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+-- Thread: How to stop Minwax spray polycrylic can from spurting so often? (/showthread.php?tid=7349970)
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How to stop Minwax spray polycrylic can from spurting so often? - KingwoodFan1989 - 08-27-2019
Couldn't find any insight on google...I like polycrylic but it dries too fast to level itself when brushing, and thus I end up sanding through the finish when trying to get it perfectly flat, even after 12 coats! Thus, I'm trying out the spray cans, which apply it nice and evenly, but I notice they like to spurt out little extra bursts of finish that form decent-sized bumps on the surface when they dry. Is there any way to get rid of this or at least minimize it? What am I doing wrong?
Forgive me if I already asked this on here in times past, but I can't remember if I have or not. Even if I have, it's been quite a long time.
RE: How to stop Minwax spray polycrylic can from spurting so often? - Stwood_ - 08-28-2019
Buy you a HVLP gun and end most of your finish problems. I imagine those cans are spendy?
No idea on the spit and sputter except, did you shake real good, or are you supposed to shake them?
RE: How to stop Minwax spray polycrylic can from spurting so often? - WoodTinker - 08-28-2019
(08-28-2019, 12:35 AM)Stwood_ Wrote: Buy you a HVLP gun and end most of your finish problems. I imagine those cans are spendy?
No idea on the spit and sputter except, did you shake real good, or are you supposed to shake them?
It is probably due to the crappy spray nozzle on those cans. The finish needs to come out of the can in a mist and yours is having difficulty. How are you holding the can sprayer when this happens? Find a one with a better designed nozzle. There used to be an aftermarket attachment to replace the crappy nozzles, but I do not remember which one. And there are brands which come with a better nozzle. Do some research and try some out. And remember to shake well and re-shake often. If you go this route, be sure to check back here with your findings to help others. Begin to spray off the material and don't stop until off the material.
Or find a better technique to flatten the finish.
Or go the HVLP route.
RE: How to stop Minwax spray polycrylic can from spurting so often? - Rob Young - 08-28-2019
(08-28-2019, 12:35 AM)Stwood_ Wrote: Buy you a HVLP gun and end most of your finish problems. I imagine those cans are spendy?
No idea on the spit and sputter except, did you shake real good, or are you supposed to shake them?
The nozzle on one of the brands of spray lacquer is pretty good, actually sprays in a vertical fan shape instead of a cone. I keep wondering if I could salvage one of those and re-use it on other cans. I like to have a can of the spray shellac around but it sometimes has the same issue with spitting no mater what one does for shaking or cleaning. So obviously that's a bum nozzle. Next time I finish off a can of the lacquer I'm going to try and remember to keep the nozzle!
RE: How to stop Minwax spray polycrylic can from spurting so often? - KingwoodFan1989 - 08-29-2019
(08-28-2019, 12:35 AM)Stwood_ Wrote: Buy you a HVLP gun and end most of your finish problems. I imagine those cans are spendy?
No idea on the spit and sputter except, did you shake real good, or are you supposed to shake them?
You are supposed to shake this particular can as per the directions, but it says for 2 minutes initially (I probably only did it for 30 seconds or so) and then 10 seconds after every minute of use. I'm assuming the 2 minutes should be repeated if the can is left undisturbed for any significant length of time. I did try shaking it for longer and instead of just shaking it back and forth, I used up and down motions, and this did seem to help. I'll just have to sand the coats I have on there now until the spots left by the bubbles are flattened out and then put like 6-8 more coats on.
I'm beginning to think that Polycrylic, although a fantastic topcoat, is best applied through spraying. Although I have succeeded in getting a nearly even finish after brushing it on and sanding it, it just dries far too fast to be able to eliminate the need for a lot of flattening. Spraying it on doesn't leave any ridges or anything, so at some point I'll definitely get a dedicated sprayer and make a poor man's spray booth. Trying to get my own house after finishing student teaching (which starts in just the next 2-3 weeks!), so I can see about building a booth after I have a garage to dedicate totally to woodworking.
RE: How to stop Minwax spray polycrylic can from spurting so often? - Stwood_ - 08-29-2019
What width brush do you use when brushing?
Whatever it is, can you go wider?
RE: How to stop Minwax spray polycrylic can from spurting so often? - KingwoodFan1989 - 08-30-2019
(08-29-2019, 06:46 PM)Stwood_ Wrote: What width brush do you use when brushing?
Whatever it is, can you go wider?
I'm ULTRA cheap with brushes, so I usually go with the widest foam brush and just wash it out with dish soap and warm water. Yes, even less than $3 still feels expensive to me in the context of a brush for some reason!
I suppose I could get a wider applicator of some kind and just pour the polycrylic into something with a wider opening than the quart size containers have. However, it's not just lap marks that I get. It's also a bunch of mini ridges across the surface (running parallel with how the finish is applied). I've never had that issue with oil based or spraying on water based, but it seems like I get it pretty often when brushing on a water based. I just assumed that was due to drying speed. I HAVE gotten better results, though, if I put on thicker coats, and I think that's because thicker coats dry slower and thus level more. Doesn't give as flat of results as spraying or using an oil based, but it is better.
I think I'll just continue with shaking the can more thoroughly for now and go from there.
RE: How to stop Minwax spray polycrylic can from spurting so often? - Rob Young - 08-30-2019
(08-29-2019, 06:46 PM)Stwood_ Wrote: What width brush do you use when brushing?
Whatever it is, can you go wider?
I've seen people using stain pads to apply WB products. Never tried it. Both the foam-wrapped-in-cheesecloth kind and the ones that I think are meant for flooring or paint, those have the plastic handles on the back side.
I've never tried this method, become a convert to HVLP spraying... (side note, the sub $100 HVLP turbine unit sold by Rockler - when on sale - and the identical one from HarborFreight does a fine job on Minwax Polycrylic by the way)
Maybe these videos might have some helpful tips. General Finishes products instead but maybe helpful to the OP.
The second video in particular is using an extender mixed into the product. No idea if there is compatibility with Minwax products or of there is an alternate source of a "universal" extender for WB products. A few drops of the Floetrol perhaps? Might be worth an experiment on some plywood.
RE: How to stop Minwax spray polycrylic can from spurting so often? - K. L. McReynolds - 09-01-2019
(08-27-2019, 10:19 PM)KingwoodFan1989 Wrote: Couldn't find any insight on google...I like polycrylic but it dries too fast to level itself when brushing, and thus I end up sanding through the finish when trying to get it perfectly flat, even after 12 coats! Thus, I'm trying out the spray cans, which apply it nice and evenly, but I notice they like to spurt out little extra bursts of finish that form decent-sized bumps on the surface when they dry. Is there any way to get rid of this or at least minimize it? What am I doing wrong?
Forgive me if I already asked this on here in times past, but I can't remember if I have or not. Even if I have, it's been quite a long time.
Not sure there is a way to make the spurts stop. Rattle can spraying is not a good way to get a smooth finish. Been trying to do that for a lot of years, using over 30 different products(brands and finishes). Not one did as good as a dedicated sprayer. HVLP is the way to go---and practice.
RE: How to stop Minwax spray polycrylic can from spurting so often? - Phil Thien - 09-01-2019
After brushing a coat, mist some Windex on with a fine mister (one of those little finger pump sprayers). The Windex will smooth it out as it drys.
Test on scrap.