What is your favourite way of plugging small holes in fibreglass?

[GILow]

Thanks guys. Some great ideas here.

I’ll see which of them is most practical to implement based on availability of materials.

Matt

[smj]

Originally Posted by skipmac

I love MarineTex. It is certainly quick, easy and strong. I only filled my old screw holes with Gelcoat because they were small and very visible. You can hardly tell where they were from inches away.

MarineTex is epoxy, is it somehow up stable?

[GeneM]

I use gelcoat close to the original color. My boat is painted with Interlux Perfection, so I can match easily.
Gelcoat hardens fast and sands down easily.
I drill out the hole to get clean surfaces. It's important to also bevel the surface so there is no sharp edge on a hole - at least 45deg or it will crack between the old and new gelcoat.

[Don C L]

Another vote for Marine Tex! The stuff is expensive though so I prep all the holes well first as others have described and I also tape under the hole AND around the hole on the top so that there is less to clean up/sand when done.

[Jim Cate]

Unfortunately for Matt, I've never seen Marine Tex for sale here in Oz. But it is only a pre-mixed putty made of epoxy and some sort of filler to bring it up to a rather stiff consistency. It isn't rocket science or even Boy Scout merit badge science to make an equivalent material yourself from your favorite epoxy and structural filler.

The two part "plumbers putty" mentioned upthread is a good alternative. I've got some that came from a surf shop, badged as instant surfboard repair stuff. Same principle...
take roughly equal parts of the two components, mash them together to mix (using your bare hands is ok) and when uniform in color, press into the hole. Skim off any excess inside and out and let set up. Bonds well, can be sanded fair if required and can be painted.

Jim

[Wotname]

Marine Tex is available on line in Oz and Bunning has what is probably an identical product - a marine epoxy putty in stick form.

https://www.bunnings.com.au/pc-produ...putty_p1560095

[Jim Cate]

Originally Posted by Wotname

Marine Tex is available on line in Oz and Bunning has what is probably an identical product - a marine epoxy putty in stick form.

https://www.bunnings.com.au/pc-produ...putty_p1560095

Wottie, the stick form putty is similar to t he surfboard repair stuff I mention. But Marine Tex isn't in stick form, rather a very stiff goo and a jelly like hardener in a jar and you definitely don't want to mush it barehanded! Actually kinda hard to get an even mixture because of the stiffness, especially if it is a bit old.

Jim

[GILow]

I’d forgotten those surfboard repair sticks. They worked very well for repairing some chunks out of the bow. I think I still have one around. I’ll test it to see if it is still workable.

[BarnaclePhil]

Watch David Johnson from West System on YouTube. It couldn't be any clearer. Plus he explains in one of the parts of the video why you shouldn't use Poly.

https://www.youtube.com/watch?v=b85sI8Re8VA

[Wotname]

Originally Posted by Jim Cate

Wottie, the stick form putty is similar to t he surfboard repair stuff I mention. But Marine Tex isn't in stick form, rather a very stiff goo and a jelly like hardener in a jar and you definitely don't want to mush it barehanded! Actually kinda hard to get an even mixture because of the stiffness, especially if it is a bit old.

Jim

Yes Jim, poor choice of words on my part, probably better written "a similar product but in stick form"

As to Marine Tex, how is it dissimilar to Epifill which is widely available in Oz?

[Chotu]

Nothing wrong with using microballons if that's what you have. It's obviously not a structural repair filling some old bolt holes. Use whatever fillers you have on hand or even neat epoxy so long as you have a piece of tape solidly below the hole.

[Jim Cate]

Originally Posted by Wotname

Yes Jim, poor choice of words on my part, probably better written "a similar product but in stick form"

As to Marine Tex, how is it dissimilar to Epifill which is widely available in Oz?

Well, no, it isn't "similar but in stick form" either! Quite a different system...

And I'm not familiar with Epifill... sounds like something I carry to jab myself with if I encounter a peanut... nooo, that's an Epipen!

The sorta unique bit about Marine Tex is the jelly like hardener. Mix is 5:1, and to be honest, not that easy to get right when the goo is either cold or old... makes it very stiff and hard to measure well. The good news is that it does not seem to be real critical. IIRC it is available in white and grey, with the latter having aluminium powder as a filler. Good stuff.

Jim

[Wotname]

Originally Posted by Jim Cate

Well, no, it isn't "similar but in stick form" either! Quite a different system...

And I'm not familiar with Epifill... sounds like something I carry to jab myself with if I encounter a peanut... nooo, that's an Epipen!

The sorta unique bit about Marine Tex is the jelly like hardener. Mix is 5:1, and to be honest, not that easy to get right when the goo is either cold or old... makes it very stiff and hard to measure well. The good news is that it does not seem to be real critical. IIRC it is available in white and grey, with the latter having aluminium powder as a filler. Good stuff.

Jim

Quite a different system?.... and here was I thinking Marine Tex, Epifill and PC epoxy putty (available in paste an stick form) were all just two part epoxies preloaded with structural filler but I guess I'm wrong (again ).

[theway]

What about WaterWeld...
https://www.jbweld.com/products/waterweld-epoxy-putty

I carry a few sticks with me. I can’t speak to details of its use (bonding, longevity, structure, etc.) but it’s worked for my small repairs and fillings... and I’m pretty sure it’s available in US and OZ at a decent price...

[Jim Cate]

Originally Posted by Wotname

Quite a different system?.... and here was I thinking Marine Tex, Epifill and PC epoxy putty (available in paste an stick form) were all just two part epoxies preloaded with structural filler but I guess I'm wrong (again ).

I guess we're arguing semantics here, Wottie. But for me, there is a big difference between a material that you can safely moosh and mix(at 1:1) in your bare hands and the sticky base material and amine-loaded jelly hardener (that makes your eyes water when you open the jar and mixes at 5:1) that is Marine Tex. They are different to use, different to smell, different in their chemistry.

But then, you are right in saying they are all two part epoxy based materials incorporating fillers.

I wish I still had some Marine Tex that I could show you when we get back to Tassie, but I used it all up some years ago.

Jim