5200 or epoxy

[jclays]

Building 12ft skiff. Shoe String Shipyard "Frugal skiff 12'. Marine Fir plywood construction. Plans calls for epoxy as an adhesive in the joints or 3m 5200. The boat will be a paint hull sealed in CPES then paint. Tape (as per plan) joints. Walter Baron( Old Warf Dory) beds his joints in Silkaflex 291. What say you guys? Is one better than the other? Or is it user's choice?
Thanks in advance
Jim

[RodB]

Epoxy, period.

R

[pcford]

Pretty much user's choice. 5200 goes off slowly so that might be appropriate if takes a while to get the panels in place.

[Bob Smalser]

3M 5200 was formulated as a sealant, not a wood glue, but can work very well providing you can get some clamping pressure on it:

http://pic20.picturetrail.com/VOL12/1104763/7738131/103956078.jpg

Joints glued with 5200 also repair very well using epoxy, and any subsequent coating of glass and epoxy will stick to it:

http://pic20.picturetrail.com/VOL12/1104763/7738131/103956083.jpg

Where 5200 can fail badly is where it doesn't receive clamping pressure and the wood is subsequently saturated:

http://pic20.picturetrail.com/VOL12/1104763/7738131/103956088.jpg

So in assemblies that can't be clamped fairly tightly either with clamps or fasteners, 5200 is no substitute for epoxy, which only requires light contact to stick. The reverse also applies.....it's relatively easy to starve an epoxy joint with clamping pressure if the the joint has to be pulled in hard with clamps, and glues that can stand heavy clamping pressure like resorcinol or 5200 are probably a better choice for those assemblies. A subsequent epoxy fillet or glass tape will stick well to either glue.

[JimD]

These boats are framed and screwed which might allow you to get away with inferior glues. Unless your joints are perfectly flush I wouldn't use anything other than thickened epoxy. How perfect are your bevels? The online building guide for the Frugal Skiffs calls for epoxy and makes no mention of 5200.
http://www.shoestringshipyard.com/images/pr20.jpg

[RodB]

Epoxy, why consider anything else...???

R

[JimConlin]

Epoxy is more versatile, is easier to work with, has a longer shelf life and is a bit less expensive than 5200. I prefer 5200 only when i badly need its flexibility or when working with a material that it sticks to better than epoxy.

[James McMullen]

Yes, but then a nice, even bead of 5200 around your bare waist is a more comfortable and flexible alternative to epoxy when your belt buckle is broken and you're tired of having to hitch up your trousers.

Either one is pretty efficient at gluing your tools down to the workbench right where you set them after a long night of boatbuilding--think of it as an anti-theft measure.

[pipefitter]

It can be used with the belt/suspenders type builds that include fasteners but it is as messy or more so than epoxy and more expensive. If you aren't accustomed to working with it and don't have a forest worth of paper rags handy along with gallons of naptha, it becomes more apparent. It is right up there with roof cement with the mess factor. We use it daily in our shop and I still don't care to mess with it. That's the rigger's job. :D
I filled empty caulking tubes with thickened slow set epoxy and found the process trouble free and quite pleasing to work with in comparison, with all of the squeeze out easily scraped off and blendable with the following epoxy steps.

[jclays]

The instruction book you buy with the plans discusses the use of urathane glues or 3m 5200 as an alternative to epoxy. The designer says he uses it in his schools. These boats are framed and screwed which might allow you to get away with inferior glues. Unless your joints are perfectly flush I wouldn't use anything other than thickened epoxy. How perfect are your bevels? The online building guide for the Frugal Skiffs calls for epoxy and makes no mention of 5200.
http://www.shoestringshipyard.com/images/pr20.jpg

[jclays]

Using epoxy as an adhesive... Should it be thickened or used as mixed with just the hardner.. Sorry first time build.

[Thorne]

The previous two posts say "thickened epoxy". Are you looking for a vote or what?

;0 )

[jclays]

Dont be soo pissy.. Im asking because I dont know. Did you catch the "First time build"??
Thickened with what and to what consistancy?
Thank youThe previous two posts say "thickened epoxy". Are you looking for a vote or what?

;0 )

[JimConlin]

...Thickened with what and to what consistancy?...

For general bonding of wood, thicken mixed epoxy to mayonnaise consistency with colloidal silica (aka Cabosil or West System #406) or milled cotton fibers (aka 'flox' or West System #403).

[Cuyahoga Chuck]

The little pram in my avatar is held together by epoxy and glass. There are no metal fasteners. Well, I cut the skeg badly and used two screws to make it fit. When I am a mile or more offshore and the wind picks up I don't have second thoughts about the quality of my construction. I didn't "get creative". I built by the book. As long as that plywood tub stays upright I'm in pig heaven. I suspect that 50 years from now, given modest upkeep, it will be just as safe as it is today.

[boylesboats]

thickened epoxy is the answer... along with taped joints

[jclays]

Thank you for the input. I will use the thickened epoxy on my build and taped joints.

[RodB]

Do yourself a favor, get the latest Gougeon Brothers Book on boat construction.... (5th edition) and also get the System III manual that is free.

Mix for gluing with epoxy and cabosil... till it looks about like Elmers glue...only not quite that white. Don't be afraid of asking questions here, many will help you.

Remember, when gluing, apply unthickened epoxy first to the bare wood and let it sit for 15 to 20 minutes... then apply some thickened epoxy (cabosil, ie., silica) and clamp her together...or screw with sheetrock screws, or whatever... till the epoxy cures.

When applying a fillet, use 50% cabosil, and 50% wood flour to thicken to the consistency of Peanut butter.... use a properly radiused round tipped stick to achieve the size of fillet you require..and clean up excess with a putty knife.


If you need more information just ask away...

Good luck

RodB

[jclays]

Roger that and thank you for the info. I'll post as I go along.

[JimD]

Jclays, I almost always thicken with fumed silica, sometimes called colloidal silica (by WEST, cuz they like to sound different to justify their higher prices), sometimes under the brand names Cabosil or Aerosil. Its all the same stuff, more or less. One reason I like it is because it cures to a semi opaque milky colour and the glue lines will barely show if you are gluing brightwork or finishing a hull or cabin bright. Like RodB says, the colour can be matched quite well to whatever wood you are gluing up by adding a little wood flour (make your own from the dust catch bag from a belt sander) to the epoxy/silica mixture so that even the colour of corner filets blend in well with the bright work. PS - Don't mind that cranky guy. He's probably just jealous cuz you're starting a new build and he isn't :)

[jclays]

Sorry to revisit this thread again. But reading my new issue of Wooden Boat mag. Page 22 has an ad for Jamestown Distributors. In that ad they have "new" from West Systems a thickened epoxy adhesive already in a caulking tube and ready to go.. Any input or has anybody used this stuff.
Thanks
Jim..

[StevenBauer]

If you want to pay for the convenience it's fine. Some would rather save their building fund money for shiny bronze bits. :)


Steven

[Bob Smalser]

Sorry to revisit this thread again. But reading my new issue of Wooden Boat mag. Page 22 has an ad for Jamestown Distributors. In that ad they have "new" from West Systems a thickened epoxy adhesive already in a caulking tube and ready to go.. Any input or has anybody used this stuff.
Thanks
Jim..

Makes it real easy to skip the step where you prime the wood using unthickened epoxy first.

I can't think of an epoxy joint in new wood that doesn't require two coats of epoxy with a practiced eye watching in the time in between in case more priming coat is required.

While a forgiving glue, it's not as hard as many think to spoil an epoxy joint by starving it either by skipping the priming coat or leaning too hard on the clamps.

[mcdenny]

System 3 has a similar sounding product. The tube has separate chambers for resin and hardener; they mix as they twirl down the nozzle. I tried a tube of the System 3 product for gluing strips together. It worked fine and was much easier and less messy than mixing regular epoxy and daubing on with a brush or putty knife. Its really expensive though - it would have cost more than the cedar to do the hull. PL Premium was just as easy to use and much less expensive. Both glues are stronger than cedar.

[JimConlin]

Gosh! I just looked at the cost of that stuff. At Jamestown prices, it's $400/gallon, plus $2 per nozzle. I'll pay that much for Plexus when I need to. It does some unique things. Not for epoxy.

[James McMullen]

The System 3 auto-mixing epoxy in the caulking tube is incredibly convenient down on the docks when doing repairs and such, but it is definitely a more expensive materials cost. I sometimes use the cartridges on field calls, but use the conventional mix-it-yourself epoxy back at the shop.

[Raka025]

Do yourself a favor, get the latest Gougeon Brothers Book on boat construction.... (5th edition) and also get the System III manual that is free.

Mix for gluing with epoxy and cabosil... till it looks about like Elmers glue...only not quite that white. Don't be afraid of asking questions here, many will help you.

Remember, when gluing, apply unthickened epoxy first to the bare wood and let it sit for 15 to 20 minutes... then apply some thickened epoxy (cabosil, ie., silica) and clamp her together...or screw with sheetrock screws, or whatever... till the epoxy cures.

When applying a fillet, use 50% cabosil, and 50% wood flour to thicken to the consistency of Peanut butter.... use a properly radiused round tipped stick to achieve the size of fillet you require..and clean up excess with a putty knife.


If you need more information just ask away...

Good luck

RodB

I wouldn't trust sheet rock screws - those buggers heads break off at the most inopportune times. I like the green ceramic coated deck screws better.