TD's Scratchy Thinline

[Trevor Davies]

A couple of spraying questions.

Finally got to try my STAR 0.8 mm spray gun, with a LINCOLN 24L oil-free 1HP compressor. Not for a guitar project though.
Just trialing it on some 140 mm x 260 mm pine boards using Cabot's water based poly. I diluted the poly to a 50% mixture. It seemed to go on quite well, giving quite a smooth finish. I ended up giving them 5 coats - probably should have gone higher - but it worked out to be a nice finish for the project.

Soooo,
knowing nothing about spraying poly, a few questions:

1. Should the poly be diluted for better spraying? Is 50% reasonable?

2. How many coats should I expect to do?

3. I recall reading that necks are more playable with a satin finish. Is this just a player's preference?

4. Is spraying a water based poly still not recommended during times of high humidity?

Thanks for any assistance.

[Trevor Davies]

Today I shaped the headstock, routed the body shape, routed the pup cavity and control cavity, and routed the neck pocket. Also routed the body a 1/4 inch round edge.

Also, patched a few dents with pine coloured timbermate, and gave the neck and body a good sand up to 240 g.

[McCreed]

A couple of spraying questions.

1. Should the poly be diluted for better spraying? Is 50% reasonable?

2. How many coats should I expect to do?

3. I recall reading that necks are more playable with a satin finish. Is this just a player's preference?

4. Is spraying a water based poly still not recommended during times of high humidity?

I have not sprayed the water-based stuff yet, BUT my wife just refinished our kitchen table with it (also Cabot's) so I had my first look at it...

1. re: thinning, I think Cabot's recommends only thinning by 10%, and I can see why. It definitely has a lower viscosity than oil based poly. My gut tells me 50/50 would be too much. I typically thin my oil based at 60/40 poly/turps for spraying and wipe-on (have also done 65/35 for spraying).

2. Until you're happy! (sorry)
Again, based solely on observation, the water-based poly did not seem to have the same build up as oil-based. ie: 6 coats w/b poly looked thinner than what I would expect from 6 coats of o/b poly.

3. I would say it's mostly personal preference, but more and more production guitars are using satin on their necks and advertising it as a "feature". Presumably because "it's what customers want" but it also reduces production costs!
So who's the real beneficiary??? (maybe win/win)
I personally prefer the feel of satin and have been using it exclusively for 3 or 4 years. I have even stripped gloss necks and resprayed in satin!

4. IME, applying most coatings in high humidity is a bad idea. The Cabot's w/b shows their drying times based on 25° C with 50% humidity but does not state "Do not... over such & such". I personally won't spray if the humidity is higher the 60% or the temp is over 25°. But that's just me, and I'm probably being over cautious. And again that's with o/b poly.



I really want to try the water-based stuff, as my work area has changed since moving house and the low odour/VOC is *really* appealing. (I used to have a big detached shed )

It's worth noting that water-based poly still has some amount of solvent in it. It's just less and somehow attached to water molecules by means of which I have no f^%&#*@ understanding of!!!