The Gurnard fixes a leak in an awkward spot...

[The Gurnard]

What advantage is there cutting a hole on the outside Officer ?

I do appreciate I can access that area easier from the inside if I do.. but so far.. I feel its not required..however you do this for a living..so I will listen

I think with a patch like this on the inside..and its really just a backup to the exteral patch which will be large and has plenty overlap to seal it properly

I will cut another hole if I think it worth while..but dont want to cut one for the sake of it if this one works ?

[The Gurnard]

Originally Posted by office888

Why not? That's the right way to do it.

Its your way.. and it could be considered the correct way..but why ? ..do you think this method will fail ?

I hope Im not sounding arrogant by asking as its not my intention..Im just wondering why ..if I get a leak..do I have to make another to repair the first..then have to repair the one I just made..if that makes sense ?

[office888]

Originally Posted by The Gurnard

Its your way.. and it could be considered the correct way..but why ? ..do you think this method will fail ?

I hope Im not sounding arrogant by asking as its not my intention..Im just wondering why ..if I get a leak..do I have to make another to repair the first..then have to repair the one I just made..if that makes sense ?

Not at all!

Glue is very weak. It is probably one of the worst ways to assemble something.

In order to maximize chances of success, you need to pave a road to success. Your method may work in the short term, but there are a lot of variables. You are mixing two different chemicals together which could yield mixed results... they operate by two completely different curing mechanisms.

PVC boat glue is nothing more than ~25% solids suspended in a lot of solvent. Typically, it is some kind of synthetic resin It is applied to the material, then, the solvents evaporate. This drives the solids in to the material, enhancing the bond strength. The problem is, is that if it is applied too thickly, it will skin over. The solids at the surface will dry, will the solids at the bottom will remain wet because the solvent is trapped with no way to escape. Then, when the part is laid up, the surface skin will break, releasing the solvents, which will then deactivate the bond you just tried to make.

Mixing with sikaflex may entrain solvents, which may weaken the bonding of the PVC glue, of the Sikaflex, or both.

Ultimately, if the repair fails, you'll be stuck removing that globby mess as well which may permanently damage the material.

By going from the inside of the boat, it allows you to:
Apply thin, even coats of glue to both the patch and the boat
It allows you to maximize your patch overlap, which will increase the holding strength of the patch.

Best of all, it is a known working method! By applying a patch from the inside, it also makes for a stronger patch than from the outside. Instead of pushing UP the patch, trying to make it bulge, instead the air pressure is trying to push that big patch through the tiny hole. The chances of the patch peeling free ever are non-existant. Since the patch is on the inside, it is no longer affected by chemical exposure, UV, and there's no mechanical wearing motion to possible cause an edge of the patch to lift.

My 2 quid. Take it as you please. I understand why you're hesitant. For the first 2 years when I apprenticed fixing inflatables, I tried to avoid doing inside outside patches at all costs because I was very bad at them...

[Poly]

G,

Do you need to prep the inside of the tube for the the internal patch as you would the outside? How sticky is PVC glue - do you get the chance to put it in and add your second bigger internal patch before it sticks to the wrong place inside the tube? Is your big internal patch robust enough to seal all round with just a 1cm pulling area?

Given your quick fix patch in a wet boat seemed to hold I can certainly understand your reluctance to get new holes - each of which is a potential leak. Of course I know nothing as I don't have these headaches!

[The Gurnard]

Thanks for the guys..and I do appreciate what you are saying and it makes total sense even to me. If I were doing it for someone else and my reputation depended on it .. making another hole is the certain way to go.

I have just applied the patch to the boat this minute though..possibly because Im a stubborn old git ..but to explain some of my thoughts..

I wouldn’t have though the glue/ sikaflex mix will be under much pressure on an internal tube?.I would have thought when the tube is blown up..the air will push against the patch.. not like the external patch which will be pushed off. The boat is kept on its trailer and never deflated.

I often mix glues and had no problems..in fact have had great success sticking things with sikaflex then running cyano around the edges to hold in position until it sets. Perhaps it weakens the glue..but those things are still stuck down and some for quite a number years ..and they still withstand stress. I have also used PVC one part glue and Sikaflex mixed before with great success..but I cant say how much it weakens the glue.

For the external patch ..I will use two part glue..and have the area spotless before applying

Correct too Poly..I have no idea what the internal surface is like..it could be greasy as hell for all I know..but Im willing to give it a try..and have just done so..in theory .. it worked a treat. The external patch will be well cleaned and prepared etc. Im banking on internal pressure assisting the glue mix to hold the patch in place when under way.

Perhaps the title of difficult to access is misleading as I had no problem accessing the leak..and now the patch is in place.. I have a wooden board applying pressure to it from the outside ..through the flattened tubes..as well as the gut being held taunt.

If I had a puncture in a bike tyre..which I have had often..I would never dream of putting an internal patch on or cutting another hole so I could repair the first..but I appreciate PVC boats are different. Its not a high pressure tube either,.. around 250 milky bars is all..not like an airfloor

If it holds another four or five years ..Im happy..its a 12 year old boat remember. Possibly only used around a dozen time a year now too..as Im using the Frib far more

But as you guys say..time will tell. I will be honest..and keep you all informed ..etc

Thanks for taking the time to write it out too Officer it is appreciate ..it will help others decide how to repair leaks on their boats etc.

The second patch before going through the hole..it all went easy enough..but I got slippery fingers..which was expected

[The Gurnard]

I am glad Im a stubborn old git..as it saves me a fortune.

The mix of sikaflex and PVC glue will be no where near cured yet.. its only an hour since I installed the patch.. however I have pumped the tube up almost to full pressure but not quite. The pressure is now holding the internal patch firmly in place and ensure it conforms to shape of the tube.. until it all cures properly.

All the wet..is a mix of fairy liquid and water flung over it..not a bubble in sight either..and that is only the internal patch.. the hole chaffed in the black layer has also just been built up flush with sikaflex once I knew the internal patch was airtight



After that ..an external patch once everything is cleaned and dried .. and its bobs yer uncle...or more correctly.. back to sea next week.

IMO Repairing leaks is not a rocket science .Those that hesitate are often folks that get hung up on the scientific gobbledygook of it all ..but thats only my opinion.. so could be wrong.

How you guys sort your leaks ..is your own business ..but I hope you found this method interesting .. if not as an easy alternative to the professional way.

I will give an update on my external patch and floor board mods as I do them

[jeffstevens763@g]

Just my two pence why would you want another hole?
When you normally repair from the outside anyway not that I agree or disagree with the mixing ot two components purely because I never tried it but what I have tried is applying marine flex under water onto a ground piece of steel achieving 200 psi pull off since the repair is being pushed on by air it mearly needs to stick as for contaminated surface the internal repair fluids stick so why shouldn't gurnard's cocktail since he has proved the mix. Once he has the inside set and he's happy he then is reverting to a normal repair.
The main reason I suggested the mushroom was they are intended for internal repair they are shaped in such away that the air flattens the outer lip to form a seal if the glue doesn't dry air tight but it's the same thing as gurnard's way in a different format hope it works for you mate.

Cheers

[Fenlander]

Oh... No.1 leak testing fluid in the glass... thought it was a somewhat frothy gin & tonic to celebrate success!

[The Gurnard]

Hi Jeff.. I have complete confidence it will work. I would have used those tyre plugs if I had one..but it wasnt worth me buying a whole kit.

The external patch will be the main one for the leak. The internal is only for a plug...and a bit of backup

Personally there is no way I would cut a big enough hole to do a nice internal repair in that position.. that is the area that takes the pounding from the transom and outboard.. so even if I still have a wee leak..its still a small hole.. an access patch on the outside would weaken the whole structure..especially .. if as officer said "Glue is very weak"

Im not so sure its so weak though ? .. I had a devil of a job trying to get the accessories off the PVC seago I scrapped..they were glued on with chinese glue..sixteen years old.. It tore the PVC laminates rather than glue separating. Makes me wonder if Chinese glue is as folks think ?

[willk]

Originally Posted by The Gurnard

if as officer said "Glue is very weak"

"Specs on" Gurnard - he's called Office888. Your repair is very novel and I'm confident it will hold. I've done a couple of "off manual" repairs myself over the years but I'd credit luck with their success. I've surprised that you feel a patch on your tubes would weaken them appreciably - after all, your entire boat is glued together, surely?

And IMO, you're a good enough engineer to know why "glue is weak" - you wouldn't be weiming that poor laminator, would you?

[The Gurnard]

Hi willk.. Im not trying to upset anyone..and I genuinely hope its not coming across that way ?

I do believe Chinese glue is stronger than the material. Only a few month back..I tried to remove the PVC backing from the fixtures on my seago..I posted about it here at that time. Here is the picture I posted ..I had the PVC tube material gripped in a vice.. hauled and hauled as much as I could.. you can see what the result is in this photo.. the PVC laminates are ripping..something had to give as I was using a tyre lever as well. I gave up in the end. That is why I question the glue as being weak ...to me its stronger than the PVC . Is that wrong of me ?



I also genuinely think for a leak that is less than a quarter inch in diameter..there is no need for an internal patch in the first place. I remember reading somewhere that an internal patch is only require if the tear is 2 inches long..again that is why I was querying it with Office888

If the thread and my repair method is not appropriate ..do feel free to tidy it up ..I don’t mind..I was trying to help others ..that was my intention..nothing else.

Re Officer..that was a genuine error..I type Jeff instead of his full name..I should be more careful and have typed Office. For that I do apologies..

[jeffstevens763@g]

Glue isn't weak it's its application that's weak I worked with underwater applied epoxy coatings for a while achieving 900 psi pull off the coating was good but all down to surface prep anyway gurnard if it works a result and a wee dram is the order of the day in fact I going to have one now in antisipation.

Cheers

[The Gurnard]

Hi again Jeff.. while you had your celebratory drink.. I had another sniff of my Glue ..its not as good as the Gravy .. but it certainly does the trick as you will see in this photo.



The external patch is now in firmly in position ..I used Poly marine two part glue..and in the instructions.. it said.. if cut is 75mm or more put on an internal patch. I do follow instructions as best I can so I am absolutely certain this patch has repaired my boat. For info..the wee red dot on the patch..is to highlight where the leak was..and is around ¼” diameter..so roughly to scale.I marked it on the photo..for info ..its not there in real life.

I confess..the glue was three months past its sell by date
but the bacon I had for breakast was a week past its date..and Im still living

Im also very happy another piece of my old seago slat floor has been re cycled and will still go to sea with me. Its the patch material.

Its worth remembering too..the floor board closed the original leak . which is how I managed to continue my 60 sea journey.. With the internal plug on the inside..the patch..and the floorboard all preventing it leaking.. im on a winner

It may look messy around the edges..Im not that messy a worker.. but there was glue left over ..so brushed excess along the edges.. it may not do much.. but Im not worried about looks ..its all under the floor boards.

I will put another patch along the rear edge..as the floor board has chaffed away the PVC at the red transom holder. No leaks there as no pressure or water in that area..but best to pad it out again. I will also sort the floor board so it is less likely to chaff my new patch

[The Gurnard]

Of course..there is little point in repairing the hole ..without sorting the problem that caused it in the first place. The angled end of the Quicksilver aluminium floor trim is quite pointed and a bit worn.



So I took a file and rounded the edge ..plus lowered it the approx thickness of a piece of PVC patch material.



I find Sikaflex is the best thing to attach PVC to metal..so I stuck a patch over the edge to help pad it. Normally I would run cyano glue (superglue) round the edge..as its quick setting and holds the patch in place as the Sikaflex cures..which takes time. As I am out of cyano at present..I have to be more patient and use clothes pegs to hold everything in place.



I have spent a life time mixing glues of all types together.. and never had any issues..but I cant say if I weaken or strengthen the final joint..I don’t test to self destruct.

I would recommend any SIB owner with a solid Floor to check these areas in their boat. The chaffing took me by surprise as I never noticed it.. but then..I wasn’t looking for it...perhaps pre warned..you can solve any problems before a leak highlights it. It took twelve years for mine to wear through..so plenty time to check.

My thanks to everyone who offered suggestions and added comments ..Im certain the Gurnard will be at sea for a few more years yet

[Fenlander]

Well done Gurnard... a pragmatic and effective solution.

[office888]

Originally Posted by jeffstevens763@g

Just my two pence why would you want another hole?
When you normally repair from the outside anyway not that I agree or disagree with the mixing ot two components purely because I never tried it but what I have tried is applying marine flex under water onto a ground piece of steel achieving 200 psi pull off since the repair is being pushed on by air it mearly needs to stick as for contaminated surface the internal repair fluids stick so why shouldn't gurnard's cocktail since he has proved the mix. Once he has the inside set and he's happy he then is reverting to a normal repair.
The main reason I suggested the mushroom was they are intended for internal repair they are shaped in such away that the air flattens the outer lip to form a seal if the glue doesn't dry air tight but it's the same thing as gurnard's way in a different format hope it works for you mate.

Cheers

To ensure strength of the repair.

Properly done, it will last as long as any other glued component, guaranteed by ISO and laboratory testing. It will not fail when you need it most.

Most factories cut 3-5 large slices (~150mm long) in the boat to install the baffles, which are patched with glued inside patches. They hide the cuts underneath the joint between the tube and the floor.

[The Gurnard]

Hi Fenlander

If Pragmatic means cheap and cheerful .. well.. thats the way of the Gurnard.

Im happy with it.. the original glue holding the black PVC to red PVC was as sound as the day she was made so I don’t expect air to pass that way. I rammed the edges of the chaff with my mix of Sikaflex and glue.. which will now be a solid plug from inside the tube to flush with the black PVC.. then a large overlapping patch stuck over the whole are.



Im in no hurry for the boat .. so on Sunday..I will fill the bottom corner with water ..( I may as well hose out the boat while I have the floor out).. pump tube up to full pressure. Leave for a day or two.. install floor permanent .. then forget it ever happened.


Hi Office888 I appreciate its not a professional job..and your way would outlast the life of the rest of this boat. As mentioned..its a Quicksilver and 12 years old. ..Im pretty confident my repair will see the boats life out though. My job is kind of messy looking too..but its under floors..so Im not troubled by that

Thanks for your comments..I do appreciate them although I didnt follow your method

[Fenlander]

Pragmatic... dealing with things sensibly and realistically in a way that is based on practical rather than theoretical considerations.

I reckon that's you to a tee!

[jeffstevens763@g]

Hi gurnard

I would be pleased with that repair not the easiest of places to repair and no sign of the internal repair either good job done.
I was thinking how you had done a temporary repair enough to allow your trip to continue which has lead me to think I will put some of the mushrooms in my kit knowing you pushed the some what stiffer PVC through the 5 MM hole these will go in a treat no glue will be needed in the short term as an emergency just a get you home they are available in large & small sizes I am away at the moment but will sort something next week & post some info.

Cheers

[The Gurnard]

Hi Jeff..good idea on the plugs for temp repairs at sea.

I confess I have had one or two at sea( Not on the Quicksilver though).. but they dont bother me..I always have a hand pump with me.

Obviously PVC glue is useless in the wet conditions that you meet outside.
My trick in that instance is mix some quick setting Araldite Epoxy with one part PVC glue.. and ram that into the hole..and cover with a patch. OK..I have yet to cure the leak fully that way..but the epoxy sets quick and forms a plug to stem the airflow to a slow leak..and allows you to continue your journey..you may have to add a few puffs on the way..but nothing drastic

When you do the final repair..its easy to peal it all off the tube again..so no mess to clean

You dont learn that in technical manuals.. but an old salt will always know a way