how to repair a stripped delf tapper thread hole in grp please

[Robin]

Two of the little screw-in do hickies that the lift a dot canvas fasters snap on to in our canvas cockpit canopy have pulled out. I just tried a repair using an epoxy adhesive (like Araldite rapid), which worked on one but not the other. Here in the 3rd world you cannot buy Plastic Padding epoxy filler or even PP gel coat filler hence my attempt with the adhesive stuff. I did buy but not tried yet an epoxy 'stick' putty that you knead to mix and is claimed to repair everything in the universe including metals.


Any ideas please? I thought about relocating the screw slightly but that had already been done, as there is another hole right by, and nowhere else suitable close by is available that would not put the thing under strain from the canvas when snapped.

Silly little task I know but it is bugging me.:disgust:


.

 

[prv]

Use a bigger screw?

Pete

 

[pvb]

Use a bigger screw?

Don't think those "lift the dot" studs come with bigger screws. The best answer is to fill the hole with epoxy, then re-drill for the screw.

 

[Robin]

Don't think those "lift the dot" studs come with bigger screws. The best answer is to fill the hole with epoxy, then re-drill for the screw.

I wondered that but finding an epoxy marine filler here is the first problem other than the stick putty thing I bought. I even though of putting a wood batten along and putting the studs in that but it would look like the bodge that it is..

 

[pvb]

I wondered that but finding an epoxy marine filler here is the first problem other than the stick putty thing I bought. I even though of putting a wood batten along and putting the studs in that but it would look like the bodge that it is..

Surely you have a West Marine store somewhere nearby? How about this stuff? http://www.westmarine.com/buy/west-marine--marine-rx-epoxy-repair-kit-2-oz--13967443

 

[johnphilip]

May not be usable in your circumstance but I have a similar problem with screws which hold the cabin sole boards to the hollow frame structure within the hull and I intend to use plasterboard fixings such as http://www.screwfix.com/p/fischer-p...n28d5UE7fE2K47XzVMNLCRw0-diZs3txgcBoCt7fw_wcB

 

[Robin]

Surely you have a West Marine store somewhere nearby? How about this stuff? http://www.westmarine.com/buy/west-marine--marine-rx-epoxy-repair-kit-2-oz--13967443

Thanks I will get some in the morning, they had nothing in the store when I looked before a few weeks back. We go there once a week or more but it is more and more boutiquey and less boaty these days than it used to be.

 

[Iliade]

Use Araldite, but warm the two components until they are really runny. Mix quickly and drip into the hole immediately.

I use Milliput epoxy putty for nearly everything, but not so good for this application.

 

[TSB240]

I soaked some matchsticks in epoxy stuffed them in the stripped hole let them set then drove screw in as if it was a new fit. Still ok two years later.

 

[Pye_End]

Perhaps use a drill bit to clean out the hole in case it has sealant in it - possibly enlarge it slightly. Have used Araldite in the past with a bit of extra powder of some sort (eg West additives) to give it a bit more strength and body.

 

[Scotty_Tradewind]

Surely you have a West Marine store somewhere nearby? How about this stuff? http://www.westmarine.com/buy/west-marine--marine-rx-epoxy-repair-kit-2-oz--13967443

that stuff is brilliant for certain jobs I bet, but might it be too closed a form and so be brittle for the job in hand?

If you test a small amount first in a lump, then drill a hole and see if it accepts the thread of the fastener male part.
If it's easy to pull out with a wrench or pliars then it may not be ok.

If you don't have the depth of hole in the first place, you may be stumped anyway, but it could help to 'open up' the body of the resin, just like a potter uses grog to open up a clay to prevent it being brittle when fired.

So, you may find the resin supplier has a filler you could add or microfibers. Check it out.

good luck
S.

 

[William_H]

Any epoxy should be good. It can be thickened with talcom powder. As said make sure the hole is clean of other sealer etc.
To my mind self tapping screws are the wrong type. They might be fine for sheet metal or wood but in thick GRP they have to crunch their way in cracking and damaging the resin glass matrix. Far better to my mind is to drill the correct sized hole in the replaced epoxy and use a tap to make a thread for a suitable sized screw. good luck olewill

 

[Robin]

Thanks all. Since there are two holes now for the same stud I can experiment and fill one with the epoxy putty stick stuff and the other with the araldite look alike mix, maybe with a matchstick in it too. I did wipe around with acetone so maybe the one that didn't work was contaminated with a trace of undried acetone? .

 

[TQA]

JB Weld is your friend. Widely stocked. Just make sure you get the original variety http://www.jbweld.com/collections/epoxy-adhesives/products/j-b-weld-twin-tube

 

[Robin]

Any epoxy should be good. It can be thickened with talcom powder. As said make sure the hole is clean of other sealer etc.
To my mind self tapping screws are the wrong type. They might be fine for sheet metal or wood but in thick GRP they have to crunch their way in cracking and damaging the resin glass matrix. Far better to my mind is to drill the correct sized hole in the replaced epoxy and use a tap to make a thread for a suitable sized screw. good luck olewill

Thanks olewill. I agree about self tappers in grp but this is a no option job as the lift the dot post only comes as a stud with a self tapping thread and spanner flats to tighten it. If I can find better canvas to grp fasteners maybe I will change them but this is on a full cockpit enclosure that is only 2 years old so messing too much with it is not a good idea although switching to a turnbuckle type in this one place had occurred to me. There are lift the dots every 10 inches around the aft end so one missing as there is is not a disaster, just irritating. Actually if canvas work is contemplated I would redesign this bottom edge with shock cord loops tp hook plate on the grp as these could conceivably be fastened by handfrom the inside whereas the current design involves getting outside in the wet to fasten it.

This pic, actually of fitting eyebrows over opening portlights shows some of the enclosure



View attachment 55673

 

[sailaboutvic]

sew bungee loops and use hook to fasting them down a lot better idea , it keeps the canvas tighter and you wont have the problem of then being pulled out , and when they wear just replace the bungee .
in the mean time has said use wood to fill the hole until you can get some kind of filler .

 

[Poignard]

JB Weld is your friend. Widely stocked. Just make sure you get the original variety http://www.jbweld.com/collections/epoxy-adhesives/products/j-b-weld-twin-tube

That is good stuff. I repaired a corroded waterway in my BUKH cylinder head with it and more than a year later it is still intact.

 

[Tradewinds]

Sounds like you're already sorted but I'd like to recommend Marinetex which is available in the USA. Brilliant stuff - pity it's not available in the UK.

http://www.marinetex.com

I suspect West Marines's Marine Rx Epoxy is their version of it.

 

[Tradewinds]

This pic, actually of fitting eyebrows over opening portlights shows some of the enclosure

Robin,

Sorry for the thread drift, but where do your eyebrows come from?

I have an opening port light that would benefit from one of those.

Edit: Found them http://www.seaworthygoods.com/index.html - unfortunately carriage makes them a no no. Shame.

Anybody know of UK/ EU suppliers?

 

[Robin]

Robin,

Sorry for the thread drift, but where do your eyebrows come from?

I have an opening port light that would benefit from one of those.

Edit: Found them http://www.seaworthygoods.com/index.html - unfortunately carriage makes them a no no. Shame.

Anybody know of UK/ EU suppliers?

They are from Seaworthy and highly recommended.