which poly for 1/3 poly, 1/3 BLO, 1/3 mineral spirits

[kooshball]

I am going to mix up a wiping varnish using a mix of poly, BLO and mineral spirits but which poly is best for this purpose?

THX

 

[Makinsawdust]

I like Helmsman spar. One third spar, two thirds BLO.

 

[eyekode]

I have used a couple flavors of minwax poly. The directions I found online suggest semi-gloss. I thought that was stoopid because semi-gloss is just gloss with stuff added to reduce the sheen. Well seems like maybe those guys know what they are talking about because with the gloss I find it sometimes ends up being glossy only in patches! After switching to semigloss I have not had that problem. I am now using semi gloss + BLO + tung oil. I have 3 coats down on my first project and it is looking great.
Salem

 

[Rob]

I second spar varnish. I use Ace Hardware brand in my mix for most of my turnings.

 

[stave]

I also use the semi gloss spar urethane from the box stores. I would stick to the equal proportions for each. The BLO is used to reduce the drying time and allow for application, the mineral spirits is for penetration so the more BLO the longer the drying time. I have used this mix for years on exterior doors and it works great.

Stave

 

[kclark]

I also use the semi gloss spar urethane from the box stores. I would stick to the equal proportions for each. The BLO is used to reduce the drying time and allow for application, the mineral spirits is for penetration so the more BLO the longer the drying time. I have used this mix for years on exterior doors and it works great.

Stave

If BLO is used to reduce the drying time, how is adding more BLO making the drying time longer???

 

[stave]

Sorry about that. BLO definitely extends the drying time. BLO is used in artist oil painting for the same purpose. In truth BLO never truly dries in its pure form but what you buy has metallic dryers in to help move it along.

Stave

 

[bluedawg76]

spar varnish is not the same as polyurethane right? Aren't longer oils used to cook the resin to make a softer finish?
I like General Finishes mostly b/c of their other products, but have never compared it to minwax in a head to head. Probably about the same though. Interesting idea regarding the gloss vs. semi-gloss. I've only used the gloss, but have noticed the glossy spots you speak of. I figured these were places where I had enough varnish coverage to form a film. Good suggestion to try the semi-gloss.

Sam

 

[kooshball]

I have used a couple flavors of minwax poly. The directions I found online suggest semi-gloss. I thought that was stoopid because semi-gloss is just gloss with stuff added to reduce the sheen. Well seems like maybe those guys know what they are talking about because with the gloss I find it sometimes ends up being glossy only in patches! After switching to semigloss I have not had that problem. I am now using semi gloss + BLO + tung oil. I have 3 coats down on my first project and it is looking great.
Salem

I have now seen quite a bit of info on using alkyd varnish for the resin part of this mixture but no reference to gloss. I wonder if the same issue would surface in an alkyd varnish formula as you have described here. Gregory Paolini reference this on his website but I am not to sure of the gloss level of the varnish.

I found Pratt and Lambert #38 that seems to fit the bill for the resin but need gloss recommendations.

 

[Howard Acheson]

It really makes little difference which brand of poly varnish or standard varnish you use. Sheen is also unimportant. They will all work equally in an oil/varnish mixture.

However, I never use a "spar" varnish. Spar varnish is already very oil heavy to make it soft and flexible. For interior applications a less oil heavy varnish or poly varnish works better for me.

Keep in mind that an oil/varnish mixture is not intended to be "built" to a film thickness. Excess is thoroughly wiped off. Two coats is optimal. More can leave a soft, gummy surface. It's an in-the-wood finish that mimics an oil finish. It is not glossy, rather it leaves a somewhat low glow to the wood

If you are looking for a harder, more protective and high gloss, use a standard varnish or poly varnish. Oil/varnish is not for that application.

 

[Howard Acheson]

>>>> The BLO is used to reduce the drying time

I'm afraid that not true. In fact, the BLO is the slowest drying component in the mixture. The BLO's function in the mixture is to highlight the grain and figure in the wood. The varnish's job is to add a little protective quality to the wood surface and the mineral spirits is to thin the mixture promoting deeper penetration into the wood. The MS completely evaporates within a few hours.

The technique for application is to apply the mixture heavily and allow to set for 15-20 minutes. Then the excess should be completely wiped off. You should never have any shiny spots. If you do, you have applied too much finish and it should be more aggressively wiped off. Go through the process again the next day including the wiping off of the excess. Then let it dry 48 hours or more (it takes the BLO that long to cure).

 

[kooshball]

Perhaps it is best to use this as coat 1&2 then mix up another batch with out the blo

>>>> The BLO is used to reduce the drying time

I'm afraid that not true. In fact, the BLO is the slowest drying component in the mixture. The BLO's function in the mixture is to highlight the grain and figure in the wood. The varnish's job is to add a little protective quality to the wood surface and the mineral spirits is to thin the mixture promoting deeper penetration into the wood. The MS completely evaporates within a few hours.

The technique for application is to apply the mixture heavily and allow to set for 15-20 minutes. Then the excess should be completely wiped off. You should never have any shiny spots. If you do, you have applied too much finish and it should be more aggressively wiped off. Go through the process again the next day including the wiping off of the excess. Then let it dry 48 hours or more (it takes the BLO that long to cure).

 

[KenOfCary]

I have had good luck on cabinet tops using a single coat of oil-varnish mixture followed by several coats of an oil-based polyurethane such as General Finishes Top Coat. You have to let the first coat dry for several days depending on temperature and humidity in the shop.

I usually don't bother with the Urethane on the body of the cabinets and just use a couple coats of the oil-varnish mix.

- Ken.