Surface bubble

[hyboats]

See the pictures. Any guys can tell me the exact reason

[PAR]

Any guys can tell me the exact reason

Nope, at least not with this level of input from you. The pictures suggest several different things, but without some understanding about what you're talking about, it'll be difficult to make a guess.

Blisters often are caused by water getting behind paint, but you haven't mentioned paint or water.

Sometimes a blister can appear when a laminate fails and hydroscopic or pneumatic pressure builds behind the laminate or gel coat.

A chemical reaction within the laminate?

A contaminated area under the paint?

Without a much better description from you Hyboats, I'm at a lose as to what you have there, let alone "the exact reason".

Have you pin pricked one to see what's in it? Obviously this area(s) have to be redone, so what's the harm?

[alan white]

Could be the Virgin Mary developing. If it starts shedding tears of olive oil, that could mean the laminate's gone, sorry to say.

I think they are styrene bubbles. One of the laminator guys can best explain how to prevent - maybe laying up too fast and didn't have a chance to outgas?

[PAR]

I think it's a wooden hull and this is a paint blister, but we're all guessing until Hyboats returns.

[hyboats]

Originally Posted by PAR

I think it's a wooden hull and this is a paint blister, but we're all guessing until Hyboats returns.

Mainly blister, I don't know why it happens.
It is a fiberglass boat hull not wooden hull, gelcoat, polyster resin, fiberglass mat,cloth

[PAR]

The right hand image sure looks like it has planks, possibly under a sheathing? What's inside the blister? Pop one . . .

[Herman]

It can be anything. Outgassing of foam, bad laminate, poor adhesion to gelcoat, MEKP contamination, MEKP containing water, wet glass.

Why not touching it with an angle grinder with grit 16 mounted? Cut one open and make some good close-up photos, this gives a better idea.

For now my thoughts go to bad laminate.

Par, I think the "planks" may just be a reflection. Notice the shoebox hull/deck flange and alumiminum rubrail with vinyl insert - poly and chop construction with voids below the style line would be my guess.

[rxcomposite]

If you prick it and smell vinegar, that is catalyst that did not mix with the resin. Assuming you used a gel coat gun.

If the gel coat and catalyst was mixed before spraying, could be that your airline contained water. Do you have water trap near the gun? You should purge before spraying.

Was the hull absolutely dry before you sprayed? could be moisture on the surface.

Last possible reason is the angle of spray. You are spraying near the chine.

[tunnels]

Originally Posted by hyboats

See the pictures. Any guys can tell me the exact reason

If its wooden boat and glassed and painted the water appears to have got between the glass and the wood . Do you have any idea if Epoxy resin or polyester was used ?? If it was polyester or vinylester resin you have a big problem and wont go away in a hurry .