I'm stumped - Brazilian Cherry Finishing

J

Jay Knoll

Member
Joined
Feb 15, 2007
Messages
132
Hi everyone

I'm putting together a mirror frame out of Brazilian Cherry.  It has some interesting grain so I really went to town sanding it, took the finishing process up to 12000 grit with micro-mesh.  Looks great, but I can't get a finish to dry on it.  Used wipe on poly first.  I've used this finish before with great results on other projects, no problems.  On this project it would look dry but when I ran a finger tip across it I'd get a smear (this happened after 24 hours, then a week)  Called the company thought I'd gotten a bad batch, they said that I was putting it on too thickly.  And that I should wipe it down with mineral spirits to get rid of the excess let that dry and then go on finishing with less on the rag.  Well that didn't work.  I let it set for a week same result.  I'm in FL so I wondered about the heat/humidity in the shop so I ran the AC for 12 hours while the finish was drying.  So, took it off again, then brought the piece into the house so it would have continuous AC when I tried to redo the finish.  Same result.

Abandoned the wipe one, took it off with acetone.  I had some conventional varnish, thinned it down by 10% for the first brush on, flowed out great.  AC in the shop, same result.  Heck, I've varnished teak on my boat in August down here without these problems!  Any thoughts?  This is getting old.  Back out to the shop to wipe clean off the varnish.  Thanks

Jay
 
I'm not all that experienced with finishing but just a thought.  By going to 12000 grit, did you burnish the wood to the point with the grain is smooth and closed?  Maybe that is affecting how it dries with the humid weather.
 
Hoover

I thought of that, but when I stripped the wipe on poly off and brushed on a coat of Clipper Clear boat varnish it set up just fine.  So, I still think that there is something wrong with the poly.  I'm going to take a swipe on a scrap that I'll sand to 220 and see what happens.

Thanks for the thought tho.....

Jay
 
I would try a layer of shellac as a base layer. Then you can use a varnish, poly whatever. The shellac will help even out the grain by partly closingq the pores, thereby precenting blotchiness or an unequal absorption of stain if you are using one. My preference for a picture frame would be a coay of shellac followed by a wax finish.

Richard.
 
You may need to wash the surface of the wood.Natural oil from that wood makes it hard for stain to dry.I can't recall what to use for that.
Also,you may want to stay with 180-220 grit.
 
For washing oily wood, acetone and lacquer thinner are good choices.  Acetone is the stronger of the two.  Alcohol will also work to some degree- that is the carrier in shellac.

Peter
 
BTW there are no cherry trees in Brazil. Do you mean Jatoba? Jatoba looks beautiful with waterlox or another tung oil varnish. Sand to 320 then finish. sanding to anything above that is just an exercise in wasting time unless you are applying an oil finish. and I mean oil not an oil based film finish.
 
Jay Knoll said:
Hi everyone

I'm putting together a mirror frame out of Brazilian Cherry.  It has some interesting grain so I really went to town sanding it, took the finishing process up to 12000 grit with micro-mesh.  Looks great, but I can't get a finish to dry on it.  Used wipe on poly first.  I've used this finish before with great results on other projects, no problems.  On this project it would look dry but when I ran a finger tip across it I'd get a smear (this happened after 24 hours, then a week)  Called the company thought I'd gotten a bad batch, they said that I was putting it on too thickly.  And that I should wipe it down with mineral spirits to get rid of the excess let that dry and then go on finishing with less on the rag.  Well that didn't work.  I let it set for a week same result.  I'm in FL so I wondered about the heat/humidity in the shop so I ran the AC for 12 hours while the finish was drying.  So, took it off again, then brought the piece into the house so it would have continuous AC when I tried to redo the finish.  Same result.

Abandoned the wipe one, took it off with acetone.  I had some conventional varnish, thinned it down by 10% for the first brush on, flowed out great.  AC in the shop, same result.  Heck, I've varnished teak on my boat in August down here without these problems!  Any thoughts?  This is getting old.  Back out to the shop to wipe clean off the varnish.  Thanks

Jay
Click to expand...

Jay,

did you get this resolved? You probably only sanded your teak to 220 or 280 tops before applying the varnish. Varnish/poly needs a rough surface of 220-280 to stick. Sanding any higher and it wont stick. I dont know why it isnt drying though. I recently brushed poly on some door panels and each coat took about 36 hours to dry enough to sand even though the can said 6 hours. Yikes.

I would go back and sand it w/ 220 then finish with lacquer, waterlox, or blo/varnish/turpentine. I would spray the lacquer. With waterlox or BLO/varnish /turpentine mix I would wet sand and wipe off. starting with 220. Wet sand with the oil once each day with 220 then 320 then 400 then 600 then 800.

I hate shellac. its not durable, its hard to apply evenly and doesnt dry hard enough to sand well. I really dont know why its so popular. Ive only used the off the shelf shellac though and cut it with DNA
 
Eiji It's true shellac is not a strong finish at all, but I used it on the floors in my home with no problems, unless  alcohol get on it.  :). Shellac buffs to a mirror finish you can see yourself in. Just look all the fine pieces that are French polished.  I normally never find a need to sand the shellac, I never get nubs or anything wrong  where sanding is required.   Any imperfections get fixed by just applying another coat and rubbing it in, there is no reason to sand for adherence at all because each coat  melts into one another..  When I do sand I get a white chalk dust, if you are not getting that then the shellac is not dry,old or does have wax in it.

I find shellac dries in 10 minutes to no longer than 24 hours. For a French polish some guys wait 2 weeks, even a month or two.  It sounds like what you are describing is what happens to me when the shellac gets old. There is only one brand of pre-mixed shellac with truly  no wax and that has been linked to, otherwise use the flakes. Even the yellow can Zinnser does have wax, don't be fooled, only their sealer  and the spray is wax free.

Applying shellac is the simplest of all finishes to apply evenly so something is amiss either with the shellac(old), the cutting material(wrong type) or mixing method(ratio or shaking it to much, etc).

Sounds like the OP sanded to a 12000! On Jatoba nothing more than 120 or at most 180 is ever needed or it simply will not hold the finish. After a couple applications then he can use the finer grits or buff it out. Jatoba is a great wood and it should not create many problems at all for finishing.

For me shellac is the best . I use it exclusively unless the piece needs more durability. I would not use it for a table top either other than a piece that is going to be looked at with no glasses(especially with alcohol) etc, put on it.
 
Good answer, Nick. Also, Shellac does not have to be the final finish. I use it as a base layer, and then I can add anything on top of it. It acts as a good sealer and a good way to prevent blotchiness before staining.

Richard.
 
Hi guys

Well, I'll let you know when I get home!  I've been on an extended road trip and the mirror has been sitting on my bench "baking" in a closed up garage shop in the FL heat.

Jay
 
Nikao,
You nailed it as usual. My shellac expirience has been out of a zinzer can. It was so frustrating. I'll have toget around to mixing up some of my own. I do like spray finishes so I dont  know if I'll ever get to it though.
 
I wish I had room to spray, I git rid of my Fuji setup. Being slow now, I need to do many different things and not having a spray unit just limits my capabilities. Spraying conversion varnish is probably the best way to go for most things. You would know better than me on the spraying.
 
My first thought is that your finish is old (and when you bought it has nothing to do with it's age).  It shouldn't matter what the wood is or what you sanded to.  It should air dry if brushed on metal...  You can try putting the finish on rougher stock, etc. but I doubt the results will change.  Get a fresh can and try it again (see if you can find a date stamp).

Chris...

Jay Knoll said:
Hi everyone

I'm putting together a mirror frame out of Brazilian Cherry.  It has some interesting grain so I really went to town sanding it, took the finishing process up to 12000 grit with micro-mesh.  Looks great, but I can't get a finish to dry on it.  Used wipe on poly first.  I've used this finish before with great results on other projects, no problems.  On this project it would look dry but when I ran a finger tip across it I'd get a smear (this happened after 24 hours, then a week)  Called the company thought I'd gotten a bad batch, they said that I was putting it on too thickly.  And that I should wipe it down with mineral spirits to get rid of the excess let that dry and then go on finishing with less on the rag.  Well that didn't work.  I let it set for a week same result.  I'm in FL so I wondered about the heat/humidity in the shop so I ran the AC for 12 hours while the finish was drying.  So, took it off again, then brought the piece into the house so it would have continuous AC when I tried to redo the finish.  Same result.

Abandoned the wipe one, took it off with acetone.  I had some conventional varnish, thinned it down by 10% for the first brush on, flowed out great.  AC in the shop, same result.  Heck, I've varnished teak on my boat in August down here without these problems!  Any thoughts?  This is getting old.  Back out to the shop to wipe clean off the varnish.  Thanks

Jay
Click to expand...
 
It absolutely matters what wood it is and what you sanded too.  :)

Anyone that works with exotics on a regular basis should know this, they all act differently. Unless you just want the finish to sit on top with no adhesion properties(ready to flake off at any time) as opposed to soaking into the wood and creating a nice bond you need to watch the sanding and know the oil content and the pore characteristics of each wood, etc.
 
nickao said:
I wish I had room to spray, I git rid of my Fuji setup.
Click to expand...

Did you like the Fuji, (I have one) I mean did it do what you needed or did you get rid of it 'cause it wasn't working? What unit did you have?
 
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