First big sheet of fibreglass, concerned about bubble on edge.

[JustLloyd]

Hey guys,

Been using this forum for a lot of advice and just to get a grasp on what to do and what not to do. Yesterday I did two layers of glass on my transom, this was the first large area I have glassed.

I’m inspecting it today after a light sand and have noticed some bubbles along the edge where the transom meets the bottom plates and on the transom itself. I’ll attach some photos.

Just wondering if these need to be ground out and filled or if these will not cause any issues in the future. Also to fix these is it acceptable to just grind out and fill with thickened epoxy as there are 3 layers of glass wrapping around from the bottom plates in the future.

Thanks for any advice!

 

[wet feet]

Those blemishes do need to be dealt with.If you already have two soundly attached plies of glass,you may get away with just filler,but if they occur over joins in the earlier laminates then you may want to add some glass for strength.You may get away with drilling a small hole at the highest point of the blister and dribbling some resin in or alternatively,you may have to cut the blister out.An air pocket is likely to either blow up and show on the finished piece or fill up with water,which may then creep into locations where it does harm.My rough guide would be that if there are blisters much larger than a fingernail-remove the glass and patch,smaller will probably be ok with a resin fill and sanding fair.The range of temperature change is something to take account of as it may be the biggest factor in causing swelling or drawing in water.A solid resin/glass matrix is what you need.

 

[Skip Johnson]

I don't see anything on the flat surface that I'd lose sleep over. For the bubbles at the corner I'd drill two small holes into the bubble and inject some epoxy thru one hole with a syringe, second hole is to let the trapped air out. Easier than grinding.

 

[fallguy]

Those are injectable as Skip says.

You buy snub nose needles and a matching drill size and drill two holes in each bubble and inject epoxy. The needles n syringe are generally not reusable although I have gotten a few redos with acetone cleaning and drying them off with air compressor.

If you do nothing; they are perfect for hydraulic movement and they will likely grow and delaminate a much larger area.

If you can’t get needles, grind them out with some taper and reglass.

Depending upon the boat and where that is, if that is a bottom chine, I may recommend squaring that corner.