Thinning the Polyester with Styrene monomer, then wetting out the Marine Plywood first and allowing the resin to penetrate the Plywood, After curing for 30 minutes to an hour, will give the Polyester a much stronger bond when used full strength.

The polyester works maybe better in reality than this. In the real world, you would wet the plywood in advance, before laying any cloth, a bit more than here. The second thing is that with poly, on the bonding layer, you usually would use chopped strand mat( emulsion bond version), as a bonding layer before any other matt. CSM helps wetting also the cloth. I am a hobby boat repair guy, and even if epoxy as a resin has a much better bond, i consider hand laminating polyester is a bit more forgiving. Alternating CSM with cloth makes polyester laminating much easier than with epoxy. particularly in difficult bends....Epoxy also needs much beter prep( due to lack of emulsion bond matt). Rotten plywood is usually due to holes in laminate, never mind epoxy or polyester. In repair jobs, I actually mostly use epoxy as then i don't need to worry what material is previously used....but I would otherwise use polyester as its so much easier to laminate.

Holy crap, this is amazing.

Great test thanks

Thanks. I am doing a refit currently on our Marine ply Eventide 26, and the majority of rot issues I encountered was where polyester resin and glass cloth was used over ply. In most of the problmem areas, it simply did not bind with the wood fibers and I could pull it off by hand. Fresh water also got trapped behind the polyester, and wood rot set in. I've now replaced the majority of the rotten wood with fresh wood. I use Aerontec Epoxy products, which is very similar to West. After watching your video, I am convinced that I am doing the right thing in using thick epoxy for gluing and penetrating epoxy and not polyester for treating wood before painting with MS primer and 2k. The cost savings in the short run, which previous owners of our boat probably chose to do, is now causing me lots of headaches. I would rather spend more and know that the boat is good for another 50 years. (She was built in 1977)

Nice this is extremely helpful. If you ever do this again you should consider that you can just use the scale to pull directly without using the weight.

Congratulations on 1000 likes. I dedicate it to you.

Great job. I really enjoyed the music, can you tell me the names of the groups and the song titles please.

After using 20ltrs. of unwaxed resin [Polyester] 200 mtrs. of 16oz. x 100mm wide fibreglass tape and 4 litres of flow coat on my foam cored project boat, I needed to finish the job, by strengthening the the transom. This was the only place that I had timber [plywood] to work with. I tried polyester, the result was that I could lift the laminated glass layer with my fingernails. For me the only way to glass wood is to use epoxy resin. I only needed 1.5 ltrs so cost is not included in my decision in this case. If cost was a factor I would take into consideration the cost of doing the job twice.

Gotta love the pommy humour.

I would like to purchase this project, but unfortunately, I do not have the resources to buy it. If any of you have a detailed 3D model of this project and are willing to share it, I would be very grateful. Buying the project is currently beyond my means, so I am forced to design it myself. However, due to a lack of experience in design, I make many mistakes and progress slowly. I promise to share a portion of the profits with those who help me with a detailed 3D model after successfully implementing my project.

Good to see you back. Has been a while.

My 50 year old plywood dinghy is still holding together well so I think polyester is good enough for this purpose. I avoid epoxy because the fumes are horrible and I end up looking like the elephant man 🙂

And mixed both epoxy dry then apply polyester?

Замечательное видео.один вопрос почему бы не поставить арку сразу на грунт.

I live in a tropical environment, and want to do my project under the shade. Epoxy looks better for what I need, I'm hoping that my project is super water proof. Epoxy over plywood. What's your recommendation ?

What kind of sextant are you using??

Spetacular vídeo. Congratulation from Brazil...😅😅😅

I love this. Great work, y'all.

You would have to have an engineer stamp for this in Canada.

I would probably automatically go with the best performing product despite material costs because I would assume the major cost would be the labor and not the materials and I would prefer to avoid doing the repair a second time.

Stupid interneters and their F’n music! F’n hell! Probably a good guy, just an idiot when it comes to making a viewable video that’s not “trendy modern tik kok’n non original Interneter generations” All the best mate!

Love the video. Awesome build. Now I have a song stuck in my head though 😜

There are many youtube shorts teaching how to connect to a rarp without holes in the tarp nor any device but a stick...and your rope.

Excellent 'shade tree' video. I really enjoyed it and found it useful. Thanks.

Excellent information mate, cheers.

Perfect job!

Hi. Great video. Thanks for posting. Are you planning any more technical videos I watched your Epoxy versus polyester video which is very well presented providing excellent information. 👍

0:20 it looks like you are surveying a line or something here. What tool are you using, or what’s going on?

It's all changed since I was a boy 1960s

That! Is a very beautiful and fitting piece of architecture. It will be a shame to ever dismantle it. Dig the music, goes with the humour.

Planning permission? Easier to ask forgiveness than permission! Get proof of the date of construction. There's often a period (5years - look it up) and if they haven't noticed and nobody has complained you get to apply for exemption. But you will probably need to get structural certification before they'll exempt you.

Great overall but don't you think pouring sand into a bucket to test more precisely the weight of the breaking strength would be, rather than 2 bricks versus 4 bricks? PLUS, there is something else you didn't discuss which is that epoxy is superior in preventing rot. West System did surveys of 40 year old epoxy wood boats that had few problems. Most 40 year old polyester fiberglass encapsulated boats have rotted wood inside.. By the way to give you an idea of the spying tht goes on, while I was watching this, an epoxy ad interrupted the video!

I have an allegro 27. The stern tube seems to be made out of two tubes placed one in front of the another. The outer tube is where the cutlass bearing is inserted to. And the other is where the sealing shaft is attached to. I noticed a leakage in between these two tubes. Im thinking if there is another way to fill epoxy in the leaking point other than to replace like you did. If someone fixed thet in an allegro 27 using other ways instead of replacing the tube like he did , please let me know how it was. Thank you for this video!

You're not supposed to use any of them for repairing teeth.

Epoxy glass may be very strong, but being that much stronger than ply, why not use poly.

Shame you didn’t do the lain poly properly. Ie prime the ply with poly thinned with styrene. So is that what plymax is

What in the hell boatyard let you put in concrete pilings and spread gravel????????????? In upper ubangi-bangi somewhere in east Africa, I can understand, but in the UK?????

This is the video I have been looking for. Excellent explanation of the pros and cons of poly vs epoxy. I am not sure why I have not seen your channel before now. I would say the YT algorithms are not working for you. Keep going.

for better polyester adhesion ont existing polyester, you must hammer the polyester with a wood chisel, to get some fibres out, then use a first coat of thin polyester resin, then proceed normally.

for better polyester adhesion on wood, you must thin the first coat with 30 % acetone, then proceed normally.

This is good stuff

So you didn't glue the spacers? Just screwed? Seems like it if you could build one of the bow / arches every 15 mins.....I will be building one for my project and not having to wait for glue to dry will save a lot of time...

SYSTEM 3 of Seattle 《 2to1》 [resin , hardener]

Great video, great shed, and great sound track!

For any kind of resin, first, score the surface with 40 or 80 grit sandpaper. After scoring, saturate the surface by resin before you place any lamination on it otherwise resin will be sucked up into the wood your lamination will be dry. Of course epoxy will be the winner of the bond test in any case but if you know what you are doing Polyester resin might be sufficient for the job. Boat manufacturers use polyester resin as they generally know what they are doing. For epoxy resin you need a workshop temperature of 15+ degrees Celcius for about 12 hours. Or make sure you work in a hot summer day. West System is a good epoxy but not my favorite. There are so many different epoxy resins available for marine use. I believe that WS is a rip off.

Excellent Tim, this could well be a very long video but doing it in shorter clips will probably make it easier to digest. I tend to sail on my own or with one or two regular crew and that is a risk in itself as it is easy to get complacent. A guy who has sailed with me for a number of years and a keen dinghy sailor was given the helm as we left Chichester Harbour, just off East Head. There was a new member of crew onboard in the cockpit. I went below to check the engine and other items, when I started to come up the companionway the crew was stood behind the spray hood and then the guy helming turned without thinking and the main gybe violently. The boom just missed the crews head. It shook me and no doubt the guy helming. My fault for not checking the helm was clear where the wind was and where we should be going and also for not telling the new crew to sit down and not stand in the target area. Cheers. Andy UK

Excellent thanks.

Enjoying this. Always nice to hear about how it really is. Particularly agree with the comment re navigation in the Solent yes it's all pilotage. 😁.