Pit Holes

[blackrose]

It always seemed to me that, when someone posted questions such as this on this forum, knowledgeable folks with experience in the subject would be along pretty soon to achieve a reasonable collection of sound advice. Lately we seem to have a preponderance of wild-ass guesses, interspersed by the odd sage comment. I can't help the OP on this subject as it's quite specialist, but I would be interested to read constructive comment that helps him to solve his problem. We have some really helpful folk here with an amazing range of knowledge and experience - perhaps we could make a little space for them?

"Make a little space"? Bit hypocritical since your posts aren't actually helping in this respect.

 

In fact everyone is free to offer thoughts and advice because there is no shortage of space. That's the beauty of the forum.

 

It's up to those seeking advice to decide which responses they find most helpful. That's always been the same since I joined this forum in 2006.

 

Paul, don't want to take sides here as there enough in fighting on this forum at times. But I read Sea Dogs post to mean that there was no comment from anyone who had first hand experience of using filler on pits. That is quite probably because nobody has tried it.

Sorry I didn't realise I had to actually spell it out. I've used epoxy filler on pits when I worked in a boat yard, but personally I would try to avoid using it for underwater applications on my own boat.

Edited September 14, 2015 by blackrose

[Traveller]

"Make a little space"? Bit hypocritical since your posts aren't actually helping in this respect.

 

In fact everyone is free to offer thoughts and advice because there is no shortage of space. That's the beauty of the forum.

 

It's up to those seeking advice to decide which responses they find most helpful. That's always been the same since I joined this forum in 2006.

 

 

Sorry I didn't realise I had to actually spell it out. I've used filler on pits when I worked in a boat yard, but I would try to avoid using it on my own boat.

Blackrose, all I gave was my interpretation of the post. And I made the point that I was not being confrontational as this forum suffers from that too much sometimes. Personally, I do not care if people have used filler or not for I would always weld as it must be the stronger answer.

[blackrose]

Blackrose, all I gave was my interpretation of the post. And I made the point that I was not being confrontational as this forum suffers from that too much sometimes. Personally, I do not care if people have used filler or not for I would always weld as it must be the stronger answer.

I didn't say you were being confrontational, and neither am I. I was simply clarifying that contrary to what you had said, some of us do speak with first hand experience.

[Traveller]

Fair enough. Best left there then :-)

[Bloomsberry]

Not necessarily, haven't you ever seen protrusions from lock walls? If contact from locks, moorings, etc, with the side of the hull is so rare I wonder why one sees so much scraped blacking on narrowboats?

 

Anyway, it may not necessarily need a "direct hit" to knock filler out.

 

 

 

Point taken, I suppose the only way we are going to know is from people who have actually used it (to fill in pitting) .

 

 

I am tempted to get some and try it out on various surfaces then see how easy or hard it is to remove.

Edited September 14, 2015 by Bloomsberry

[Paul C]

As I read things, 1) the OP hasn't come back to clarify what he meant by spot welding - I asked about this in post #2; and 2) some things are widely accepted in engineering/boat building/boat maintenance/science/technology in general. These things are often assumed unless a poster comes back specifically seeking clarification on it. Since the OP hasn't come back, I'm still awaiting their clarification on what they meant by spot welding. The relative strength (or the requirement of strength, or durability, etc) of fillers is potentially an interesting subject but nobody yet has posted a coherent posting in support of it vs the widely accepted practice of welding the holes up. Threads are not limited by "space" and every post is capable of being read, but someone would have to actually post it. I don't think its necessarily right to assume that there is a viable alternate which is somehow being suppressed.

[blackrose]

Point taken, I suppose the only way we are going to know is from people who have actually used it (to fill in pitting) .

 

I am tempted to get some and try it out on various surfaces then see how easy or hard it is to remove.

As I haven't used it on my own boat I don't know how well it stays put. I was just saying it may have the potential to become dislodged with impacts and flexing of the hull and that won't happen if the pits are filled with weld.

[magnetman]

As I haven't used it on my own boat I don't know how well it stays put. I was just saying it may have the potential to become dislodged with impacts and flexing of the hull and that won't happen if the pits are filled with weld.

Maybe another option would be to drill the pit out then tap it and screw a bolt in the hole with a thread sealant of some sort. Depends how many pits there are - it could become time consuming..

[gazza]

As I haven't used it on my own boat I don't know how well it stays put. I was just saying it may have the potential to become dislodged with impacts and flexing of the hull and that won't happen if the pits are filled with weld.

This^^^^

 

Epoxy fillers are brilliant when used in the correct application. A rusty boat prone to walloping things is not the right application.

[gazza]

Maybe another option would be to drill the pit out then tap it and screw a bolt in the hole with a thread sealant of some sort. Depends how many pits there are - it could become time consuming..

Noooooo!!!!

 

We have a ships lifeboat conversion at our club, its a nightmare! The things were not very thick when new, its got to be getting on 60+ years old. A previous owner has coach bolted and self taped thin sheet all over it then covered it in hot tar.

Its current owner hot tars it less than is prudent for a frail thing like that.

 

Sorting it out properly would be a time consuming messy hateful job, one that I won't put my hand up for

 

Shame, as its a proper nice looking boat, the guy that converted it originally had a good eye, the last few owners the less said the better

Edited September 14, 2015 by gazza

[Pot Noodle Adventurer]

Thanks for all your input.

 

As boat is not yet dry docked I cannot report on state of pitting so the question was in effect hypothetical in anticipation!

 

Paul C is right to query what I meant by spot weld and as I am not a technical bod I accept his clarification, thank you.

 

Just having a look on tinternet I came across an epoxy based product called J-B Marine Weld (other products are available!) which claims to be a cold weld system that sets in 20 -25 minutes and is fully set in under 24 hours, for above and below water line achieving a tensile strength of 3960 PSI. Interesting.

[gazza]

Thanks for all your input.

 

As boat is not yet dry docked I cannot report on state of pitting so the question was in effect hypothetical in anticipation!

 

Paul C is right to query what I meant by spot weld and as I am not a technical bod I accept his clarification, thank you.

 

Just having a look on tinternet I came across an epoxy based product called J-B Marine Weld (other products are available!) which claims to be a cold weld system that sets in 20 -25 minutes and is fully set in under 24 hours, for above and below water line achieving a tensile strength of 3960 PSI. Interesting.

Honestly, forget JB weld and the like.

I would use that on a damaged aluminium outdrive/outboard casing and the like.

 

I would not use it for repairs to a mild steel hull.

 

If you want a boat you can mend with epoxy fillers you need to get a GRP boat.

[Murflynn]

exactly

[bizzard]

Cohesion is the main reason why goo's like Epoxy can eventually come unstuck, the different rates of expansion and contraction of the steel and the goo due to sudden temperature changes between them and not so much getting knocked off because once cured and sanded nice and flush and painted over it would be difficult to knock it off unless struck an enormous blow directly on it. So goo applied to pits on a steel hull under water would not be subject to much expansion and contraction, only very gentle seasonal water temperature changes therefor it should stay stuck if applied properly. Just sayin.

Edited September 15, 2015 by bizzard

[Neil2]

In view of Seadog's comment I'll elaborate on my own suggestion.

 

I've used Belzona as a metal repair alternative to welding, as I can't weld, with good results.

 

I was so impressed with it that when my own hull was grit blasted I considered using it to fill in some pitting below the waterline, and I actually discussed this with the Belzona rep who confirmed that it has been used for this purpose numerous times.

 

In the end I decided I decided to have the pits welded as I was paying to have the rubbing strakes continuously welded anyway (they had originally been stitch welded) and the only real advantage of epoxy is it's a feasible DIY solution.

 

I don't really see where Seadog's coming from personally, but I agree it would help if members backed up their suggested solutions with a bit of evidence.

 

Having said that I think sometimes a bit of "wild ass" guessing can be constructive if it helps look at a problem from a new angle.

 

 

 

[ditchcrawler]

The only type of filler that would work for underwater applications would be a two part epoxy marine filler. Don't use car body filler.

 

http://www.boatpaint.co.uk/acatalog/International_Fillers.html

 

However the best solution is to get the pits filled with weld.

Would it be OK if you were selling the boat, I knew people who did car bodies up with Poly Filler before painting and selling on.

[gazza]

Would it be OK if you were selling the boat, I knew people who did car bodies up with Poly Filler before painting and selling on.

On a practical level or a moral one?

 

I have seen some horrendous bodges to sills and chassis rails, a magnet would have been better than an MOT testers hammer!

 

I can remember old Vauxhalls and Ford's being sold in the classifieds of our local paper with '12 months mot, recent new sills' which is code for scraped thru a ticket, rotten as a pear!

[Pot Noodle Adventurer]

In view of Seadog's comment I'll elaborate on my own suggestion.

 

I've used Belzona as a metal repair alternative to welding, as I can't weld, with good results.

 

I was so impressed with it that when my own hull was grit blasted I considered using it to fill in some pitting below the waterline, and I actually discussed this with the Belzona rep who confirmed that it has been used for this purpose numerous times.

 

In the end I decided I decided to have the pits welded as I was paying to have the rubbing strakes continuously welded anyway (they had originally been stitch welded) and the only real advantage of epoxy is it's a feasible DIY solution.

 

I don't really see where Seadog's coming from personally, but I agree it would help if members backed up their suggested solutions with a bit of evidence.

 

Having said that I think sometimes a bit of "wild ass" guessing can be constructive if it helps look at a problem from a new angle.

 

 

 

 

Thanks for that information. I had not heard of Belzona so have just had a look at their website (other products available of course!). Based in Harrogate, they appear to have an array of products for numerous repair or protection situations including marine/offshore. An epoxy filler that can be used for filling pit holes is mentioned as well as for the repair pf damaged rudders and propellers where of course movement/ cavitation is the norm. I am keeping an open mind on this.

[ditchcrawler]

 

Thanks for that information. I had not heard of Belzona so have just had a look at their website (other products available of course!). Based in Harrogate, they appear to have an array of products for numerous repair or protection situations including marine/offshore. An epoxy filler that can be used for filling pit holes is mentioned as well as for the repair pf damaged rudders and propellers where of course movement/ cavitation is the norm. I am keeping an open mind on this.

The first time I came across Belzona they were using it to line open drainage channels in the floor of a food factory so they could sanitise them properly, couldn't get concrete clean even with a steam lance. Then saw it used for repairing castings where lump had got broken off

[Bee]

If the holes are deep and worrying then weld is probably best, I wouldn't worry too much about slightly dissimilar steels, plenty of old boats have rivets welded over and they never seem to suffer. If the pits don't need repair then I think proper paint ought to stop them.

[Bloomsberry]

Would it be OK if you were selling the boat, I knew people who did car bodies up with Poly Filler before painting and selling on.

 

And what do surveyors think of using epoxy filler ? It can be the best stuff in the world but if a buyer's surveyor isn't happy with it then you may have to get it welded anyway and this may complicate the whole selling process. It may even put some potential buyers off ?

[cuthound]

And what do surveyors think of using epoxy filler ? It can be the best stuff in the world but if a buyer's surveyor isn't happy with it then you may have to get it welded anyway and this may complicate the whole selling process. It may even put some potential buyers off ?

Excellent point. Have a greenie.