damien Coudreuse - 4/13/2020 8:55:20 AM

+x

 

zeda3000 - 4/13/2020 6:39:25 AM

+x

 

Damien Coudreuse - 4/11/2020 8:15:01 AM

Hi Zeda3000,

Sorry for the late reply. I don't have a picture of the pinholes at the moment.
So until now, here was my process:

-  Mould: I was using a black gelcoat that  I bought in a composite shop for kayak builders here, backing it with glass woven and polyester resin.
- Release agent: I was using either wax, or EasyLease from EC. Except recently, but that has been solved, I did not have any issue with releasing my parts.

But then the issues start. Initially I was using for my carbon fiber parts a 200 gr/m2 carbon  fiber cloth very similar to this:
https://www.easycomposites.co.uk/honeycomb-bonding-epoxy-adhesive

My epoxy was also epoxy sold by this kayak builder shop. It is relatively thick. I am mixing it quite well. The temperature of the room is fluctuating as I am doing this in my garage, but I tried to heat the working area as well as possible with some hot radiator. Then I apply my layers of carbon +epoxy (in a 1:1 or 1:1.2 carbon/resin ratio). Then I was using peel ply, perforated film and a breather layer (which is a bit thicker but less dense than the EC one). And then in a vacuum bag with uncontrolled vacuum (small pump with which I cannot control the vacuum. Basically, the film is really against the part and it is not easy to manually pull it away while the pump is running). I would leave the pump ON throughout the curing process.

The result initially looked like I had resin starvation. Theses are lots of gaps between the carbon fibers. I was advised to limit resin flow by adding a second layer of perforated film, which helped. But nevertheless, at the end, I had still lots of small gaps...so the only method I found was to use a brush and put an extra layer of the same epoxy resin, sand (because I would still have hole and the brush does not give a nice flat surface in my hand), do it again, sand, do it again. etc...etc... this was the mots time consuming part of all.

Then I was suggested to put a layer of transparent gelcoat in the mould which would be nice and uniform, let it mostly cure, and then do my carbon epoxy layup. But this never worked because that gelcoat would make massive fish eyes all over the place (whether with wax or easy lease). So I gave up on this, although I was hoping it would be the solution.

Thing is that I  have indeed been using chemicals (epoxy, mould gelcoat, transparent finish gelcoat, release agent etc...) for all kind of source and in particular that kayak builder shop. But it may not be the ideal stuffs for carbon parts like what I am trying to do.

So  now (but I have not tried yet), I have EG60 and EMP60 systems for my mould, Easy Lease for the release agent, and the EL2 laminating resin. So will see if this helps...Also I got EC breather layer.

Any idea ?

In the meantime, I am building myself an oven for out-of-autoclave prepreg, because I think (possibly wrongly !) that it would make my life easier and better finish right of the mould (using of course temperature resitant mould materials, resins etc...).

Thanks !

This is a lot of details hard to tell or comment without see by picture. But main suggests

Change your resin. Use resin suitable for infusion or hand lay up. Prefer good brand names

Change your vacuum pump. Buy somehting you can control the pressure.

Please consider. More pressure is meaning better surface. Sound like to me you have poor resin flow and poor pressure.

Thanks a lot !

I have now the EL2 resin from Easycomposites. I also have a bit of infusion resin from sicomin that someone gave me to try.

Very interesting about the pressure and pump. Do you have any vacuum values that you would consider to be good ? Do you think this pump would do ?
https://www.easycomposites.co.uk/release-film

I could connect it to a vacuum regulator to have a good vacuum. Do you think that would be enough or even better pump would be necessary ?

Thank you  so much for all your help.

First of all Vacuum pressure calculating according to your composite part size and lamination thickness. After your information i could tell you this pump will good for you or not.May i ask your part size or sample picture  and what is your lamination thickness and layers. Is your process Hand lay up and vacuum press or direct infusion?
I am sorry i have no clue about EL2 Resin. I am working most Professional Level Brand names. 
Thanks

+x

 

Damien Coudreuse - 4/13/2020 9:49:16 AM

+x

 

zeda3000 - 4/13/2020 9:43:24 AM

+x

 

Damien Coudreuse - 4/13/2020 8:55:20 AM

+x

 

zeda3000 - 4/13/2020 6:39:25 AM

+x

 

Damien Coudreuse - 4/11/2020 8:15:01 AM

Hi Zeda3000,

Sorry for the late reply. I don't have a picture of the pinholes at the moment.
So until now, here was my process:

-  Mould: I was using a black gelcoat that  I bought in a composite shop for kayak builders here, backing it with glass woven and polyester resin.
- Release agent: I was using either wax, or EasyLease from EC. Except recently, but that has been solved, I did not have any issue with releasing my parts.

But then the issues start. Initially I was using for my carbon fiber parts a 200 gr/m2 carbon  fiber cloth very similar to this:
https://www.easycomposites.co.uk/honeycomb-bonding-epoxy-adhesive

My epoxy was also epoxy sold by this kayak builder shop. It is relatively thick. I am mixing it quite well. The temperature of the room is fluctuating as I am doing this in my garage, but I tried to heat the working area as well as possible with some hot radiator. Then I apply my layers of carbon +epoxy (in a 1:1 or 1:1.2 carbon/resin ratio). Then I was using peel ply, perforated film and a breather layer (which is a bit thicker but less dense than the EC one). And then in a vacuum bag with uncontrolled vacuum (small pump with which I cannot control the vacuum. Basically, the film is really against the part and it is not easy to manually pull it away while the pump is running). I would leave the pump ON throughout the curing process.

The result initially looked like I had resin starvation. Theses are lots of gaps between the carbon fibers. I was advised to limit resin flow by adding a second layer of perforated film, which helped. But nevertheless, at the end, I had still lots of small gaps...so the only method I found was to use a brush and put an extra layer of the same epoxy resin, sand (because I would still have hole and the brush does not give a nice flat surface in my hand), do it again, sand, do it again. etc...etc... this was the mots time consuming part of all.

Then I was suggested to put a layer of transparent gelcoat in the mould which would be nice and uniform, let it mostly cure, and then do my carbon epoxy layup. But this never worked because that gelcoat would make massive fish eyes all over the place (whether with wax or easy lease). So I gave up on this, although I was hoping it would be the solution.

Thing is that I  have indeed been using chemicals (epoxy, mould gelcoat, transparent finish gelcoat, release agent etc...) for all kind of source and in particular that kayak builder shop. But it may not be the ideal stuffs for carbon parts like what I am trying to do.

So  now (but I have not tried yet), I have EG60 and EMP60 systems for my mould, Easy Lease for the release agent, and the EL2 laminating resin. So will see if this helps...Also I got EC breather layer.

Any idea ?

In the meantime, I am building myself an oven for out-of-autoclave prepreg, because I think (possibly wrongly !) that it would make my life easier and better finish right of the mould (using of course temperature resitant mould materials, resins etc...).

Thanks !

This is a lot of details hard to tell or comment without see by picture. But main suggests

Change your resin. Use resin suitable for infusion or hand lay up. Prefer good brand names

Change your vacuum pump. Buy somehting you can control the pressure.

Please consider. More pressure is meaning better surface. Sound like to me you have poor resin flow and poor pressure.

Thanks a lot !

I have now the EL2 resin from Easycomposites. I also have a bit of infusion resin from sicomin that someone gave me to try.

Very interesting about the pressure and pump. Do you have any vacuum values that you would consider to be good ? Do you think this pump would do ?
https://www.easycomposites.co.uk/release-film

I could connect it to a vacuum regulator to have a good vacuum. Do you think that would be enough or even better pump would be necessary ?

Thank you  so much for all your help.

First of all Vacuum pressure calculating according to your composite part size and lamination thickness. After your information i could tell you this pump will good for you or not.May i ask your part size or sample picture  and what is your lamination thickness and layers. Is your process Hand lay up and vacuum press or direct infusion?
I am sorry i have no clue about EL2 Resin. I am working most Professional Level Brand names. 
Thanks

Thanks ! I only do small parts for my motorcycle. So maybe 20 inches are the largest parts I make. I don't quite have a picture at hand, but I will try to make one. For instance right now I am doing protetors for my radiator, which are 10 inches long and 2 inches wide. Thickness is from 1 mm to 6 mm max (I have made some carbon plates of 6 mm. But most of the things I do are between 1 and 3 mm thick). My process is hand layup and vacuum press. I don't do infusion (it's a bit more tricky it seems). My layup is carbon (using 200, 450 and 650 gr/m2 depending on the thickness I want), peel ply, one or two layers of perforated film and a layer of breather. This pump, however, does not come with a vacuum regulator, but this is something I can get (though it's quite expensive). But I don't know whether it's absolutely necessary for what I do...or not.

Thanks again!