Uv Proof Oil Finish For Purpleheart

[Robert_the_damned]

Hi All

Just wondering which, if any, oil finish will give UV screening? I want a quite 'natural' feeling neck with the minimum of finish on it and I'd like my purpleheart to stay purple! never used oils and I have no idea about properties such as UV screening, I tried several searches but they never came up with anything. I'm guessing they would seeing as all sun screen (for you skin) is is a whole load of differant oils, but I'd rather be sure! any help is appreciated.

Robert

[oz tradie]

As far as I know , the more transparent the finish the less U.V. blocked out.

I know with Autimotive tint there are layers at differing angles within the tint film to reduce glare and U.V.

Although that works great, I am not aware of anything which does the same job in a clear finish.

Anybody else out there able to help on this one ?

[rsguitar]

Just woundering why you need it to be a UV protective finish. For a natural finish why don't you use tung oil.

most of the finishes that i have used with UV protection usally are not very clear. I have built log Homes and used several different types of finish. All of them were translucent, but never totaly clear in apperance.

Mike

[Robert_the_damned]

if you leave purpleheart exposed to UV it turns from its nice purple colour to a nasty brown...not what I really want....so I was looking for a finnish that would prevent this. Though by the sounds of it it doesn't exist! I was going to finish with tung oil but then I don't know if it offers any protection.

Thanks for the help so far guys.

Robert

[al heeley]

UV-blockers tend to be 2 types: sacrificial UV-absorbers or blocking, like titanium dioxide. The TiO2 is the most effective but gives a big reduction in transparency and a milky coating. The sacrificial route involves a special varnish with HALS (hindered amine light stabilisation) chemicals in or the Ciba Tinuvin type, which can make the varnish yellowish, and will eventually lose effectivity after a year or so.

I would advise that either present an unsuitable finish for a guitar.

The solution: Store your guitar in a case, do not leave it lying round in the sun for extended periods and play mostly at night. You can then use a decent normal varnish.

Question: Is the purple discoloration directly and only UV-that causes it or a mixture of UV and oxidation?(<-more likely, wood seldom hasd any chemicals that show a photochromic effect) in which case just the act of sealing from the oxygen with a standard varnish would greatly enhance the preservation of the colour.

Edited May 19, 2006 by al heeley

[unclej]

i'm not 100% sure about this so take it with a grain of salt..my business partner at the shop has his own company making short scale custom basses. he uses a lot of purple heart and it would appear that oxidation is more of a culprit than uv. he uses a homemade oil finish with equal parts of poly, linseed oil and thinner and so far has had no problem with the purpleheart changing colors after the finish has been applied.

i use an older formula for my guitars..equal parts of linseed oil, varnish and turpentine. if it sounds like something you'd like to try then substiture regular varnish with spar varnish made for marine applications. it has uv protectants added.

[Robert_the_damned]

thanks very much for the replies guys!

UV-blockers tend to be 2 types: sacrificial UV-absorbers or blocking, like titanium dioxide. The TiO2 is the most effective but gives a big reduction in transparency and a milky coating. The sacrificial route involves a special varnish with HALS (hindered amine light stabilisation) chemicals in or the Ciba Tinuvin type, which can make the varnish yellowish, and will eventually lose effectivity after a year or so.

I would advise that either present an unsuitable finish for a guitar.

I'd have to agree there! Neither sounds like its going to look particularly apealing!

play mostly at night.

not a problem!

Question: Is the purple discoloration directly and only UV-that causes it or a mixture of UV and oxidation?(<-more likely, wood seldom hasd any chemicals that show a photochromic effect) in which case just the act of sealing from the oxygen with a standard varnish would greatly enhance the preservation of the colour.

yeah now I think about it far more likely to be an oxidation problem. I'll probably just seal with a standard finnish.

i'm not 100% sure about this so take it with a grain of salt..my business partner at the shop has his own company making short scale custom basses. he uses a lot of purple heart and it would appear that oxidation is more of a culprit than uv. he uses a homemade oil finish with equal parts of poly, linseed oil and thinner and so far has had no problem with the purpleheart changing colors after the finish has been applied.

i use an older formula for my guitars..equal parts of linseed oil, varnish and turpentine. if it sounds like something you'd like to try then substiture regular varnish with spar varnish made for marine applications. it has uv protectants added.

Thanks for the info UncleJ, I've never mixed my own finish before but it sounds like now is the time to try it out. If your bussiness partner isn't having any problems then that seems like the finish to go for! your finish also sounds like a good idea....I might have to do some experimenting on some scraps.

Thanks for the help again!

Robert