I have recently noticed a measuring stick for sale for thinning Flex coat, acetone is what they recomend. I have not tried this process and wanted to hear results from those who may have had good or bad experiences with this process. Does it affect drying times? Hardness in curing? or any other pros or cons.
What is the recomeded amount to use per batch of mixed twopart?

Here are the instructions from Flex Coat ... [www.flexcoat.com]

Jim , Thanks for the link to flex coat. I still have one question if some one could answer , Acetone used as a thinner is flamible, can you still use a light torch to remove any air bubbles?

Tom,

To my knowledge it is CO2 that causes the air bubbles to break. I would think blowing on it with a coffee straw would be your best bet. I'm fairly certain the acetone would ignite.

Thinning with acetone can change the inherent properties of the epoxy. Heating the epoxy can do the same thing. Proceed at your own risk with the understanding that too much of anything may cause problems down the road.

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To my knowledge there are some thinners in the epoxy components straight out of the bottle as mixed.
Some are less volatile than others.
ie
International brand epoxy thinners are a different hydrocarbon to acetone & are a lot less volatile than acetone.
Because acetone evaporates off quickly I get the impression it results in a tougher epoxy coat as the 'crossbonding' in the epoxy as it hardens is more thorough ......... whereas other epoxy thinners ( such as the International brand ) are slower to evaporate and tends to be more patchy in the drying so the 'crossbonding' between the epoxy molecules is not all taking place at the same time.
drying time is a lot longer with the International brand epoxy thinner than acetone too.
The thinners gets in between the molecules of the two epoxy components and stops their reaction, simply because the two components cant 'get together' until the thinners has evaporated off.
With 'thinned' epoxy there is no rush to release bubbles until the thinner has evaporated off as the epoxy reaction is not taking place to start hardening the coating.

Yes exposure to raw flame can be a problem with thinners until they have evaporated off.
See the next post about a tool that uses a catalytic burner with no exposed flames and some other potential advantages for bubble eradication.
I had one of the kits on my boat for soldering electrical connections for many years with the 'hot air' attachment unused, until one day the sudden idea of " I know what I can use that for" kicked in & I have not looked back since.

DenisB

Tom M. I have quite a bit of experience in this area if you would like to drop me an email. I looked for yours but it is hidden. My email is docski377@aol.com

100% solids epoxies do not contain any solvents in the component parts.

The fact is, the epoxy is indeed curing even while any added solvent is still in the mix and thus if the epoxy sets before the solvent can fully leave the mix you're looking at problems down the road. This is why epoxy formulators don't recommend adding solvents to their products and if you feel you must, use the most volatile product possible - acetone is usually the best in this application. But again, you're going to be hard pressed to find an epoxy formulator that would ever recommend adding a solvent to his product.

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As an epoxy formulator I agree with Tom Kirkman 100%.

The post by Dennis Brown above, is entirely erroneous. I have been formulating epoxies for about 50 years, and have never heard of any international brand of epoxy thinners and doubt if such things exist. The nonsensical statement that thinners get between the molecules of two epoxy components and stops their reaction-- is just exactly that --pure nonsense. Posts such as this cause considerable harm and create wild rumors in the industry---especially to the newbies who are searching for answers and might read it and take it as sound information. It isn't.

Epoxy paints contain solvents, as they are intended to be sprayed, brushed, or rollered onto a surface and act as a coating. The solvents are designed to escape quickly as the coatings are quite thin and the surface is considerable. Our rod finishes are not paints, they are 'casting resins'. Casting resins are designed to be used in a mass wherein no solvent is necessary or desireable. The formulator of the casting resin is free to utilize components that are not necessarily compatable with solvents Adding a solvent to this casting resin runs the danger --probability, that some component in the resin will be degraded resulting in the overall reduction of properties of the finished product. I have seen test samples of casting resins with and without solvent wherein the specimens with the solvent addition were badly degraded while the non solvent specimens were intact. I have seen rods that were painted with a casting resin the entire length of the rod, and in order to get a thin paint like finish on the rod, the resin was thinned. That coating was removed via a thumb nail about a year after it was coated, actually I am acquainted with several rods of this nature.

This compulsion to thin a perfectly good resin started back when epoxies first became fashionable for rod building. Gene Bullard introduced the first epoxy finish for the rod building industry, followed by Flexcoat. Once it was established that epoxy is the in thing for thread finishes, to many guys went to their local paint store and bought epoxies intended for other purposes and used them on their rods. These epoxies are thick and viscous and really not suitable for rod finishes ---- thus began the campaign to thin the finish and it has never ended. The Bullard materiel named Diamond coat, then Diamond Coat 2. and Flexcoat were/are perfectly suitable unthinned, but somehow the word got around that you have to thin an epoxy and it has never gone away. I think that some of the worst perpetrators of this sin today are some of our most prestigious custom builders. I have got into it with a few of them, some of them have seen the wisdom of my ranting and ceased and desisted - others have written me off as some kind of a nut and gone about their wicked ways.

I am well acquainted with Flexcoat and see no reason for the thinning of it. Certainly do not thin the hi build. If the hi build is to thick for you, then use the regular. Why thin either of them? What do you expect to gain by thinning?

Flexcoat regular has been around for many years and is on thousands and thousands of rods all over the world. 99.9% of the finish went onto the rod unthinned. Some of you out there will remember the first rod finish that Trondak marketed, it was named Duragloss. I used Flexcoat regular as the standard to formulate Duragloss, then about a year later I got to thinking ---it don't make sense to try and compete with Flexcoat in their own game, and since every body wants to thin flexcoat, and now they want to thin duragloss lets give them a thinned product. "If you can't beat em --join em" So I formulated LS2000 to be the same thickness as a Flexcoat mixture of 6cc thinned with 1/2cc of Acetone. The present day LS Supreme also adhers to that standard. In other words we have given the industry a thinned epoxy without the thinner.. This product stands up on heavy offshore rods in the tropic sun with the entire rod painted with two coats, I have seen rods still going strong after three years in the sun. Why ---- Because it was formulated to be painted without a thinner. Take a thicker casting resin, thin it down with Acetone, and the coating will strip off in less than a year.

In summary Tom, Trondak does not recommend the thinning of our (i'm referring to our industry) casting resins under any circumstances. However if your compulsion insists that you just gotta thin --- then by all means adhere to the Flexcoat method and thin only the first coat and call it a primer coat. I have never done any testing of this method, so can't speak from actual data, but I have a gut feeling that any degradation will be very very minimal. When thinning it is VERY important that you use only ACETONE. Acetone is the fastest solvent that you can readily acquire, and you want the fastest solvent -- the guys that really get into trouble with thinning are those that try to use something like Alcohol, or one of the slower Ketones. If that solvent is still in the mass when those amines and epoxides get together, there's really gonna be @#$%& to pay. After those little buggers have done their thing, its an entirely different piece of cake. Oh I nearly forgot --- don't worry about flaming the bubbles, the solvent escaping is so infinitely small that absolultely nothing will be apparent when you flame. Be sure and flame in such a manner that you DONOT raise the temperature of the curing epoxy ---- do it rapidly.

Ralph


PS. DO NOT, repeat DO NOT ever attempt to thin LS Supreme, or LS HI Build.



Edited 1 time(s). Last edit at 06/23/2008 08:08AM by Moderator.

Well Ralph
We will just have to disagree on a couple of things
Firstly "International " brand epoxy thinners are available worldwide.
and a newbie can come across a can marked epoxy thinners & think it will do the job.
Its a ketone............. the can just says Epoxy Thinner for the contents.
If its not in your backyard I can send a photo of a can in my shed, so we both know the context of what we are talking about there.
Now as for thinners in the components of 100% 'solids' epoxies I agree with the very clear context of Tom's comment & take your comments in the same context.

Unfortunately they are not the only clear 'epoxies' around in the world today.

As for the effect of the addition of thinners to 100% solids epoxies they do in effect stop the proper reaction between the components of the mix............... where the thinner is present in the mix until it evaporates.
Therein lies the biggest danger of using thinners in 100% solids epoxies - it weakens the 3 dimensional crossbonding of the epoxy.
The generally accepted rule of thumb is that 5% acetone in an epoxy weakens the final epoxy by about 35%.( If my memory serves me correctly ).
and 5% acetone thins an epoxy a @#$%& of a lot.
Ralph, we will not go into what other effects the thinner can have on the epoxy chemistry ............. its all in the estimated 35% strength loss.

I agree entirely with the approach ( where you want /must thin ) to its use in the first coat and not in topcoats................. but thats exactly the place people want to thin their epoxies on their bindings.
If we get technical about the use of thinners in epoxies it makes a difference whether the thinner is added to one component before the mix of the two epoxy components or after.
It makes a difference in the bond strength.

I should have added more column inches about "thinners" in epoxies, and been more specific about the context of my comments.

Yes, not all of the crossbonding reactions will be stopped by a solution of less than 5% thinners.
Some will be taking place at their normal pace. Thats where the thinner weakens the 3 dimensional crossbonding , because the reaction will have taken place in some molecules but not others until the thinner has evaporated & when it does, the full 3 dimensional bonding cannot now take place to get what should be one big epoxy "molecule" that is your perfect coating on the binding.
It looks OK ........... but its not the 100% thing.
At less than 5% acetone its strong enough as a first coat and the top coats ( unthinned) give the binding its full strength coat.
Hey.
At less than 35% weaker than a full strength epoxy cure its still stronger than your CP !!!!!!.

Ralph, you are in the business of making & selling epoxies.............. how about an article on the epoxies...........their differences...............the hydrocarbon chain lengths of the components giving different viscosities and the characteristics of the cured epoxies; 'thin' ones, standards; & high build ( or thick ones ).
If this is somewhere on the site already I apologise ...........As I did not come across it...... I would appreciate directions to it if it is there.
While information is not out there & epoxies & what you can do with them remain a "black art" there will be misinterpretation; misinformation; poor explanation ( I plead guilty ) & myths are born.

Rod builders have a lot more time & effort invested in wrapping than in epoxy use . if things are going 'problematic' with an epoxy finish coat ...............you don't care about losing 5 or 10% of the strength of the epoxy, you just want it to look OK at that point & you are prepared to accept compromises on the "perfect" epoxy cure to get a decent outcome.

Hence the use of thinners in first coats
Hence the use of heat to deal with bubbles.
We are not going to rip it off & start again just to give your product its perfect cure, we are going to adapt.
Rod builders have been doing these things since there were epoxies.............a bit more knowledge about what using a thinner or heat does to an epoxy is all to the better............. especially the commonsense limits & why............. especially for the newbies.
Good on Flexcoat for coming out with its advice on thinners................... it had been going on for decades at end user level before any manufacturer provided advice beyond the anti-litigation advice of " you should not do it"
Same with heat.
It helps no end if people understand WHAT they are doing rather than simply doing things by rote. problemsolving when all you know is rote is a real @#$%& & leads too often to misty eyes & bad language.

Looking forward to a great article on 100% 'solids' epoxies, Ralph.
Then you can do one from your expertise on CP's ; both hydrocarbon solvent acrylic solutions & waterbased acrylics & what they are actually doing in/on the wrap threads before the epoxy coats & the bond between the CPs & the epoxy topcoats.
I've been building rods, lures & boats since before fibreglass , let alone carbonfibres were in the marketplace. I built my rod lathe in 1967 & its still going. If what I want is not in the marketplace I adapt or make it................ I've found the commonsense limits of what you can do and found what you shouldn't do quite a few times too. I have a personal Quiver of some 40 rods & build for myself , family, presents for friends & the very occasional arm twist. ( but did build commercially for a couple of years back in the ' 60's )

Disclosure: Unless its been 're-branded' in my country I have never knowingly used Flexcoat................. just an availability issue.

DenisB

The articles with the information you ask for have previously appeared in RodMaker Magazine.


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