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BarPar
12th April 2015, 12:01 AM
Hi French polishers
I am making stringed instruments, stick dulcimers also known as a Strum Stick. The last one looked good to start with but after about one month the French polish has crazed. I have been applying it with
a rubber. Any ideas?
Cheers
BarPar

q9
13th April 2015, 11:57 AM
How well was it sealed before you started polishing? My guess is if itis cracking then too much oil is either in the timber or being used full stop. without knowing more about how you applied it i'd say it is getting in the grain and causing cracking as it dries out.

BarPar
15th April 2015, 10:37 AM
Thanks for that. You might be right with the oil. I first brushed on a couple of coats of shellac then used 600 wet and dry to level it out and I used oil as a lubricant. The wood is Western Red Cedar.
Cheers BarPar

q9
15th April 2015, 09:13 PM
Yeah, you need more than a couple at first. When dropping oil on as a lubricant, use tiny amounts. Sometimes I dip a rag in the oil and just wipe a little bit on. Not over the whole piece, just a small area and let the rag grab it up. Just enough so it doesn't drag too much. You also don't want the mix too thin or the alcohol seems to wash out the oil, which makes you wanna put more oil on...which is bad. Least you can get away with is best.

ubeaut
17th April 2015, 10:24 AM
Nice looking instruments...... :2tsup:

What sort of shellac are you using?

How old is the shellac if premixed?

Did you use Industrial Methylated Spirits (either 95% or 100%) or stuff of the shelf in the supermarket?

What oil did you use?

What else did you put on the timber before applying the shellac?

Did you put anything else on the finish after applying the shellac?

Was the shellac well mixed (stirred/shaken) before each application?

Shoot off a response to all the above and I might be able to let you know what caused the problem. All or any of the above in conjunction may have an affect on the finish.

Cheers - Neil :U