Harry,
It's just general confusion as much as anything. I hear many different things from different folks, and I haven't found the magic combo yet. I hear about what kind of paper towel to use, whether to sand or not between coats, accelerant or no accelerant, BLO or no, etc.
Currently, I'm using the blue shop towels on a roll, Duro brand CA in the little tubes from the dollar store,
Blue shop towels are fine, but I would drop the Duro. I started with the Stick Fast system and it works very well.
and so far, no accelerant. First coat goes on okay, but the 2nd or 3rd gums up,
the Duro is probably not set, but just getting sticky by the time you come back with coat 2 and it is all over.
and I get blue paper towel bits in a very lumpy finish. I have gone so far as to allow 24 hours between coats.
Should be set by then, so it could be too much time in the application.
My thought is that I may be applying too much CA per coat, and the solvent in the excess CA is softening the previous coats. Also, I'm probably guilty of using the same spot on the towel to apply subsequent coats.
Try using a fresh spot - two approaches a) 2" squares folded to roughly .5x.5, or b) a half inch wide strip 4-6 inches long and you snip off the end that has the CA after each coat. I do both, but I think b) might be more efficient.
I've dabbled with using a plastic bag as an applicator with similar results. I don't think I have yet tried sanding between coats.
You don't need to sand between coats if you get your application technique down.
I have tried thick/medium, thin/medium. Summer and winter require some adjustment. Probably the biggest cause of rough finishes, assuming a good CA product in the right viscosity, is over-working the application. If you have ever watched a pro do sheetrock (drywall) they lay on the mud and one pass with a trowel and leave it alone. Most of us amateurs go back over and over trying to get it smooth and just mess it up more.
I have tried various combinations, here is what works best for me:
- wipe the blank down with denatured alcohol to remove any grease and natural wood oils, also takes sanding dust off and absorbs moisture.
- I use a thin CA with about a 5 second cure time. Stick Fast or EZ Bond are a couple of IAP favorites. Hobby Lobby has a decent brand called "Extreme Power Thin" if you run out of the good stuff.
- 400 rpm
- 2 drops on my towel and a fast wipe down and back - about 1 second in each direction - 1 pass you don't need to smooth it out
- alternate starting from left end/right end
- no waiting necessary with the thin. by the time you snip your towel and get two more drops, you are good to go.
- quick blast of aerosol activator after every 4 coats to harden
- 20 coats - takes about 7 minutes once you get it down. As you get better, the finish will be so smooth you can probably drop to 16 coats because you won't need to sand very much.
- I like to hit a double shot of activator when I finish. If I have the patience, I let it sit for 20-30 minutes before I start sanding to get really set.
- start with 400 abranet wet (CA doesn't like the heat of dry sanding) After sanding longways, you should be level with no shiny dips. If not, give it as little sanding as possible to eliminate the shiny spots. Then repeat with 600 and on to micromesh pads wet. Sanding longways with the lathe off between each grit and wiping the grit off before moving on.
- If your finish was level after the 400 - use minimal sanding since you are only taking out the longways scratches of the previous grit. Common mistake #2 is over-sanding through to the bare wood.
Thanks to Martin Beauford for getting me to try 20 thin process -- no more ripples and ridges! If you have a blank with lots of open pores or grain, you can do a coat or two of medium to help fill in the holes.
Sometimes the towel wants to stick to my nitrile gloved finger. I found that the smallest poly pen component bag will stay on my index finger and the glue won't stick to the poly, so you only need 1 bag per pen.
There - I saved you a road trip :biggrin: Good luck Dave!
I think my next step is to lock myself in the garage, turn a fresh blank round, and have a knock-down, drag-out where I try various techniques until I either get it right or I end up with a bare brass tube. I know this really isn't the thread for this, but if anyone has any suggested formulae, I'm all ears...or eyes.
-Dave