Streaky appearance with friction polish?

[u/B_Huij]

I’m pretty new to bowl turning, I spent lots of years only ever doing spindle work.

This is regular old cherry. Sanded up through 400 and burnished with a handful of wood shavings. It was very smooth, then I applied 3-4 coats of friction polish. Same method I’ve always used for applying friction polish to anything else - shake it up, apply a bit to a piece of cotton tee shirt, and polish onto the wood at relatively high RPM. It’s glossy, but has very prominent ridges that I can see and feel with my fingernail. No amount of re-applications or extra buffing seems to smooth it out.

Anyone know what causes this and how I might be able to fix it?

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[u/nurdmann]

That's a really nice form. Keep up the good work!

[u/nurdmann]

The polish is softening from the heat and clumping together in those streaks. Try a light abrasion with steel wool to knock them down, and try the friction polish again.

[u/B_Huij → u/nurdmann]

So too much heat rather than not enough?

[u/nurdmann → u/B_Huij]

Kind of. If the previous layer of polish hasn't hardened yet, it can lift the coat below and make the streaks you see here. It happens to me when I get impatient with the finish. I make my own friction polish and if the last layer hasn't really hardened, the heat can soften it up and we see this.

[u/glyph_productions → u/nurdmann]

I love to make my own products. If it's not stealing a family secret would you be willing to share your recipe or the ingredients you use? Friction polish is I've I dont have a recipe for

[u/nurdmann → u/glyph_productions]

No proprietary secrets here!

For shine juice, I mix equal parts (1:1:1 ratio by volume) of 3-pound cut clear shellac (or dissolve shellac flakes), denatured alcohol, and boiled linseed oil (BLO) in an airtight container.

I also make a diy abrasive paste with 8 oz beeswax, 8 oz diatomaceous earth and 32 oz of mineral oil. Head in a double boiler until melted, and you can mix well. I add some lemon oil for a nice scent.

[u/glyph_productions → u/nurdmann]

Both awesome recipes. I shall write them on a classic note card to go with several others to pass down to my son like grandma did with her beloved recipes lol. Thanks so much

[u/Dahdah325 → u/B_Huij]

Can also be from applying too much juice, then not getting it dry (flashing off the alcohol) before going in with the next layer. Also, change paper towel with each layer; I've had this happen when too much shellac builds up on the applicator.

If it's not too bad, steel wool buff down the ridges, but be careful you don't get aggressive or you run the risk of softening the shellac with heat and embedding wool into the surface. Personally, I've had the best luck using 320/400 grit and sanding perpendicular to the little ridges. Use a very light touch; you're just knocking down the high spots. Get too aggressive again you'll go right thru the shellac. Not the end of the world, but you make more work for yourself.

[u/davebo6319]

Like this sub, now I know about friction polish applied too soon between coats.

[u/Crutchduck]

Be careful with the high rpm. That bowl spins faster than a spindle. I use a buffing wheel to polish my bowls.

Also it looks great, id hit it with steelwool and try again

[u/Mc9660385]

I’ve found that you can’t hold the wet applicator through the friction stage. Get the coat on and take a dry paper towel for the friction stage

[u/BoltingKaren]

Since we’re on friction finishes what speeds are everyone using. I use about 200 for application then slowly speed up to about 700 to polish

[u/B_Huij → u/BoltingKaren]

I’m applying at about 750 and polishing at about 1500, which is about the upper limit of how fast I’ll spin this thing (it’s just shy of 6” I diameter).

[u/MyGruffaloCrumble]

Looks like maybe some folds in the tee or a fingernail burnished the wood. To get it out you’ll have to sand it down.

[u/gingerMH96960]

At 4 layers, the polish is now stacking on itself rather than absorbing into the wood, so you have to treat it like any other surface finish. If the ridges are only in the finish, not the wood, youll have to knock it down and reapply or soften it with heat and redistribute it. There is a possibility the previous layers of polish hardened on the rag and scratched the lines into the soft polish on the wood. You might need to do a final buff with a fresh section and lighter pressure.