Violin Forum/Message Board

[catbrain]

2 thoughts on ground---
someone was talking about using a coffee and gypsum mix (wet) as a ground.
(paint it on--- massage it in--- wipe excess off- let dry-- scrape lightly----then sealer)

The term Gypsum could be a lot of different products. Are people using just plain plaster of paris ? or some kind of agricultural gypsum ? pretty vague---

I have some casting material I bought at hobby lobby called perfect cast.
It says it contains gypsum and silica flour-- and says its 5 times stronger than plaster. would that be a good thing or a bad thing in a ground ?????

Another thought is maybe using epsom salts as a ground. Anyone tried that ?

Tim B.

[catbrain]

I started with a slurry of the plaster -silica mix plus a little water based dye.

next day It had a thin layer of "concrete" - like a thick film. REEAAALLLLYY hard . The scrapers wouldn't cut it. I had to use some sand paper.

Sanded some then a very light scrape all over with a un-turned single edge razor blade. The curved scrapers.

It looked really nice after the scraping. The reeds popped out nice and glossy and reflective. Then I painted on two thin film coats of linseed oil.
Then a 3-rd coat dyed with some red-brown dye. Thinned with turpentine.
(dye in turp- then stir- then into the oil and stir again. Painted the oil on with a dollar store white bristle brush. That went on REALLLLYYY nicely. Like how you wished oil varnish would go on. The linseed is very easy to brush out just like you want it. self leveling and each coat was starting to dry in about 5 min. (!)

That 3-rd coat is drying out now. It seems to shrink down tight better than varnish. The reed geography is still showing nicely.

At some later point - after I get the bar glued in--- I will scuff it and do a coat of oil varnish. That should take about a week or more between coats.

The current very low humidity seems to be helping the linseed oil to dry quickly.

What I am not really sure about is--- when I scraped off the plaster coat-- was there REALLY any left down in the pores of the wood ? Thats why I decided to do oil over it. as a back-up.

Tim
B.

[Michael Darnton]

Don't scuff up the ground. It's not needed, and if at any point you cut through it you will regret it! Guaranteed.
_________________
new blog at my site! http://darntonviolins.com/blog
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[catbrain]

I did 3 coats of linseed thinned a little with turp. I should be sealed now-- whatever happened with the plaster that got scraped underneath.
The formulas for the plaster ground said to re-scrape back down to get rid of the plaster laying on top of the wood (as opposed to IN the wood)
So im hoping the linseed will be a nice insurance policy. It didnt hurt that the linseed looks very nice too. Should make a good base for the first varnish coat. I thought i'd give the linseed till next week to cure out fully... then maybe do 1 thinned coat of brushed on oil varnish to protect the surface since
it will be a little while till it gets glued onto the body. Still have about 1/3 of the scroll to go and about 2/3 of the back plate to work on. That one piece back is like trying to carve solid aluminum ! Slow going. frequent sharpening.

T

[MikeCooper]

Has anyone tried gum tragacanth as an initial size or sealer? It was mentioned in Librum Segreti de Butegha.