Sealer before or after grain filler

[hummingbird]

I have Mohawk vinyl sealer. I'll be using Watco spray can nitro. I have some of that hoods Laquer based grain filler.
This hoods was recommended by a poster last year. It is supposed to be sealer as well.
So, my plan was to apply Mohawk vinyl sealer to the entire guitar. Then grain fill the padauk and mahogany. Then spray Laquer.
Is it wrong to seal before fill or does it really matter?

[tippie53]

that is what I do. I use Pore o Paq. I have tried many fillers , and the mineral spirit base is what I like. Also the Z poxy. Any filler that dries too fast can be tricky and messy.
try a test piece first

[pete nardo]

Always seal first. Otherwise, you risk unsightly staining to the wood (I learned this the hard way).
Shellac makes a great sealer, aka 'wash-coat', thinned w/alcohol.
Good luck.
PS Your vinyl sealer should work fine as well.

[Zen]

Always seal first. Otherwise, you risk unsightly staining to the wood (I learned this the hard way).
Shellac makes a great sealer, aka 'wash-coat', thinned w/alcohol.
Good luck.
PS Your vinyl sealer should work fine as well.

I used this but not sure how many coats to use or if I should be sanding between coats--any suggestions? Its a sanding sealer called Rustins Shellac


http://www.rustins.eu/Details.asp?ProductID=793

[Darryl Young]

I'll repeat John's advise.......try everything on scrap pieces from your top/back before trying it on your guitar. Make sure there are no adhesion issues.

[tippie53]

I use a sealer that is recommended by the manufacturer as this as much about comparable chemistry in the finishing products. Years ago the shellac may have been reliable but today it isn't the same product. Often adhesion issues don't show themselves for a season or 2 . I used to use shellac but I will not risk it .
Also we are talking about manufactured not button shellac as this is 2 different things entirely. Now when you seal , a coat or 2 is all you need, I sand 120 grit and I do it lightly as to just level things up then do my fill. I AVOID water based or acetone based fillers. I find they are great on furniture but not guitars.
Zpoxy and Pore O Paq may still be the best out there. When filling follow the instructions on the container. Again this is about finish compatibility . When it looks good repeat one more time then seal. Once that is done you can do your finish .

[B. Howard]

Not familiar with the brand of shellac sealer you mention, but in general the problems that crop up with pre-packed shellac sealers are due to the preservatives added to it to keep it fresh. Typically if I need to seal or bond coat with shellac I will mix it fresh from de-waxed clear platina flakes. Consumer grade finish materials like Minwax Polyurethane etc. are much more forgiving in their adhesion to a soft ( stale) shellac than things like nitro. As for how many coats of sealer.....the object of sealer is just that to seal the wood. One medium wet coat should be all that is needed. it should leave a rather dull, but even looking coat on the wood. As for sanding..... a light scuff to knock down any nibs should be all that is needed, this is where finish system compatibility really comes into play. I do most of my inter coat sanding with 320, sealer being an exception. A lot of times I will scuff my sealer with maroon Scotchbrite. Do not use steel wool as you risk fisheyes from any oil that it may leave behind. If you scuff through to bare wood anyplace, that area will need re-sealed.