Preferred epoxies

I'm curious as to what is the preferred epoxy by the boatbuilding community. I started my first boat with West System because the is what the local supplier carried. Personally, I think it is great stuff, but a little pricey. I did some looking and found www.raka.com. Substantial decrease in price. Another builder on another thread switched to MAS for the same reason. I ended up doing some price comparison and hear are the results.

West System 61.00 / gal.
MAS 56.00 / gal.
USComposites 31.00 / gal.
RAKA 48.00 / gal.

I tried to compare pricing based on a 3 gallon purchase. West System was closer to a 4 gallon purchase. USComposites certainly wins out on price, but has used it and if so, how in it tho use. Is it, "You get what you pay for."? Their thin resin is said to be semi-clear. Is that going to negate using it for brightwork? Their thick was said to be too thick for a quick wetting out of cloth. I still like to use West System 207 for bright work anyways.

I'd be interested in comments on the other products as well. What other epoxy systems are out there that I have missed?

I've been using RAKA for everything, but brightwork. I don't use the fast hardener because it goes off too fast for me. The slow hardener is very workable and I use it exclusively.

Curious about the othe products.

 

EPON/us.composites

2 years ago I bought a gallon of US.Composits thin resin with medium hardner. It was winter time and the shop was heated to around 60 degrees. I ran the heat up to 70 and did a test pot. I bonded some osage orange, 2 layers of 6 oz glass to A/B foam, and glass to osage orange. Also did a 6 oz glass strip, epoxy poured into a strip, and left about 8 mm in the bottom of the plastic cup.

Left the heat at 70 and came back the next day. I was suprised that the epoxy had not fully hardened. The heat was too low. (probably was not a true 70) Brought the sample back home and put them on a heat radiateur. There is a stronger smell than West System. It is not offensive or over powering ... if the room is not small and confined.

A few days later, I sawed, cut, pounded on the samples. It was a tough resistant resin.

The next year when starting my project, I order 55 gallons of the Thin and 55 gallons of the thick (thinking it was the same stuff as the thin, only thicker ... It isn't) Bought Fast and Medium hardners to go with it.

I am still quite statisfied with the thin. It is epoxy like the other thin epoxies I have used. Silica mixes quickly into it. It wets out glass instantly. Sets in the same way. It does blush a tiny bit. Water cuts the blush. I was getting "fish eye" on the second coat even after sanding, so I wiped the pannel with MEK between coats of resin. No more "fish eye"

The thick doesn't seem to blush. It bonds cypress well. I used it for bonding strip planking. the bond is stronger than the wood (destruction testing). It cure funny. It sets then goes hard ... but brittle. With time the resin continues to cure and becomes tough and not brittle. This fast solidification makes it excellent for bonding pieces because 2 hours later I can unclamp, move and cut or grind on it. About 3 hours before I can sand it. the thick does not like cold weather below 70 degrees do not use it.

These resins are from EPON. I have not researched which hardner uscomposits is selling with it. google EPON for the corporate web sight with lots of information on their resins.

My 1 cents worth.

 

uscomposites

Here is the link to my source for USComposite. http://www.uscomposites.com/epoxy.html
Is this the same product you used. The blush washes off? Do you get a good clearcoat with it?

 

Yes the blush is very thin. When I rub my finger on the cured thin epoxy, like on a plywood pannel, it feels a bit greasy. Then after a quick rub with only water and a few paper towels, rubbing it with my finger makes a squeeky sound like on freshly washed windows.

The white paper towels come out orangy color from the blush ... so it is not dirty oily hands. smile.

after washing, I sand with 80 grit or 180. Then I flow coat the pannels to fill in the weave. For some reason, I got occasional fish eye when the resin started to cure. Wiping with MEK did away with most of it. There seems to be some tiny bubles in the cured resin. Can not be out gassing, because it occurs over glass.

The resin is as clear as West 105 or 205 (forgot the numbers). The coats look nice and glossy but they are not perfect. My shop is full of dust, and I am going to paint everything on my boats interior, so No, I would not use it for a top clear coat. If you wanted to do a build up before the final coat. The thin or thick resin would work well.

Yes the link is the same place I buy from. If your interested order a gallon and compare it. I am using it in hand layups of uni and biaxel glass over wood. No vacume bagging or infusion. This is my limited experience.

 

Hey LP,

I'm planning on purchasing everything I need from the same guys who are selling me the plans. http://www.boatbuildercentral.com/

I have a buddy who can get construction supplies wholesale. I'll price everything out in the next week or two and where prices end up.

 

Epoxies

I get the impression that any of the marine epoxies available perform as expected or predicted. I expected some criticism of sorts, but haven't really heard any. There is quite the ranges in pricing of products. Fortunately, it looks as if more expensive is not necessarily better. Any dissension in the ranks? I can't see paying more if there is no benefit.

 

Well, couple months ago I was asking the same question on epoxies. After that time I have done lots of research and by pure luck I have hit a high school friend of mine who is a cost accountant on an epoxy company. Actually there are only a handfull raw material manufacturers in the world and all the marine brands are buying their raw materials from these factories and making their own mixes. At tops 4 $ per kg of mix selling price will give to any of them a great profit margin. But because it is called MARINE and as being classified as HIGHTECH boat building material of our time with lots of advert and marketing gimmick it is on the market with the prices of what learpilot have mentioned above.
I have got my materials through my friend, from his company, as his own need so I did not have a problem with the prices.
I just wanted to inform you guys on the subject

 

From what I read, EPON is one of the big producers. They sell there resin by the railtanker load. They do not sell direct.

 

Epon Resin

Have used Epon resin made by Shell in composite aircraft fabrication. The local salesman said it is a base product and sometimes mixed with other material to produce marine paints. I remember there are several hardener that can be used. It is of good quality but you have to buy in bulk, say a 55 gallon drum.

 

Epoxies

I used to work in Uk selling for International Paints(Interlux for you yanks) and was selling/trying to sell Epiglass epoxy to builders.

There isn't huge differences between all the suppliers. It depends what you are used to and what you are building ie epoxy/wood or epoxy/composite. Are you wanting lots of different hardner speeds, wanting long working time, fast cure, no sweat etc etc.

All have pluses and minuses depending on what turns you on.

Yep price is important but so are stuff like support, availability. friendliness of rep .

I came down to conclusion, it was like women. Some gentlemen prefer blondes, some brunettes etc.

ps i did ok. I sold some, I got laughed out of other yards.

 

I started to use in 1966 epoxies when a guy from the garage hijacked my corvette to impress his girlfriend and collided with a lamppost. Since the insurance company refused to pay for the damage, I started to look for a repair shop. Even in yachting, fiberglass was not that common, and the majority of bodyshops chased me away.
A business relation that was working on some mysterious projects, brought me two cans of liquid, together with some sort of little manual.
The material was called Araldit and it came from Ciba-Geigy. At the same time I glued an antique washbasin that the plumber broke, baked it in the oven and it still holds after 40 years. The car was repaired, after a weekend of careful work,
and I could bring the car to the bodyshop to be sanded, faired and sprayed.

Since that time, I have used many different kind of epoxies, and yes, they have all the same flaws and no, they are all different. The best but most difficult to use epoxy was undeniable SP, followed by Araldit. Very good working properties were ofered by a local shop in Amsterdam that sells their own brand and that is simple to use, even forgiving in some cases and has no tendency to seep away whilst the curing process starts.

I learned from the Ciba-Geigy factory that epoxy can be formulated as just as you like to have it.

So, whatever your observations are, they might be all true.

However, there are a few basic rules:
1 - they are sensitive to moist;
2 - they are sensitive to draft;
3 - they require a stable bonding temperature between 22 degC and 24 deg C for regular curing;
4. Bonding specs can be improved at higher bonding temperatures;

Epoxy is not cheap. The rising oilprices certainly won't improve the pricesetting of the stuff.

Last but not least: Bonding, glueing is an irreversible process. When it goes wrong, it goes wrong.
Whatever you do when you work with glues, prepare yourself and the materials you want in the process.

 

Epoxy

I'm looking at purchasing some USComposites epoxy. I believe it is their 635 thin epoxy. Has anybody used this with the slow, medium and fast hardeners. I currently use RAKA epoxies and find that their slow epoxy suits my my needs well. I curious if anyone has used both RAKA and USComposites and could offer a comparison. Also, Has anyone used their color additives? Would this be a good option for bottom paint? (trailered boat) Is the coloring dense enough to provide an attractive finish and would it also provide the required UV protection?

I've used both West System and RAKA. I like West better than the RAKA. The price just kills me though. West goes through more definite stages than RAKA. The transition from liquid to solid is more defined. RAKA starts out fluid and just keeps getting thicker. For me, it seems like the thickening process starts immediately and is a gradual continuous process. It gets pretty gooey before losing it's tackiness. The fast hardener goes to goo extremely fast and thus I only use the slow hardener.

I feel the West system mixes thinner and remains thinner until it starts to "go off." I think that it wets out glass a little quicker. Maybe because it is thinner. I believe the West fast hardener has a longer work life that the RAKA slow hardener. It's been a while since I used West, but that was my impression when I first switched RAKA.

West also cures harder, at least initially. This observation comes from the pot cleaning process. This happens anywhere from 24 hours to days after mixing and I pull the residue out of the pot in preparation for further glueing. West is generally harder and is more brittle that RAKA. i.e. Raka is more likely to bend than break. That should be a good topic for further discussion. With substance will be more durable? Hard? Soft? Rigid? Pliable? ETC.

 

Have the fast and slow hardners.

For flow coating (a thick coat all at one time) I use the thick resin and medium hardner. Have tried the thin for this also, but do not get a thick enough coat to fill the weave.

Both resins from us compositis are like west in that they will flex in the pot but then break. The medium hardner smells just like west slow hardner (as best as I can remember.

When I use the thin to wet out 10 oz uni and bi axel glass: I have time to pour on a small batch and swipe it with a squeegy. I can do this process twice in succession before the first pour and swipe has turned the glass clear. Works well for me.

It will also wet out 4 to five layers of glass at a time. takes a bit longer for the resin to get down to the bottom layer.

No nothing about their pigments

 

I just like it...

Just my thoughts on the issue:

I build wood composite boats in both cedar strip and cold molded methods. I have been using West System products for about 8 years and have had really good luck with them. I must confess that I have often thought of buying the less expensive alternatives, but I am so comfortable working with the West System, that I never changed.

It costs a little more (well, sometimes a lot more), but I have never had a problem, always get good bonding, can harden at any speed / temperature, can color, can finish clear, and never have "blush" issues.

I agree with the comment above, just go with what you like.

Stephan Bradley
Bradley Boatworks

 

Pigments

In response to my own question, I talked to a USComposits rep and was told that the piment only provides a minimal amount of UV protection. Basically, the epoxy still needs to be painted to get the UV protetion that it needs.