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You may be on to something Chuck. I haven't used z-poxy, and I haven't had this problem......but my neck blanks are very old and dry. That isn't by design, it's just what I've got. I couldn't understand why it only happend on necks. but "green" blanks makes sense. The thin body woods will dry/season much quicker.

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I don't play well enough to get up to the heel of the guitar all that often yet this is where I have the most fuzz, up at the heel. The heel is 'the' most protected area of the instrument against perspiration, especially when I play. I still think we have some sort of chemical reaction going on here and that it only becomes an issue at a certain point of saturation 'into' the epoxy by the chosen finish. I say epoxy rather than Zpoxy because the other area most affected by this fuzz is the ever so thin glue line between the fretboard and neck which also happened to be glued on with epoxy, I say ever so thin because the fuzz follows this line like a hair. Nothing either side, just the glue line fuzz.

So far in this topic we have had folks come forward with this same issue who have top coated over zpoxy with truoil, nitro, and FP, the only constant we have here is epoxy. As explained, perspiration just does not add up for my circumstance. Also this does not seem to be happening with backs and sides. The argument that there is more moisture in the neck and 'that' is causing the problem does not take into account that the thinner wood of the back, sides and top take in and expel 'more' moisture just from changes in relative humidity due to the fact that they 'are' so thin and have much greater surface area for this exchange to take place. So all I can think it is that there is indeed a chemical or physical reaction between epoxy and what ever is coating it, and when what ever is coating epoxy is in a thick enough film, it restricts the exchange or passage of that chemical of physical reaction to expel it's energy through the finish and causes the finish itself to blister and produce this fuzz.

As mentioned, I suspect that the reason we see this reaction occur more so on necks than backs and sides is because of the natural attraction to apply more finish to the neck to protect it, coupled with the fact that the application method would be well practiced by many of the builders I have met on these forums

Cheers

Kim

Have never used Truoil but have used polymerized Tung oil over Zpoxy on my last six ,same result as the previous posters. Slow learner here but think its time to change.Have used the poly tung oil on unfilled necks and this results in a nice smooth feel but has the open pore look of course.May go back to this method.

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I found this topic on The Mandolin Cafe forum.
http://www.mandolincafe.com/forum/showthread.php?t=49464

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Thanks for the link Bob

So what is being suggested is, that as epoxy cures, "amines" which are a chemical byproduct of that process, rise to the surface of the epoxy. These amines then cause an interference with driers found in poly or varnish finishes which prevents them from curing properly. It is also suggested that these amines are only ever displaced by sanding, not removed. However they can be easily washed from the surface of the epoxy with a simple application of soap and water 'BEFORE' sanding takes place.

Now this makes sence to me But why only the neck? Because here, through ease of application and a desire to protect the wood in a higher wear environment, there is a natural attraction to apply more epoxy. As more epoxy is applied, more amines are excreted introducing greater potential for the reaction now commonly know as "The Fuzz" to take place.

Thanks again Bob, I think we now have our culprit, and hopefully a cure.

Cheers

Kim

Bump because it may help some folks who have been having the same issue.

Cheers

Kim

Thanks Bob,
I agree, this sounds like a very likely explanation.
Terry

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Kim,

The Mandolin Cafe post says that the amines stop the drying/curing of oil/varnish and I know that this happens with Tru-oil and Rosewoods because of the oils etc there, but I wouldn't have thought that the same is true with shellac and the FP reported by Pat or with nitro in terms of the way they dry/cure. If Tru-oil doesn't cure it's not a "fuzzy" feeling but an "icky" feeling.

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Great advice thanks Carey . Seems an obvious question , but has anyone tryed filling the pores as per the Tru-Oil instructions ? i.e. with the Tru-Oil itself , rubbing back with steelwool between coats ..

The Epoxy amines sounds like it could be the culprit when using Zpoxy IF it weren't for the fact that no members have reported a problem on the body of their instrument . Surely if epoxy amines were the culprit , " the Fuzz " would occur all over the body as well .
Kim, I can't buy the fact that it occurs on necks only because we ( MAY ) use more of the products in that area.If the problem is going to occur , I think it will regardless of it's thickness.

Another culprit, ( Wood oils, as in Rosewood etc ) could be ignored too, as Mahogany isn't that way inclined.

Once again ,I wonder if it's not hand perspiration causing a reaction of these two products when they are joined together . You may not play up at the heel end of your guitar much Kim ( cause you're such a crap player ) , but I bet when you are handling your guitar ( taking it in and out of it's case ) or hanging it up somewhere , or whatever , it's natural to grasp the guitar around the heel area and leave you oily mit prints . I have "the Fuzz " in the heel area too B.T.W. Actually ,the fuzz has occured most at the nut end and the heel end . The two areas handled the most ?

Again, has anyone filled their pores using the manufactures instructions ?

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CRAIG LAWRENCE of AUSTRALIA
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You can add my tru-oil over zpoxy to the long list of problem necks. My current build will be ktm9 over system 3.

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Joe Beaver
Maker of Sawdust

Dave,

I'm really not sure why Pat had issues, but as I recall from topics I have read in the past relating to this fuzz, the general consensus would indicate that this reaction is not very common under FP or nitro and this may in fact be a different thing all together. In past threads some have suggested that sealing well over the epoxy with shellac had solved the problem, so if I were still able to use epoxy safely, this is what would do.

Also, the post at mando cafe does not suggest that the reaction caused by amines will totally prevent the finish from drying which would indeed leave an "icky" mess. Rather it states that the amines will prevent the finish from drying "totally" and this partial cure may present itself as the fuzz.




Yes they do Craig. In past threads, others have come forward with this same issue and to add to the list, I am one who will also report that a fuzz has occured on the back of the body of my EIR guitar. It is quite bad at the waist area however I am of the opinion that this is a similar 'symptom' caused by that reaction that Dave mentioned between the oils in EIR, and truoil and is not a symptom of amines as I believe we are seeing on necks.




I disagree Craig, to say the reaction would happen regardless of the thickness is to say that water will boil regardless of the amount of heat applied to the pot. At some point, as you reduce the flame, heat being lost from the surface will exceed that being applied to the base, and then the temperature of the water will remain relative to that exchange, but, it won't eventually boil. Just because you can't 'see' a reaction, it does not mean that it is not happening at a lesser level.



Again I don't see perspiration being the issue. As you know, the bracing on my guitar is somewhat experimental and it had been suggested by some after showing the design for critique that it may well experience issues with distortion once under string tension. Since early January when first strung up, I have made a point of giving distortion every chance to take place. It's just good science, started with a theory, and then do all I can to prove the theory wrong.

So, my guitar has rarely seen the inside of a case. Instead it sits in my lap being played, or it held by the nut end of the neck as it is rested against my amp to be ready for the next bash (I may play pretty bad, but I do so loud and proud ). The point here is that I just don't handle the heel of the guitar at all, ever. Quite frankly, I never even noticed the fuzz at the heel until well after the discovery of fuzz at the nut end had caused a closer examination where upon I found it to be the worst affected area.

Why is the fuzz more prevalent at the nut and heel and not so bad on the shaft between? Well I don't really know, but it could be that your hand is stationary at the nut and heel and therefore does not provide the abrasive friction associated with the periodic sliding of ones hand up and down the neck. This in itself may be enough to wear down the fuzz as fast as it is produced?

Another point to consider is that my house is in Western Australia. January, February and March are VERY hot here often topping the old 100 degree F and the house not air conditioned. Some days when playing in temps like that, I'll have sweat literally dripping all over the top, back and sides of the guitar. (part of the distortion testing ) All surfaces are finished in truoil but no fuzz presents at the contact points, in fact the truoil has held up MUCH better than a nitro finish will under these conditions as nitro tends to milk out and soften at the contact points and this does get icky. The fuzz on the back that I mentioned earlier is apparent on both halves from the outer extremities of the waist and in to the centre seam. This waist area never really sees much contact or perspiration.

I still think that the amines theory is by far the most logical cause of the fuzz on necks. I would suggest that to wash the neck with soapy water after application of epoxy, then to sand, then to seal well with shellac, is a regime which shall see and end to the dreaded fuzz.

Cheers

Kim

Funny it should be mentioned that it's a sometimes a problem under varnish and not under shellac. One guitar with varnish over Zpoxy did not have the problem, but two with FP over Zpoxy did have it. One had a bit of it on the body and on the two necks, it was where I most often play.

The fuzz I got seemed to have been only in the pores and it did indeed appear that the shellac didn't cure over the pores.

Pat

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Here is an interesting read about amine cured epoxies. Seems to me if you are using epoxy to pore fill, regardless of your planned finish, you would do well to limit carbon dioxide in the environment you are mixing and applying the epoxy in and also maybe to wash down the cured epoxy with water and vinegar or citric acid so that a salt conversion of the residual oils takes place. I am also wondering if there is a relationship between amines and those reactive oils found in some of the rosewoods???

http://www.huntsman.com/performance_products/Media/Blushing_of_Amine-cured_Epoxy_Resins.pdf

Here is another read from West Systems site about wet sanding to remove amine blush, interesting the author states "All room temperature cure amine-base hardening epoxies are susceptible to amine blush to some degree. This amine blush is soft and can be a little greasy or gooey; it doesn't cut, but clogs or balls up so you can go through a lot of paper with little progress. (Balling of epoxy is also symptomatic of inadequately cured epoxy.) Amine blush has to be removed, as it can cause a number of problems: adhesion quality of subsequent epoxy applications, interference with paint or varnish drying, paint "bleed-through" and, of course, difficulty sanding.

Washing with water is effective for blush removal, but wet sanding is far more efficient for large areas. Solvents such as acetone and lacquer thinner won't touch it, and are hazardous. I've used cabinet scrapers with good success, but find wet sanding with water is the best approach."


http://www.epoxyworks.com/17/wetsand.html

Also interesting that he mentions "interference with paint or varnish drying" are the words 'paint' and varnish used generically to cover most finishes?? It would appear so.

Egg whites for me from now on.

Cheers

Kim

Very interesting Kim, what I don't know would fill volumes. I think I'm going to stick with epoxy for the time being but wet sanded before finish, assuming I get a continuious film to seal the wood from the water. And at least 48 hours cure time at 75 degrees.

Joe

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Joe Beaver
Maker of Sawdust

Many thanks for taking the time and trouble to gather all that info Kim. I wasn't aware "The Fuzz " has appeared on bodies as well . Based on that ,and the info you've provided , I have to agree that amines must be the culprit.

Is there some sort of adverse affect if , whilst your wet sanding ( with water ?),you come through the epoxy ?

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CRAIG LAWRENCE of AUSTRALIA
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