epoxy resin

[1962 31]

has any one used aero marine epoxy before seems inexpensive was wondering if any body has any experience with it
www.jgreer.com

[JP Dalik]

Ditto.

That pricing for Epoxy looks awesome, I like the 2-1 mix.

Downsides...........anyone

[scot]

Those prices are Ok-to-normal. There are several companies out there that sell epoxy resins at that price range. The West System pricing is all about marketing and packaging (IMHO) so don't let those lower prices spook you.

Check out these guy's, I have used their epoxies extensively and have zero complaints. www.fgci.com

[CaptPatrick]

I've never used this system, but have been using a wide range of epoxies since the early '70s. Everything from off the hardware store shelf Devcon type 1:1 tubes, to "high performance" Gougeon, (West System), 5:1 systems.

Applications include: Bonding, (gluing two items together), Layups with fiberglass, inlays, anchoring, & encapsulation. These applications with an almost endless list of associated materials.

From this, there is a short list of things you need to know about epoxy systems:

1. Epoxy is epoxy. There are only a few chemical companies in the US that formulate epoxy resin, DOW being the largest. Everybody selling epoxy systems is basically getting their resin from the same few sources. The only key factor in buying from a seller is being sure that the resin is in the form of 100% solids. (Some low end sellers have been known to cut the resin with liquid fillers to stretch the volume.)

2. Hardeners make the difference. As opposed to resins, epoxy hardeners are manufactured by a larger number of chemical companies. In most cases, a hardener that works for brand X system will also work for brand Y system, as long as the intended hardener ratio to resin is used.

For example, if system X is a 3:1 ratio system & system Y is a 5:1 ratio system, system X's hardener can be used with system Y's resin so long as the ratio is maintained at 3:1. Same in reverse, X's resin with Y's hardener at 5:1

3. The speed of a system is dependant on the hardener chemistry, never by the volume of the hardener. Adding or reducing the volume of hardener in the designated ratio does not speed or slow the time needed to cure the mix. It doesn't work the same as polyester/vinylester systems where more or less MEKP will affect the set up time.

You MUST maintain the designed hardener ratio within a very narrow window. A 3:1 hardener mixed at a 5:1 ratio will result in a soft rubbery and much weaker cured material. NFG!

Slower hardeners will yield the least amine blush, fast hardeners will produce the most amine blush. Amine blush is the result of free amine molecules that did not cross link with resin molecules and rise to the surface of the cured mix. Amine blush leaves an oily feeling surface layer & will act as a release agent for sucessive coatings. It must be removed before re-coating. The good news is that the blush can be easily removed with soap, water, and a scrub pad.

When you want to add multiple coats of epoxy, (encapsulation for example), and won't need to sand between coats, add sucessive coats before the previous coat cures beyond a tacky stage. The free amine from the earlier coat will be absorbed into the new coat without affecting the bond strength.

A slight off ratio mix can, however, sometimes be to your advantage, but I'll leave that discussion for a later time...

4. Price does not indicate quality. Quality is dictated by the purity of the material, (100% solids). Price is largely dictated by the expense that the seller incurs to market the material. Gougeon is one of the largest sellers of "Marine Grade" epoxy in the world. As such their overhead is far larger than companies like MAS & System 3.

Then there are, what I call, the "generic distributors" who buy their resins and hardeners pretty much from the same chemical houses, but have very little overhead compared to the "big guys". They buy their bulk material, re-package it into less fancy containers, don't advertise on a national level, don't produce fancy literature & manuals, and rely more on local trade & the Internet to get the word out.

I have been using generic distributors for over 20 years, both without any problems and with a vastly reduced cost of materials.

My suppliers include: US Composites & Glue Products

So, from my experience, J Greer is most likely a good source for your epoxy needs. His prices are very comparable to what I pay at my distributors.

Another note: The lower ratio systems are easier to work with & much more forgiving of slight off ratio mistakes than are the high ratio systems. I prefer a 3:1 ratio & occasionally even drop to a 2:1 ratio for certain applications.

Br,

Patrick

[Capt. DQ]

Captain Patrick:

My suppliers include: US Composites & Glue Products

This is good epxoy, I use used it on my boat and was very pleased. Also there expanding 2 & 4 lb foam for the fuel tanks is very well priced.

R,
DQ

[Marshall Mahoney]

I used Aero Marine epoxy and did not like it. It was quite viscous and very difficult to wet fiberglass properly. I had to soak it in a warm water bath to drop the vis. After a couple of months, the container of resin phase separated (solids dropped out?) and I had to toss it.

I have been using low vis "Max Bond" by Polymer Products and like it. I bought by first batch off of e-bay. My later orders were purchased directly at a discount. They even threw in 1-1/2 gallons of white epoxy bottom coat to trial. They were very helpful and over the phone as well.

--Marshall

[CaptPatrick]

I used Aero Marine epoxy and did not like it. It was quite viscous and very difficult to wet fiberglass properly. I had to soak it in a warm water bath to drop the vis. After a couple of months, the container of resin phase separated (solids dropped out?) and I had to toss it. -- Marshall

Marshall, good report on a bad product. Hopefully 62 gets the message before he buys from them...

Br,

Patrick

[IRGuy]

Thank you for the first clearly worded, no nonsense, explanation of epoxy quality as relates to various sources I have ever seen. This has been a mystery to me for several years!

As an FYI.. I have been using West Systems epoxy for a while, but recently switched to MAS Epoxy primarily because they claim that their present hardeners do not cause amine blush. They admitted that some time ago their fastest hardener did have that problem, but after reformulating their present chemistry does not.

I also like the fact that they have two basic resins (one less viscous which is designed to be better for wetout and one more viscous for filleting, laminating and glueing), and they have three hardeners, for slow, normal and fast curing times. The hardeners can be mixed to provide curing times that fit the application.

While we are looking at epoxies I have an application question..

The aluminum window frames on my boat were painted some time in the past, but the paint is now peeling and chipping. What do you think about me mechanically or chemically removing this paint and putting a coat of epoxy on the bare aluminum before repainting?

[CaptPatrick]

Frank,

Painting over aluminum has always been a tricky set of techniques at best... There are two principles hurdles to over come:

1. Corosion instability of raw aluminum - Aluminum must be passified and immediately chemically treated to block out free oxygen. If oxygen can reach the surface of the metal, it will immediately oxidize. Once oxidization starts, it breeds to adjoining molecules and becomes a cancer.

2. Mechanical bond of paint to metal - Beyond cleanliness, the ability of paint to stick to metal is highly dependant on surface abrasion. The coarser the surface, the better the bond.

To most sucessfully paint aluminum, it must first be thoroughly abraded with nothing finer than 180 grit. Absolutely no bright spots left behind...

After sanding, the aluminum must be thoroughly cleaned, rinsed, and treated with an acid solution such as AlumaPrep, according to product directions. After rinsing the acid off, immediately treat with Alodine. Alodine is also an acid, but additional chemistry causes a microscopic protective film over the aluminum.

After the alodine treatment has been rinsed & dried, the metal is ready to accept paint.

Awlgrip primers are true epoxies, so there's no advantage to epoxy coating the metal with standard epoxy. Several coats of Awlgrip 545 primer can be built up & then sanded, being careful not to sand down to metal. Use 220 grit here. Virtually any solvent based paint can then be used as a top coat.

If everything is done correctly, and a little luck is thrown in, you can expect about 3 - 4 years before an oxidation spot pops up and the process begins again. I have seen painted aluminum stand up to over 10 years without any sign of blistering.

Br,

Patrick

[Hyena Love]

Great info Capt. Pat.

Related question - short of painting, what can we do to improve - protect the alum. frames? Specifically, I have some rather deep, pitted corrosion spots. Last owner filled with grey colored sillycone. Looked almost as though it was welded up, but alas, it was just a filler. That sillycone is now coming off. I was tempted to fill with JB weld. The sillycone did last for a number of years though.

Sure, then one might inquire as to whats the next step in the plan. Perhaps paint in a couple years. Or, better still, rip them out in favor of fiberglass fixed pane windows.

[CaptPatrick]

Ernest,

Goes back to the original part 1 of my answer above... There's nothing you can do without dealing with the origin of the corrosion first. Silicone, in my estimation, is one of the worst contaminants that you can bring onboard a boat. It falls right in with Starboard.

Once silicone has been applied, any surface that it even touched in the non-cured state, will become an un-paintabe, un-bondable surface because of the film. Sanding it away often gets rid of macro particles, while just smearing around the micro particals to contaminate even more of the surface...

J-B Weld is an excellent filler patch when using it to plug a ground out spot. But, the aluminum still has to go through the proper cleaning & acid steps BEFORE the J-B Weld is applied.

Leaving the aluminum only alodined is a sort of protection, but the film is very thin and isn't going to last long without further protection. Alodine will also tint the aluminum a piss yellow where ever it hits raw metal. If the original anodization still exists & you've sanded to raw aluminum in places, the yellow tint will not hold to the anodized areas, but will be on the sanded areas, leaving you with a speckled pup to look at.

I'm going to call this an All or Nothing Project. Either bite the bullet and do an in depth attack to solve the problem on a long range basis, (replace or repair), or leave it alone, other than to keep the aluminum wiped down with CX...

Br,

Patrick

[Rawleigh]

Ernest: You might try Labmetal as a filler. it is one part, but seems to be at least equal to epoxy fro filling. They even have a high temp that can be powdercoated. I would at least run a drill bit in any pits to clean out the corrosion.

http://www.alvinproducts.com/Products/Products.asp?id=1

[Hyena Love]

Thanks.

[Bruce]

You can buy different viscous epoxy resins depending on the application.

So make sure of your application before ordering and if your not sure, ask.

[IRGuy]

Capt Pat...

Thanks again. And thanks as well for all the other info everyone posted.

I can't keep the window frames as they are.. the paint is flaking off and was applied unevenly to begin with. I might try the rough sanding, chemical treatment, epoxy primer, final paint process, but there will be an edge where the coating ends (where the windows slide) and I suspect this is where the coatings will first let go when the time comes. I did not like to see your 3 year potential lifespan comment.. I hate to think of redoing the whole process after only 3 or 4 years.

Damned if I do, and damned if I don't!