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Why is my lacquer crackling??

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Forum topic by JMB posted 03-25-2009 06:10 AM 7113 views 0 times favorited 6 replies Add to Favorites Watch
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JMB

18 posts in 2142 days


03-25-2009 06:10 AM

Topic tags/keywords: finish lacquer crackle cracking clearcoat clear coat coat clear gloss satin question finishing refurbishing modern

Howdy Fellas.

Once again, I’m not certain this is the proper category for this. Perhaps we ought to lobby the Website administrators to create a “HELP?” category in the forum topic list.

I’m trying to do a finish coat on a small woodworking piece. I am getting a lot of crackling in the finish. Can’t seem to eliminate it.

Basic details:

Object is made from Poplar

Primer coat is Krylon’s white primer, sanded and re-coated 2 + times until completely smooth no grain whatsoever

Paint is two + layers of Krylon enamel sanded until absolutely smooth and even color

I’m using a store bought, aerosol spray can, gloss lacquer by Watco for my finish coating. I have used their satin before without any problems.

Here’s where I’m at:

First thing today, I put a second coat of paint on. I allowed it to dry a few hours, then sanded it smooth with 320. I removed the dust and debris with a barely wet rag, allowed the moisture on the surface to dry, then hit it with lacquer. No problems so far.

I let the first coat of lacquer dry for a few more hours then scuff sanded it with 400 grit. I used the barely-moist rag again to remove all dust and debris from sanding, then allowed it to dry for a few moments.

I set it on the spray rack and hit it with the final coat of lacquer, and again with the crackling.

It only does it in spots. I suspect I am not allowing the water to dry long enough. I’ve tried several different approaches to eliminate this crackling effect and no luck.

The only other time I have run into this is when I was a novice and sprayed wayyy to much on at a time. Now I know better and try to spray multiple very light coatings with plenty of dry time in between. I’m not completely eliminating over coating as a factor in this case, but I’m fairly certain its not the cause.

Anyone ever run into this? Please advise. Thanks.

JMB

-- If I can't fix it, it wern't broke in the first place!


6 replies so far

View Douglas Bordner's profile

Douglas Bordner

3966 posts in 2780 days


#1 posted 03-25-2009 07:17 AM

I was all keen to jump in here until I read your last paragraph. I had trouble laying on MagnaLac too thick and then got cracking across the grain, long after the finish had cured. It’s likely not a fisheye/silicon contamination situation as you don’t describe cratering.
I’d probably use a microfiber “tack” cloth after the scuff sand, and a blast of air to clean out the sanding debris and avoid the wet rag altogether. Pretty mystifying though.

-- "Bordnerizing" perfectly good lumber for over a decade.

View John Gray's profile

John Gray

2370 posts in 2602 days


#2 posted 03-25-2009 07:42 AM

Lacquer and enamel do not work together. I sprayed lacquer over enamel on a motorcycle paint job it was a very time consuming process over 2 days just dusting the lacquer over the enamel sealed and allowed heavier coats of clear and I never did that again. I’ve painted a lot of show motorcycles over the years. The process was paint the color coats with lacquer then applied gold leaf and pinstriped enamel around it without a problem, but when I went to clear coat over it with lacquer the gold leaf and the pin striping began to lift that’s why it was dusted with a very dry lacquer until the enamel and gold were sealed, then apply about 20 coats of lacquer over that to produce a super fine finish.
PS – I wet sanded with 600 to scuff between coats and over the last coat and then came back with rubbing compound until the job looked deep and shiny. Then apply several coats of wax.

-- Only the Shadow knows....................

View Al Killian's profile

Al Killian

273 posts in 2469 days


#3 posted 03-26-2009 03:43 AM

Poly would be a better topcoat Less problems with sticking and/or delaminating.

-- Owner of custom millwork shop

View closetguy's profile

closetguy

744 posts in 2609 days


#4 posted 03-26-2009 03:46 AM

Try Minwax clear poly spray.

-- I don't make mistakes, only design changes....www.dgmwoodworks.com

View marcb's profile

marcb

762 posts in 2390 days


#5 posted 03-26-2009 03:37 PM

I’m not sure if the Krylon is done drying in 2 hours. Mixing paints can be tricky (even though this is enamel).

What does the directions on the can of Krylon say, sometimes they have strange times between coats. Usually its like within 1 hour or after 24 hours. Anything in between causes issues.

View Roper's profile

Roper

1363 posts in 2430 days


#6 posted 03-26-2009 05:04 PM

my first suggestion is to let the paint dry longer, it may be dry after a couple hours but it takes days to cure. also if you use a shellac coat in between the enamel and laquer it may help with the cracking. just my 2 cents, have fun and let us know how it turns out.

-- Roper - Master of sawdust- www.roperwoodturning.com

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