Epoxy resin cloths

[gtflash]

I am about to undertake a bit of a project, still in negotiations about price, but it will need some repairs, namely stringers and some beefing up in the hull area. Its previously been repaired (badly) using epoxy resins. Therefore I believe I will be stuck with using epoxy later on.

Simple question, I do not understand all the cloths used with epoxy resins. I believe bi-axial is the commonest strong one used from googling, however Im not entirely sure. Are they just as easy to lay up as CSM and wovens roving?

Stringers are ply and good and strong, but the glassing is patchy, therefore I intend to get it back to a flat surface, then cover over whole stringer with glass. Any ideas how many layers I will need of which cloth??

Hull is very light, and could do with some extra strength, I toyed with skinning the whole interior of hull with a carbon fibre, but it seems the hard material stuck to the softer one can break away???? SO next idea was to add a core in the stressed areas, if so how many layers of epoxy/cloth will be needed to seal the core, without adding too much weight. I believe I understand how to stick a core to the old inner hull, but most core layup descriptions are for polyester fabrics.

Thanks in advanced GT

[gtflash]

West Marine epoxy at the boatshow, were very helpful. He suggested a minimum of 2 layers of 450g bi-axial, thats 15oz 738 fabric, and the 2nd layer 90degrees to the other. Could anyone confirm this ??

[Rogue Wave]

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did you get the West systems how to CD?

[captnjack]

Originally Posted by gtflash

West Marine epoxy at the boatshow, were very helpful. He suggested a minimum of 2 layers of 450g bi-axial, thats 15oz 738 fabric, and the 2nd layer 90degrees to the other. Could anyone confirm this ??

You are asking for comments on how to best repair a hull which was underbuilt. By how much? What size hull? What is the original layup? What is wrong with it? And also have not seen. How are is anyone supposed to know if this is adequate?

Yes normally biaxial fabrics are laid across one another. The West system products are fairly easy to work with and straighforward.

[gtflash]

apoligies, I thougt I mentioned it is a rib, 28ft hull length. Further investigation, she had some laminate issues, not specifically sure what, but has had some poor wood stringer rplacements.

Wood all looks good, but the glassing is very patchy. The layup was only one less layer of fabric than normal production craft, and it had a special resin which begins with d, but i forgot its name.

[captnjack]

Layup on the top and sides of wood stringers does almost nothing except keep water out. Foam stringers need a "box" of GRP around them to a much greater degree.

So these stringers were replaced once already and the repairer did a poor job? For all the issues you are having I think you need an in-person professional consultation, not just us internet lackies.

[Rogue Wave]

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was the place I meant it's actually East Coast Fibreglass.

[gtflash]

Originally Posted by Rogue Wave

Buy fibreglass supplies online UK - East Coast Fibreglass Supplies

was the place I meant it's actually East Coast Fibreglass.

Thanks rogue.

[gtflash]

Originally Posted by captnjack

So these stringers were replaced once already and the repairer did a poor job? For all the issues you are having I think you need an in-person professional consultation, not just us internet lackies.

Yes. Stringers need help. From further advice the wood ones need beefing up.. Still unsure how many layers of bi-axial. Thanks for comments About professional advice. Would kinda defeate the object of a forum though!

I have been in contact with the builder, and the bloke who actually laid her up. She is derakane resin.

[Rogue Wave]

Originally Posted by captnjack

Layup on the top and sides of wood stringers does almost nothing except keep water out. .

How are they held on to the hull. if not for the layup on the top and dides.

i genuinely thought the strength came from the glass being shaped over the wood, i just thought you went foam to save weight. I am obviously refering to GRP hull and am happy to learn something

CHEERS STU

[m3mm0s rib]

My opinion. Never wood in stringers . 6 -7 600 layers of matte and you have a very robust whole.

[captnjack]

Originally Posted by Rogue Wave

How are they held on to the hull. if not for the layup on the top and dides.

i genuinely thought the strength came from the glass being shaped over the wood, i just thought you went foam to save weight. I am obviously refering to GRP hull and am happy to learn something

CHEERS STU

Every wood stringer I have ever seen is covered with one layer or two of mat/roving to keep out water and yes hold them to the hull too. But the whole point of the stringer is to provide stiffness and for wood stringers that stiffness is not provided by the mat layers on top. Slapping on more GRP more won't do much. Foam stringers have basically no stiffness by themselves at all, the "box" of GRP around them provides their structure.

Originally Posted by gtflash

Yes. Stringers need help. From further advice the wood ones need beefing up.. Still unsure how many layers of bi-axial. Thanks for comments About professional advice. Would kinda defeate the object of a forum though!

I have been in contact with the builder, and the bloke who actually laid her up. She is derakane resin.

Maybe so, but seems like you are in over your head. Its not clear what the original problem is and whether 2 layers of bidirectional mat are going to address that problem at all. Especially given this new revelation that you need "beefier" stringers.

[gtflash]

Originally Posted by captnjack

Every wood stringer I have ever seen is covered with one layer or two of mat/roving to keep out water and yes hold them to the hull too. But the whole point of the stringer is to provide stiffness and for wood stringers that stiffness is not provided by the mat layers on top. Slapping on more GRP more won't do much. Foam stringers have basically no stiffness by themselves at all, the "box" of GRP around them provides their structure.



Maybe so, but seems like you are in over your head. Its not clear what the original problem is and whether 2 layers of bidirectional mat are going to address that problem at all. Especially given this new revelation that you need "beefier" stringers.

I am being cautious what I say, as a deal is still being done. I dont know your background, nor you mine, you have not provided a specific laminate schedual (which I wouldnt expect, just a general idea) despite the fact I answered your questions, therefore, as my boss says, if your not part of the solution your part of the problem! Cant a guy think allowed

Maybe I didnt make myself too clear, the additional stringers are wood, but the quality of laminating is poor. Even though I am in over my head, I know that the wood needs to be covered in something, and not just paint!! The boats history is unclear. In all fairness most boats dont tell you their entire story when you shake their hand on 1st introduction. Difference is, I am going out of my way to find this ol girls history out and the price will reflect my findings....

As a hobiest I have laminated plenty, just not so much with epoxy cloths. Hence the original question.

[gtflash]

Originally Posted by m3mm0s rib

My opinion. Never wood in stringers . 6 -7 600 layers of matte and you have a very robust whole.

thankyou. I watched your video over half a year ago.. Good to see, new stuff arriving, and the locals watching too

[jwalker]

Originally Posted by captnjack

But the whole point of the stringer is to provide stiffness and for wood stringers that stiffness is not provided by the mat layers on top.

Yes...

Foam stringers have basically no stiffness by themselves at all, the "box" of GRP around them provides their structure.

Yes...

Slapping on more GRP more won't do much.

Erm...isn't that a bit contradictory? If there are wood longitudunals and they are well laminated over, won't you have the best of both worlds? Even further, foam filled longits often fail because there is no internal of worth to prevent the laminate deforming, with consequential failure. As well as the gross load in the first place of course.

Maybe so, but seems like you are in over your head.

Hehe, not after we've finished with him!!

[gtflash]

Originally Posted by Rogue Wave

How are they held on to the hull. if not for the layup on the top and dides.

i genuinely thought the strength came from the glass being shaped over the wood, i just thought you went foam to save weight. I am obviously refering to GRP hull and am happy to learn something

CHEERS STU

I "THINK", there are active and inactive cores. The ones under engines are frequently active cores, in other words the wood, takes some load, and not just the outside shape. The inactive ones, are the foam/hollow ones for example. But I think many people more smart than us, debate this frequently.. I love modern stuff and think wood has been replaced, but when cookee and others stick a tree in their boat.......... Its pretty obvious there is a good reason!

[captnjack]

Originally Posted by gtflash

I am being cautious what I say, as a deal is still being done.

<snip>

Difference is, I am going out of my way to find this ol girls history out and the price will reflect my findings....

So the boat is beat to hell. She has been repaired before but the stringers are still in poor shape and delaminating. You are asking on the internet how to DIY repair them and not posting pictures of the issues or full details because you are afraid your eventual sale price might be compromised by your repair inquiries...

Shadey.

Originally Posted by gtflash

As a hobiest I have laminated plenty, just not so much with epoxy cloths. Hence the original question.

Maybe there's a language issue here, but I'm assuming you are using glass cloth and epoxy resin...

Originally Posted by jwalker

Erm...isn't that a bit contradictory? If there are wood longitudunals and they are well laminated over, won't you have the best of both worlds? Even further, foam filled longits often fail because there is no internal of worth to prevent the laminate deforming, with consequential failure. As well as the gross load in the first place of course.

Hehe, not after we've finished with him!!

Maybe. But the "box" won't be the right shape for the load compared to a designed foam stringer so slapping more GRP on a wood stringer may or may not accomplish anything. It will seal it from water (yay!) and add weight (boo hiss). Structurally its hit or miss. I've seen some good stringer repairs and some that made matters worse (sealing in water, yikes)

[m3mm0s rib]

look at this

Making stringer system for 19 Panga - YouTube

[m3mm0s rib]

Originally Posted by gtflash

thankyou. I watched your video over half a year ago.. Good to see, new stuff arriving, and the locals watching too

I think the exchange of views never hurt anybody.