What is the maximum amount of time you can allow between coats of Threadmaster, without preparing the surface of the existing application?
Tight lines,
Hunter

From ghoulies and ghosties,
and long leggedy beasties,
and things that go bump in the night,
Good Lord deliver us!

That depends on your cure conditions. If the next coat shows a slight tendency to pull and streak when you first apply it without messing with it to get perfect coverage you have waited too long. The only time I get in a bind with this is when late arriving decals are involved using Micro Sol forced me into a 60 hour delay. If there is any question I normally lightly Scotch Brite or hit with a 600 Grit Stick.



Edited 1 time(s). Last edit at 02/26/2007 01:14PM by Bill Stevens.

I will let the experts chime in but if I remember seeing it correctly it is around 72 hrs.

I have went near 72hrs with no trouble, but when I get close to that I hit it with 1200grit paper and then re-coat.

DR

&2 is on the very outside with any resin....within 24 is best, 48 is ok, but 72 is really too long. Anything over 48 I would scuff with scotchbrite. You can actually apply a second coats as soon as 4-6 hours if you like...sooner is better than later.


Andy Dear
Lamar Fishing

Thanks, everyone. Looks like I will need to find my Scotch-Brite!
Tight lines,
Hunter

From ghoulies and ghosties,
and long leggedy beasties,
and things that go bump in the night,
Good Lord deliver us!

Can someone explain why it is necessary to apply a second coat of epoxy within a fairly short period of time. This does not make a lot of sense to me. When you apply a coat of epoxy to a blank the coating on the blank may have been there for months or in some cases maybe even years and there is no problem with the epoxy adhering to the blank.

maybe to get the "water -break- free" surface for maximum bonding capability ? maybe it can apply nicely, but if you attempt to peel it out, it may just come off easily.

personally i have no trouble applying finish over one that has been already on the blank for months or years.. never tried peeling them off to see how it is though..

-
Give a man a fish, he'll eat for a day..
Teach a man to fish, he'll be broke!

Blanks aren't covered with epoxy, if anything, they are covered with paint. Epoxy finish is NOT an adhesive and is fairly easy to remove from a blank or guide. You want both coats to sort of meld or fuse together into one. If you wait to long, scuffing the surface will help the coats to bond together and avoid possible separation

Mike (Southgate, MI)
If I don't want to, I don't have to and nobody can make me (except my wife) cuz I'm RETIRED!!

Emory, if you want to apply a second coat of finish, over thread, the time involved has a lot to do with the top coat wetting out on the underlying coat to prevent streaking and pulling of the top coat. There is a time in the cure period of the underlying coat when it "glazes" and will exhibit repelling features if not placed in the waterbreak condition by scuffing. It can really look horrible if scuffing of the "cured" underlying coat is not done. The finish can appear to just move around after application causing open areas and streaks. The best finish, with a minimum of prep work, can be achieved by adhering to a reasonable time period between coats. I also think the casting resins require a much longer time to full cure and will tend to bond forming a more homogeneous mass and not separate layers with shear planes between each coat. I build quite a few rods and the waiting periods really gets in my way when waterslide decals are involved. I have to plan when things will happen so that I do not have to scuff the area under a decal and use the Micro Sol to shrink. I try to schedule my work where most first coat finish applications are done late in the work day and then allowed to dry overnight. Then I can finish rod the next day with decal application and application of second coats.

Mike,
I understand that the finishes on blanks are not epoxy but when removing a guide I find that the epoxy has adhered to the blank pretty darn well. In fact, sometimes too well. If a second coat of epoxy on a guide adheres to the first coat that well it would be more than good enough. Plus I have on occasion in the past waited more than a couple of days before putting the second coat of epoxy on and did not do anything to prep the surface and have never had any problems that were the result of waiting more than a couple of days between coats.
When a polymer catalyzes the molecules link together in long chains. Its strength is the result of this linking but I don't think that once a layer has catalyzed that another layer over the top of the first would link to the first layer.
I am not trying to start an argument. It is just that I have heard numerous times that the second coat should be applied within a couple of days and I just wondered what the reason for this is or what is the logic behind it.
Maybe Ralph can jump in here and straighten me out.

Bill,
I also build a lot of rods but I have never had the same experience that you have had with the second layer looking horrible. Maybe I have just been lucky and my day is coming.

I have seen second layers that actually peel off from the first.

Within a certain amount of time, and this will be dependent on temperature and the specific product being used, a second layer or coat will actually become one with the first - if you could cut a cross section of it and look at it close enough, you would not see two layers. After some amount of time between applications, however, you do actually have two layers.

..........

Tom,
It takes several days for the epoxy, at least Flex Coat, to get completely hard. What you say suggests that until it is completely hard or completely cured that the molecules in the two layers will link together. Interesting.

If I recall correctly Ralph uses the term application when referring to applying the finish a second or third time in a limited time frame, generally under 72 hours, after that time you are applying a SECOND COAT which can react differently then applying the finish in a short time frame
John

John,
Thanks. Where is Ralph anyway? It seems that he is never around when you need him. He is probably off fishing or something.

Emory,

Ralph has told me this as well as the guys at Valspar. But there is definitely a specific time window you have to work in.


..........

Tom,
I have never had the experience that you have had with the coats separating but I do not dispute that they will. It would be interesting to know just what is happening. Without knowing what the mechanism is I have to say that I am still suspicious.

i normally reuse the condiment cup which i use to mix my finish in.. even within 12 hrs, 2 distinct layers of finish can be seen .. i dont know about the strength tho.. i have a cup with six layers, mixture of application within hours to weeks

-
Give a man a fish, he'll eat for a day..
Teach a man to fish, he'll be broke!