Sanding color coat before clear, pigtails persist

[jhaley]

tjbnwi

Thanks for the lumber tip.

You're not kidding about the paper and glue, are you? Radical.

Found the paper at HD here, have the glue. Sounds like another experiment.

Wondering how I can do just the top and the doors, treatment of edges. Have sharp corners now.

Does the water glue mix flow out well? Brush on?

Toxins in alcohol affecting the shellac - so use 100% ethanol? Not DNA? Haven't heard that.  I mean, shellac is alcohol.  I do recall lots about some alcohols being wrong for shellac. Alcohols is another area where there's too much to know. Don't recall it all just now but I spent time on that before mixing my shellac. Lots of seemingly conflicting info, same product being called different things, sometimes because the same alcohol has more than one correct name, other times just misinformation, .  .  ..

If I had a good memory I'd know way too much, but it does get old reinventing the wheel.

 

[tjbnwi]

Store bought DNA is required to have a toxin in it. Prevents consumption.

Yes, shellac is alcohol based, not sure if the large manufactures are required to taint the product.

Brush will work, flow as even as you can. Try it.

Tom

 

[jhaley]

Tom-

Store bought DNA is required to have a toxin in it. Prevents consumption.

Yes, shellac is alcohol based, not sure if the large manufactures are required to taint the product.

I just never heard anything about the additives in DNA being an issue for finishing. Arsenic, Lead, they make good paint. I googled pretty deep on what alcohol to use, found knowledgeable confusion. chemistry. Don't recall much beyond that I settled on a certain common brand of DNA. On my desk now is a Bob Flexner book that just summarizes - ethanol, expensive; methanol, not safe; use DNA.

Partly since freshness is an issue - not so much if just being used for barrier coat - I had the impression that purists favored mixing from flakes. Something about rolling your own .  .  ..

Recent experience with Shellac was on Jeff Weiss' recommendation, barrier coat for filling red oak. After that, since I had it on hand and understood you could put it on anything, I used it on a table I was refinishing and wasn't positive what kind of polyethylene was already on it. The table needed refinishing because my daughter had done a science project on it, best cleaner for pennies, over newspaper, and .  .  . enough said. A case for a barrier coat.

I sanded the thing down to get rid of discoloration, which was quite a bit of sanding. The shellac went on great but dried to a surface-of-the-moon appearance. You name it, it was going on. Tried sanding and reapplying shellac a couple of times, no go. The shellac wasn't handling the contamination. No barrier effect there for sure, as the additional coats of Shellac showed little difference, and what there was probably came from the additional sanding.

Finally just went with poly - oil I think - and only issue was uniformity - the wood, red oak again, "taking" the finish more readily in some areas - which was solved with recoats. So it's good, 'cept it remained in my shop and got a spot of EM6600 thru the paper I had on it. The color came off but left a blemish. Like daughter .  .  .. The finish was "good enough" but I was thinking of sanding out the few nibs and trying some polishing, so maybe I will.

 

[tjbnwi]

With all the issues your having with finish compatibility, I'd suggest you just move to another location. Has to be something in the air.  [eek]

Tom

 

[Scott B.]

With all the issues your having with finish compatibility, I'd suggest you just move to another location. Has to be something in the air.  [eek]

Tom

Anywhere you go, you always take the weather with you. 

On further review, I am leaning toward capillary action as the culprit.

 

[tiralie]

John:
Thanks again for posting and letting us comment/help you with your issues. I am sorry it's been such a problem for you but if it's a small consolation, I have enjoyed the discussion and the learning.

So we don't bog down in endless speculation, I would suggest that you make some tests (Tom's suggestions, your original recipe without the shellac, etc.) on either maple or mdf and then if you want tell us what happened.

Hopefully my comments below help and don't add more confusion.

Waterborne, shellac, no. Fesh from flakes dissolved in alcohol. On advice of Jeff to to deal with the Red Oak tannic acid, a barrier coat. Applied over filler, around halfway thru the filling process. Should have been done first, but I didn't  know about then. I see waternborne shellac is questionable for the purpose, don't think I ever knew it existed.

Target's water borne shellac (UltraSeal-WB Shellac Sealer) is very good. On stained pieces, I have used it as a sealer under EM 6000 it cancels out the blueish haze common with most waterborne lacquers. I use it regularly and you can see some of the results on previous projects posted here and on the Target site.

If I stain a poorly sanded board and then clear coat with 60000 and then SC 9000, my sloth is quickly exposed through the coating.
So the lesson for me is if my substrate preparation is crap, I won't get away with it and  it will be exposed through the clear coating.

That sounds like the 6000 will burn in and hide a bad scratch, but not lesser scratches? Or is it just hiding finish issues and - of course - not hiding unaddressed wood/substrate issues?

The oak was a pretty surface before the first filler.

I won't hide pigtails etc. in substrate but when the EM 6000 is sanded and re-coated the burn in covers the scratches from sanding the previous coat of EM 6000

If you are afraid of trapped solvent etc. spray two coats of EM 1000.

I don't think my speculations are worth much - If you think there's a chance that would get me back on track I'll order some tomorrow. Meanwhile, what sanding, if any, would you recommend?

If the 1000 will really isolate the underlying solvents and thus stop shrinkage showing thru - whatever's happening - no sanding should be needed? Just apply it, sand smooth, and go to color coat again?

No, forget coating with 1000. You have sanded enough for now. I doubt sealing the 5100 will help because it appears the 5100 is not curing properly. Since I am not able to see your finish and I have engaged in enough speculation I don't think it's fair to you to continue to do so.

using the same techniques you have to this point, get a new piece of oak and a new piece of maple. On half of the piece of oak, fill the grain (only half, we want to see if the filler is screwing with you). Once done shoot the products on the test pieces. Lets see what happens.

Worth a try. However, the filler, if that's the issue, didn't start screwing with me till I had - well, let's just say over ten coats on. That's a long test.

I think you should do the test Tom recommends, but with out the shellac step.

One thing further, about changing to a new material - I have noticed that the EM6600 does not seem - before clearcoat - to be really jet black. It's a deep gray. For me, blacker is better.

You would know if you had done a test board prior to this.and this is just another reason to do a sample board or your intended recipe. You really need to understand what is happening at each stage of the process so you can be confident that you see at any stage during the process is not the final or end result. Test panels do this for you. If you can create it once and repeat it then you have it down.

So, OK, just what is the best material to use for a black color coat and top coat id I'm still looking to polish out to gloss?  Soooo open ended.

I noticed that General finishes makes a waterborne black polyurethane. I would definitely try that, (test it first) as traditionally that is part of how to achieve a "piano black".

Good luck. If you have time please post your tests, I (we) would love to see them.

Tim

 

[jhaley]

Scott-

capillary action

That's a new one on me. Have to try some insecticide.

[attempted humor] Not sure what you refer to, unless something being sucked up from underneath the finish surface. Certainly something is causing the surface to change a lot as it hardens.

I am trying to see if I have pigtails in areas with no or little filler, like the drawer sides and the back of the cabinet. It seems they are there, perhaps not in same degree. The finer the finish the easier they are to see. Not conclusive yet.

Festool did suggest sending in the sander, but I am focused on the material being soft an I could not - can not - imagine what malfunction in a sander, not in the pad (changed pads several times), could cause this. But I found:

http://www.woodtalkonline.com/topic/2989-orbital-sander-pigtails/

Interesting. Especially the exchange between Abita Dave and P Elliot a few pages down. I've ordered another ETS/3 sander. And I'll try others I have on hand.

Several users there remark that using the edge of the disc can cause pigtails to appear earlier earlier than they might otherwise. This is reasonable if the edge is damaged somehow, but just because it was carefully lightly used at a like a 3-5 degree lift? I've been doing that to help with blemishes. I don't think it should hurt the pad, and as soon as the material shows any wear - rare - I toss it.

Also, I've often lately been working on pieces with no blemishes using a fresh abrasive, still get the same pigtails.

Maybe I'll try a virgin pad and abrasive.

______________________________________
Tom-

Has to be something in the air.

That or I'm holding my mouth wrong.

_________________________________________
Tim-

You guys have been great. I'll do some researching and testing.

Tom's test you refer to is, I believe

Using the same techniques you have to this point, get a new piece of oak and a new piece of maple. On half of the piece of oak, fill the grain (only half, we want to see if the filler is screwing with you). Once done shoot the products on the test pieces. Lets see what happens.

But skipping the shellac, as there's no red oak to worry with here.

I can get MDF and Poplar with no trouble, so I'll use those.

I'm thinking there's an argument to me made for MDF over any wood under a finish that isn't intended to show grain or wood. It just isn't fun stuff. And heavy.

You say

forget coating with 1000.

but note that

Target's water borne shellac (UltraSeal-WB Shellac Sealer) is very good. On stained pieces, I have used it as a sealer under EM 6000 it cancels out the blueish haze common with most waterborne lacquers. I use it regularly and you can see some of the results on previous projects posted here and on the Target site.

Not sure if you recommend I use - or test - Target's shellac at this point. I think it was Jeff himself that put me onto flakes.

I noticed that General finishes makes a waterborne black polyurethane. I would definitely try that, (test it first) as traditionally that is part of how to achieve a "piano black".

I've ordered the black poly plus the clear they recommended over it. Will test and report.

I've said I'd do quite a bit - and it is my intention to do it all - but I don't always find time to do all I intend!

Rest assured, though, that all this isn't just an exercise - it will be acted on.

Again, You guys have been great.

 

[tiralie]

Tom's test you refer to is, I believe

Using the same techniques you have to this point, get a new piece of oak and a new piece of maple. On half of the piece of oak, fill the grain (only half, we want to see if the filler is screwing with you). Once done shoot the products on the test pieces. Lets see what happens.

But skipping the shellac, as there's no red oak to worry with here.

I can get MDF and Poplar with no trouble, so I'll use those.
I'm thinking there's an argument to me made for MDF over any wood under a finish that isn't intended to show grain or wood. It just isn't fun stuff. And heavy.

Yes, that's the test I was referring to.
And yes definitely use MDF or Poplar. You can buy MDF with a plywood core which reduces weight but it may be difficult to find in your area.

You say

forget coating with 1000.

but note that

Target's water borne shellac (UltraSeal-WB Shellac Sealer) is very good. On stained pieces, I have used it as a sealer under EM 6000 it cancels out the blueish haze common with most waterborne lacquers. I use it regularly and you can see some of the results on previous projects posted here and on the Target site.

Not sure if you recommend I use - or test - Target's shellac at this point. I think it was Jeff himself that put me onto flakes.

I was recommending for future. It's compatible (doesn't react) with all other water borne coatings and Target's shellac sealer has never given me any problems. Unless I am doing a French finish I won't bother with mixing my own shellac from flakes.

I noticed that General finishes makes a waterborne black polyurethane. I would definitely try that, (test it first) as traditionally that is part of how to achieve a "piano black".

I've ordered the black poly plus the clear they recommended over it. Will test and report.

I've said I'd do quite a bit - and it is my intention to do it all - but I don't always find time to do all I intend!

No worries, take your time, we're not going anywhere  [big grin]

 

[jhaley]

4-20-13 Update - The real news here - not good - is at the end of this post.

Have received and tried a new Festool ETS 150/3, just in case mine was somehow misbehaving. No difference in results.

One coat of clear has been on drawer fronts for about three weeks. Have been working on the sides since they are unimportant and still not sure how to proceed with critical areas. Changes under clear - pinholes and grain appearing - are holding steady since they appeared at about ten days after clear coat. (Finish had appeared steady for weeks before clearcoat, in fact had never in this long project seen these blemishes.

Lightly Sanded drawer #4 using fresh abranet 600g. Same pigtail issue. Changed to 400g and got less loading but still pigtails. Tried Festool Brilliant 400, no good, loading. Disappointed the finish even now apparently still not hardened enough for critical sanding.

Recoated #4 with color due to discolorations showing, as I'm either down tru the clear to color or almost there. Maybe even to filler or close.

Have poplar and MDF on hand. Planning to apply EM6600 direct to surfaces, also some HSF5000 and then EM6600. For a sanding test I have to get a pretty smooth finish - pigtails won't "show" the same on a rough unbuilt finish.

Sprayed 2nd coat clear on drawer #3 after light sanding of the clear. Surface about what I've been seeing, not perfect. Will swirl marks show under this clear-on-clear? The verdict is in, and it’s not good. They do show, in spite of what everyone’s universal experience is. Seems I'm just not getting any burn-in at all between coats?

 

[Scott B.]

jh

This is starting to keep me up at night. Actually, I really don't sleep much, so when I am up at night, I do think of this issue.

My question for you today: the batches of product that were used on this project, were they existing stock or newly purchased for the project?

 

[tiralie]

jh

This is starting to keep me up at night. Actually, I really don't sleep much, so when I am up at night, I do think of this issue.

My question for you today: the batches of product that were used on this project, were they existing stock or newly purchased for the project?

I'm assuming they have been properly stirred...I know it's pretty basic but I suppose it doesn't hurt to ask. I was testing some EM 9000 satin and didn't stir it (thinking it was fine) and got an extremely glossy test board!
Duh!
Tim

 

[jhaley]

Scott-

Short answer, purchased for the project.

Long answer:  Bought original lot of material from Target 6/11. Jeff Weiss advised. Original pressure pot spray set from Homestead same time. Jeff Jewitt advised.

In unopened cans for some time. Probably early 2012 first applications. Think I first sprayed the entire project with EM6600, got it black. Probably two coats, used most of a gallon. Then started HSF 5100 filler (tinted black) and worked with that a loooong time. Then on Jeff Weiss's advice hit it with dewaxed shellac for barrier against red oak acid. More 5100, a lot more. Using most of a gallon on just the critical surfaces (top, front, sides, not insides or back and drawer fronts only). Put it on, usually with a brush and scraping excess, then sand it down, off. Not that much build.

Got new materials 7/12, started using HSF 5000 (gray) and spraying it. Ordered fresh EM6600 3/5/13 when ready for color coat - not enough old batch left. Have used almost all of that and most of a gallon of EM6000 clear now.

This is starting to keep me up at night.

Now, that's what I call support! At that level of involvement you can imagine what my state is.

__________________________
Tim:

About stirring:

It's a thought. Could be an issue some of the time when drawing from the pressure pot. Can't see it, out of sight .  .  .. I let the material sit there, sealed, rather than clean the pot daily. But with the 6600, realizing it separates, I've been pretty good about opening the pot and stirring, not just swishing.

Almost all of the HSF 5100 was applied by brush. Couldn't forget to stir.

Now I have 6000 in the pressure pot and I've been less concerned. When I originally opened the can, after it had been sitting - what, since 7/2011 without much attention, and stirred, I saw little need, and I always thought it was pigments or tints that separated mainly, and with none in it .  .  .. Anyway, both materials, the stirred 6600 and the less stirred 6000 are acting the same.

I always stir when I go to the original can, and with using the clear disposable cups on the SATA I just swirl/shake it if it's been a while, like a day.

About materials:

It's been mentioned several times that I should move on from the EM6600. Haven't talked to Jeff Weiss yet intend try Mon. Since I need more materials anyway - about out - I'm expecting I'll not continue with Target.

Have already ordered Polys from General Finishes.  Tim, that was your last recommendation:

I noticed that General finishes makes a waterborne black polyurethane. I would definitely try that, (test it first) as traditionally that is part of how to achieve a "piano black".

But before that you made another material sound attractive:

I would strip off as much of that 6600 as you can, sand back and then I would seal with a 2 part polyester sealer (ICA makes a post catalyzed water borne sealer, but I have never tried it), it's high build and marketed as low shrink back. This gives you a "level" playing ground and a coating that can handle the sanding. I would level sand the sealer and coat with 2 coats of EM600 tinted with Black Mixol let cure and buff etc. or coat with EM 9000.

Quick look at their site is - well, they're marketing to me:

Claiming almost "nonexistent" shrink back and:

   -Looks like - and stays looking like a mirror
   -No more fear with putting down hot cups or wine spills
   -Far fewer coats than with conventional materials
   -Wet on wet cycles mean fewer sanding steps and faster processes
   -the ultimate "piano finish"
   -Can be used to build, with polyurethane as a top coat

Q: Forgetting that I already ordered General, would you care to advise between the ICA 2 part and the General product? I might go ICA left to myself.

Finally, you mention tinting the EM 6000 with black mixol. Clears are used for some reason. Depth? They're harder?

If there is no down side to tinting the clear there is, for me, a huge up side. The tint will cover my pigtails and I'll only have to worry about rubbing out the top layer. That's attractive.

I asked about using EM9000 instead of 6000 when I last ordered from Target, since their site makes 9000 sound like improved 6000. Wound up with the 6000, recall no specifics why.  Care to comment on 6000 vs 9000, and would you tint the 9000?

There's still the issue of putting a good hard coating over a soft one. I understand it's a finisher's maxim not to.

 

[tiralie]

About stirring:

It's a thought. Could be an issue some of the time when drawing from the pressure pot. Can't see it, out of sight .  .  .. I let the material sit there, sealed, rather than clean the pot daily. But with the 6600, realizing it separates, I've been pretty good about opening the pot and stirring, not just swishing.

Almost all of the HSF 5100 was applied by brush. Couldn't forget to stir.

Now I have 6000 in the pressure pot and I've been less concerned. When I originally opened the can, after it had been sitting - what, since 7/2011 without much attention, and stirred, I saw little need, and I always thought it was pigments or tints that separated mainly, and with none in it .  .  .. Anyway, both materials, the stirred 6600 and the less stirred 6000 are acting the same.

I always stir when I go to the original can, and with using the clear disposable cups on the SATA I just swirl/shake it if it's been a while, like a day.

Hmmm, hard to tell by this account if that's a problem or not. Wouldn't be a bad idea to get an "agitator" for that pressure pot if you are going to keep your material in there any length of time. When I tint EM 6500 with BM Aura tints, I need to stir before every coat. Both Binks and CAT make agitators for their pressure pots.

About materials:

It's been mentioned several times that I should move on from the EM6600. Haven't talked to Jeff Weiss yet intend try Mon. Since I need more materials anyway - about out - I'm expecting I'll not continue with Target.

I think you should do a test with the EM 6600 on MDF. Based on this discussion I really don't think that is the problem area. If I understand correctly, my guess (it's really only a guess) is the layer of shellac between the two layers of 5100 is the issue.

Have already ordered Polys from General Finishes.  Tim, that was your last recommendation:

I noticed that General finishes makes a waterborne black polyurethane. I would definitely try that, (test it first) as traditionally that is part of how to achieve a "piano black".

I would definitely do a test run with this spray wet on wet (spray second coat of black polyurethane as soon as the first gets sticky or "stringy") to get a good build, wait till your coats cure completely and then add your top coats etc.

But before that you made another material sound attractive:

I would strip off as much of that 6600 as you can, sand back and then I would seal with a 2 part polyester sealer (ICA makes a post catalyzed water borne sealer, but I have never tried it), it's high build and marketed as low shrink back. This gives you a "level" playing ground and a coating that can handle the sanding. I would level sand the sealer and coat with 2 coats of EM600 tinted with Black Mixol let cure and buff etc. or coat with EM 9000.

Quick look at their site is - well, they're marketing to me:

Claiming almost "nonexistent" shrink back and:

   -Looks like - and stays looking like a mirror
   -No more fear with putting down hot cups or wine spills
   -Far fewer coats than with conventional materials
   -Wet on wet cycles mean fewer sanding steps and faster processes
   -the ultimate "piano finish"
   -Can be used to build, with polyurethane as a top coat

Q: Forgetting that I already ordered General, would you care to advise between the ICA 2 part and the General product? I might go ICA left to myself.

I would hold off on the polyester, and based on the additional information you have provided I don't think the polyester will help as your original coating still seems to be soft. Also, my apologies but I made a mistake and referred to the ICA polyester as water borne but it is solvent only. My rep tells me that Steinway in NY is using this product so it should be good, but that is a production environment and they have access to so much more (spray booth, venting etc.) so I would try the General black polyurethane first.
If you go ahead with the polyester, you must seal the substrate (MDF, maple etc.) first so the polyester can adhere. Generally the sealer of choice is a vinyl sealer but there are others depending on manufacturer. There are some good priming and Leveling application for MDF and Wood on the Hawkeye Industries Inc. site.

Finally, you mention tinting the EM 6000 with black mixol. Clears are used for some reason. Depth? They're harder?

My understanding is that there usually more control over custom color tints etc.

If there is no down side to tinting the clear there is, for me, a huge up side. The tint will cover my pigtails and I'll only have to worry about rubbing out the top layer. That's attractive.

Other than (for some reason) black pigment extends the curing time in any coating (even Mixol pigments added to clear) there is no downside that I am aware of...

I asked about using EM9000 instead of 6000 when I last ordered from Target, since their site makes 9000 sound like improved 6000. Wound up with the 6000, recall no specifics why.  Care to comment on 6000 vs 9000, and would you tint the 9000?

Hmmm, EM 6000 is marketed as a water borne version of a pre-cat (nitrocellulose) lacquer, whereas EM 9000 is a water borne polyurethane. They are two different products. Polyurethane is typically harder finish than a nitrocellulose lacquer. Some people have problems spraying polyurethane so that may be why they steered you away from it. I have never had any problem spraying 9000, but like all polyurethanes, it can be unforgiving if you make a mistake. It really is not fun to sand out errors. I wouldn't tint 9000 but that's me. I often make errors, and I wouldn't want to have to sand a tinted 9000 and then try to match the shade. It would be impossible.

There's still the issue of putting a good hard coating over a soft one. I understand it's a finisher's maxim not to.

Unless my clients are keeping something from me, I have not had any problems with EM9000 over EM6000.

 

[jhaley]

Tim-

wouldn't be a bad idea to get an "agitator"

My pot's a Walcom - I've asked them about it via email. Been using a stick-stuck-to-the-end-of-a-stick to get in there.

I think you should do a test with the EM 6600 on MDF. Based on this discussion I really don't think that is the problem area. If I understand correctly, my guess (it's really only a guess) is the layer of shellac between the two layers of 5100 is the issue.

Straight to the bare MDF?
The shellac seems remote now. Jeff Weiss knew the situation - the shellac not going on first, 5100 already there and more coming - when he recommended it.
Haven't been able to get in touch with him for a while.

spray second coat of black polyurethane as soon as the first gets sticky or "stringy"

Meaning no longer

wet

? "Stringy" isn't translating. Appx. time?

Re the test run with the GF Polys on MDF, again, no base coat or filler, straight to naked MDF?

If the test run with the GF Polys goes well, I'll sand down some of my Target materials to some point and shoot the poly to the project. Sound right?

An aside re the solvent polyester: My hesitation in using it would simply be lack of "explosion proof" fans. Safety first, I know, but I wonder if anyone has any experience .  .  .. The closest fan isn't often used during spraying and since it draws in outside air it shouldn't see solvent. The exhaust fan is in a ducted space in the attic more like 15' as the spray flows up and out. Stuff should be pretty dry by the time it sees a spark. I just haven't heard of any spray booth terror. Don't want to, though.

Other than (for some reason) black pigment extends the curing time in any coating (even Mixol pigments added to clear) there is no downside that I am aware of...

If the new clear material burns in enough to hide sanding marks, I'll go without pigment. A down side that occurs now is matching. If I'm rubbing out the pigmented topcoat and get thru it to color, and it doesn't exactly match . . ..

like all polyurethanes, it can be unforgiving if you make a mistake.

Anything special to look out for?

I have not had any problems with EM9000 over EM6000

I was thinking thinking my EM6000 isn't behaving like yours. Staying soft, at least acting that way toward high grit paper. And that putting anything over a soft finish was a no-no. 

 

[Scott B.]

jh

This is starting to keep me up at night. Actually, I really don't sleep much, so when I am up at night, I do think of this issue.

My question for you today: the batches of product that were used on this project, were they existing stock or newly purchased for the project?

I'm assuming they have been properly stirred...I know it's pretty basic but I suppose it doesn't hurt to ask. I was testing some EM 9000 satin and didn't stir it (thinking it was fine) and got an extremely glossy test board!
Duh!
Tim

Tim

Thats not the angle I was asking from.

After significant cranial time, if this was old (previously opened) or new (unopened), its a drier failure. Regardless of what Jeff Jewitt or Jesus Christ himself may say here, all other variables have been exhausted. Drier failure resulting in flawed cure, resulting in loaded abrasives, resulting in swirls, resulting in hours and hours of analysis.

Product failure.

 

[Scott B.]

Now, that's what I call support! At that level of involvement you can imagine what my state is.

I am going to guess that you are being serious and not sarcastic here, and I will respond in kind...

This dog didnt hunt. Fortunately, it is a DIY project. You are not being paid, and you have no customer other than a wife who just wants the darn thing in the house. At this point, honestly, you would be best served to get rattle cans of spray paint and spray the thing gloss black and be done with it.

This is getting silly. Learn from it, and move on. The next project will be a grand slam.

 

[tiralie]

I'm assuming they have been properly stirred...I know it's pretty basic but I suppose it doesn't hurt to ask. I was testing some EM 9000 satin and didn't stir it (thinking it was fine) and got an extremely glossy test board!
Duh!
Tim

Tim

Thats not the angle I was asking from.

After significant cranial time, if this was old (previously opened) or new (unopened), its a drier failure. Regardless of what Jeff Jewitt or Jesus Christ himself may say here, all other variables have been exhausted. Drier failure resulting in flawed cure, resulting in loaded abrasives, resulting in swirls, resulting in hours and hours of analysis.

Product failure.

LOL, Yes I know.
Tim

 

[tiralie]

I think you should do a test with the EM 6600 on MDF. Based on this discussion I really don't think that is the problem area. If I understand correctly, my guess (it's really only a guess) is the layer of shellac between the two layers of 5100 is the issue.

Straight to the bare MDF?
The shellac seems remote now. Jeff Weiss knew the situation - the shellac not going on first, 5100 already there and more coming - when he recommended it.
Haven't been able to get in touch with him for a while.

Yes, you can spray 6600 on bare wood, but I would get a new can so as to make sure you are not introducing any of the previous problems from your old batch. 6500 and 6600 will adhere/stick to bare wood. I would apply/spray a minimum of 3 coats, the first is the primer coat and scuff sand between coats. If you want get some EM 1000 (it's good to have around) and seal first but really not necessary.

spray second coat of black polyurethane as soon as the first gets sticky or "stringy"

Meaning no longer wet? "Stringy" isn't translating. Appx. time?

Just before the surface gets hard, so the timing will vary depending on how warm your space, mil thickness and the humidity but I would say about 15-30 min after finishing your spraying....it should be sticky to the touch. It's not super critical but easier to get a higher build when it's wet on wet.

Re the test run with the GF Polys on MDF, again, no base coat or filler, straight to naked MDF?

I would spray the 6600 as above as a base coat, and then when completely cured, spray the GF poly over it.

If the test run with the GF Polys goes well, I'll sand down some of my Target materials to some point and shoot the poly to the project. Sound right?

Wouldn't hurt to try, particularly as you will have the test piece to compare it to.

An aside re the solvent polyester: My hesitation in using it would simply be lack of "explosion proof" fans. Safety first, I know, but I wonder if anyone has any experience .  .  .. The closest fan isn't often used during spraying and since it draws in outside air it shouldn't see solvent. The exhaust fan is in a ducted space in the attic more like 15' as the spray flows up and out. Stuff should be pretty dry by the time it sees a spark. I just haven't heard of any spray booth terror. Don't want to, though.

Yes, don't do it I think you will arrive at a reasonable solution to the problem without going that direction.

like all polyurethanes, it can be unforgiving if you make a mistake.

Anything special to look out for?

Sags and runs and bubbles. Bubbles usually means too much air but that is not always the case. Extremely visible on gloss but you do have to have enough coating on otherwise it won't level properly. Shouldn't be a problem with the tests.

I have not had any problems with EM9000 over EM6000

I was thinking thinking my EM6000 isn't behaving like yours. Staying soft, at least acting that way toward high grit paper. And that putting anything over a soft finish was a no-no.  

Get some new EM 6000 and some new 6600. Stir them well before using and spray them with your cup gun vs. your pressure pot. Hopefully these test will give you the results you deserve.

 

[jhaley]

Tim-

Once again, you have addressed every issue I have raised. Thanks so much. My GF poly arrived yesterday. I think next I will test them as advised. If that goes well, I'll likely not order fresh Target for testing, though I am curious. May test the old stuff just for that. Anyway, I know for sure it works for others.

Still no word from Jeff Weiss. Think we may have our Jeff's confused, re your Scott's (?) mention of Jeff Jewitt on 4/23.

You might be interested in: http://www.targetcoatings.com/forum/viewtopic.php?p=11389#11389

Seems like a similar case. Similar response from JW (none yet).

Oscar Wilde said (not my favorite quote, but perhaps applicable here) "To lose one parent is a misfortune. To lose both appears careless." I'm afraid I have so much going on I appear careless. Can't really blame JW if this DIYer doesn't attract his attention. Such a mess, eyes glaze over, folks just want to move on. So I certainly appreciate those who stick around and try to help.

 

[jhaley]

The materials change:
-The GF poly materials are working better for me but it's a matter of degree, not a cure. They get much, much harder, and get there quickly. They sand better and I can even wet sand them. But pigtails persist.

Mirka sanders:
-Tried Mirka sanders. Believe they are better, but again it is a matter of degree, not a solution. Pigtails were tad less obvious - maybe - and seemed less likely to include the random non-uniform worse problematic pigtail. This is with the same abrasives, mainly abranet.

-Their finest (3/32 orbit) machine is air only and I don't like that. It's damn cute, light, and maneuverable, but so small that with the the air line and vacuum hose attached - at the bottom of the machine - you have to lift those to keep them from rubbing the work edge. And I'm doing some fairly large surfaces.

-Though it does pretty work it's more demanding that the festool. You must always start with the machine on the work or you'll make a mess when you contact the work. Every time. With the Festool I get away with it every time.

-With the Mirka you cannot finesse narrow work like the edges of doors. I can sand out finish on the edge of a 3/4" board with the Festool, don't try it with the Mirka. The pad edge on the Mirka is very hard and cuts thru the finish immediately with slightest misalignment. I'm generally using the hard pad on the Festool so that's my standard for comparison. (I use the hard pad to protect the edges of the work from wraparound sand-thru when working with the edge of pad out past the edge of the work - project is all flats, with hard, sharp, vulnerable, square edges.)

-It may be the harder GF materials or the Mirka - I'm going to say it's both - but I have almost forgotten the dread of sand-thru when working with the pad edge over the edge of the work. I know it's partly the material because I'm back to mainly using Festool and still no edge worries.

-The finest Mirka Ceros (brushless DC) is 3/16 orbit, not quite as fine as the ETS/3. It's very nice, but you do have to mess with a transformer switch, vacuum hookup is a headache if you're switching back and forth with Festool, and my understanding is that even if you get a Mirka vacuum (I have the Mirka hose and it fits my Festool vacuum) it does not have the convenient feature of auto start. Doubts, but that's what they said. Bottom line is I'm pretty much back to Festool for convenience and ease of use.

Test Popular, MDF:
-On my popular and MDF test pieces I have three coats of color. Sanding experience is as above. Now several coats of clear on the Poplar.

-I am getting no burn-in effect on sanding marks, none any time, even with the GF materials. If there are scratch marks on the surface, they will be amplified under the clear. No hiding at all. I'm mystified that the whole world of finishing - including mfg's directions uniformily saying to sand to 220 or so, sometimes 400,  between coats of clear - says there it no need to, in effect, polish under clear. Not happening in my world.

-However, to my surprise, as I have never seen it mentioned, additional coats of clear will obscure and then hide the pigtails and any other marks. (There is some confusion in this result - see below on polishing top coat after sanding out imperfections.) This assumes, of course, that I don't sand at all between coats. Which means accumulating lots of imperfections. It got pretty bad so I sanded them out on one area before the last coat, and sure enough, that area has less imperfections but plenty pigtails.

-Not sanding between coats of clear presents the problem of flaws in previous coats showing under/thru the top coat, or it being impossible to sand out the accumulated visible flaws (without going way down thru previous coats). I was apprehensive about this, but when I sanded out the top coat on the popular I got rid of imperfections without a great deal of sanding, starting at 800g. No evidence of "buried" flaws, flaws in lower unsanded coats. Started with 800g abranet, then 1000 g abranet, then 2000g abralon, then 4000g abralon.  No pigtails evident on the top even on inspection - I'd been unable to get that result in color. But the finish was still semi-matte, no see-thru. So I polished an area to see-thru and saw - pigtails. I had been looking to see - or not - flaws in the underlying unsanded clear coats. I could, but only on close inspection. What was more evident was - pigtails. Pigtails that I had not been able see under the top layer of clear before sanding out imperfections and polishing to see-thru. It seemed those pigtails must be in the color coat, and before the sand/polish they were invisible under the third coat of clear. The color was sanded at least to 1000g abranet.  (Must confess some lack of certain memory in this experiment - perhaps I need to give the matter more of my attention but I'm sure I should have already lost my wife and job over it!!)

So: Can't see the pigtails under several coats of clear. Good. Sand and polish and there they are again. Where the heck does this leave me? Went back and for some reason polished a lot more - and voila! The pigtails disappeared. They were in the top coat of clear. I had looked so carefully before polishing and not seen any sign of them that I was sure there were none.

So now: I can get rid of pigtails. But only under with multiple unsanded coats of clear, and not  until the top is polished. Fine, but now that I have polished the whole piece I can see - in the right light, which is sky or diffuse, not flashlight inspection - what must be the imperfections in the unsanded layers. Like pimples, but you can't feel anything, so they're subsurface. And I find them objectionable. Where to go from here?

Experiment more, I guess.

-I have applied three coats of GF poly color to my doors, roughly 2'x2' panels. They are sanding just like the "virgin" poplar so I may be getting away with applying the GF over the apparently failed Target materials, including all the filler.