Blush - Yeccchhh
-
- Blackwood
- Posts: 183
- Joined: Wed Jul 24, 2013 1:51 pm
Blush - Yeccchhh
Never had blushing before and I've sprayed in pretty awful conditions. Yesterday afternoon and this morning however, spraying black acrylic coats has blushed like crazy. It is 79% humidity and 11degC here
Wondering which is the most efficient way to deal with this.
Will blocking it back with 600 grit make it disappear permanently?
Should I just wait for better conditions and respray over the top of the blush?
As I understand it moisture trapped in the finish causes blushing
Wondering which is the most efficient way to deal with this.
Will blocking it back with 600 grit make it disappear permanently?
Should I just wait for better conditions and respray over the top of the blush?
As I understand it moisture trapped in the finish causes blushing
Re: Blush - Yeccchhh
Too much blush...you see this a lot. One of our finishing experts will be along shortly to provide advice.
Martin
Re: Blush - Yeccchhh
Spray a mist coat of thinners over the surface, it will hopefully soften it long enough for the moisture to escape
Steve
Steve
-
- Blackwood
- Posts: 183
- Joined: Wed Jul 24, 2013 1:51 pm
Re: Blush - Yeccchhh
give that a try and it did knock it back quite a bit but with black it's gotta be 100%.
I'll block it on Monday, shoot clear over that and see how she looks
I'll block it on Monday, shoot clear over that and see how she looks
-
- Blackwood
- Posts: 776
- Joined: Tue Aug 27, 2013 6:36 pm
- Location: North East Victoria
Re: Blush - Yeccchhh
You answered your own question here, in a way. Was the guitar fresh out of a lower RH environment? That might have helped. Also, I have had good results in low temperature by making sure the guitar timbers are at low RH, using a heat gun to keep the guitar a little warmer, or better still, heat lamps, (particularly with volatile finishes like nitro which could explode with a heat gun if any lacquer fumes are about), and warming the gun pot in hot water to raise the temp of the paint in question. This also has the effect of thinning the lacquer which means it can be sprayed using thinner coats. It will also flash off faster. My thinking is to get the surface temp and the lacquer to be the same when the spray hits the surface, and the wood has very low moisture content so that water doesn't migrate out and cause the blushing. I also think that, given the thinner coat, it is like sealing the wood with a flash coat first. Alan will probably chime in and he is the expert with spray finishes. Get the data sheet for the finish in question and look at the minimum spray temp they specify. And allow longer at 11 degrees for the finish to fully harden prior to polishing and buffing.It is 79% humidity and 11degC here
-Ross
"Everything I say on the topic is based solely upon inexperience and assumption!"
-
- Beefwood
- Posts: 23
- Joined: Tue Sep 08, 2015 11:00 pm
Re: Blush - Yeccchhh
I've managed to get blushing out by spraying a light mist coat in lower RH conditions a couple of times. It does work. It was with clear though.
- WJ Guitars
- Blackwood
- Posts: 375
- Joined: Thu Jan 26, 2017 4:28 pm
- Location: Sutherland NSW
- Contact:
Re: Blush - Yeccchhh
Very helpful advice. Will keep this in mind when planning spraying.
Wayne
Wayne
Re: Blush - Yeccchhh
Very good, sometimes it’s too late, had one guitar that I couldn’t resurrect, man that drove me nuts that one. Back to wood finish, and it was gorgeous at that point mi us the white haze everywhere.
Stev
Stev
Re: Blush - Yeccchhh
There is absolutely no time whatsoever that you should not add 5-10% of extra slow or retarder to your mix. It helps with flow and leveling. Allows you to spray thin coats. And if you ever get blushing with that mix, then you shouldn't have been spraying then.
Re: Blush - Yeccchhh
Speaking of retarders, I once had a problem with blushing of a nitrocellulose finish. I googled for help and found some advice from a "finishing expert" (which I am not) to spray lightly with retarder. I did that and the blush disappeared instantly and completely (as far as I could tell). I have no idea if that always works or if I was just lucky. I'm also not sure if it works with acrylic but it's worth thinking about.
Richard
- WJ Guitars
- Blackwood
- Posts: 375
- Joined: Thu Jan 26, 2017 4:28 pm
- Location: Sutherland NSW
- Contact:
Re: Blush - Yeccchhh
I also am not an expect on spraying, however, on one occasion I had an blushing problem when spraying with Nitro Lacquer and eventually discover that the air hole in the HVLP spray gun canister lid has partially become clogged. This had constrained the Nitro Lacquer flow in the spray gun and i ended up with a blushing problem.
Wayne
Wayne
-
- Blackwood
- Posts: 183
- Joined: Wed Jul 24, 2013 1:51 pm
Re: Blush - Yeccchhh
I blocked it today and conditions good this arvo - so a couple more coats of black and I'll start in on the clear. BTW first job in the brand new workshop whoo hoo - builder isn't out yet but not back here again for a few days - while the cats away
Who is online
Users browsing this forum: No registered users and 147 guests