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Finishing Question

2K views 8 replies 3 participants last post by  TZH 
#1 · (Edited by Moderator)
Have any of you LJer's tried to use water based poly as a glue size to seal end grain instead of using a glue/water mix? The process I'm using is to apply a coat of Minwax hand rubbed oil based varnish first (maybe I should be using unwaxed shellac instead?), then a coat of water based poly, and 3 or 4 coats of the hand rubbed poly over that. I've tried it now on several of my pieces with good short term results so far, but am wondering if the results will still be okay over the long term. Any ideas/suggestions?
 
#2 ·
TZH,

I would use de-waxed shellac instead. However, if you do the end grain first you should be ok using just your chosen finish. End grain absorbs more quickly than face or edge grain and thus drips and runs over the edge will show up if the entire end is not done at once. Just do them first-on scrap, naturally-and see how it looks.
 
#4 ·
Thanks, fussy and a1Jim. fussy, when you say you would use de-waxed shellac instead, I guess I need to know instead of what - the oil based poly or the water based poly? I've read on other posts here on LJs that de-waxed shellac should be used underneath a coat of oil based poly to help prevent problems down the road, but my process involves a "middle" layer of water based poly, and that's what I'm concerned about. The first coat I lay using the oil based poly is intended to give the wood the color I ultimately want for the piece, and the second coat using water based is intended to seal the ends and open grain so the next four coats don't soak in so much. a1Jim, I've tried sanding this wood down to more than 600 grit, but because I'm using slabs cut right off the ends of juniper logs, the grain still absorbs the oil based poly to the point I'd need to give it so many coats it just wouldn't be worth the effort. Anyway, thanks again for the input. Any more ideas would be welcome, too.
TZH
 
#6 ·
YZH,

If I understand you correctly, you're using the end grain of the slab as the face of your piece. Is that right? The first coat of oil-based poly will add a warm, slightly yellowish colour to the wood, but I'm not sure of the rationale for using water-based poly over the oil and before more oil-base. If the wood is darkening too much due to too much absorbtion of oil, I'd give it 1 or 2 coats of shellac, sanding lightly between all coats, and then build up the finish until I'm happy. Shellac is compatible with nearly any finishing scheme and is predictable. I've not been happy with water-based poly's as they've all given me fits of one kind or another, but if you're happy using what you are using, I wouldn't change. What are you building?

I still can't figure out the problem, because a good coat of poly should swL END GRAIN so that color differences shouldn't be a problem. Ae you using wipe-on or brush-on?
 
#7 ·
fussy, thanks again for your advice. Here's the link to the project I'm referring to (http://lumberjocks.com/projects/35030). You are right in that the end grain of my slab is the face of my piece, and the first coat of poly did give me the color results I wanted but didn't seal it enough for my liking. I really want the color differences to actually show because of the type of work I do. In fact, the more differences there are, the more I like it. I read someplace that glue size woulld seal end grain so I tried it and didn't like the results at all because it dried unevenly and some areas of the end grain sealed while others didn't seal at all giving that "blotchy" look that everyone tries to avoid. Also, I do build up the finish until I get the sheen I want, but I'm just concerned about down the road if the oil on water based will have problems. I use wipe on as much as possible on all my projects. Thanks again for your adivice.
TZH
 
#8 · (Edited by Moderator)
Nice work, my friend. I had never seen red juniper before. Beautiful stuff. It's beautifully finished, really glossy. I guess what I don't understand is the need to switch to water-based for one coat. Poly is poly as I understand, only the carrier-oil or water is different. I wouldn't think one would seal any better than the other
and since you're using so many coats of oil-based anyway, why not avoid the risk and simply stay with oil? Mind, this is not criticism in any way. You have impressed me with your finishing skills. That piece is BEAUTIFULLY done. I bow before you. By the way, I looked at your other projects, and I have to say that I wish I had the ability to see the potential in a piece that you have. I can build from plans, but I have no vision to see that way. Carvers too. Wow.

Steve
 
#9 ·
Steve, thanks. I guess I need to be more clear when I post in the forum. The reason I went to water poly for the second coat is because it's thicker and seems to seal up the face grain better than the oil based I've been using. Maybe if I used a regular oil based poly instead of the hand rubbed (which is much thinner) I might get better results. I just don't want to have it dry out too fast. I need to admit I'm a novice at this type of stuff, so advice is always welcome.

Ted
 
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