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Anyone ever sprayed Rockhard
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Author:  Michael Dale Payne [ Mon Oct 06, 2008 10:43 am ]
Post subject:  Anyone ever sprayed Rockhard
I have used rockhard for years on necks thined to 40% and padded on. I was just courious if anyone has ever tried to spray it?
Author:  John How [ Mon Oct 06, 2008 10:53 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
Sure, I have sprayed rockhard. I used to ad a capful of acetone and a capful of rockhard's varnish reducer jus before it goes in the gun. The acetone is to help it bite into the previous layer since there is no chemical bond.
Author:  Michael Dale Payne [ Mon Oct 06, 2008 11:43 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
Thanks John [:Y:]
Author:  Todd Rose [ Tue Oct 07, 2008 9:05 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
Bruce Sexauer sprays his guitars with Rockhard. He's a good guy to talk to about it.
Author:  Hesh [ Tue Oct 07, 2008 10:01 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
Is rockhard a product?
Author:  WaddyThomson [ Tue Oct 07, 2008 10:09 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
Product of a product! :o
Author:  Arnt Rian [ Tue Oct 07, 2008 10:30 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
Hesh, Waddy, I don't know if you guys are kidding or not (now, why would anyone wonder about that :? ), but they are talking about this stuff.

Image

There was some talk about spraying Rockhard in this discussion on MIMF a while back

http://www.mimf.com/cgi-bin/WebX?50@223.WXyCaKsyAcl.11@.2cb68103

Mandolin maker John Hamlett has used it on some of his instruments. Interestingly, he mentioned using Tru-oil as a top coat to avoid the witness lines you can get while sanding it.

Of course Al Carruth uses it, but I believe he brushes it on.

I'm getting ready to do my first sprayed Rockhard varnish finsish as well, so I'm interested in hearing what everybody has to say. So keep quiet, Hesh and Waddy! :geek:


:lol:
Author:  Hesh [ Tue Oct 07, 2008 11:15 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
Thanks Arnt I was asking an honest question............. :D
Author:  WaddyThomson [ Tue Oct 07, 2008 11:42 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
And I gave an honest answer......... :D
Author:  Ken Franklin [ Tue Oct 07, 2008 6:05 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
The last time I talked with Bruce Sexauer he was brushing the Rockhard, but maybe he sprays it, too.
Author:  SniderMike [ Tue Oct 07, 2008 7:17 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
I emailed Bruce Sexauer about spraying varnish, back in April. At that time he was no longer using Rockhard, as he said they had changed the formula, giving it a bad color and poor drying. He was trying several different products at the time. Very nice guy.
Author:  Todd Rose [ Tue Oct 07, 2008 7:25 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
Sounds like SniderMike has the most up-to-date info on what Bruce is up to. I spoke with him last at the 2007 Montreal Guitar Show. That's when he told me he had gone from brushing Rockhard to spraying it.

Now, I wonder why they went and changed the formula...

Has anyone else here who uses it noticed a change?
Author:  Mike OMelia [ Tue Oct 07, 2008 9:56 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
Who is Rock and why are ya sprayin' him?

Mike (sorry) pfft
Author:  Michael Dale Payne [ Wed Oct 08, 2008 9:19 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
Well I did some test sprays last night It sprays easy enough but you need a very good air cleaner running. Since this was a test only I did not kick the air cleaner on just the exhaust fan in my spray room which I keep clean and dust free the best I can. I laid down a nice smooth wet coat. I Left the room for a couple hours. When I came back there were noticeable dust dimples in the film. That said the film self levels very nicely at 50%/50% varnish /retarder. Set touch dry in 3 hours, not bad for a varnish. I am not sure when they changed the formula but it is darker amber than my last gallon, I bought. It seemed a bit thicker un cut as well. It is almost as thick as a heavy duty marine Spar Varnish. this has not always been the case. So far my only real complaint about the formula change is the darker color. But the sprayed film appears to be a nice clear amber. We will see later this week how the test plate turns out.
Author:  Colby Horton [ Wed Oct 08, 2008 9:58 am ]
Post subject:  Re: Anyone ever sprayed Rockhard
The only reason I have never really liked it too much is because of the color. It has always seemed like a pretty dark amber to me. It makes getting the nice white top look impossible.
Author:  Laurent Brondel [ Wed Oct 08, 2008 12:17 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
I've been spraying Rockhard for the last 6 guitars, I used to brush it. This is the only finish I use. Yes they've changed the formula, although it looks to me quality control went down as it's slightly different with each can, especially in terms of thickness/fluidity. Colour is the same, it seems a hair more opaque lately with a greenish/bluish hint.
Right out of the can is the perfect consistency for spraying (or used to be…). I use Bloxygen and pour the varnish in Mason jars or similar, and go smaller as I use up the varnish. As it inevitably thickens a tad, I add turpentine as needed to regain the original consistency, as I remember it. Too thick and it won't level properly, too thin and it will run. I do not use Behlen's varnish reducer, pure turpentine (from pine…) works perfectly, and possibly better for my purpose. Depending on your seal coat you can spray the 1st Rockhard coat as it comes out of the can. For subsequent coats I add a bit of acetone, and a bit of turpentine as needed. The acetone, as mentioned, makes witness lines less of an issue as it bites onto the preceding coat. It also makes the varnish cure faster, the turpentine is added to slow that down. I found that for the first few coats a quick sanding with 400 grit or the maroon scotchbrite pads, without trying to level things too much, works best. After 3 or 4 coats I start leveling the finish with 600 wet-or-dry sandpaper (wet…), spray another coat on the thick side, level with 800, another coat and level with 1000. The last coat is sprayed as thick as possible without runs (preferably with varnish from a brand new can). That seems to eliminates issues with witness lines, the very faint ones disappear with buffing anyway.
There are 2 major issues with Rockhard: adhesion, and for those who prefer a clear finish, colour.
The adhesion issues I'm still working on, Bruce uses Behlen's violin varnish (a spirit varnish, really) as a seal coat and IME it improves things a bit compared with pure shellac. On my last guitar I used Waterlox as a sealer and it seems even better, except one really has to wipe oily woods with naptha before applying Waterlox. Otherwise it will take forever to dry, if it ever does, on, say, cocobolo. Waterlox really makes the grain pop out and gives extra depth.
For the colour I will try a new schedule on my next build, which is to use Behlen's restoration varnish (transparent) for the finish build up and Rockhard for the last 3 coats.
From my last conversation with him, Bruce is now using Ace hardware varnish after trying McCloskey spar, and is thinking of going back to Rockhard.
Author:  Michael Dale Payne [ Wed Oct 08, 2008 12:30 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
Larrent, what I am getting right out of the can has the visosity of cold STP oil tratment. Very thick. No way would it spray through my HVLP gun and a 1.4mm air tip
Author:  Laurent Brondel [ Wed Oct 08, 2008 1:58 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
Works for me, I use a touch-up HVLP gun with a 1.0mm tip.
Perhaps I should ask: how old is the can you're using? When I say out-of-the-can I mean a just opened, brand new can of Rockhard. I buy it in quarts. Like all varnishes the more oxygen it sees the more it polymerizes. Brand new it has the consistency of, say, nitro sanding sealer, but obviously much more viscous.
Author:  Michael Dale Payne [ Wed Oct 08, 2008 2:31 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
I have been buying rock hard for years for my necks. It has never been the viscosity of sanding sealer. This is a new can just purchased a week ago and is typical of every can of Rockhard I have ever had. To be a bit clearer the viscosity is somewhere between a thick lube oil and say a 5# cut of shellac. I can dip a stick in it and it will fall immediately towards the side of the can but if I lift the stick the varnish will not immediately drip off and when it does it is semi slow and peanut sized drops and strings out for a good 3" before the droplet lets loose. It is liquid enough to run but is pretty viscous. At least twice as viscous as nitro lacquer. This is as every can I have ever bough has been. No way would I ever think of shooting it without thinning. Now you have peaked my interest there is a high end painter/finisher supply house just down the street from me I may have them order me a quart and just check to see if SM’s stock is old or something.
Author:  Laurent Brondel [ Wed Oct 08, 2008 3:37 pm ]
Post subject:  Re: Anyone ever sprayed Rockhard
Michael, I see fluidity and viscosity as different things. This varnish is viscous, but fluid. I still have a can of McFadden vinyl sealer and it is the same "fluidity". Lube oil is much less fluid IMHO.
It really is ideal to spray out of the can and I have a small gun with a small tip, and a small compressor. No issue there, try it. I do it, Bruce does it, as others I am sure.
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