How does putting a correct ratio finish over an uncured, uncorrect ratio mix fix the problem. I've never had the issue but I would like to know how it corrects the problem. I dont doubt that it does but I cant grasp how combining an unbalanced ratio and a balanced ratio equals a balanced ratio therefor allowing a complete cure of the finish. It seems like it would be similar to putting a chocalate shell over soft ice cream, only less tasty!

Because as long as the first application is not properly nor fully cured, it does not constitute a "coat." A 2nd application melds into the first and they become one. The more epoxy you have the greater is the margin for error in measuring. Being off a drop on a 1cc mix may be enough to keep the mix from setting up properly, but that same drop on a larger volume may not be. So you're essentially increasing the total amount or volume of epoxy when you apply a second application over the first.

The other factor concerns the fact that our finishing epoxies are actually casting resins. They are formulated to encapsulate items and as such, will encapsulate an earlier application of epoxy as well. So even if it the 2nd application didn't correct the first (and in some cases it may not) you'll never know it because the earlier application will have been encapsulated and covered by the 2nd.

................

Jim,
In spite of comments to the contrary, I agree with you 100%. Although I have read numerous comments about results to the contrary, I very much agree that I believe that you will tend to have a soft layer of finish on the rod with a hard outer shell.
I would equate it much to like building a house on a foundation of sand. It can be done and the final product is wonderful, until the first storm comes along.

Even though it is more work, anytime this has happened to me, I have always taken the time to strip the rod down again, and start over.

But, everyone is entitled to do what they want to do with the rods that they are building.

As many others have said, it does give a nice finished product when correct epoxy is put over an uncured layer of epoxy. BUT!!

Good luck
Roger

Have not had it happen to me But I was thinking that maybe the bad coat can be heated with the rod still And wipe off as much as you can as it drips.

Then start turning
Then there is less under the good coat to mix with ???

Don't know what may happen with any CP if the dripping finish will take it also

Bill - willierods.com



Edited 1 time(s). Last edit at 02/02/2012 10:53AM by bill boettcher.

That all makes sense, and my chocolate shell over soft ice cream is not a bad comparison to encapsulating uncured finish either. He He.
Thanks

The chocolate shell will not meld with the soft ice cream underneath.

The scenario described above pertaining to epoxy will not result in two coats - one soft and one hard on top. It will result in one, and only one coat.

...........

Good morning,
For those who use epoxy as their main finish and are interested in this question, this provides an opportunity to determine which process actually occurs. One could mix up a batch of epoxy finish that was intentionally mixed with an incorrect ratio and then use it on some test wraps. After allowing it to cure for a reasonable time, a second coat of a properly mixed epoxy could be used to cover it. Let the second coat cure for about two or three weeks and then cut into the wraps and see if it is still liquid underneath the second coat. Have fun.

Mike Blomme

Good point Mike Test

Bill - willierods.com

Michael Blomme Wrote:
-------------------------------------------------------
> Good morning,
> For those who use epoxy as their main finish and
> are interested in this question, this provides an
> opportunity to determine which process actually
> occurs. One could mix up a batch of epoxy finish
> that was intentionally mixed with an incorrect
> ratio and then use it on some test wraps. After
> allowing it to cure for a reasonable time, a
> second coat of a properly mixed epoxy could be
> used to cover it. Let the second coat cure for
> about two or three weeks and then cut into the
> wraps and see if it is still liquid underneath the
> second coat. Have fun.
>
> Mike Blomme




I've done it! The result was exactly what Tom described above. There is no evidence of there being two separate coats. There is just one layer to be seen when you cut into it. But I wouldn't want others not to try it for themselves so test away!

Its common when fiberglassing a new deck on a boat (or anything for that matter) to apply the second layer of fiberglass and new resin the first coat is in a tacky state, it creates a "wet bond" and helps the fiberglass stop de-laminating and the end result is 1 solid layer of fiberglass after the last coat of epoxy is allowed to cure. the principle would be simular just no extra thread between the layers of epoxy.

Strong wraps, calm seas
Derek

This is why most epoxy formulators advise scuffing the first application if you've waited more than 3 or 4 days to apply the second. Once the first application has reached a certain point in its cure, it does indeed become a separate "coat" and therefore would require a water break free surface if the second application is to properly bond to it. At that point you would indeed have two separate coats. Within the window of a 3 or 4 days, however, no surface prep is necessary and the second application will simply become part of the first resulting in a single "coat."

In the case of a first application that has not and will not set fully, you will never reach the point where it becomes a separate "coat." So any subsequent application simply becomes part of the first.

There may be rare instances when the first application is so far off that a second application will not solve the issue insofar as the two becoming one coat. But again, this would be very rare and occur only if the builder was extremely careless on the measurement of the first application.

.............

And this second coat would only be done over a tacky first coat, meaning the mix ration is close but not good enough to completely cure. Anything more gooey, and you'd wipe it off before recoating.

"So even if it the 2nd application didn't correct the first (and in some cases it may not) you'll never know it because the earlier application will have been encapsulated and covered by the 2nd."

This is what I meant by the ice cream comparison, a has a hard shell over a soft base..

If you are unsure of how it will be - rewrap the guides

Bill - willierods.com

Such a thing would be extremely rare and is not going to be the usual result of adding a second application over the first. Barry covered that scenario pretty well.

...........

The only concern I see is if the builder mixed two parts out of the same bottle. Have heard of being done. This is where a strip would be necessary.

Freddwhy (Rapt-Ryte)

Two out of the same botle won't even stay on the blank, will drip constantly.

There are only two types of rod builders, those who have done that, and those who refuse to admit that they've done that!

Hi Ken,
I've been building for a long time, started when varnish was the only wrapping finsh available and touch wood I haven't mixed two from the same bottle YET!!
Had a couple of batches not set properly back in the days when I was using little spoons for measuring and another batch that was mucked up by a mixer that I bought and that was more than enough.
I've got a routine for mixing and it has served me well so far.
I've still got a few years for it to happen and it probably will.

ESFNEM Col
Port Kembla, NSW
Australia