Nitrocellulose thinning confusion

Hello

I'm making a couple of guitars at the moment and have enough of the equipment, and possibly enough of the knowhow, to get started on spraying nitro lacquer.

I'll be using various colour and clear coats from Tonetech in the UK, if this has any bearing on the lacquer itself, and just need to know about thinning the nitro.

Roughly what am I aiming for in terms of viscosity? Are there different rules between sanding sealer and clear/colour coats? And are there 'magic ratios' for each if there is a difference?

Any help is appreciated so I can get started on some test pieces within the next few days (member of the 'fools rush in' camp, at least when it suits me)

Thanks, Phil

ed: probably should have made clear i'll be using a compressor and small 'touch-up' spray gun

Hi Phil Collins!I take it you've bought the nitro in bulk....or have you bought the aerosols? Anyways...a lot of guys do things differently as regards to spraying etc.As for me...I'll thin the sealer 70% sealer..30% thinner...3 coats is usually enough...4 to be safe.Lacquer I'll thin 50/50..usually 12 coats minimum...18 or so max.The thinner helps the flow thru the gun.I spray about 10" away keeping the gun moving side to side at all times...if you stop in one place you'll probably get a run,if you do get a run it's not the end of the world as the next coat should burn into the last.

I get my lacquer and sealer from a much cheaper supplier.Tonetech are good but are way too expensive and charge a fortune for post and packing....and there's a minimum order price.For example...I got a gallon of sealer and six aerosols of lacquer (in winter I use aerosols in the lobby when the wife is out...she's none the wiser) for £50.Aerosols came in at £4.50 a can compared to £13 at Tonetech! The same order at Tonetech....£115+ !!!!

That's very helpful, thankyou!

I did indeed buy in bulk, and didn't really think to look around a lot... Just out of uni so having some money to spend is a novelty :)

For some reason I had it in my head that it should be more thinners than solids for the sanding sealer, I'm glad I asked!

I spray it by the bucketful and I mix to a single cream consistency except for the final coats which are thinner and I finish off with a pass over with pure quality thinners ,called levelling . I tend to use a higher rather than lower pressure .Dont bother spraying it if it too cold (like now) or humid (we should be so lucky)i use mixers from motor spares places and mix my own .I am not spraying guitars but did do a couple quite a few years ago and they came out OK .

Take if from a guy that has painted classic cars for a living.

The thinner the better. lacquer is lacquer. Start at 50/50. Depending on the wearher Hotter = more thinner. Max thin 175%. Look at how the pain sprays and then flows on the surface. if the finish is orange peeled (craters or bumps-looks like an orange skin) more thinner. If the finish is flowing good then you are ok. If it starts to develop a whitish haze then it is blushing and that means too much thinner. the final coats should be as thin as possible without blushing ... Think thin even flowing coats and don't rush

Bottom line is paint is much like music. Watch the paint and let it tell you what is needed.

I am sure there are viscosity recomendations for a zhan cup, and probbaly available on the net.... However every good painter I know uses feel. Hope this helps-good luck

Well you’ve got all kinds of advice so I guess I’ll try to mix you up a little more. Well I think most people think the lacquer will lay out better the thinner it is I have found that not to be true look at your thinner is a dryer so if it’s two thin it will dry to fast causing those fogy looking spots. Also what I’ve started doing I put a very small amount of retarder in the lacquer for the last 3 to 4 coats I found this to really make a big dereference in the amount of wet sanding needed. I use the paint stick attached to the neck pocket but I made a simple holder so the guitar sits flat when I spray it using a C clamp to hold so I can turn it. Just remember your trying to get material on the guitar. It’s just a learning experience take your time you can’t rush the finish. IMO finishing is one of the hardest things to master.
Sanding sealer I use to use but on the last couple guitars I’ve built I used Grain Filler instead didn’t even use it. I think by reading the post about finishing you can see there is no Golden rule Have fun.

Lots of good advise so far! The different ways to apply finish are as different as the people spraying them.

FWIW here is how I do it.

-Two coats sealer (regular laq thinned 50/50)
-pore fill, sand back
-Two to three more coats of laq thinned 50/50
-level sanded in prep for color
-color
-5-6 coats of un-thinned laq (straight McFaddens from the can)
-level sand with 600
-one last coat of laq thinned 50/50

This is what the final product looks like. Not too bad!

http://i211.photobucket.com/albums/bb138/jaydawg76/IMG_2139.jpg
http://i211.photobucket.com/albums/bb138/jaydawg76/IMG_1763.jpg

Bottom line is paint is much like music. Watch the paint and let it tell you what is needed.


+1

Well thanks for the info everybody, its all been very helpful. had a bit of a go on a scrap piece of birdseye maple from the front of the headstock, and it looks lovely!

Added a drop of Vintage amber colortone stain to the thinners before mixing with the solids (125ml/ 1/2 cup of each) to try and tone down the white of the neck some. Didn't have a piece without VA stain to compare it to, but it looks nice, so i figure 'if it ain't broke, don't fix it.'

Anybody have any idea how much difference anoth drop or two would make to the amber effect? I presume it will continue to get darker as i continue to lay down more coats?

I get my lacquer and sealer from a much cheaper supplier.

Come on Tweeet spill the beans. Who'se you're supplier ?:wink:

I get my lacquer and sealer from a much cheaper supplier.Tonetech are good but are way too expensive and charge a fortune for post and packing....and there's a minimum order price.For example...I got a gallon of sealer and six aerosols of lacquer (in winter I use aerosols in the lobby when the wife is out...she's none the wiser) for £50.Aerosols came in at £4.50 a can compared to £13 at Tonetech! The same order at Tonetech....£115+ !!!!

I'm also very interested in where you get your aerosols at that price. Please do tell :).

[QUOTE=jaydawg;2327028]Lots of good advise so far! The different ways to apply finish are as different as the people spraying them.

FWIW here is how I do it.

-Two coats sealer (regular laq thinned 50/50)
-pore fill, sand back
-Two to three more coats of laq thinned 50/50
-level sanded in prep for color
-color
-5-6 coats of un-thinned laq (straight McFaddens from the can)
-level sand with 600
-one last coat of laq thinned 50/50


AWESOME finish! After your last coat of laq - what do you do/use?

thanks
Dave