Filling a hole

[JimC]

I've a 10mm diameter underwater hole to fill from a redundant anode bolt. Skin thickness is about 10mm. What's the best stuff to use? Ideally not something you have to buy a lot of. It's a GRP boat.

 

[VicS]

I've a 10mm diameter underwater hole to fill from a redundant anode bolt. Skin thickness is about 10mm. What's the best stuff to use? Ideally not something you have to buy a lot of. It's a GRP boat.

With a hole that small in that hull thickness. Bevel the hole from both sides, fill with a thickened epoxy or epoxy putty then glass over the inside ( after thoroughly cleaning around the hole) with epoxy and woven glass mat.

For larger holes see the procedure described on the "West" resins site ............... it can become a huge repair out of all proportion to the size of the original hole

 

[Poignard]

"Restoring skin continuity
Skin continuity can be restored if enough fibers can be bonded across a damaged area to equal the strength and stiffness of those that were damaged or removed. The lay-up schedule for your repair work should duplicate thickness and types of materials used in that area as closely as possible. However, heavy woven roving may be replaced by more layers of lighter weight woven or bidirectional fabrics. Although more layers may mean extra work, lighter weight fabrics are often easier to find and their tighter weave results in a higher fiber to resin ratio, which can result in a repair that is actually stronger than the original panel.

As a general rule, the bonding area of the repair patch should be 12 times the thickness of the damaged skin, on each side of the damage. To maintain the necessary bonding area and keep the repair flush with the surface, the edges of the repair area are beveled to a 12-to-1 angle and each piece of repair fabric is cut progressively smaller. The bevel provides the proper bonding area and also allows the patch to be bonded below the surface where it can be faired flush with the surface."

From the WEST Fibreglass Repair Manual. https://wessexresins.wpenginepowere.../08/Fibreglass_boat_repair__maintenance-1.pdf

 

[Restoration man]

If you want easy solution get a 316 stainless m10 dome head carriage bolt, stick it in with sikaflex , job done ,

 

[KompetentKrew]

Sorry if the answer is obvious, but does the hole go all the way through?

 

[JimC]

Sorry if the answer is obvious, but does the hole go all the way through?

Yes

 

[geem]

If you want easy solution get a 316 stainless m10 dome head carriage bolt, stick it in with sikaflex , job done ,

I would not like to buy a boat you previously owned?

 

[Restoration man]

I would not like to buy a boat you previously owned?

no offence taken ???
but in my defence the the op did say he didn’t want buy much to fix this and seeing as he’s asking how to do the job I think a carriage bolt fitted with silkaflex and nut and washer on the inside could well be safer repair than potentially doing poor job with fiberglass ?

 

[JimC]

Actually I think a 316 10 mm csk machine screw, countersunk into the outer skin with a nut & washer on the inside, the whole being set in epoxy e.g. Araldite, and skimmed over with epoxy on the outside would be quite a good solution?

 

[Fantasie 19]

Actually I think a 316 10 mm csk machine screw, countersunk into the outer skin with a nut & washer on the inside, the whole being set in epoxy e.g. Araldite, and skimmed over with epoxy on the outside would be quite a good solution?

Damn right...