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problems with polycrylic

DRose's picture

Ladies and Gentlemen,


I think my problem may be technique, but I don't know.  I have sanded 4 coats of bubbles off my bookcases and am getting irritated.  I am using a new can of polycrylic satin, a quality synthetic brush and tackcloths.  I get bubbles pretty much everywhere on the finish, regardless of the number of brushings.  one spot would get 2 brush strokes and still yield bubbles in the finish just the same as the spot that got brushed 7 times trying to stop a run.  the humidity is pretty high, but the finish is still dry enough to touch in less than 20 minutes.  Anything I am not including or doing?


thanks


Dustin

USANigel's picture

(post #108041, reply #1 of 19)

I have had better results using the paint pads with the very short hairs. Another method is to use a cloth and wipe on thin coats. When you stir the poly go slow as air gets mixed in. Let the can settle for a few days and try again.

JohnWW's picture

(post #108041, reply #2 of 19)

Dustin,


If you are dipping the brush into the finish and then drawing the brush across the inside of the can's rim to remove excess finish before brushing it on the bookcase, that may be the source of your bubbles. 


With certain finishes "striking" the brush on the can's rim will cause the finish to foam and leave numerous small bubbles in behind on the wood.  The solution is to dip less deeply in the can, to prevent overloading the brush, and then going directly to the wood.  When starting each round of finishing, condition the brush by first dipping it into the solvent for the finish and lightly shaking the brush out before dipping the brush into the finish for the first time.


Also, as mentioned in an earlier post, don't stir bubbles into the finish by stirring too vigorously.


John W.

John White Shop Manager for FWW Magazine, 1998 to 2007

jazzdogg's picture

(post #108041, reply #3 of 19)

Dustin,


You could be having problems with flow-out (in addition to bubbles from stirring, etc.), which can be ameliorated by thinning.


I generally thin the first coat 50%, and the second coat 25%.


BTW - I don't recommend applying finish directly from the can. Pour a little finish into a small container used specifically to apply finishes and thin as needed. I usually strain finishes to eliminate contaminants that could make the finishing experience less enjoyable.


Good luck,


-Jazzdogg-


Whether you think you can, or you think you can't, you're right.

-Jazzdogg-

"Don't ask yourself what the world needs. Ask yourself what makes you come alive, and go do that, because what the world needs is people who have come alive." Gil Bailie

10fingers's picture

(post #108041, reply #4 of 19)

Hello,


this may or may not help you.  In the crafts lab at school we used a lot of 2 part epoxy bar top stuff.  To get the bubbles out, we used a propane torch pointed directly down about 5 or 6 inches above for a couple of seconds.  The bubbles disappeared quickly.  If you try this, do it outside.

hmltnalan's picture

(post #108041, reply #5 of 19)

Dustin,


What kind of wood are your bookcases?  Have you used any grain filler or a sealer?  How heavy are the coats you're applying?


Alan

DRose's picture

(post #108041, reply #6 of 19)

Alan,


the cases are hard maple, no filler, no sealer, just acrylic.  It was suggested that I thin the finish, but with what?


Dustin

hmltnalan's picture

(post #108041, reply #7 of 19)

Dustin,


The label will usually (always?) include what thinner to use.  If not, I would use your product's solvent, e.g. mineral spirits, alcohol, water, or with whatever they tell you use to clean your brush.


As to your bubbles, you've got me stumped.  The only thing I can think of is what others have already gone over:  that you're creating bubbles by the way you load your brush.  Other than that, I haven't a clue.


As to the brush.  I always pour whatever product I'm using into a paint pot.  It's more convenient and allows me to use proper technique loading my brush.  After pouring, I look carefully to see if I've made any bubbles; whether I have or not I wait five or ten minutes before I get started--just in case.  I dip my brush in solvent and work it into the bristles, and then squeeze out as much solvent as I can.  Then it's just loading the brush and tipping off by gently patting the bristles on the side of the paint pot.  But do whatever works for you.


Alan

nikkiwood's picture

(post #108041, reply #8 of 19)

I would be careful about thinning this product -- ordinarily manufacturers will advise thinning only by 10% or so with a water-based poly.

I think you should save your propane torch for plumbing tasks. But,if you have a good brush (which I assume is one intended for water-based material), and you've tried the other good suggestions from this thread, then I think you need to look at the product you are using.

Maybe twice in 20 years I had the same problem, and I just switched to another brand. It is possible there was some momentary glitch on the production line and something was either added or omitted from the mix.

Some brands of WB poly do seem more prone to bubbling than others, but the bubbles dissipate almost immediately. If you end up having the same problem with another brand, then I would definitely say your application technique is the problem.

.

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
Sphere's picture

(post #108041, reply #9 of 19)

Add a about an oz of milk to a quart..it'll act as an emulsifier and about an oz of ammonia (non-sudsing) it acts as a surfactant..makes it wetter.

 


Spheramid Enterprises Architectural Woodworks


Repairs, Remodeling, Restorations. 


 


 

Spheramid Enterprises Architectural Woodworks

Repairs, Remodeling, Restorations

PROUD MEMBER OF THE " I ROCKED WITH REZ" CLUB

 

nikkiwood's picture

(post #108041, reply #10 of 19)

How about adding a couple drops of soap -- like a dishwashing liquid?

Somewhere in the back recesses of my memory, I seem to remember that too acts as a surfacant.

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
Sphere's picture

(post #108041, reply #11 of 19)

only if an emusifier is added, and it's a non-sudsing type of soap.


I worked with Michael Dresdner for quite awhile..we devolped the Clearwater Color Co. and it's line of gels..as well being a distributer and manufacturer for Hydro-Cote.


There are a plethora of things one can add..the most user friendly and safe remains ammonia and whole milk.


 


Spheramid Enterprises Architectural Woodworks


Repairs, Remodeling, Restorations. 


 


 

Spheramid Enterprises Architectural Woodworks

Repairs, Remodeling, Restorations

PROUD MEMBER OF THE " I ROCKED WITH REZ" CLUB

 

nikkiwood's picture

(post #108041, reply #12 of 19)

re: ammonia and milk

I guess that rules out dishwashing liquid -- still another old myth put to rest.......

Aside from inhibiting bubbling, are there any other qualties a little ammonia and milk will add to WB poly? BTW, is it one or the other, or both?

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
Sphere's picture

(post #108041, reply #13 of 19)

It really depends on what WB finish you are dealing with..there are many more now then there was back then, and each manufacturer has a propritary blend of resins..


Poly and lac. subs. all behave differently..I do have a fair understanding of the drawbacks of the Minwax..having used it with so-so results ( for what I was after). I also had a foaming problem, likely from a contaminated paint pad..and it was a helper working for me that was the applicater. He had used (get this) Dishwashing soap to wash the pad..to add insult to injury, he replaced the left over from the pan BACK into the gallon can.


I saved the gallon by doing what I said earlier..1 oz. each per quart..in that case it was about 3 quarts left.


I'll often add lac. thinner to waterbased lac. to help with flow out..that or ethylene Glycol, or dB which is an ether not readily available to the GP..(read hazardous) ...almost all wb fins. contain VOC's such as these..just in smaller quantites than what you would have in a solvent based vehicle.


I would not recommend anyone without a basic understanding of the chemistry involved, add anything other than milk or ammonia, in moderation and with experimentation..lest ya wind up with cottage cheese.


Even ammonia in some other fins. may cause an undesireable result..but with the Poly-cyrlic it is a safe bet, and MAY help..I don't have all the info. as to what the OP'er was doing wrong, or the condition of the material, or application techniques.


9 x outta 10..leave it alone and follow the label..that 1 time, experiment a bit..you'll soon learn what don't work and why.


 


Spheramid Enterprises Architectural Woodworks


Repairs, Remodeling, Restorations. 


 


 

Spheramid Enterprises Architectural Woodworks

Repairs, Remodeling, Restorations

PROUD MEMBER OF THE " I ROCKED WITH REZ" CLUB

 

mbl's picture

(post #108041, reply #14 of 19)

Friends,

What would you say is water polycrylic advantage over water polyurethane, say on the same brand, for instance Minwax?

Have used water based polyurethane but just started testing and trying to find out more about Minwax polycrylic.

Seems that polycrylic is more expenssive, and it is a newer develompent, so what rationale is there behind presenting a new product (not meaning that it is that recent)?

Thanks for any replies.

-mbl-

Mach70's picture

(post #108041, reply #15 of 19)

IS Polycrylic new?  I seem to recall it being around (and certainly easier to find) back at the dawn of the WB movement.

nikkiwood's picture

(post #108041, reply #16 of 19)

Isn't "polycrylic" just the brand name used by Minwax for their line of WB poly?

I don't think I have ever seen it used by any other mfgr.

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
mbl's picture

(post #108041, reply #17 of 19)

Thank you nikkiwood.

You are most likely right. Have not found anywhere or anyone that can say there's any advantages to 'polycrylic' over water-based polyurethane.

Unless anyone says different, will lean to it's just another water-based polyurethane.

If so, it'd then be a marketing trick to lead people into thinking that it is something different than polyurethane? Did find a site of a fellow that says that "Minwax polycrylic is not the same as polyurethane" and he refers to Minwax's description of the product and does not dwelve into any specifics.

The Minwax description of the product does not say that it is different and avoids the use of the word "polyurethane" and even "acrylic".

Minwax does not sell a water-based polyurethane other than "for floors" and it is probably a better product than their "polycrylic".

Now keep reading that "polycrylic foams" so that be a reason to go back to the water-born polyurethanes that have used and did not foam.

Thanks a lot.

-mbl-

nikkiwood's picture

(post #108041, reply #18 of 19)

I've never used the "polycrylic" myself, but it would not surprise me if Minwax threw some chemical in the vat that others don't. With the trouble you've had with foaming, I guess I would move on to another product. I am still inclined to think it was just a bad batch.

I have been through a lot of different WB poly brands, and to tell the truth, I haven't been able to tell the difference among them (unlike oil based varnishes). I generally buy the cheapest I can find in a home center, and use that for utility projects or undercoats.

But I always keep some more expensive brand around for special projects and final coats. Not that I can see a difference, it's just that I can't rid my mind of the notion that you "get what you pay for."

******************************************************** "It is what we learn after we think we know it all, that counts." John Wooden 1910-
DRose's picture

(post #108041, reply #19 of 19)

Gentlemen,


thanks for your input.  I threw out the old (3 days old from home depot) and went to my local hardware store down the street, got the same can, and it works flawlessly.  Got a pad, as well and cut my time for a coat by about 15 minutes.


Dustin