When to epoxy
- Thread starter funbun
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Bun, You will get LOTS of different answers for this one. I put a soaker coat of epoxy on the boat prior to glass. I do this because I think it makes it easier to wet out the glass if you don’t have to soak the wood at the same time.
Others will say to just wet out the glass over dry wood. Either method will work. I just have a problem with the later method. I tried it once and it seamed to me that it was harder to get the glass wet out. I wound up using a lot more epoxy than I do if I pre-treat the wood. That’s just one mans opinion.
As far as glassing the inside, just putting an epoxy coat helps but, the glass gives so much more strength at so little “extraâ€Â
Bun, You will get LOTS of different answers for this one. I put a soaker coat of epoxy on the boat prior to glass. I do this because I think it makes it easier to wet out the glass if you don’t have to soak the wood at the same time.
Others will say to just wet out the glass over dry wood. Either method will work. I just have a problem with the later method. I tried it once and it seamed to me that it was harder to get the glass wet out. I wound up using a lot more epoxy than I do if I pre-treat the wood. That’s just one mans opinion.
As far as glassing the inside, just putting an epoxy coat helps but, the glass gives so much more strength at so little “extraâ€Â
You need to epoxy saturate the boat before putting on the glass , the epoxy soaks into the wood and gives the epoxy you will put on the glass something stronger to bond to plus it helps to protect the wood if you get a scratch threw the glass and into the wood when paddling.
Make sure you lightly ( by hand) sand the boat to remove the whiskers ( small wood fibers that fill with the epoxy and like to stand up) or you will put some runs in the glass when you lay it down.
I have built boats both ways , glassed out side and epoxy saturated on the inside without any glass , or glass both the outside and inside ... that will give you a stronger boat. I prefer glassing the whole boat. This way it is glass encapsulated and totally protected.
If you don't glass the inside then glass the area where it will receive the foot traffic , the paddler getting in and out of the boat , this is for added wear and tear protection of the wood.
Chuck.
Make sure you lightly ( by hand) sand the boat to remove the whiskers ( small wood fibers that fill with the epoxy and like to stand up) or you will put some runs in the glass when you lay it down.
I have built boats both ways , glassed out side and epoxy saturated on the inside without any glass , or glass both the outside and inside ... that will give you a stronger boat. I prefer glassing the whole boat. This way it is glass encapsulated and totally protected.
If you don't glass the inside then glass the area where it will receive the foot traffic , the paddler getting in and out of the boat , this is for added wear and tear protection of the wood.
Chuck.
Funbun, I've written this before, but it bears repeating. Yes, saturate the the wood inside (and any wood you will glass) with epoxy and let it dry before you glass. As Chuck says, hand sand off the whiskers or feathers that will otherwise grab your cloth and be a real PITA.
Glass both inside and outside for hull integrity. That's HULL INTEGRITY. When (not if) the boat runs up on a rock, stump, whatever and the wood gets bent inward, you do not want to hear a CRACK!
When in deep water, windy conditions, rain blowing in your face, paddling nearly blind and praying pretty hard, you hit an obstacle you do not want to hear a CRACK!
When crossing a beaver dam, log, shallows with rock and gravel with a fully loaded boat, and it gets hung up. You take hold of a gunnel and start to rise, placing all your weight on one foot, you do not want to hear a CRACK!
There are other scenarios, but the last few words is always the same.
Glass both inside and outside for hull integrity. That's HULL INTEGRITY. When (not if) the boat runs up on a rock, stump, whatever and the wood gets bent inward, you do not want to hear a CRACK!
When in deep water, windy conditions, rain blowing in your face, paddling nearly blind and praying pretty hard, you hit an obstacle you do not want to hear a CRACK!
When crossing a beaver dam, log, shallows with rock and gravel with a fully loaded boat, and it gets hung up. You take hold of a gunnel and start to rise, placing all your weight on one foot, you do not want to hear a CRACK!
There are other scenarios, but the last few words is always the same.
If you work within the guidelines of the manufacturer, you can put the glass on "wet on wet"
What that means is not exactly what it sounds like.
For example, your previous coat of resin needs to be at least tacky to touch dry before the next coat. There is a curing period after the resin has become touch dry. With West Systems, that period is 12 hours. You can apply successive layers of resin without sanding if you do so within that 12 hour period. This will also give you the strongest bond - a chemical bond. (less chance of de-laminating)
Outside that curing period, you need to sand and ensure that your sanded surface is spotlessly clean before applying the next coat. This will give you a mechanical bond. (still very good).
I like to apply successive resin coates and filler coats within the successive 12 hour periods with a light scraping in between to remove any lumps or bumps in the resin. This way, I can completely fill the cloth with no sanding at all.
8)
What that means is not exactly what it sounds like.
For example, your previous coat of resin needs to be at least tacky to touch dry before the next coat. There is a curing period after the resin has become touch dry. With West Systems, that period is 12 hours. You can apply successive layers of resin without sanding if you do so within that 12 hour period. This will also give you the strongest bond - a chemical bond. (less chance of de-laminating)
Outside that curing period, you need to sand and ensure that your sanded surface is spotlessly clean before applying the next coat. This will give you a mechanical bond. (still very good).
I like to apply successive resin coates and filler coats within the successive 12 hour periods with a light scraping in between to remove any lumps or bumps in the resin. This way, I can completely fill the cloth with no sanding at all.
8)
Funbun, I wet the plywood with epoxy then I lay the glass directly onto the wet epoxy. Then I add more epoxy on top of the glass to make sure it "wets out" properly. Then I let it cure long enough to stiffen up before I add more epoxy to "fill the weave".
After this, I let it all cure until the next day, then I will wet sand the epoxy -- taking care to NOT sand into the glass -- because sanding the glass weakens it, and if I'm using it for strength I want it as strong as possible.
If I haven't used enough epoxy to sand it without cutting into the glass, I add another layer of epoxy before I start sanding. The idea here is to never sand any glass, and only sand as much epoxy as you have to.
Some builders plan to not glass the inside of their boats. This can be a bad mistake. When, not if, a boat - especially a flat bottomed boat - gets hung up on an underwater object (rock, stone, stump, etc.) the wood will bend inwards.
THIS IS A CRITICAL TIME in the life of the boat. If the inside is glassed, the wood is MUCH less likely to break wood fibers into splits and splinters. An unprotected boat floor is easier to break than a protected one. Do your boat, and yourself, a favor. glass at least from the waterline down on the inside of your boats.
THIS IS A CRITICAL TIME in the life of the boat. If the inside is glassed, the wood is MUCH less likely to break wood fibers into splits and splinters. An unprotected boat floor is easier to break than a protected one. Do your boat, and yourself, a favor. glass at least from the waterline down on the inside of your boats.
Has anyone thought about glassing the inside of the boat after you rough cut the panels, and then assemble perinstructions?
Always glass the inside to a little above the waterline when loaded heavily. When the boat runs up on a snag and gets hung up, the wood can get bent inwards badly. Without glass on the inside, it can split badly. May even split a bit with glass if wrestled around trying to get loose?
Now, I've never run up on a rock, log, or beaver dam - but have read of those clumsy clods who have. ;-)
Now, I've never run up on a rock, log, or beaver dam - but have read of those clumsy clods who have. ;-)
YES... Others have tried it and later said it was not that good of an idea.
The consensus was that by glassing the panels before assembling them made the panels harder to bend and shape when attaching them to the ends. In plain language it really stiffen up the panels so they were not as flexible as the plain UN-glassed wood.
On the plus side .... It made glassing the inside of the panels a lot simpler and easier then glassing them after they were installed.
Sort of a six of one and a half of a dozen of the other sort of thing.
I was still sleepy eyed when I read it the first time. Glass AFTER your boat is assembled. Thanks for catching that, Chuck.
Heck Jack , Ya just got a little ahead of the build by trying to make sure he builds the boat correctly for his safety.
Well, actually, I was more concerned about the boat's safety, Chuck. Paddlers like us are a dime a dozen. But! A good boat - there is a thing to be revered.