Dry-ice blasting to prep surface for next layer?

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ElEsido

Member
Joined
Oct 21, 2015
Messages
18
Location
Switzerland
Hi

Can you use dry ice blasting to prep a cured carbon/epoxy laminate surface for good adhesion of the next layer?

Thanks
ElEsido
 

karmarepair

Well-Known Member
HBA Supporter
Joined
Jan 13, 2011
Messages
606
Location
United States
ANY process that uses impact is going to induce micro-fractures. IMHO, if you didn't peel ply, sand: very, very lightly so you don't damage the carbon.
 

Fiberglassworker

Active Member
Joined
May 28, 2021
Messages
40
Hi

Can you use dry ice blasting to prep a cured carbon/epoxy laminate surface for good adhesion of the next layer?

Thanks
ElEsido
You can use it or plastic pellets on paint over a gel coated surface. You have to be extremely careful, the paint is only marginally softer than the gelcoat, and in the resin glass/carbon fiber mixture underneath that the resin is quite a bit softer. So you can quickly blow a hole in your structure. If you use Garnet or CO2 to abrade the surface for later bonding, you have to use large volume low pressure i.e. 1/2" dia. nozzle at 20 to 25 psi. this requires a very large volume of air ,and most home builders do not have that capability. However you can rent a 40 to 50 cfm compressor from a rental company. If abrading for bonding the object is to lightly abrade the surface by keeping the angle of the gun low so that all you do is to remove a thin layer of the resin without tearing off the fibers and impacting the surface. You then have a prepared surface surface for bonding.
It is so much quicker to use peel ply. But there you have to be careful selecting your peel ply, and do peel tests before bonding. The problem with peel ply is that as you tear it off it will give you a fractured, and molded surface The fractured surface is at the top of the layer where the resin breaks, the molded surface is at the bottom of the threads, and will contain any contaminant on the surface of the peel ply. A light sanding will remove these weave marks if your peel ply is fine enough.
 
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