are Well Nuts the way to go

[Dignity]

Mupster, I gather you are talking about type R60.

[Mupster]

Datacol, only 3 mm to work with, the holes in middle pic, I'd probably drop more down the holes than I'd managed to set.

Mupster, sound interesting, I'll give it a go on some scrap first, do you think it would be worth drilling larger holes so that there's more body for the screws to purchase.

No just fill it as it is, unless the holes are a bit daggy then maybe! It's strong stuff!

[Mupster]

Mupster, I gather you are talking about type R60.

👌 That's the stuff!

[Fed]

How about some longer screws.

[scottar]

Thinking outside the box a bit - if the glue doesn't work and you can weld - I would pull the tank and make inserts that fit via the tank well wall - sort of a "t" or an "L" shape with a thread tapped into them. Self tap and sika to the well wall to seal.

[Dignity]

How about some longer screws.

Doesn't matter on the length of screws, I can go a bigger size but same problem, it's what the screws are going into, 3mm fibreglass and a blind hole as well. See pics earlier in the post.

[Dignity]

Thinking outside the box a bit - if the glue doesn't work and you can weld - I would pull the tank and make inserts that fit via the tank well wall - sort of a "t" or an "L" shape with a thread tapped into them. Self tap and sika to the well wall to seal.

That could work, weld some nuts on the underside of the top flange, drill larger holes to accept the nuts. Screw the L shaped bracket to the wall and it doesn't matter if these never come out.

[Fed]

Sorry Dignity, when I looked at the pics last night on my mobile for some reason I thought the holes were in something solid completely forgetting about the 3 mm talked about earlier. Could be going a bit senile here.

[Dignity]

Thanks guys, I now have several ways to go, unfortunately the company I found with SS Well Nuts didn't have any but would manufacture them after going through design, samples being made and finally manufactured, not a viable solution for 12 nuts. Techniglue seems to be the initial way to go, just have to find a local supplier, I'll probably cut some lengths of plastic strips, thread some line through the middle, bend in half then push through the holes (enlarged to make it easier) then pulled up so that I have a plate so that I can push as much in without it all falling away underneath. As never having used techni glue, can this stuff be applied via a syringe. To stop any further movement I will then sika the joint between the 2 flooring sections.

[Chimo]

Dignity

If it was my problem I think I would explore whether aluminium angle could be sikaflexed onto the side of the well with the unstuck side laying on top of your worn out holes.

After the sika goes off drill and tap a thread into the stuck in place angle and replace top and fasten and go boating.

No sika between the bottom of the cover and thin angle eg 1 or 1.6mm should fit .

Tell me why it wont work.

Cheers
Chimo

[Fed]

I think I'd make a very thick bog from resin & finely chopped up mat, poke it down the existing holes & wipe it on the way back up then fill it in completely, you may have to do it in two goes.

[Mupster]

Thanks guys, I now have several ways to go, unfortunately the company I found with SS Well Nuts didn't have any but would manufacture them after going through design, samples being made and finally manufactured, not a viable solution for 12 nuts. Techniglue seems to be the initial way to go, just have to find a local supplier, I'll probably cut some lengths of plastic strips, thread some line through the middle, bend in half then push through the holes (enlarged to make it easier) then pulled up so that I have a plate so that I can push as much in without it all falling away underneath. As never having used techni glue, can this stuff be applied via a syringe. To stop any further movement I will then sika the joint between the 2 flooring sections.

You can buy it of eBay, from memory the seller was in Qld and yes you can use a large syringe!

[Dignity]

Dignity

If it was my problem I think I would explore whether aluminium angle could be sikaflexed onto the side of the well with the unstuck side laying on top of your worn out holes.

After the sika goes off drill and tap a thread into the stuck in place angle and replace top and fasten and go boating.

No sika between the bottom of the cover and thin angle eg 1 or 1.6mm should fit .

Tell me why it wont work.

Cheers
Chimo

Thanks Chimo, yes that's something similar to what Scottar advised, my reluctance is that I'm depending on SS screws into Alum, I've had no end of screws snap once the ally corrodes and if that happens I will have great difficulty in getting to my fuel tank. At this stage my preference is now to stay away from dissimilar metals.
Cheers Sam

[Chimo]

Then get stainless steel angle and sika short lengths of it at the locations where the top screws down into the worn out holes.
No more dissimilar metal the issue is resolved

Angle sikaed to the frp will not affect the tank either.

C
C

[Dignity]

Chimo, why not just the full length of the fuel well, it would definitely hold better than short lengths.