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Mike_P
 Post subject: Pore Filling
PostPosted: Wed Jun 22, 2016 4:35 pm 
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Yeah, this subject has been covered a bazillion times.

I have a specific query on the subject: lately I've seen at least 2 guitars up for sale that look like *edited*...why?, because most every pore looks white/crystalized.

what I theorize (and wish for others who have exact knowledge to step in and clarify) is that they either used epoxy or some other clear filler...and did NOT get complete filling of the pores at the onset...e.g. upon first application air got trapped in the pores and was not displaced by the clear filler.

Is this a great problem, or just a case of improper use?

It makes me wonder if perhaps a first coat of colored (traditional) filler be applied, sanded back, then epoxy used over that to pop the grain and give the other nice effects of epoxy filling.
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kjaffrey
 Post subject: Re: Pore Filling
PostPosted: Wed Jun 22, 2016 5:50 pm 
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I had that happen on a Wenge guitar (cavernous pores) when I used Aquacoat clear pore filler. Unfortunately it didn't turn crystalline looking until after the first several coatsof lacquer went on [xx(] . I then stripped it all off and finished with an oil based paste filler. Like you I surmised it was from two layers of pore fill not adhering to each other and then opening up after the finish was applied.

I have never seen this happen with epoxy, only the water based clear filler.
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kencierp
 Post subject: Re: Pore Filling
PostPosted: Wed Jun 22, 2016 7:10 pm 
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Quote:
because most every pore looks white/crystalized.


Yep -- that happened to me on dark woods when I ran tests with all the so called clear Water Borne pore fillers. Now I did use four coats, I think its the silica in the formula that builds up. Silica is kind of translucent but not transparent. The Hood lacquer base clear did the same thing, but on their can label if does state you should only use two coats.

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Tom West
 Post subject: Re: Pore Filling
PostPosted: Wed Jun 22, 2016 8:29 pm 
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Mike: Think you are also asking if anyone has had this problem also with epoxy. I've used Zpoxy for quite a while and have never had anything like this happening. Todd Stock has a good series on YouTube on Zpoxy pore filling if you are interested.
Tom

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Jim Watts
 Post subject: Re: Pore Filling
PostPosted: Wed Jun 22, 2016 9:39 pm 
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Mike, I have had this happen to me using epoxy for pore filling on a few of my guitars many years ago. It seems to have happened to others also. The pores turned whitish several years after completion. I will no longer use epoxy for pore filling as I don't like refinishing guitars.
There is a good chance that this was not Z-poxy, which everyone seems to like. Still, I will not use epoxy for pore filling.
just my experience.

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kencierp
 Post subject: Re: Pore Filling
PostPosted: Wed Jun 22, 2016 9:54 pm 
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Pictures?

But no -- no problems with Zpoxy.

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BradHall
 Post subject: Re: Pore Filling
PostPosted: Thu Jun 23, 2016 12:12 am 
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Jim, what is it you do use instead of zpoxy or epoxy? I have a walnut b&s, redwood top guitar nearing the pore filling stage. This is my second build. I use TruOil on the first and even with an oil sawdust slurry I still had open looking pores in the rosewood. My plan is to use rattle can lacquer on this one. Any advice welcomed.


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kencierp
 Post subject: Re: Pore Filling
PostPosted: Thu Jun 23, 2016 7:55 am 
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I much prefer the depth and clarity of Zpoxy --- we have tested easy to use Timbermate and it does a very good job of filling the pores but not really a finish enhancer. With proper color matching its at least as good as the water borne "Pore o Pack"

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Trevor Gore
 Post subject: Re: Pore Filling
PostPosted: Thu Jun 23, 2016 8:37 am 
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Jim Watts wrote:
Mike, I have had this happen to me using epoxy for pore filling on a few of my guitars many years ago. It seems to have happened to others also. The pores turned whitish several years after completion. I will no longer use epoxy for pore filling as I don't like refinishing guitars.

If a standard epoxy laminating resin is used for pore filling, that can happen. Anyone using epoxy to pore fill needs to be sure they are using a specially formulated clear coating resin system designed specifically not to bloom or whiten down the track. WEST 105 resin with 207 hardener is one such system. (105/206 isn't).

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These users thanked the author Trevor Gore for the post (total 2): TimAllen (Thu Jun 23, 2016 12:12 pm) • kencierp (Thu Jun 23, 2016 9:01 am)
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Mitch Cain
 Post subject: Re: Pore Filling
PostPosted: Thu Jun 23, 2016 10:11 am 
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Been using Good-Filla water-based with excellent results. I do color the first coat.

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Mike_P
 Post subject: Re: Pore Filling
PostPosted: Thu Jun 23, 2016 5:02 pm 
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kencierp wrote:
Pictures?

But no -- no problems with Zpoxy.


Image
Image

that's what I'm referring to...have not idea of what was used...and have seen this on other guitars also, and had a Taylor limited edition 710KCE from '96 that had a bit of that also.

since I find it rather repugnant, was wondering if the cause was known and identified...
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kencierp
 Post subject: Re: Pore Filling
PostPosted: Thu Jun 23, 2016 5:24 pm 
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Sorry I mis-read I thought that this had happened to you.

Actually looks like mineral deposits to me. Pretty common on the Rosewoods, can be blended with acetone (mixes with the oils and becomes a stain) or removed using CLR, recently I tried lemon juice and that works great.

Or sanding dust that was not tacked off properly.

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Trevor Gore
 Post subject: Re: Pore Filling
PostPosted: Thu Jun 23, 2016 6:55 pm 
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I don't think mineral deposits. Check out the glue line, photo 1.

It looks like sanding residue to me. If it was a pore fill gone wrong I'd think you'd see it in nearly all the pores rather than just some of them.

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Jim Watts
 Post subject: Re: Pore Filling
PostPosted: Thu Jun 23, 2016 7:16 pm 
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BradHall wrote:
Jim, what is it you do use instead of zpoxy or epoxy? I have a walnut b&s, redwood top guitar nearing the pore filling stage. This is my second build. I use TruOil on the first and even with an oil sawdust slurry I still had open looking pores in the rosewood. My plan is to use rattle can lacquer on this one. Any advice welcomed.


Sent from my iPad using Tapatalk

I usually do something like you did with the true oil slurry, only I sand egg whites into the pores with 320. That is I use egg whites instead of true oil. It takes several sessions of this but it dries very fast. If I want a clear pore fill I've been using aquacoat lately, and it seems to work well, but again it takes several session to get everything filled. It too dries very fast.

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Colin North
 Post subject: Re: Pore Filling
PostPosted: Fri Jun 24, 2016 2:30 am 
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I've had some good results from Art Resin, water clear and sands well.
http://www.artresin.com/pages/faq

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.
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kencierp
 Post subject: Re: Pore Filling
PostPosted: Fri Jun 24, 2016 10:20 am 
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Artresin sounds interesting clear is good -- done any contacts regarding compatibility? Since even second coats on itself require scuffing the surface, are all top coat bonds mechanical?

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WaddyThomson
 Post subject: Re: Pore Filling
PostPosted: Fri Jun 24, 2016 4:23 pm 
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Seems it would be thick if you use their directions! Thick Epoxy has some drawbacks.

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Colin North
 Post subject: Re: Pore Filling
PostPosted: Sat Jun 25, 2016 3:24 am 
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kencierp wrote:
Artresin sounds interesting clear is good -- done any contacts regarding compatibility? Since even second coats on itself require scuffing the surface, are all top coat bonds mechanical?

"Done any contacts"? Not sure what you mean, but I have tested adhesion to Enduro-Var and had no problems http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=47497&p=628231&hilit=+adhesion#p628231
I'm no expert, but my understanding is that pretty much anything on top of epoxy pore fill (including more epoxy) benefits from scuffing of the surface and is a mechanical bond.
Waddy, it's quite thin actually, similar to Z-epoxy, and I applied it in the same way.
You could pour it over like the "general" instructions, and let the excess drip off, but it might not be as acoustically transparent as french polish. :D

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.
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kencierp
 Post subject: Re: Pore Filling
PostPosted: Sat Jun 25, 2016 7:01 am 
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By "contacts" I mean -- contacted the manufacture of the product. For me the only place to get the real scoop on compatibility and just about anything else is to discuss the issues with the tech staff at the place of origin.

With this product I find it odd that scuffing is needed between coats. If it does not easily stick to itself for me that's a red light for adhesion problems. As far as I can remember there is no mention of that requirement with Zpoxy, West or System lll -- I could be wrong.

Before I started using Zpoxy I made the factory "contact" I was told that the product was compatible with Nitro lacquer and that the nitro indeed did etch and chemically bond. I realize the Enduro Var does not etch Zpoxy but again I was reassured by the General Finish techs that the WB product will work well with the Zpoxy.

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kencierp
 Post subject: Re: Pore Filling
PostPosted: Sat Jun 25, 2016 7:01 am 
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By "contacts" I mean -- contacted the manufacture of the product. For me the only place to get the real scoop on compatibility and just about anything else is to discuss the issues with the tech staff at the place of origin.

With this product I find it odd that scuffing is needed between coats. If it does not easily stick to itself for me that's a red light for adhesion problems. As far as I can remember there is no mention of that requirement with Zpoxy, West or System lll -- I could be wrong.

Before I started using Zpoxy I made the factory "contact" I was told that the product was compatible with Nitro lacquer and that the nitro indeed did etch and chemically bond. I realize the Enduro Var does not etch Zpoxy but again I was reassured by the General Finish techs that the WB product will work well with the Zpoxy.

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Colin North
 Post subject: Re: Pore Filling
PostPosted: Sat Jun 25, 2016 8:50 am 
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OK Ken, that's clear.
Z-epoxy themselves appear to recommend sanding between layers https://supergluemsds.com/Docs/PT40%20-%20%20Z-Poxy%20Finishing%20Resin%20System%20-%20PSS%20-%20rev%204%20-%202013.pdf
Any pore filler required sanding anyway (wish it didn't!)
Anyway, I didn't see the point in waiting for replies from manufacturers (GF and Artresin) who probably don't know the answer to such a specialised question anyway.
So I just did my own test panels and abused them horribly - no problems
Adhesion Testing -
Quote:
There are two methods described in the ASTM Specification;[3]
Test Method A

An X-cut is made through the film with a carbide tip tool to the substrate. Pressure-sensitive tape is applied over the cut. Tape is smoothed into place by using a pencil eraser over the area of the incisions. Tape is removed by pulling it off rapidly back over itself as close to an angle of 180°. Adhesion is assessed on a 0 to 5 scale.

[0- Greater than 65% area removed & 5 is 0% area removed]
Test Method B
A crosshatch pattern is made though the film to the substrate. Detached flakes of coating are removed by brushing with a soft brush. Pressure-sensitive tape is applied over the crosshatch cut. Tape is smoothed into place by using a pencil eraser over the area of the incisions. Tape is removed by pulling it off rapidly back over itself as close to an angle of 180°. Adhesion is assessed on a 0 to 5 scale.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.
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Alain Desforges
 Post subject: Re: Pore Filling
PostPosted: Sat Jun 25, 2016 9:12 am 
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Jim Watts wrote:
I usually do something like you did with the true oil slurry, only I sand egg whites into the pores with 320. That is I use egg whites instead of true oil. It takes several sessions of this but it dries very fast. If I want a clear pore fill I've been using aquacoat lately, and it seems to work well, but again it takes several session to get everything filled. It too dries very fast.


I've always been interested in using egg whites. I tried it a while back but I didn't get good results. Do you simply add 320 dust to the egg whites?

I've had great results with pumice too. I have a Wenge Baritone that is about 5 years old now. The surface is perfectly flat and those cavernous pores filled up in about 2 passes. Unfortunately, my lacquer technique was lacking at the time. Pumice and shellac is quick to dry as well.

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kencierp
 Post subject: Re: Pore Filling
PostPosted: Sat Jun 25, 2016 9:17 am 
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Colin -- good stuff thank you

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Jim Watts
 Post subject: Re: Pore Filling
PostPosted: Sat Jun 25, 2016 9:33 am 
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Alain, I simply add some egg white onto the wood and then sand the area with 320 then wipe off any excess. It works up a nice slurry that gets packed into the pores.
Give it a try on some scrap.

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Colin North
 Post subject: Re: Pore Filling
PostPosted: Sat Jun 25, 2016 11:19 am 
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Done the egg white thing that way too, seems to work fine, and dries quick. Just you don't get the same "grain pop" epoxy gives.

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The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.
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