Hello builders. I'm ready to fiberglass the inside of the hull and building the Redbird. I used West System epoxy on the outside and had a difficult time keeping up with the relatively short set time. I'm applying it by myself and was a struggle to keep up with the wetting out and squeegeeing timing.
Green Valley Boat Works has a Builders Notes section in their website. One topic is Epoxy Resin. They explain that using System Three Clearcoat epoxy is much easier to use due to a slower cure time. They explain to use System Three Clearcoat to wet out the fiberglass and then use West Syestem 105 / 207 for filler coats. Anyone ever used this method? I'm wondering about the long term durability of the System Three, and how the West System would bond to the System Three. Thanks for any advice.
Andy K.
Fiberglassing the hull
Re: Fiberglassing the hull
Hi Andy,
I haven't actually mixed and matched epoxies, but everything I have read suggests that is a valid strategy.
Another point to consider with the inside hull, is only apply 1 fill coat and leave the interior hull dimpled, a bit of texture there is better for traction so you don't slip on a slick hull.
I use East System, which handles almost identically to West. I usually do the inside solo, so I am wondering at the mention of short pot life and timing issues. I am assuming you use the 207 hardener, so pot life is ~25 minutes, then you have another 30 minutes or so to do the squeegeeing .... obviously, you can impact those times with ambient temperature and handling.
To apply I use a 7" epoxy roller, preweigh all of the resin portions (usually 6 oz batch for initial layer). The roller really distributes the epoxy quickly and nearly half the canoe is done before that first 25 minute timer goes off. Test the first area, if it's not ready yet, do another new section. you likely have ~30 minutes to squeegee any single batch area, so there is no real critical timings involved.
You don't see it mentioned much, but be aware that epoxy does not stop moving after it kicks, it keeps flowing (albeit slowly) for about another hour, this is why you get runs/drips etc and should babysit for an hour or so after application, the excess will flow down the cloth.
The preweigh is quite useful for West system as it is a 5:1 product and the hardener is thin, so quick to pump, the resin is thick and quite slow to pump bigger batches. It will be less useful for the S3 as I believe it is a 2:1 product.
I have bought plans from Green Valley and read the site, Martin is offering his experience (and by extension, that of John Winters) which is a solid source IMO. Just pay particular attention to the additional requirements (also mentioned by Martin) that using the thinner epoxy requires, namely a hull precoat and babysitting the coated hull for much longer to make sure defect don't manifest and using slightly more epoxy initially to make sure enough is applied.
Epoxies can create amine blush on surface depending on the curing conditions, both West and East are more prone to this, but my understanding is that any epoxy can throw a blush. Washing the unsanded hull with warm water (a drop of dish detergent optional) and a scuff pad is a good idea, followed by a good rinse. If you hadn't heard of blush, it is a waxy substance that will interfere with the varnish curing, creating a sticky mess that is a pita to fix.
Another suggestion, before you sand the outer hull, layout and cut your interior fiberglass ends, by laying it out and cutting to fit the outer shell minus a bit .... obviously you don't want a tight fit along the sheers, but you can get the stern/bow shapes down so you don't have to try and trim in those tight spaces.
Brian
I haven't actually mixed and matched epoxies, but everything I have read suggests that is a valid strategy.
Another point to consider with the inside hull, is only apply 1 fill coat and leave the interior hull dimpled, a bit of texture there is better for traction so you don't slip on a slick hull.
I use East System, which handles almost identically to West. I usually do the inside solo, so I am wondering at the mention of short pot life and timing issues. I am assuming you use the 207 hardener, so pot life is ~25 minutes, then you have another 30 minutes or so to do the squeegeeing .... obviously, you can impact those times with ambient temperature and handling.
To apply I use a 7" epoxy roller, preweigh all of the resin portions (usually 6 oz batch for initial layer). The roller really distributes the epoxy quickly and nearly half the canoe is done before that first 25 minute timer goes off. Test the first area, if it's not ready yet, do another new section. you likely have ~30 minutes to squeegee any single batch area, so there is no real critical timings involved.
You don't see it mentioned much, but be aware that epoxy does not stop moving after it kicks, it keeps flowing (albeit slowly) for about another hour, this is why you get runs/drips etc and should babysit for an hour or so after application, the excess will flow down the cloth.
The preweigh is quite useful for West system as it is a 5:1 product and the hardener is thin, so quick to pump, the resin is thick and quite slow to pump bigger batches. It will be less useful for the S3 as I believe it is a 2:1 product.
I have bought plans from Green Valley and read the site, Martin is offering his experience (and by extension, that of John Winters) which is a solid source IMO. Just pay particular attention to the additional requirements (also mentioned by Martin) that using the thinner epoxy requires, namely a hull precoat and babysitting the coated hull for much longer to make sure defect don't manifest and using slightly more epoxy initially to make sure enough is applied.
Epoxies can create amine blush on surface depending on the curing conditions, both West and East are more prone to this, but my understanding is that any epoxy can throw a blush. Washing the unsanded hull with warm water (a drop of dish detergent optional) and a scuff pad is a good idea, followed by a good rinse. If you hadn't heard of blush, it is a waxy substance that will interfere with the varnish curing, creating a sticky mess that is a pita to fix.
Another suggestion, before you sand the outer hull, layout and cut your interior fiberglass ends, by laying it out and cutting to fit the outer shell minus a bit .... obviously you don't want a tight fit along the sheers, but you can get the stern/bow shapes down so you don't have to try and trim in those tight spaces.
Brian
Re: Fiberglassing the hull
Thanks for the epoxy information Brian. To clarify the timing concept I mentioned, I applied the wetting out coat to the outside hull with a brush as the CanoeCraft book suggests. This was a time consuming chore for me and as I worked down the hull section by section. Eventually towards the end of the process the section needing squeegee attention had started to kick. I just wasn't moving along fast enough to keep up with the squeegee the epoxy part of it. Admittedly, I move slower than most as medical issues has slowed me down somewhat. Anyhow, that was the reason for my inquiry about using the System Three Clearcoat. I'm on the fence regarding to switch brands halfway thru the project though.
The preweigh idea will shave off some prep time in finishing the inside, I will use it for sure. Thanks for explaining it.
Your goto method of applying epoxy to the inside is with a roller as you mentioned. Does this mean you are wetting out of the glass with a roller? This seems like a much more efficient way to spread epoxy which would help me a great deal to keep up with the squeegee process. One point here that I find confusing. The CanoeCraft book explains rolling on epoxy to the glass can cause troubles (at least if I remember correctly). However, youtube has many videos of folks doing just that, applying epoxy with a roller. There are of course many different ways of accomplishing the same task but what gives here? My intention is to move along on the inside with the West System brand if possible.
The Green Valley Boatworks website has another article in the Builders Notes section called " An easy way to Fiberglass the inside of the hull" (along with several others). Anyone getting close to glassing the inside hull stage should take a look there. Appears to be a more problem free method than the published books provide, IMO. Thanks for responding.
Andy K.
The preweigh idea will shave off some prep time in finishing the inside, I will use it for sure. Thanks for explaining it.
Your goto method of applying epoxy to the inside is with a roller as you mentioned. Does this mean you are wetting out of the glass with a roller? This seems like a much more efficient way to spread epoxy which would help me a great deal to keep up with the squeegee process. One point here that I find confusing. The CanoeCraft book explains rolling on epoxy to the glass can cause troubles (at least if I remember correctly). However, youtube has many videos of folks doing just that, applying epoxy with a roller. There are of course many different ways of accomplishing the same task but what gives here? My intention is to move along on the inside with the West System brand if possible.
The Green Valley Boatworks website has another article in the Builders Notes section called " An easy way to Fiberglass the inside of the hull" (along with several others). Anyone getting close to glassing the inside hull stage should take a look there. Appears to be a more problem free method than the published books provide, IMO. Thanks for responding.
Andy K.
Re: Fiberglassing the hull
Hi Andy,
The Bear Mountain Building series is a good source of info, if you haven't found them, the link is here : https://www.bearmountainboats.com/pages/videos
It is important to realize that all these videos and comments are for the environment they are working in and with the experience the filmers have .... the biggest take away for me is seeing what has to happen and then adapting my shop and experience to make that happen. The important thing is to take the time to understand the process that people are proposing first, then go ahead and figure out how to make it work for you.
Epoxy is a good example of this IMO, once mixed you need to get it out of the mixing cup because it will heat up and set quicker and the goal is to have as much working time as is reasonable. However, you will also be told that pouring it on the cloth can make the cloth float up away from the wood .... so that seems like the only solution is to get a shallow tray to dump it out on and dispense it from there (and you will see that suggested).
This creates extra steps and more mess IMO .... instead I envision a 2 foot hull section and take a mixed batch and just pour a band of say ~1" wide epoxy directly on to the cloth, in a looping, back and forth pattern. Then use the roller to help distribute the excess around the area you have selected. If it is a bit heavy, spread it a bit further, if it is light, don't try and cover it all .... the trick is to just get it distributed, the roller or brush is just a distribution tool ..... the epoxy has to absorb and sink it on it's own.
The next cup is the area next door to what you just did, if you have area that is a little light, just add a dollop and distribute .... this is not like painting where you are trying to make it all even, you need to put enough epoxy to allow it to absorb, then later you are going to remove the excess. So don't worry too much about making it look even and pretty, it is more important IMO to keep it all moving ....
If you don't finish the entire interior before the first batch kicks (likely), just go back and squeegee the first section, add a section and go back and squeegee the next section, repeat till you finish the hull. You can be a little less precise with the timings after the first section and until you get the hull coated. You should be done with the hull and still have about half a hull to squeegee, which gives about the right timing for the last batch applied, but I basically time the first and last batches.
I did a detailed posting for my last build, which is aimed specifically at newer builders, to share what needs to happen along the build process, you may find some useful information there as you move along, it can be found here: https://www.canoetripping.net/threads/l ... ld.105054/
Good luck on the rest of the build
Brian
The Bear Mountain Building series is a good source of info, if you haven't found them, the link is here : https://www.bearmountainboats.com/pages/videos
It is important to realize that all these videos and comments are for the environment they are working in and with the experience the filmers have .... the biggest take away for me is seeing what has to happen and then adapting my shop and experience to make that happen. The important thing is to take the time to understand the process that people are proposing first, then go ahead and figure out how to make it work for you.
Epoxy is a good example of this IMO, once mixed you need to get it out of the mixing cup because it will heat up and set quicker and the goal is to have as much working time as is reasonable. However, you will also be told that pouring it on the cloth can make the cloth float up away from the wood .... so that seems like the only solution is to get a shallow tray to dump it out on and dispense it from there (and you will see that suggested).
This creates extra steps and more mess IMO .... instead I envision a 2 foot hull section and take a mixed batch and just pour a band of say ~1" wide epoxy directly on to the cloth, in a looping, back and forth pattern. Then use the roller to help distribute the excess around the area you have selected. If it is a bit heavy, spread it a bit further, if it is light, don't try and cover it all .... the trick is to just get it distributed, the roller or brush is just a distribution tool ..... the epoxy has to absorb and sink it on it's own.
The next cup is the area next door to what you just did, if you have area that is a little light, just add a dollop and distribute .... this is not like painting where you are trying to make it all even, you need to put enough epoxy to allow it to absorb, then later you are going to remove the excess. So don't worry too much about making it look even and pretty, it is more important IMO to keep it all moving ....
If you don't finish the entire interior before the first batch kicks (likely), just go back and squeegee the first section, add a section and go back and squeegee the next section, repeat till you finish the hull. You can be a little less precise with the timings after the first section and until you get the hull coated. You should be done with the hull and still have about half a hull to squeegee, which gives about the right timing for the last batch applied, but I basically time the first and last batches.
I did a detailed posting for my last build, which is aimed specifically at newer builders, to share what needs to happen along the build process, you may find some useful information there as you move along, it can be found here: https://www.canoetripping.net/threads/l ... ld.105054/
Good luck on the rest of the build
Brian