Can you thin Spar varnish?

[sachbvn]

You know that marine grade stuff? I've never used it - can you thin it with something and then just apply more coats rather than putting on a couple of extra thick, hard to manage, coats?



Thanks,
Zac

[Beamer]

I'm sure ya could .. check it's cleanup instructions - that'll tell ya the solvent to use to thin it.

Give it a try and see what kinda results you get.

[TDHofstetter]

That's what wiping polyurethane is - just thinned polyurethane.

Marine spar varnish is just polyurethane with extra yellowing qualities - the yellowing blocks UV.

Dunno that I'd try it with water-based stuff, but oil-based stuff - definitely. Thin with mineral spirits (slow dry) or VM&P naptha (fast dry).

[cabinetman]

Apr 20, 2010 20:50:41 GMT -6 sachbvn said:

You know that marine grade stuff? I've never used it - can you thin it with something and then just apply more coats rather than putting on a couple of extra thick, hard to manage, coats?

Thanks,
Zac

Marine spar is usually oil base and thinned with mineral spirits. It is not intended to be used indoors. It has UV additives and has a higher oil content ratio than interior varnish. It does not dry hard, but rather stays flexible to cope with outdoor conditions. It can take a very long time to completely dry.

[Ruffnek]

Zac,

Spar varnish is nothing more than a long-oil varnish which, like Cab wrote, helps to keep it flexible so that it doesn't crack when the wood moves.

I use Epifanes spar varnish on outdoor projects and the directions instruct you to thin the first several coats. Of course, they recommend using their proprietary thinner but mineral spirits works just as well.

Epifanes recommends applying 6 coats as follows:

• thinned 50%
  
• thinned 30%
  
• thinned 15%
  
• full strength
  
• full strength
  
• full strength
  

I've had a Cedar board, (Eastern Red Cedar) laying on the patio table for several months now (August will be one year). I coated half of it with Epifanes Varnish and half with Helmsman varnish...both applied per the schedule above. So far, both are holding up very well. I'm really surprised that the Helmsman is still looking so good.

[TDHofstetter]

I built a birdfeeder coated in Helmsman that's looked new for some eight years now.

[sachbvn]

This is going to be covering oak boards that are being used as the bed in someone's old restored pick up truck.....it's not a "show truck" in the sense that it will be hauled to car shows on a flat bed and hopefully win money - but it is a show truck in the fact that likely nothing will ever be hauled in the back - it's chopped way down and rides low. Custom metal work done on the back..... the guy wants me to do the bed for him - he had no idea what to use for the back, it's going to be driven some in the winter time so...... while it will always be protected - it may get wet/damp sometimes.


I'll go with the spar varnish. It was recommended to me by my lumber guy - I had thought of it, but had a brain fart and was thinking maybe just regular poly.


Zac

[gomer]

Nice choice Zac w/ spar. Just make sure that you give it the FULL drying time between coats, otherwise it will start peeling like a banana.

[Ruffnek]

Zac, for something like that, I would strongly recommend the Epifanes varnish. I don't think there is a better product on the market and PU bed floorboards are not something that you will want to re-finish every year.

Even using Epifanes, if the truck sits outdoors a lot the boards will likely need a light sanding and re-coat every 2-3 years.

I'd also use QSWO if possible. It will hold up well to the weather and cupping won't be as big an issue as with flat sawn.

[sawduster]

For a pickup bed, I'd recommend a good oil based exterior paint.

[Ruffnek]

Zac,

One more thing. If the boards are already in place in the PU bed, it would be worth the time to go underneath the truck and cover the bottom side of the boards, too. If one side is finished and the other left bare, especially in a non-climate controled environment, the boards will almost surely cup.

It would have been much better to have finished the boards befoe installation.

[Ruffnek]

Apr 21, 2010 8:18:12 GMT -6 TDHofstetter said:

I built a birdfeeder coated in Helmsman that's looked new for some eight years now.

Only it's not subjected to the Texas sun and heat.

Strong sunlight and the associated UV rays are much more detrimental to a finish than rain or anything else.

Is the birdhouse shaded much of the time? Even if it isn't and even in Vermont, 8 years is a pretty long time for any varnish to last, especially Helmsmans.

[gomer]

Apr 21, 2010 9:36:38 GMT -6 sawduster said:

For a pickup bed, I'd recommend a good oil based exterior paint.

DO NOT paint that beautiful oak. That is a sin of the highest order.

[sachbvn]

The boards are not even purchased yet - so - I will surely be covering both sides. Not really sure if I'm going to sand then to the "enth degree" and do the same finishing method I'd do for a table top or something of the like. I will put on several coats.

Cody - where can I find that Epiphane stuff at?


Zac

[Ruffnek]

Some marine centers carry it but I order it from Jamestown Distributors.

www.jamestowndistributors.com/userportal/show_product.do?pid=92&familyName=Epifanes+Gloss+Clear+Varnish

Don't choke on the price. This is really one of those cases where you get what you pay for.

[TDHofstetter]

Apr 21, 2010 9:47:26 GMT -6 Ruffnek said:

Apr 21, 2010 8:18:12 GMT -6 TDHofstetter said:

I built a birdfeeder coated in Helmsman that's looked new for some eight years now.

Only it's not subjected to the Texas sun and heat.

Strong sunlight and the associated UV rays are much more detrimental to a finish than rain or anything else.

Is the birdhouse shaded much of the time? Even if it isn't and even in Vermont, 8 years is a pretty long time for any varnish to last, especially Helmsmans.

Aa, Vermont sees nearly as much UV as Texas does. VERY nearly, in fact... with most of the difference made up by the shorter days granted to us by the vertical landscape (mountains make for late mornings & early evenings).

The birdhouse sees full sun nearly all day, and gets washed heavily by rainfall running off the roof during every rain.

I did take the extra steps to finish it carefully, initial apps thinned to 50% & following apps working up to full concentration. I didn't sand between coats, though.

[Ruffnek]

Apr 21, 2010 15:16:57 GMT -6 TDHofstetter said:

Apr 21, 2010 9:47:26 GMT -6 Ruffnek said:

Only it's not subjected to the Texas sun and heat.

Strong sunlight and the associated UV rays are much more detrimental to a finish than rain or anything else.

Is the birdhouse shaded much of the time? Even if it isn't and even in Vermont, 8 years is a pretty long time for any varnish to last, especially Helmsmans.

Aa, Vermont sees nearly as much UV as Texas does. VERY nearly, in fact... with most of the difference made up by the shorter days granted to us by the vertical landscape (mountains make for late mornings & early evenings).

The birdhouse sees full sun nearly all day, and gets washed heavily by rainfall running off the roof during every rain.

I did take the extra steps to finish it carefully, initial apps thinned to 50% & following apps working up to full concentration. I didn't sand between coats, though.

Got a pic? I'd be interested to see the condition of that 8 year old Helmsmans.

[rnemtp3]

Zac, it is funny that you asked this question because I was just about to do the same.
My dad has a 68 chevy stepside shortbed that we are getting ready to turn into a daily driver. I have been looking at the bed kits there are several vendors who sell them but they are proud of them, like $650-$900 for the boards and rails.
I have found some pics of people with show trucks that used purpleheart and other exotics for the wood. The shortbed Stepsides came with wood beds where as most of the fleetside and long beds had metal bed floors. Pine was the standard wood and is what most people use that are going back to original specs but the woodworking to cut the boards are straight foreward. I was planning to make the floor myself (that makes it a woodworking project right?)
You can google pics of either Ford or Chevy trucks of the year you want and find alot of information and ideas. If it is chevy between 67-72 there is a great forum called 67-72chevytrucks and there is alot of information there too.
Looks like I will be going with the marine spar as well. Where does one find it? I am in the mountains of Southwest Va. There is a woodcraft about 1 1/2 hours away but I don't remember seeing it there. But it has been awhile since I was in there. I think I saw Helmsman at the borgs though.
Thanks.

[TDHofstetter]

Apr 21, 2010 15:25:32 GMT -6 Ruffnek said:

Apr 21, 2010 15:16:57 GMT -6 TDHofstetter said:

Aa, Vermont sees nearly as much UV as Texas does. VERY nearly, in fact... with most of the difference made up by the shorter days granted to us by the vertical landscape (mountains make for late mornings & early evenings).

The birdhouse sees full sun nearly all day, and gets washed heavily by rainfall running off the roof during every rain.

I did take the extra steps to finish it carefully, initial apps thinned to 50% & following apps working up to full concentration. I didn't sand between coats, though.

Got a pic? I'd be interested to see the condition of that 8 year old Helmsmans.

I'll see if my ex will pass on a pic - I try not to go there any more'n I'm begged to.

[cabinetman]

Apr 20, 2010 20:50:41 GMT -6 sachbvn said:

You know that marine grade stuff? I've never used it - can you thin it with something and then just apply more coats rather than putting on a couple of extra thick, hard to manage, coats?

Thanks,
Zac

Was this your question on thinning or not and what to use for thinning? How difficult would it have been to describe your proposed use.

With never having used it, your friend is trusting you to do the floor of a show truck? IMO, coating exterior wood in a varnish of any kind is a waste of time and money. Spend what it costs for those special "spars" and you'll be refinishing it sooner than you think. With 5-6 coats on, have fun sanding.

It's not news that wood used outside is exposed to all sorts of conditions...moisture changes, heat, cold, and UV. Applying a film finish can sufficiently seal off the wood from it's natural properties. It just won't breathe.

Using an oil finish may not satisfy our needs for a plastic look, but it's a whole lot easier to maintain.