Lets Talk Epoxy

[Raymond]

Let’s Talk Epoxy

We have used epoxy in composite layup, as an adhesive, as a barrier coating and as a surface finish foundation. We have used West Systems, MAS and ADTECH. We have learned a lot along the way and developed some opinions on materials and techniques. To round out our developing expertise, we are interested in your experiences, preferences and opinions on this subject.

What do you use and why do you use it?

What others have you used and why have you moved away from it?

What application method works best for you? Which ones have tripped you up?

If you have pics to help describe your processes, challenges and achievements, please post them.

[Yellowjacket]

One word... Raka...

They have normal and low viscosity resins as well as UV resistant resins for doing topside work, and their prices are most reasonable.

I've used the thinner resins and they wet out very well, and I've used both their slow and faster hardeners and have been very pleased with the results.

West System is expensive. A gallon of resin and .33 gallons of hardener will cost you $185 at West marine Raka sells a gallon and a half (6 quart kit) of resin and hardener for just under $100, and the UV inhibited kit is $110.

Their low viscosity resin is really thin, good for working on plywood or wetting out cloth to make it disappear.

Did my whole boat with them and am most pleased with the results. Good tech support and fast and reasonable shipping.

[ZUL8TR]

Back in the early 70's while working at a Marine Research company we used an epoxy that was a 1:1 no error mix for the inexperienced workers. Resin was a thicker white material like honey and the hardener was a stiff golden gel. Dried golden white. Great industrial strength product that we used for all types of marine construction from water tanks, flumes, pump sump pits, etc. I did use it on race boat construction/repair and it was a great product but NLA. Can't recall the name.

I have tried West, good but way to expensive and I don't care for the mix ratios and pumps, some error there if not careful and pumps not kept accurate. Tried MAS, also good, also expensive and possible mix ratio error issues as well. Presently use Clark Craft Epoxy Plus, 1:1 easy no error mix even for a very small amounts, also a very good epoxy, no amine blush, good wet out, more flexible than others, sands without clog, relatively inexpensive and have used it even after 3 years on the shelf (in dark closet) with no issues. Only disadvantage is no different hardeners for cure control but that can be worked around once you deal with it.

All I have tried have great adhesion, strength, and clarity and provide strength way beyond the strength of the wood. I use cabisil for strength thickener, and wood powder for non structural filler. No joint failures with any of these epoxies. For UV protect I have tried a many expensive varnishes like Petitt captian, Interlux, Epifanes, and others and have found Minwax Helmans gloss spar urathane varnish just as good and 1/2 the cost and dries quicker than the others used and buffable. Since these race boats sit out of the weather when not in use it is very adequate. Have not tried the auto clears, I like the rich amber look of the varnish for bringing out the wood grain.

As always to each his own preference for what works.

[Bill Huson]

WEST. Yes, pricey, but over the decades I have found WEST to be consistently foolproof. I have small batch gram scale for little mixes, and keep the pumps clean and working for large batches. I did try B&B Yacht's resin, a 2:1 mix ratio generic epoxy - fast hardener, slow hardener available. ran about $50/gal. B&B did not like cool, even inside the house with A/C running the resin would cloud up and jam pumps. Stuck stuff together fine but it was a PITA to use. Back to WEST for me. Note: anyone want 1 1/2 gallons (gal resin qt each slow & fast) of B&B? Free, you pick up.

My latest discovery in application is Peel Ply. After laminating fiberglass to a part I lay on Peel Ply and squeegee, saves weight and forget amine blush, won't happen, and after you strip the Peel Ply the epoxy surface is glue ready, no sanding required.

[Raymond]

Thanks for the lead Yellowjacket,

I went to the RAKA website ( www.raka.com ) and found it informative. It looks like a one stop shop for epoxy and composite needs. They seem to play up their low viscosity resin characteristics stating it has good flow and air release characteristics. The ADTECH I have been using is also supposed to be low viscosity but that term might just be relative because when compared to low viscosity paints or oils, low it is not.

I never gave viscosity much thought until just now; I am thinking I should be using a lower viscosity product when applying barrier coats as theoretically it will absorb into the wood fibers more readily.

One thing that I perceived with West Systems is that mixing ratios seemed to be very critical. I have ‘cooked off’ more than one batch faster than I could use it. The ADTECH seems to be very mix ratio friendly allowing plenty of work time when using their medium hardener. I did not really realize this until after using the ADTECH for a while.

The ADTECH costs are a bit higher when compared to West Systems whereas RAKA seems to be a few bucks cheaper. If all other variables the same I would say RAKA is the low cost leader. I may give it a try.

[Shane_B]

I've only used WEST but found it performs extremely well - found it cheapest so far at Discount Marine Supplies (http://www.discountmarinesupplies.com), a gallon of 105 and .33 gal of 207 is under $150 - much cheaper if you go for the 205 or 206 hardeners (plus they have occassional 10% discounts and free shipping offers). I have used WEST with micro-balloon (407) and graphite (427) fillers with good results. The reps at WEST gave me some good pointers, example, compatibility with various stains; use a atomizer with denatured alcohol and spray above epoxy to get rid of bubbles (warming up wood with a hairdryer prior to applying epoxy also helps...); etc. I haven't seen any failures of WEST epoxy, wood seems to break before the epoxy if joint is good. Anybody have any luck with System 3? Would be great if someone has access to several epoxies and conducts an unbiased comparison (sheer breakpoint, torque breakpoint, sealing, etc.)

[Team B&H]

West epoxy is much cheaper if you buy it in 5 gallon size containers direct from them in Bay City MI. Am not sure what their requirements are now for new customers but it is worth a try if you like their products.

Paul Pittman's dad worked in a testing lab for wood products and West was the standard they used but that was probably 25 years ago.

[PittmanRacing]

My father (Raymond Pittman) did perform tests on all available epoxies in a lab at Masonite Corporation. They were testing adhesion, penetration, durability, and contrasted it all relative to price. Bottom line, West was the standard, although one of the most expensive. Of course in two decades, products may have changed. West Systems became the benchmark against all which they tested.

[Yellowjacket]

I buy my fiberglass cloth from Infinity Composites

http://stores.infinityfrp.com/fiberglass-cloth/

They have cloths that are treated with a special sizing that makes them wet out very clear. That's what I've used and have been very pleased with the results. They have 4 oz and 6 oz cloth that is treated that way and if you are doing something that you want a clear finish on I recommend them. The Raka low viscosity resin and slow hardener will wet out totally transparent without a lot of effort or worry.

[Smitty]

Ed Karelsen was the big hydro builder in Reg. 10, outboards, inboards, unlimiteds, from the late-'50s until he retired (in the '80s, I think); he used System 3.

[ZUL8TR]

Interesting: I have a 1981 Karelsen 25ss Pickle hydro that I restored a few years ago. Mr. Karelsen constructed it with Weldwood Plastic Resin glue (powder and water catalyst) easily seen by under deck inspection. The boat was in excellent shape and no failed joints when I got it. I know epoxy was available in the 80's so possibly cost was a factor and the glue joint strength was not an issue to him as time has proven? One thing for sure using Weldwood type glue requires real good joint carpentry as witnessed in this 1981 hydro, and projects I have made that required joint accuracy for excellent bond like for my avatar and still running.

I am not discounting epoxy great stuff, as noted in above post I use it.

[Dave M]

I prefer West System, no sense in re-inventing the wheel.

System 3, I used to build my very first boat many years ago, a Sorenson Kit. Darrel provided System 3 with the Kit. I was cluseless on epoxy at the time. It worked great. Of the three or four boats I built using it, all survive to this day. Only had one issue with it and after calling them we straightened out the problem reasonably.

I have tried a few differnt brands and always fall back to West.

[brboatbuilder]

I had the good fortune of attending a series of six weekly evening programs/classes at the West factory in Bay City before I left the snow belt. (The class built six Optimist sailing prams for the local Saginaw Bay Yacht Club.) Our instructors were the technical staff members from West. They taught dozens of tricks and techniques which are nearly all outlined in their "FREE" literature. Since then I have tried other epoxies, but keep returning to West which I generally order from Defender. The best improvement I can suggest is to transfer the resin to clear poly "ketchup" squeeze bottles which I buy at Walmart and store in a dark cupboard when not in use. And I picked up a used Ohaus triple beam balance, as used in highschool chemistry labs before electronic balances tool over. It is easy to use and rugged and NO batteries. They can be found on eBay. I have never mixed a bad batch with this setup. I can mix as little as I need, down to less than half a teaspoon accurately or up to a quart. I do use the slow 206 catalyst because I'm slow also!

[kampkurz]

I am a big West System fan. I know there are others but I like the way West System has offered up tech to me and even overnighted a users manual to me. I did not even ask for the overnight...I was working on a radius'd support beam for a porch.... But thought that was pretty fine. I have been using the digital scale the they offer for making small batches with deadly accuracy. I found that I get all those 'little' jobs do e right away instead of waiting for left over epoxy from a larger job. Covering fabrics with shower curtain that I get at the dollar store, and then squeegieing is the best tip I've been given yet. Works just like stated above, and is very inexpensive. I am sure the other brands are good to but I see no reason to use anything but West. Shop around for a deal. I have seen Jamestown put the resin on sale for $80 a gallon.

[Smitty]

ZUL8TR, I guess I should have specified that WHEN Ed started using epoxy, System 3 was what he told me he was using.

[ZUL8TR]

Ok, I did not know that. BTW since System 3 didn't start epoxy manufacture until the latter 1970's Ed Karelsen used Resorcinol 2 part glue, nasty black formaldehyde stuff on his 1967 Miss Bardahl, 1968 Miss Budweiser and 1969 Notre Dame. Other builders probably used the same stuff. Interesting that in 1981 when Ed built the Pickle hydro I have he used the Weldwood when System 3 was available?

[Mrs blueskyracer]

What I know is that I should of purchased stock in West System before we ever started running boats and I might be rich now!

[bill boyes]

We could go on and on about Epoxy and what is best. Frankly they are all good.
I use System 3 because i bought a Sticky Stuff Model B pump keyed to 2 to 1.
I have used the small pumps with the gallon jugs etc. The Model B pump has saved me $$$$ because I can make small amounts for small jobs. Epoxy is expensive so less waste is desired. I like West System but at 4 to 1 it just does not work for me with my Model B Pump. Note that I use nbr 2 Hardner. I cannot handle nbr 1 ( too fast even at 30 degrees in the shop ) and nbr 3 is too slow. Again it is all good.

[Smitty]

FWIW, the tech experts contributing to WoodenBoat magazine say that resorcinol is the "strongest" method, with a bond that is both mechanical and chemical. But how much stronger does the joint have to be, when good old Weldwood powder makes a joint that will rip the wood loose? Resorcinol has a couple of advantages, one being that it's a better gap-filler when the joint match-up is imperfect, and it is waterproof rather than merely water-resistant. But it leaves a black line at the joint edge, where the powder glue is a good color match for the woods generally used in raceboats.

The great thing about epoxy as a glue is that you don't have to go back and figure out how to seal the remaining bare wood after you've put the deck on. I remember pouring a gallon of pentachlorophenol (about equally toxic to dry-rot bugs and humans) into one side of a newly-built hydro, holding the boat upside-down with a helper, sloshing the brew around with the boat held at various angles so the stuff would get into all the corners, and then standing the boat on its transom and draining all the excess out of the drainhole and into a container . . . . and then doing it again on the other side!! Of course, fifty years ago we were too young and dumb to wear rubber gloves or any other protection when using that stuff (now prohibited) or lacquer thinner, Stoddard solvent, xylol, etc., etc.. When we finally croak, we won't need embalming.

Someone later told me the way to avoid this is to just "paint" the Weldwood glue all over the underside of the deck panels as you get ready to nail them on. Now you do it with epoxy.

[ZUL8TR]

When I visited his shop back in the 1970's I asked Harry Pinner what he used for the deck underside with his epoxy glued hydros - cured Polyester resin wiped with acetone to remove wax, epoxy adheres to it very well.

[CSR4C]

In the '70s when I lived in the cool NW I used Weldwood glue, worked fine, cleaned up with water. When I moved to CA in 1980 I switched to System Three, they were in Richmond CA at the time. I have used it ever since. The only time I used west system was at someone else's shop, did not like the smell.
When repairing boats built with Weldwood in hot day CA, most of the time the glue had dried up to a power and held nothing. One time restoring a Lauterbach I had to take it all apart and reglue everthing.