Behlens nitro

[dmraco]

I have decided to use some behlens nitro for my current build.

Questions:

--does this need to be thined with lacquer thinner?  The directions do not say but the thinner is recomended for high humidity
--Compatible with StewMAC liquid dyes??  StewMAC says they are.
http://www.stewmac.com/shop/Finishing_supplies/Colors,_tints,_and_stains/ColorTone_Liquid_Stains.html

Any other tips??

 

[Cagey]

The Behlen stuff works well. I use a lot of it.

It does need to be thinned, anywhere from 25% to 75% depending on what step you're doing. You will also need some retarder, which is another type of thinner but you use dramatically less of it. It slows down the evaporation rate of your nitro/acetone mixes. How much you use depends on the temperature, humidity and what step you're at in the process. If you don't have any 1oz measuring cups, StewMac sells some for metering out various chemicals. A standard 2 to 4 cup Pyrex measuring cup like you'd use in your kitchen comes in handy, too.

You may want to read this article. Replace the callouts for the brand mentioned with "Behlen's" and you're all set.

 

[dmraco]

Mixed up my first batch.  Stuff dries very fast.

Worked well.  Your directions say to let it stand a few hours before sanding, I am going to let it go overnight.

Funny thing happened.  I mixed everything up in a plastic solo cup.  When I came back to my bench after spraying, the mixture melted the cup!!!  I guess it was the thinner.  Wow.

 

[Cagey]

Lacquer does dry pretty quickly, at least to the touch. Often within minutes. But, it's not really dry, so don't be fooled into thinking you can manhandle it. However, you can sand on it an hour or two later, as long as you aren't too violent about it. I regularly take 320 grit after finishes that are only two hours old. Be careful about letting it sit too long, or you may need to rough it up again. One of the magical things lacquer does is melt the previous finish (actually, the acetone (thinner) does it) so you sorta grow the finish. If it gets too hard, that may not happen.

As for the mixing cup... yeah. Acetone is a pretty aggressive solvent that will attack a lot of things like other finishes (including lacquer) and/or some plastics. Use glass containers. Also, be aware that acetone is highly combustible. I don't mean flammable, I mean combustible. It also has a very low boiling point (130F) so it evaporates quickly in atmospheres humans are comfy in. Get too high a concentration of fumes and it won't catch fire, it'll go BOOM! Treat it like unstable gasoline mixed with extra evil. That is, LOTSA ventilation.

 

[dmraco]

Thanks.  I think 12 hours should be ok.  I have left nitro go over 48 and not had and issue.
I will be sanding it with 320 so I should not have an issue.

One thing that surprises me is how low the gloss is.  I guess that will build up as I go on. 

Right now I am mixing 3:1.  The directions say go to 2:1 for the final coats.  What does this achieve? The only thing I can think is assist the "melting" of the finish do to the higher concentration of thinner.

 

[Cagey]

If the gloss is too low, you may not be using enough retarder, are shooting too light, too fast or from too far away. It's a tricky balance. More often than not, it's timid shooting. A great deal of solvent will boil off right in the air on its way to the part you're painting, so you either have to get closer, change the mixture, or slow down. This is where practice comes in real handy. Overcompensating any of those things can result in runs/sags that you then have to repair.

Be aware that fresh lacquer never does look really glossy. A perfect finish will often have a slight satin sheen to it. It's not until later when you sand/buff it out that it gets that high shine you're expecting.

The difference in paint/thinner ratios has to do with how much product you're putting on the part at once. When you're doing "build" coats, you put it on slightly heavier. Finish coats, not so much.

 

[dmraco]

Thanks.  Looks very satin like now.  I think my spraying technique is ok. This is the first time I have not used nitro in an aerosol can.  But I have painted motorcycle parts using this sprayer.

I was likely spraying light too.  Took me forever to spray just 8 oz. 

 

[dmraco]

Cagey, how long will nitro stay in the sprayer?  Can I mix it, spray, and leave it in the sprayer for an hour or two.  Then come back and spray the rest?

 

[Cagey]

I don't know if you're supposed to do it, but I do. For instance, when I'm spraying clear coats I know I'll be putting multiple coats on so I'll mix up a whole pint, shoot one coat, wait an hour or so, shoot another, wait another hour or so, then finish off the gun. Depending on the time, maybe start level sanding, then do all that again with sanding in between. A second and maybe a third day like that, then it's hang time for a couple weeks.

 

[dmraco]

All the lacquer in the gun?
Thank you.

 

[Cagey]

Yup - all in. But, I may be getting away with it because of my gun. It's pretty well closed up, so the acetone doesn't evaporate away and change my mix. My gun looks sorta like this...

​

While some guns look like this...

It's the difference between suction vs. gravity feed.
​

 

[dmraco]

I have a gravity.  But I am only looking for a few hours, not overnight. 

It's air tight.  In fact I need to open a valve on top or the liquid will not feed.

I also wipe the nozzle with thinner when I put it down.

 

[Cagey]

I'm sure it'll be fine. Just don't go too long and be sure to fire off a few shots away from the object you're painting to make sure you're still getting feed.

 

[dmraco]

Cagey...you seem to be in the know about this.  I am wrapping up my clear.  Quickly running out of the Behlens.  Any other nitro (that I can buy at the store) compatible with the Behlens??  I hate to have to order and wait for it to come it.

 

[bagman67]

Where are you located?  Rockler and Woodcraft stores carry Behlen nitro spraying lacquer in those rectangular quart cans.


http://www.rockler.com/retail/retail.cfm


http://www.woodcraft.com/Stores/Default.aspx

 

[Cagey]

I hate to commit on something like this because there are often unknowns, but here's my take on it. If you're using the Behlen's "Stringed Instrument Lacquer", it's probably a good idea to keep using it. There are differences in the chemistry designed to reduce yellowing, crazing/spiderwebbing, and blush. So, I would hesitate to put straight nitro over it. It would probably come out ok, but you may suffer life expectancy or durability issues. But, Behlen also sells just straight nitro, in which case it wouldn't matter.

I have mixed brands before, and even chemistries, going from fillers to sealers to color coats to clears, and from water to solvent based products, all without issue. But, I tend to drag these things out longer than a production shop or a more ambitious DIY user, so it may be that the coverings have always had enough time to stabilize and harden to the point where it wouldn't be a problem.

Behlen's isn't rare; you may be able to get it locally. It's pretty popular stuff among the woodworking crowd. I know for fact Woodcraft carries it - the link is to a list of store locations. I'm also sure they're not an exclusive distributor.

 

[dmraco]

Thanks.  I will stick to the Behlens.  It is going on really nice.  I am also at the point where it is 2:1 withthe thinner so it is going a little further.