Repairing self-tapper hole

[Observer]

I have an inspection hatch set in a GRP console that's secured by self-tappers. One of the screw is not biting at all on the hole. Is there an easy way to repair the hole or otherwise fix the problem? Larger screw is possible but not first chioce because won't match the others and they're ll pretty large anyway.

 

[webcraft]

Wooden matchstick / dowel cut to size and stuck in with epoxy?

- W

 

[lenseman]

The first thing, it is very important to know whether the self-tapping screw is supposed to 'bite' into raw fibre-glass or whether there is any metal form-work into which it is supposed to bite?

Normally, a Self-Tapper screw had a small flat metal plate and it is into this metal that the Self-Tapper holds. Often, in the motor trade a similar fault occurs where the small metal plate rusts and the hole becomes too large but in this situation this metal plate is replaceable whereas if this is the fault on your boat it will have been built into the moulding.

With a metal plate, you cut away the fibre-glass and replace the plate and then re-build the moulding.

If on the other hand the Self-Tapper bites directly into the fibre-glass mounding, have a very good look for stress cracks radiating out from the hole as you will need to deal with this and repair before filling the enlarged hole and re-drilling to the correct core size for your self-tapping screw.

 

[VicS]

Fill the hole and re-drill,

Epoxy eg Araldite (slow not rapid) might do it if the hatch is well secured by the other screws.

Sounds daft but a rawlpug, provided you have some space behind.

What is behind, can you use a longer screw into a wooden block or through bolt it.

 

[ShipsWoofy]

fatter screw

next...

 

[VicS]

[ QUOTE ]
fatter screw

[/ QUOTE ] He said, "Larger screw is possible but not first chioce because won't match the others and they're ll pretty large anyway."


Next ?

 

[BrendanS]

If the other screws are holding well, the matchstick works wonders for a one off self tapper that is loose.

 

[oldsaltoz]

G'day Roger,

We have always used the moulding as a template to mark out the hole pattern and predrill a suitable material as a backing for the screws.

After cutting the circle of material cut it in half so it fits inside.

Timber soaked in thinned epoxy works, stainless steel is also good, another method is to glue a washer and suitable nut on the inside, hold in place till dry with a thru' bolt.

Hope this helps.

Avagoodweekend......

 

[Observer]

Thanks for all the suggestions - much appreciated.

 

[homa]

Slow not Rapid

Hi VicS

I'm curious, why slow not Rapid Araldite - what's the difference other than the curing time?

Cheers
Homa

 

[philip_stevens]

Drill the hole oversize and bond-in a smallest plastic (rawl) plug. This is what I am having to do in two stripped ST holes.



Araldite question -
Slow Araldite is harder when cured than Rapid Araldite.

 

[rogerdog]

[ QUOTE ]
Drill the hole oversize and bond-in a smallest plastic (rawl) plug. This is what I am having to do in two stripped ST holes.


[/ QUOTE ]

My favoured method -works a treat and lasts better then you would expect -an almost 'permanent 'repair.

 

[mixmaster]

I asked a similar question the other week. Cosmetics aren't important in my context. Going down to the boat tomorrow. Hopefully can use bigger screw, then I'll try the matchsticks. Last resort will be fill and re-drill.
What "stuff" would I use to hold the matchsticks in the hole? What "stuff" would I use to fill the hole for re-drilling?
Thanks.

 

[mixmaster]

I know it's some sort of epoxy but there are like a million kinds...

 

[Slowtack]

Epoxy in some rivnuts and use bolts instead of screws

 

[seumask]

How about a plain old nut bolt and washer, could even be a locking nut. Just drill through and place nut with washer on the inside.