Official Luthiers Forum!

Hi everyone,
I am currently re-finishing a rickenbacker bass. I was planning to spray Nitro...after sanding back to wood...BUT...While doing some research I find that the rics are apparantly sprayed with a "conversion Varnish" at the factory. I assume "conversion" means "Catalized". Anyone have experience with this stuff. please explain everything. THANKS SO MUCH for taking your time to respond. If you would like to email me you can do so at skg@siestakeyguitars.com . THANKS!

_________________
Dave Bland

remember...

"If it doesn't play in tune...it's just pretty wood"

I have used CV (Sherwin Williams brand- solvent based) extensively for
furniture work. I'm not sure why it's not more popular with luthiers, but
here are my observaions:
Yes, it's a catalized varnish. Solvent based and lower VOC than Nitro.
They make a water based version, but my experinece with it was not
pleasant.
It's much higher solids content than Nitro- it runs around 24% compraed
to nitro's 15 or so . It behaves in the gun alot like nitro, but there are
some limitations. You can't exceed the reccomended coating thickness (I
seem to remember 6 mil) or it will crack and lift. It does not "melt
together" with subsequent coats like nitro so repairs are much harder to
do (you'd have to do a complet re-spray, & remember about that max
thickness...) The thinner solvent is dependent on the temperature you're
working in. As I recall you can use Naptha in higher temps (summer) and
xylol or tolulene in lower temps when you want a quicker flash off.
Needless to say, use a good respirator...
It is very hard and more chemical resistant than nitro, so it should buff to
a gloss well and resist sweat, etc better. It does chip a little easier on
account of it's hardness, but it's very scratch resistant, etc.
Get it out of your gun completely when you're through or it'll harden and
be a stinker to clean up later. I usually had to change the fluid hose on
my pressure pot every month or so.
I would say try it out on something less precious at first and see if it
behaves the way you want it to.
-C

_________________
Freeborn Guitars
and home of BeauGuard©

Dave,
The catalyzed urethane I mention in my finishing dvd is basically a conversion varnish and should suit your needs when refinishing your guitar. I prefer it to nitro any day.

What type of spray schedule? do you sand in between coates? My understanding is that you don't need to apply too many coates...whatis enough? Also when you catalyze what do you do... spray catalyzer on directly or mix with the CV ( I assume mix with CV)? What brand do you recommend?

Robbie, What brand Do you recommend and what type of spray schedule? Also what do you use to clean the gun?

THANKS GUYS!

_________________
Dave Bland

remember...

"If it doesn't play in tune...it's just pretty wood"

Dave,
I use a brand called ILVA. It is a European brand but they have a Stateside distributor. I use number TP60 with Hardener TX75. You might want to thin it up to 10% as needed. Mix it one to one and spray just as you would any other topcoat. It builds in layers as oppossed to melting into the previous layers. Two coats a day (for three days) at 1 and 1/2 hour intervals sanding at the beginning of each day. On the fourth day, wet sand and buff. Clean up the gun with lacquer thinner.

It's been a while, but as I recall with the Sherwin Williams variety (ChemVar) I
used to seal with vinyl sealer catalized per instructions, sand with 280 or so
then spray 2 medium wet coats. Sand again the next day with 280/320 and
shoot 1 more wet coat. Most of what I was doing was medium rubbed effect
(satin finish) so if I didn't have any flaws or dust it's done. For gloss/ rubbed
I'd probably shoot 2 medium-wet coats on day 2, give it a couple of days
and sand/buff.
Catalyst is mixed into the finish before spraying. The catalyst for the sealer
and the Convar is different as I recall.
This link should get you started:
http://www2.sherwin-williams.com/oem/wood/default.asp

-C

_________________
Freeborn Guitars
and home of BeauGuard©

very interesting stuff! Boy they make everything...

_________________
John Mayes
http://www.mayesluthier.com