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 Post subject: Paint Bonding Issues
PostPosted: Mon Sep 08, 2014 8:08 am 
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I have had three boards delam this summer. Bummer. Originally thought the delam was because of a poor bond with the polyurethane rail on my boards, but with the latest delam I see that it is a paint to core bond issue. I am using Liquitex acrylic Basic and Heavy products. All colors seem to equally delam. I am using resin research epoxy, they recommended the Liquitex brand. When failure happens the glass is bonded to the paint, the area where the paint peels leaves the core looking dry and as if there never was any resin near the area. Not sure how to correct the problem (other than no paint) and could use some help. Not sure if I need a primer? If the paint is not dry? Advice is welcomed.


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File comment: Crummy photo but; if you look closely you see the dry core where the paint used to be. Peeling stops once it hits a non painted area
tip delam m2 board.JPG
tip delam m2 board.JPG [ 2.72 MIB | Viewed 434 times ]
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 Post subject: Re: Paint Bonding Issues
PostPosted: Mon Sep 08, 2014 10:21 am 
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Location: The Naki
Are you painting your core and then glassing over the painted surface getting delamination and wondering why?

If so the answer is don't paint your core first before glassing. The resin needs to make a chemical bond with the core. If you paint first, then the bond between your core and glass is only as strong as your strong your paint bond. Not good.

Never paint the core.


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 Post subject: Re: Paint Bonding Issues
PostPosted: Mon Sep 08, 2014 11:19 am 
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You basically answered yourself.
Use a primer or don't use a paint or use a different paint.
However, there is still a possibility that primer won't bond well with the rail, so I would suggest you make test samples.


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 Post subject: Re: Paint Bonding Issues
PostPosted: Mon Sep 08, 2014 2:25 pm 
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plummet wrote:
Are you painting your core and then glassing over the painted surface getting delamination and wondering why?

If so the answer is don't paint your core first before glassing. The resin needs to make a chemical bond with the core. If you paint first, then the bond between your core and glass is only as strong as your strong your paint bond. Not good.

Never paint the core.


+1


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 Post subject: Re: Paint Bonding Issues
PostPosted: Tue Sep 09, 2014 6:12 am 
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Dang. Must have been asleep during that part of class. Back to the lab again. Thanks for the tips.
Brad


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 Post subject: Re: Paint Bonding Issues
PostPosted: Thu Sep 11, 2014 6:22 pm 
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sijandy wrote:
plummet wrote:
Are you painting your core and then glassing over the painted surface getting delamination and wondering why?

If so the answer is don't paint your core first before glassing. The resin needs to make a chemical bond with the core. If you paint first, then the bond between your core and glass is only as strong as your strong your paint bond. Not good.

Never paint the core.


+1


+ one more :thumb:

Only-- I look at the resin bond to the core is a mechanical bond , (not a bond between atoms).
Wikipedia makes it difficult to decide, in there definition .

I know that a bond between cured epoxy to cured epoxy, is also a mechanical one ;but
a bond between uncured epoxy to another layer of uncured epoxy, will result in a chemical bond
because the atoms that make up the atomic weight-chins , are now interlocked .

From http://en.wikipedia.org/wiki/Mechanical_bond
A chemical bond is an attraction between atoms that allows the formation of chemical substances

The mechanical bond is a type of chemical bond found in mechanically-interlocked molecular architectures ...

Bille


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 Post subject: Re: Paint Bonding Issues
PostPosted: Thu Sep 11, 2014 6:57 pm 
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@sinker: What kind of wood do you use for core?


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 Post subject: Re: Paint Bonding Issues
PostPosted: Thu Sep 11, 2014 10:51 pm 
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Bille wrote:
sijandy wrote:
plummet wrote:
Are you painting your core and then glassing over the painted surface getting delamination and wondering why?

If so the answer is don't paint your core first before glassing. The resin needs to make a chemical bond with the core. If you paint first, then the bond between your core and glass is only as strong as your strong your paint bond. Not good.

Never paint the core.


+1


+ one more :thumb:

Only-- I look at the resin bond to the core is a mechanical bond , (not a bond between atoms).
Wikipedia makes it difficult to decide, in there definition .

I know that a bond between cured epoxy to cured epoxy, is also a mechanical one ;but
a bond between uncured epoxy to another layer of uncured epoxy, will result in a chemical bond
because the atoms that make up the atomic weight-chins , are now interlocked .

From http://en.wikipedia.org/wiki/Mechanical_bond
A chemical bond is an attraction between atoms that allows the formation of chemical substances

The mechanical bond is a type of chemical bond found in mechanically-interlocked molecular architectures ...

Bille


hmmm.... you could be right there Bille.

Though we do soaking of the resin into the core structure. So even if the resin doesn't chemically bond with the core it chemically bonds with its self interlaced within the core.....

So string as Fuck either way.


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