Drilling into Fiberglass

One of the biggest issues with drilling fiberglass is breaking thru the gelcoat. Gelcoat is very hard / brittle topical coating over the polyester resin and fiberglass structural component. This Gelcoat layer delaminates and chips very easily from the underlying structural component.
Very similar to paint on top of wood.

Standard drills are right hand spiral - right hand cut and pull themselves into the material quickly with each rotation. Anybody ever drill thin sheet metal ?

Running the drill in reverse abrasively moves the drill bit thru the gelcoat without pulling it thru and chipping. A straight fluted drill will also work very nice.
I like the 5200 solution on a larger surface block if you can.
 
quote:
Originally posted by Ghost

I I strongly suspect a plastic other than starboard was used by mdoherty. That or something else is going on here as its a well known limitation of those two materials.

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Yes, I used a plastic similar to G10 glass filled epoxy or a piece of carbon fiber sheet that most people don't have ready access to so I substituted starboard which I thought more people would be familiar with, didn't think about adhesion to that surface.

The adhesive I used was some out of date epoxy used to put threaded inserts into spacecraft. Doubt if many people here would recognize it so I substituted 5200 after researching the material properties.
 
That makes perfect sense now. Are you an MSE? You seem to know your way around a material or two. Unfortunately, it's easy to misspeak when the atmosphere gets made contentious such as it was.

I do worry about trying to educate the general population about materials and adhesion, as attention to detail and fundamentals are so critical. I worry it gives a license to the many looking for an easy route where they don't have to think. It's just my opinion, but that's why I think so many just knee jerk and turn to 5200 when it's often not necessary, and I'm a big proponent of keeping future jobs easy so they are likely to get done. There is nothing wrong with using mechanical fasteners and sealant, but then you have to think about those materials too, or too many will just reach for stainless fasteners and use them below the waterline.

I think I might have just helped to make your argument! In any case, we can't win. Those who seek out fundamentals will succeed with either approach they choose. Those that won't, maybe should just use 5200 on everything. I think I'm getting cynical.
 
quote:
Originally posted by Ghost

That makes perfect sense now. Are you an MSE? You seem to know your way around a material or two. Unfortunately, it's easy to misspeak when the atmosphere gets made contentious such as it was.

I do worry about trying to educate the general population about materials and adhesion, as attention to detail and fundamentals are so critical. I worry it gives a license to the many looking for an easy route where they don't have to think. It's just my opinion, but that's why I think so many just knee jerk and turn to 5200 when it's often not necessary, and I'm a big proponent of keeping future jobs easy so they are likely to get done. There is nothing wrong with using mechanical fasteners and sealant, but then you have to think about those materials too, or too many will just reach for stainless fasteners and use them below the waterline.

I think I might have just helped to make your argument! In any case, we can't win. Those who seek out fundamentals will succeed with either approach they choose. Those that won't, maybe should just use 5200 on everything. I think I'm getting cynical.

Click to expand...


Well if your not sure 5200 is the answer there is always 4200 so you can change your mind :D
 
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