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Re: Barrel Back Build

Posted: Sat Jul 20, 2013 5:29 pm
by John56
Well, taking advice from Carl, I re-read everything again and it seems that the "fine wood worker" in me misunderstood "Laps". Looking again I see that the boards are just layed against each other, not half-lapped like traditional woodworking.
I also read some more and learned that notches in the frames come later.

Oh well. I promise more questions goofier than this will follow........ :)

Re: Barrel Back Build

Posted: Sat Jul 20, 2013 6:08 pm
by Bill Edmundson
John

Ask away. We'll answer best we can. Don't worry, somebody else has the same question. I may answer only to find that someone has a better way. We all win!

Bill

Re: Barrel Back Build

Posted: Sat Jul 20, 2013 6:47 pm
by mrintense
John56 wrote:Well, taking advice from Carl, I re-read everything again and it seems that the "fine wood worker" in me misunderstood "Laps". Looking again I see that the boards are just layed against each other, not half-lapped like traditional woodworking.
I also read some more and learned that notches in the frames come later.

Oh well. I promise more questions goofier than this will follow........ :)


My frames are getting everything except the notches. That includes encapsulating them in multiple coats of epoxy. Only the edges of the frames remain bare for now as well as the top edge of the floor timbers.

I did cut batten notches in my transom frame (but not sheer or chine notches) for two reasons. First the batten notches need to be angled to match the transom angle which I also cut. Secondly, they set the location of the battens from centerline. My thinking is that once I get the frames mounted to the building form and after I have completed the chine and sheer, I don't want notches on all the other frames in case they are not in the right position. Better to set the location at the transom and then see where the battens cross the other frames. Then I can cut the notches in the correct locations.

Re: Barrel Back Build

Posted: Fri Aug 02, 2013 6:32 pm
by John56
Ok, a pic of my first frame. Second one is almost done. Can someone tell me about the "blush" or whatever it is on the surface of epoxy?


Image

Re: Barrel Back Build

Posted: Fri Aug 02, 2013 7:14 pm
by mrintense
John56 wrote:Ok, a pic of my first frame. Second one is almost done. Can someone tell me about the "blush" or whatever it is on the surface of epoxy?



I am not sure of the technical description of what the blush is, but it should be removed before sanding or applying additional coats. I originally tried using alcohol on this but it didn't work. I found out later that the correct way is to use warm soapy water and then wipe with fresh water and dry.

So what I have been doing is to have two bowls of warm water, one with a bit of dish soap in it. I use a regular dish sponge (the kind with scotchbrite on one side). I will go over the blush with the soapy water using the scotchbrite. Gentle scrubbing is sufficient. Then follow up with wiping down with fresh water and paper towels. Then dry. Then sand to smooth (if you want to do that). Sanding lightly will help the next layer adhere better.

Wipe again and then dry once more. It's a bit of a pain but I usually do that, then come back in an hour and apply the next coat of epoxy. On the last coat just use the sponge side when washing and rub a bit more.

The process is pretty effective, if not a little time consuming..

Two other things. The drying process will leave a small amount of paper towel lint that should be brushed off. I found using my hands works best for this (as long as they are clean).
Secondly, since washing will get water everywhere, I like to raise the part off the table with small blocks. And you should coat both sides at least once before washing too much to avoid water soaking into the wood. Otherwise you have to let it dry out before you can continue.

There may be better ways to do this, but this is what I did and it worked for me.

Re: Barrel Back Build

Posted: Fri Aug 02, 2013 7:25 pm
by Bill Edmundson
Amine blush is a waxy film that develops on some epoxy. It usually occurs in cooler humid weather. Paint and the next coat of epoxy won't stick to it. The exception is if you recoat epoxy as soon as the first one is dry to the touch but still "green".

Carl is right simple soap and water will wash it off.

Some brands of epoxy say they don't blush.

Bill

Re: Barrel Back Build

Posted: Thu Aug 08, 2013 2:55 pm
by John56
I asked about encapsulating frames on the woodenboat forum, and got this reply. Now I'm really confused....

T-88 is of a viscosity that makes it perfect for an adhesive, but not particularly useful for coating, fiberglassing or laminating.

I don't know what vintage your Glen-L plans were, but many of them are a bit older and don't incorporate all of the state-of-the-art that is known today. "Encapsulating" frames made out of timbers as big as that is an unobtainable and counterproductive goal. Wood that thick should be sealed and painted with a proper marine paint or a spar varnish. You cannot "encapsulate" it in epoxy in the long term. Much better to use a more flexible paint that is compatible with the wood movement from moisture and temperature cycling than just coating it with a brittle film of epoxy that will eventually fail with microfractures that let in enough moisture to create a spore-friendly microclimate inside the hard candy shell.

Re: Barrel Back Build

Posted: Thu Aug 08, 2013 3:17 pm
by Bill Edmundson
Where did that blurb come from? I haven't seen it before. We have many, many boats encapsulated with epoxy. Wooden Boats tends to be very purist. They look down on us. But, few of them really know a lot about their boats.

Their boats tend to be restorations. And, they're right in that case. The old boats should not be encapsulated. They all think a 3M5200 hull is the great fix. But, it seals water in also.

Bill :?

Re: Barrel Back Build

Posted: Fri Aug 09, 2013 4:13 am
by Bob Perkins
I "encapsulated" by frames during my build and was not a fan of the process or how they looked. It is pretty hard to not have runs, sags, etc. and when you are done - you have to (or should!) then varnish over the epoxy to keep it from breaking down in UV (sunlight). To get the varnish to stick - you really need to sand the surface for a good mechanical bond. It was too much work and too time consuming.
The Frames were the only thing I encapsulated with standard 2 part epoxy.

I used CPES after that. My interior got fully coated with CPES and then ~4-5 coats of marine varnish.
- The CPES penetrates into every little corner and seam - it is epoxy and *encapsulates* and a microscopic level.
- It goes on with a brush and is as thin as water. You can really get in everywhere very fast. There are a lot of corners inside these boats.
- CPES is a primer for any coating going onto it. Varnish sticks tenaciously. I sprayed the varnish on my interior.

This combination is more flexible than standard encapsulation an there is no chance of crazing that allows water to get under the finish.

I've had plenty of water in my boat and there is not even a hint of intrusion.

FWIW: My deck had the same process. Except stain first, then CPES, then many layers of varnish.
I do not see the need of epoxy and glass over the top. I didn't want to take any chance of UV causing any issues with the epoxy and ruining the finish.

Finally - you can do an entire boat with a 2 gallon CPES kit with plenty left over. I'm certain that can't be said for any of the 2 part epoxies. So the final cost is better too.

I use CPES as a primer for any wood that may see water.
HTH

Re: Barrel Back Build

Posted: Sat Aug 10, 2013 5:24 pm
by John56
Still thinking about encapsulating.

But, I did finish my 4th frame today. Woohoo!!

Now I start tracing the left side of the large lay out drawing. Frames 3 to Transom.

Re: Barrel Back Build

Posted: Sat Sep 07, 2013 5:43 pm
by John56
Finally, all the frames are made, and the transom. Question.
The plan says to add a "Doubler" to forward part of transom on top. What is a Doubler?

Re: Barrel Back Build

Posted: Sat Sep 07, 2013 7:27 pm
by mrintense
A doubler is essentially another piece of structure added to the frame to stiffen it up. Not sure of the exact place you are talking about, but if it's the plywood , then a doubler would be probably another piece of plywood (or possibly hardwood).

Another way of looking at it is the consider the gussets on your frames. They are a type of doubler for the frame joints.

My boat will have doublers alongside the inner side of the cabin walls near the aft cockpit to help stiffen up the plywood making up the "wings"

Cabin Doubler.jpg

Re: Barrel Back Build

Posted: Thu Oct 10, 2013 5:25 pm
by John56
Pics coming soon. Frames made, stem made and stringers almost done. Got 5 pounds of Colloidal Silica yesterday. Free. We use it at another sister plant, and never knew it!! Didn't steal it, it was scrap as they use about 4 tons per month.

Re: Barrel Back Build

Posted: Tue Oct 22, 2013 3:20 pm
by John56
Frames done, and laid them on the stringers just to remind me that I'm building a boat!!

Still need to trim stringers to length and notch them for the frames.

Dumb question number 8. Are stringers temporarily bolted to form 2x4 uprights?

And yea, shop is getting a little crowded.....

Image

Re: Barrel Back Build

Posted: Wed Oct 23, 2013 4:35 pm
by John56
Was my dumb question really that dumb.....?