What did I do wrong? CA/BLO finish...

[itsme_timd]

OK, I thought I had this finish down pretty well. I turned my pen and started the finish and after the 1st application it looked like it coated in glass... that was the *POP* I'd been looking for.

However, I went back for a 2nd application and then I went to wipe it off with a clean paper towel, the finish "smudge" (can't think of a better term, it just started looking cloudy instead of clear and shiny) and I went back through the MM and that wouldn't fix it - looks like I'll have to sand and refinish.

Here's my method.

1) Went through all the sanding steps.
2) Applied BLO with a paper towel.
3) Apllie 3 passes medium CA with same paper towel I applied BLO with.
4) Sprayed accelerator on the blank.
5) Waited about 60 seconds.
6) Went through all MM (looking really good here!)
7) Used a clean paper towel* to wipe the blank.
8) Smudge the blank and can't fix it!

* The only thing I think may have happened was some sweat on the towel, but would that cause this to happen. The finish is very cloudy in the center of both blanks but the ends look great???

I'm going to sand and refinish this one but would like to know how I messed this up!

Thanks,

 

[Monty]

What wood are you using it on. I've had that happen with oily woods like coco & BOW.
Found that it helps if I wipe the blank with accelerator after sanding and before applying BLO or CA.

 

[leehljp]

First of all, think of this as a learning process and that while you will get several answers as to the cause, the final determination for cause and fix or prevention will be from your own experience.

Some people get cloudy CA from their accelerator or not letting it sit long enough. Old CA will do this in some cases. If the wood was green or not totally dry, rubbing it or heat building up from sanding and wiping will cause it to "heat" of course, which will cause moisture, even oily moisture - to be released into the finishing process. Moisture is often the culprit for cloudy finishes.

 

[DCBluesman]

Here's my method.

1) Went through all the sanding steps.
2) Applied BLO with a paper towel.
*
3) Apllie 3 passes medium CA with same paper towel I applied BLO with.
4) Sprayed accelerator on the blank.

* Probably cause: Not allowing the BLO to dry. It really needs overnight and a full day is better...unless you add heat, which will shorten the drying time.

 

[itsme_timd]

Thanks everyone. The wood is Amboyan burl and the glue is a brand new bottle.

Lou, aren't you supposed to put a couple of coats in one after the other? This happened when I was trying to apply the 2nd coat.

 

[DCBluesman]

Lou, aren't you supposed to put a couple of coats in one after the other? This happened when I was trying to apply the 2nd coat.

If the BLO is not dry, it will release moisture under the CA due to the heat CA gives off as it cures. That can happen at about any time. Generally, the BLO will dry over time and the cloudiness will disappear. It may take a week or more.

 

[stolicky]

I am running into the same exact thing. Its crystal clear on the ends and cloudy in the middle. I have even had matte (cloudy) streaks in different areas before.

I two (the latest case at hand) have some beautiful amboyna burl which I intentionally took my time, over a couple of weeks, to complete. I applied BLO three different times and let it sit for days. I did heat it up when I applied it. I gave it the new bottle (thin) CA treatment, a couple of coats worth, and let it sit over night. The next day, I sanded it briefly with 600 grit and went back to the CA/BLO; with no more than 2 drops of BLO. The end result, cloudiness except for ends.

I purposely did not install the kit yet to see how the finish holds up/changes. I am carrying the pieces around today and playing with them every so often to see what happens. I would hate to dress my Lotus kit with these formally beautiful blanks... : (

Darn it, I want exterior beauty here, not just what's inside!! : )

 

[itsme_timd]

Yep, that's exactly what's happening to me. The ends look phenomenal but hazy in the middle...

 

[stolicky]

If the BLO is not dry, it will release moisture under the CA due to the heat CA gives off as it cures. That can happen at about any time. Generally, the BLO will dry over time and the cloudiness will disappear. It may take a week or more.

So, even with layers of CA over the clouding, it will clear up?

 

[marcruby]

I too experienced this problem -- on a smaller scale, and with rosewoods and cocobolo. I attributed the fault to me -- It had been a while since I had made a wood pen and I figured I had screwed up the process somehow.

If what you are saying is correct, and I have no reason to think it isn't, then it changes my understanding of how the CA and BLO interact. I thought the two layers intermingled somehow, with the BLO and the paper towel acting as accelerants for the CA and when the CA had set then it was good to go with the next layer.

If I understand what you are saying than the finish is really a sandwich of BLO and CA layers. And that early application of a CA layer can seal moisture into the BLO layer and interfering with the setting. That would explain the phenomenon and certainly explain which subsequent layer pairs only seem to make things worse.

At this point, I'm wondering what purpose the BLO layer actually serves, other than as filler. And whether something else (shellac, waterlox sealer, or even something like Velvit Oil) might work as well or better. The Velvit Oil is of special interest because it doesn't darken the wood as much as the others do. Well, obviously, I've just invented a project for myself.

In any case, would you mind listing out your own steps, and their timing. I know that's an imposition, but it would help me to use a successful process as the basis for further research.

Marc

If the BLO is not dry, it will release moisture under the CA due to the heat CA gives off as it cures. That can happen at about any time. Generally, the BLO will dry over time and the cloudiness will disappear. It may take a week or more.

 

[itsme_timd]

* Probably cause: Not allowing the BLO to dry. It really needs overnight and a full day is better...unless you add heat, which will shorten the drying time.

I guess this would make sense with the ends looking fine. It's more likely for the moisture to be trapped in the center however the ends will dry easier. My deduction skills could be faulty, but that would make sense.

So, if you're doing the CA finish and see the center is hazy but the ends are crystal clear then the most probable cause is the BLO not being dry, I think... :biggrin:

 

[stolicky]

Do you think the age of the BLO could have on impact? I bought it late last fall and with the the heat and humidity we have, could it have changed the properties some how?

The only reason I ask is because I did not used to have this problem with CA/BLO finishes; at least, not that I noticed.

 

[leehljp]

Do you think the age of the BLO could have on impact? I bought it late last fall and with the the heat and humidity we have, could it have changed the properties some how?

The only reason I ask is because I did not used to have this problem with CA/BLO finishes; at least, not that I noticed.

I had some real old BLO at least 10 years old that I used until recently when I bought a new bottle. Neither gave me problems specifically.

Just because a routine is followed step by step exactly each time with the same quality materials - this will not guarantee the same results every time.
Sometimes it will be a small change in our routine that we do not notice,
sometimes it may be the material or finish itself,
sometimes it will be the weather (humidity/temp)
sometimes a combination of two or more of the above.

 

[DCBluesman]

Please note two things. First, based on Tim's description, I offered a "probable" cause. It's also one of the easiest to correct. Second, finishing is an art, not a science. The only way I know of to guarantee no blush or cloudiness is to use no finish. That's easy on acrylics and not so easy on wood.

 

[leehljp]

. . .Second, finishing is an art, not a science.

Lou,

This is a masterpiece: "Second, finishing is an art, not a science."
Get this message out! :biggrin:

 

[itsme_timd]

Lou,

This is a masterpiece: "Second, finishing is an art, not a science."
Get this message out! :biggrin:

Well, it sure would be easier if we could just use some scientific reasoning here and "clear" things up (pun intended)!!!

 

[stolicky]

Just because a routine is followed step by step exactly each time with the same quality materials - this will not guarantee the same results every time.

Wouldn't expecting that be the definition on insanity? : )

I guess, it could be the humidity?

I began turning last fall and made several pens over the winter and did not have the problem. It seems to be only a recent problem this summer.

Are there any other turners in the extreme humid swings of the northeast that experience this issue?

Not to make it a geographical issue, I'm just thinking out loud. I know its typically humid year-round down south (where I grew up) and predominantly dry out west. [as a grand general observation] It may be the swings in weather that dictate finishing techniques?

 

[bdonald]

I thought the two layers intermingled somehow, with the BLO and the paper towel acting as accelerants for the CA and when the CA had set then it was good to go with the next layer.

If I understand what you are saying than the finish is really a sandwich of BLO and CA layers. And that early application of a CA layer can seal moisture into the BLO layer and interfering with the setting. That would explain the phenomenon and certainly explain which subsequent layer pairs only seem to make things worse.

At this point, I'm wondering what purpose the BLO layer actually serves, other than as filler. Marc

Yeah, I could use some clarification of this as well. From my understanding <which could very well be wrong> the BLO acts as an accelorator and curing agent for the CA, not so much as seperate layers, one impacts the other. As far as the CA setting and being good to go, that is what I gathered from Russ' excellent video in the how to forum, and have had great results so far doing one layer after another with minimal time between coats. I did notice that my finish improved drastically when I pulled my little shop fox VS out of retirement and use it just for finishes now, switching to high speed at the last stage.

 

[bdonald]

Wouldn't expecting that be the definition on insanity? : )

I guess, it could be the humidity?

I began turning last fall and made several pens over the winter and did not have the problem. It seems to be only a recent problem this summer.

Are there any other turners in the extreme humid swings of the northeast that experience this issue?

Not to make it a geographical issue, I'm just thinking out loud. I know its typically humid year-round down south (where I grew up) and predominantly dry out west. [as a grand general observation] It may be the swings in weather that dictate finishing techniques?

No, actually it's doing the same procedure wrong everytime and expecting different results As far as humidity, we can get pretty nasty here in MI, and I havent experienced that problem with my CA finish yet, but then again I havent hit the lottery yet either, and the commercials keep telling me that I may be the next big winner, so.... But, it is a good point and I'm curious as to how others from all parts of this great country chime in. Would be useful knowledge for us novices to have.

Bob

 

[DCBluesman]

Excerpted from my book. If you quote this, please give proper attribution.

The Physiology of a Good Finish

There are three components of any good finish: base coat (s); build coat (s); and top coat (s).

* The Base Coat – The Most Important
(Shellac, sanding sealer, friction finish, CA, etc.)

First, before reaching for any finishing product, it is critical to have a well-prepared surface. The best finish in the world cannot overcome a poorly prepared blank! Sanding, grain filling, and defect filling are of paramount importance prior to beginning the finish process.

The first (or only, in some cases) coat on a new wood surface should seal and even out the porosity and the density. On soft woods and end grain, multiple coats are desired in order to provide an even base for the build coat (s). Any unevenness needs to be addressed with additional base coats. The build coats depend on it!

* The Build Coats
(CA, CA/BLO, lacquer, polyurethane, etc.)

In general terms, the build coat is where we introduce moisture resistance, durability and depth of the finish. The base coat may provide some of these, but its primary purpose is to prepare the wood for the build coats.

Build coats should be gloss only. Anything else reduces clarity of the structure, grain and tone of the wood. In almost all products, the glossy version is the hardest. That's critical in build coats. Do not confuse this glossiness of the build coats with the final appearance, which is controlled by the top coat.

The number of build coats is dependent on two factors – the desired depth of finish and the softness of the wood. Softer wood requires more coats to provide overall moisture-resistance and durability. Durability of finish increases geometrically with the number of coats applied. Depth of finish is easy—more coats equal more depth!

* The Top Coat – The Ooohhh Factor
(Paste wax, Renaissance Wax, buffing compounds, TSW, etc.)

Many of us rush to this step as we are looking for the gratification of bringing to life that which we originally envisioned. Cutting short the two prior steps will insure that this step does not produce the original desire.

The top coat is almost all about esthetics. Matte, satin, semi-gloss and gloss sheens are imparted in this step. Surface preparation comes to the front again. The surface must be "roughed up" a bit in order to provide proper adhesion to the build coat (s). After light sanding, the surface must be cleaned thoroughly. Careful removal of dust and contaminants will save lots of time and aggravation. Pressurized air is one of the best means of cleaning the surface. If you're like me and don't have an air compressor, use the dust blower cans that are intended for cleaning out computers and electronics.

Since most of our finishes require buffing or polishing, it is critical that the prior layers of finish are completely dry and, for the most part, cured. This is the hard part since most lacquers take 2-3 weeks to fully cure and shellac (and friction polishes) can take 30 days or longer. In any case, one of the worst things you can do is rip the just-finished pen off the mandrel and begin assembly. Waiting even a few days will make a remarkable difference in how the end result looks and wears.

How CA Works

CA or cyanoacrylate is acrylic resin that cures (forms its strongest bond) almost instantly. The only trigger it requires is the hydroxyl ions in water, which is convenient since virtually any object you might wish to glue will have at least trace amounts of water on its surface. [NOTE: This convenience can become a disadvantage if you are using CA in a highly humid environment.] Cyanoacrylate molecules link up when they come into contact with water, and they whip around in chains to form a durable plastic mesh. The glue thickens and hardens until the thrashing molecular strands can no longer move. Cyanoacrylate glues are moderately toxic by skin or eye contact. They can glue the skin together or glue the skin and other materials together, sometimes requiring surgical separation. Acetone can be used to break these bonds. Eye contact can cause severe eye irritation. Their long term hazards are not well studied, especially with respect to inhalation.

Boiled linseed oil (BLO) is sometimes used in conjunction with CA in finishing. The primary purpose of the BLO is as a lubricant which allows you to level the surface. The accelerant action is really secondary. The BLO does not "mix" with the CA and does not form another layer or strata in your finish. In fact, excess BLO should be wiped off before each re-application of CA.

 

[bdonald]

Thanks Lou, great advice and information!

 

[itsme_timd]

Thanks for all the input everyone!