Varnish finishing

Hello All. I'm working on a speaker project using Bamboo ply. I read and learned so much from this forum but in some case it's information overload. What finish I elected was a wipe-on varnish after a few trial pieces of different products. I'm using Pratt and Lambert 38, gloss so far. I've been diluting it 50/50 with MS. At first I had slight issues now I have my application down pretty good.

I followed the bus boy wipe-on procedure at first now I adjusted it somewhat, I just wipe on a thin coat with the grain like Marc from the woodwhisper shows. I apply two coats a couple hours apart, repeat after 24 or 48hrs sanding lightly after the first two sets. Anyway that's not my issue. I'm starting to be concerned with the final rub out process. Basically I just want an even sheen, ideally satin, very smooth to the touch. A couple issues I see. One is the open grain of the bamboo (I didn't realize it was that much until now). Sanding a trial piece the ingrain remains gloss while the surface could be sanded to the sheen I like. I guess I will continue to apply coat with some sanding in between to help fill them in. Another is that I may have over sanded the raw wood. What I mean by that is the front baffle is ever so slightly wavy...around the speaker cutouts it's recessed a little as are the baffle perimeter so sanding with a block shows high and low spots. The tops are also a little wavy as they are stacked end pieces.

Anyway this is an all out effort to get it the way I would like. I have Abralon pads, a Festool ETS EC 150/3 at my disposal..so any products available to help I will consider. I guess one of the hardest parts is waiting 3-4wks before I can try it and if I fail...ugh...start over. So I'm trying to find a pretty fool proof method. Oh if you haven't noticed I am pretty new at this.

Here's a few pictures. They kind of show it worse than it really is. In fact I could almost leave it as is...no runs or imperfections yet...but I'm not. I can give more details if it helps...suggestions much appreciated.

-Scott
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Scott,
A couple of suggestions-
1) for filling the grain- Apply another coat and light wet sand with 320 or 400. The slurry you create will fill the open grain.
2) for rubout- MicroMesh, this is a great product and will allow you to achieve any sheen within the range of the P&L gloss. It is virtually idiot proof.
regards - Bill

Thanks Bill. Could you describe your process with each. Do you wipe off the slurry... I have little time before it starts tacking up. Also with micromesh...how does it compare with Abralon pads?

Scott, the job looks pretty good. In fact your workmanship is excellent. The product you are using is good enough for the job. It's limitation in your case is that it is not filling the grain. This is because, in common with most over the counter products, it is not very high in solids ie what you have left after the solvent has evaporated. This means you either have to use a grain filler or else patiently apply coats until you get the look you want.

At this stage of the job, grain filler is not an option. What you need to do is use a flat cork block and 320 paper and sand it flat. You may have to wet sand it given the type of coating, but do it dry if you can. Sand just far enough to flatten the area between the pores. In the areas where you fell you have a wavy surface, use a soft faced block with your paper. I have a cork block with a layer of felt glued on one face just for this purpose. You can also buy high density foam blocks that work too. The important thing at this stage is don't sand too far. If you go through the coating, you are back to square 1 and have made work for yourself.

When it is ready for coating, apply the coating liberally without thinning. Work it into the grain with a circular or figure 8 pattern until it starts to get sticky. If you work with the grain, you are pulling coating out more than putting it in. Just do the bare minimum with the grain rubbing and only if there are visible swirls. You only need to do your absolute final finishing with the grain. Observe the drying time and repeat the whole procedure as many times as necessary to get the look you want.

This will work even if the advice will give the french polishers a collective heart attack. Cheers!

Good information Wayne. I'm a little reluctant to go without thinning and in a circular pattern. I started that way and started getting swirls even when thinned. I think I will try a reduced thinning. Also I should be able to apply a thin coat...yet thick enough so that when applied initially it looks nearly flat w/o the grain streaks until the solvent starts evaporating. I think that's the best I can hope for.

Anyway a couple more thoughts/questions. If I plan on doing a pretty aggressive sanding to flatten the finish what would be a good amount of time to wait for the finish to harden. Generally I've waited 2 days and get pretty fine white powder. Also is it possible to bind coats of this varnish by waiting only 1-3hrs between coats? If there is a likely chance I will sand through a coat I wonder if I shouldn't just go ahead and sand flat and not worry sanding through then build back up hopefully with a flat starting surface.

I am currently "finishing the finish" on a dresser. I use an oil/varnish blend padded on and wiped off like you hear and read about. An unforeseen work stoppage left me with a few coats to go the last coat applied and not fully dealt. Like you I now had to wait for the curing process to place the finish in a state where additional surfacing could be done; hard, not almost hard :).

The following assumes you have enough of a film to allow some sanding. I use 1500 grit wet/dry wrapped around a cork block and lube this with mineral spirits. I have a hand spray bottle of mineral spirits and spritz the abrasive block or the surface as required. I also change abrasive as it wears and do NOT try to milk an extra mile out of a sub-optimal abrasive material.

I work a specific area at a time going back and removing spoil with a rag damp with mineral spirits. As I get a few areas away and the previously done areas are completely dry I wipe them down with a soft, dry cloth and inspect for the look I am after. The finish may be a bit more glossy than you are after. If so, it is easy enough to test an area with 1000 grit or 1200 grit. If you don't like it a few moments with the 1500 will bring you right back. Another option for knocking down the gloss is to apply paste wax with 0000 steel wool once all your other surface prep is complete.

Don't be too concerned about swirls until you think you don't need to sand any more. Rubbing across the grain pushes the coating into the grain. It sounds like you may be rubbing for too long. The thin coat is good for final finishing but while you are trying to fill the grain, keep it full strength. It will fill the grain more effectively. If you can sand it to powder, that is a good cure time. Try to avoid sanding through. You end up with areas with different coating application and that affects appearance ie patchy look. I will get back to you with info on shortening redcoat times. Cheers

Just had to remind myself. The coating you are using is an alkyd. If you apply this type of coating too soon, you risk a wrinkling effect. This should not happen as you are rubbing but you may also damage the partly cured film. I only ever do wet on wet like this when spraying and only with a much shorter interval say 15 minutes or less. Cheers

Update...It became apparent it would be difficult to fill the grain and I didn't particularly want to build it that thick. I was shooting for a close to the wood (grass ;)) finish. I purchase a quart of satin P&L 38 varnish and initially I though it was a little streaky and might cloud the finish. I tried it on a test piece and the streaks sanded out and didn't appear to cloud the finish. So my abbreviated steps were; three coats gloss, wait 48hrs, sand with ROS and Abralon 360 grit. Three more coats gloss, wait 48hrs, block sand with P400 grit to level. Apply 8 coats gloss two per day for 4 successive days without sanding. Wait 5 days and sand fairly aggressive with P600 grit block and ROS with 500 grit Abralon. This was the point to see if the grain could be filled. It was apparent it would take many more. There I switched to P&L 38 satin, 6 coat two per day, for three days with light sanding in between. I then waited 3 weeks to cure. Block sanded with a foam block and P800 grit paper dry. From there I wet sanded with ROS, soapy water and Abralon 1000 grit then 2000 grit. I was concerned of rubbing through the finish but all went well. There is some waviness and scratches but not really noticeable unless under close inspection...I am very happy and it's sooo smooth. Thanks for the help!

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Really beautiful, Scott!

Looks good, Scott! Cheers

Very nice, well done sir.

Thanks for the kind words everyone!