do i use nitro sanding sealer or not?

[rolloman]

i've heard on other threads etc. that nitro sanding sealer should never be used under plain nitro because "The problem is it is so soft from all the stearates they put in it to help it build that when the lacquer (which is much harder) starts to really cure and shrink the whole finish begins to check. Which is a good thing it you want to have a vintage style finish."

do you all subscribe to this or not?  also if not nitro sanding sealer then what, shellac, vinyl sealer, etc. etc.?

 

[Cagey]

I think that was true years ago, but with modern formulations that doesn't happen.

What's worked out well for me lately has been Behlen's sealer and topcoat, which uses a vinyl sealer. I've also tried the Seagrave's stuff, but I wasn't as happy with that. The sealer seemed too soft. Made it difficult to level sand between coats.

 

[rolloman]

Great, I got some re-ranch sanding sealer I can use. Please look at this schedule. Feel free to comment away if you see anything wrong or should be changed with it.  Thanks so much. Great forum we have here.  :guitaristgif:

Alder warmoth body.

1) sand bare wood to 320
2) apply a wash coat of 50% alcohol / Zinssers shellac..
3) let dry to manufacturers reccomendation.
4) sand to 320
5) wipe on oil base grain filler with course cloth against the grain or rub in with fingers against the grain.
6) let dry for about 15 min. and wipe off excess with cloth mineral spirits absorbed cloth.
7) let dry for 1 hour.
8) repeat steps 5-6
9) let dry 24 hours.
10) sand to 220
11) spray or brush on nitro sanding sealer, or Zinssers shellac.
12) let dry.
13) spray or brush on nitro sanding sealer, or Zinssers shellac.
14) let dry overnight.
15) block sand to 320
16) repeat steps 13 - 15 until all shiny spots (small pits) are gone and you have a level matte finish with no sand thru's.
17) spray or brush on 2 coats of Zinssers white pigmented shellac sealer primer.
18) let dry.
19) block sand to 320
20) repeat steps 17- 19 until surface is fully covered, smooth, level and has no sand thru's.
21) wipe down with naptha
22) use tack cloth
23) spray my custom color tinted nitro lacquer with my hvlp spray gun.
24) spray coats let dry
25) repeat steps 23 -24 until all primer is covered then spray 2 more coats. (may have to experiment with lacquer thinner)
26) wet sand to 600
27) wipe down with naptha
28) use tack cloth
29) spray clear nitro lacquer with my hvlp spray gun wet coats. (may have to experiment with lacquer thinner)
30) spray the number of coats you are happy with then wet sand to 1500.
31) polish with 3M finnesse it II Machine polish compound.

 

[Cagey]

Looks like a good plan to me. I never use any shellac, but it'll work.

 

[rolloman]

Looks like a good plan to me. I never use any shellac, but it'll work.

I haven't either but I think I'll give it a try since it is so readily available and safer. Brushes can be cleaned also in water and Amonia mix. I'll let ya know what I think about it.
It has to be this exact shellac or one like it that is de-waxed so we have to be careful. Or else you can buy flakes also at that site below and mix it yourself with denatured alcohol. Heres the info about it right from the Woodcraft website.

Woodworkers use sanding sealers to speed the progress and improve the appearance of their finishing and refinishing projects. SealCoat Sanding Sealer offers time-saving versatility in a pre-mixed 100% wax-free formula manufactured using revolutionary, patented shellac. The 2-pound cut formula penetrates the surface of wood and dries quickly, giving a rich, beautiful tone to wood grain. Since it contains no waxes or stearates it's guaranteed to be compatible with oil-base polyurethane, acrylic polyurethane, lacquer, varnishes, even catalyzed finishes. It seals all types of wood including oak, maple, chestnut, mahogany, walnut, birch, poplar, cherry, exotic woods, etc. Recommended for interior woodwork, including paneling, molding, trim, windows, doors, cabinets, furniture, and toys. One quart. - See more at

: http://www.woodcraft.com/Product/2004758/7876/Sealcoat-Universal-Sanding-Sealer-Quart.aspx#sthash.2a9YDlpH.dpuf
http://www.shellac.net/sealcoat_info.html

 

[Cagey]

Speaking of safe, among other things shellac is sometimes used to coat candies and pharmaceuticals for appearance's sake. Makes things shiny and smooth.

It's just bugshit. Everybody unknowingly eats that sort of thing all the time.

 

[rolloman]

lol.  I had no idea what shellac was until last week when I started lookin into it. Your right just bugshit. Couldn't get any safer of course unless they been eating all that lethal bug killer that never seems to work. lol

 

[dmraco]

Am I wrong with just using a quality grain fill amd shooting a few coats of lacquer?    I have never used a sealer

 

[rolloman]

I don't suppose there's any right or wrong unless the material used are not compatible with each other. I'm just starting to learn this finishing stuff. Between asking questions on this thread and finding this finishing schedule here is gonna be my guide. This schedule is where I learned about using shellac. http://www.reranch.com/solids.htm  In the end you or your customers if you build for others are the only ones that have to be happy with it. Maybe shoot us some pics and closeups of your work might help. Maybe you spend a ton of worthwhile effort up front, sanding, etc. that you can get by with less steps.

 

[Cagey]

Am I wrong with just using a quality grain fill amd shooting a few coats of lacquer?    I have never used a sealer

Generally speaking, a sealer is just a "wash" coat of the final finish. They call it a "wash" because it's usually a much thinner mixture than the build and finish coats. You heavily dilute the finals to like 75% or so, and it "seals" the wood so it won't absorb any more. That way, your build and finish coats will stack up rather than get drawn into the wood.

Some sealers are designed to work with certain topcoats to achieve the best results, so they may have other things in them besides reduced amounts of final finish. I'm on the fence about these claims, as I suspect they just want to sell you every chemical needed out of their inventory rather than allow you to find things that will work for less money. They want to sell you a "system". But, I could be wrong, so I drink the Kool-Aid. Still, I've mixed oil/water based fillers/sealers/finals without punishment so far, so...

As for when you should seal/stain/fill/build/finish, opinions vary. Depending on the material you get used to and the end result you're trying to achieve, you may do it different ways. The best schedules I've seen anywhere for the various guitar finishes is at LMII. I try to follow them for lacquer, and while I don't use the materials they recommend, I still generally get good results unless I screw something up myself. Reading through it, you might be discouraged, but don't be. It's not as bad as it sounds, and it returns excellent results.

 

[rolloman]

Thanks Cagey. I had forgot about LMII's schedule. I had that one bookmarked in my pc too. Gonna take another look at it again.