Replies

1. 
   HowardAcheson | Sep 17, 2004 05:30pm | #1

   In general, exterior finishes are softer and more flexible than interior finishes. That said, there are exterior marine varnishes(not spar varnish) that are harder than a spar varnish but they still are softer than the interior.

   However, even a hard interior poly varnish will be scarred by cat claws. DAMHIKT.

   Minwax ClearShield is probably the most yellow finish I have ever seen. I tested it on a cedar/redwood picnic table and it lasted about two years but I generally kept a cover on the table and took it in for the winter.

   Do you have UV rated glass in your windows? Is the wood stained?

   At this point, I would go for a good interior finish like Pratt & Lambert #38 or a McCloskey Heirloom. Both are light colored varnishes. But any varnish will yellow over time.

   Howie.........
1. 
   lesleypf | Sep 17, 2004 10:02pm | #2

   My cat is actually very well behaved, but my windows don't have much UV protection so that is the bigger issue. In fact, I may violate the warranty if I don't use an exterior grade product. Can I get UV blockers that I could mix with an interior finish? Or can you recommend another exterior product that isn't quite so yellow?

   Nikkiwood recommended an oil/varnish mix (ClearShield and Helmsman together) but I wasn't sure that would work over the shellac sealer coat. I don't plan on staining the wood because I like the light color of the clear pine.

   All this makes installing the windows seem easy!

1. 
   HowardAcheson | Sep 17, 2004 11:20pm | #3

   >>an oil/varnish mix (ClearShield and Helmsman together)

   Both ClearShield and Helmsman are varnishes. Both are very yellow, but any exterior finish with UV inhibitors are going to be yellow. However, both will work with a dewaxed shellac undercoat.

   I don't know about the warranty but you could call them.

   Here is some info regarding "spar varnish" that may be helpful.

   True spar varnish, made of tung oil and phenolic resin, has a natural resistance to UV degradation. When UV absorbers are added to it, they are there to protect the wood below more than the finish itself.

   Not all products labeled "spar varnish" are true spar varnishes. Some of it is a mixture of spar ingredients and exterior polyurethane. In spite of its name, exterior urethane does not hold up as well, and, when exposed to sunlight will degrade and delaminate, peeling from off the wood in time. No true marine spar varnish contains polyurethane. You will only find it in some consumer grade finishes. In contrast, true spar varnish tends to chalk from the top down, and can be maintained for a long time by simply sanding the top surface and reapplying extra coats.

   However, UV will erode the wood interface, and if it does enough of that, even true spar will delaminate. One way around that is to add more protection to the wood itself. You can do this by staining the wood with a 100% pigment stain. Most pigments are not affected by sun exposure, and will in fact block the sun. Hence, if the pigment is on top of the wood, the sun can't get through to do its damage. This is why paint and richly colored stained exterior coatings will consistently outlast clear finishes on wood.Howie.........

1. 
   lesleypf | Sep 18, 2004 01:03am | #4

   Howie,

   Thanks for your informative post. I'm starting to think I should go shopping at the local West Marine rather than Home Depot!

   I just talked to tech support at Minwax and McCloskey. Here are some interesting things they said:- don't even use dewaxed shellac under any of their products; instead use a light first coat of their product to seal the wood (a clever ploy to get me to use more of their stuff??)- don't use ClearShield for an interior application as there could be a recurring odor problem- don't close the windows or patio door until the product cures (somewhere between 7 and 30 days!) to avoid the finish sticking to itself

   So, unless I go shopping again, I'm down to Minwax Helmsman Spar Urethane or the McCloskey Marine Spar Varnish (an alkyd resin product). What would you vote for? What I would really like is a water-based finish with UV inhibitors -- does that exist anywhere?

   Thanks again,Les

1. 
   HowardAcheson | Sep 18, 2004 05:51am | #5

   >>- don't even use dewaxed shellac under any of their products; instead use a light first coat of their product to seal the wood (a clever ploy to get me to use more of their stuff??)

   They are absolutely correct. The best first coat in most cases is to use a thinned coat of the final finish. An intermediate coat is only required when a barrier is needed between incompatable finishes or surfaces.

   However, unless you are working with clear pine(no knots or resin defects), shellac is an excellent barrior to future bleed through problems. You will have to make that assessment.

   Did Pella make a specific recommendation as to a finish? If so, go with it particularly if a warranty issue is involved. Absent that, I would go with the MdCloskey. It's not the best spar varnish but it is better than Minwax IMO.

   >>don't close the windows or patio door until the product cures (somewhere between 7 and 30 days!) to avoid the finish sticking to itself

   All oil based products take 20-30 days to fully cure and develop full hardness, not only the ClearShield. Any oil based varnish will be the same. You will have to keep two finished surfaces out of contact for quite a while. After a week, you may be able to get them together. I've heard of folks using wax paper between newly finished surfaces but have no experiance or opinion on that. I left my front door open for about a week after I finished it and clear coated it.Howie.........

   Edited 9/17/2004 10:57 pm ET by Howie

2. 
   lesleypf | Sep 18, 2004 06:50am | #6

   The pine is clear but there is some sap that has come out. I will wipe it off and hopefully there won't be any more. Zinsser claims that their SealCoat is compatible will all finishes but the McCloskey rep wasn't so confident about it.

   Thanks for the tip on the wax paper -- since the weather is getting chillier it will be nice to have a way to close my windows.

   You have been so helpful, Howie, I really appreciate it!

3. 
   HowardAcheson | Sep 18, 2004 07:01pm | #7

   >>Zinsser claims that their SealCoat is compatible will all finishes but the McCloskey rep wasn't so confident about it.

   Zinsser is correct. McCloskey doesn't know what he is talking about.

   On the wax paper, remember, I am only passing along something I heard. I have no experiance with it. At the very least, you need to leave the windows and doors open for a number of days.Howie.........

4. 
   lesleypf | Sep 19, 2004 12:02pm | #8

   >> The best first coat in most cases is to use a thinned coat of the final finish. An intermediate coat is only required when a barrier is needed between incompatable finishes or surfaces.

   So, will I have any incompatibility between the Elmer's Carpenter's Wood Filler (stainable interior version) that I have just used on the raw wood to putty up all the nail holes?  If not, then I guess I am ready to break open the McCloskey's Spar Varnish.

   Any tips on how to get a nice application on vertical surfaces? I have seen on this forum where folks thin their varnish 50-50 to create a wipe-on version. But the McCloskey rep told me (he couldn't tell by law) not to thin more than 10%. Any advantages to going  with a more or less thinned product?

   I suppose if I could master the brush application I would only have to brush on 3-4 coats instead of wiping on twice that number. Any hints for brushing?

   Thanks again,Les

5. 
   HowardAcheson | Sep 19, 2004 07:41pm | #9

   >>Elmer's Carpenter's Wood Filler (stainable interior version)

   I have never used the product but I doubt there will be any problems.

   Here are some instructions for making and using a wipe-on varnish. They come from a friend of mine and work well for me.

   QUOTE

   There are a number of suggested application regimens that are totally subjective. The number of coats in a given day, the % of cut on various coats, which coat to sand after, when to use the blade and a whole host of other practices are all minor differences between finishers. There are some things that I consider sacred when applying a wipe-on finish.

   If you are making your own wipe-on the mix is scientific - thin. I suggest 50/50 because it is easier to type than any other ratio and easy to remember.

   The number of coats in a given day is not important. Important is to apply a wet coat with an applicator and merely get it on. Think of a 16 year old kid working as a busboy at Denny's you have sent over to wipe off a table. The finish should not look wet and shiny but damp. The applicator can be a paper towel, half a T-shirt sleeve or that one sock left after a load of washing. Then leave it alone. If you have missed a spot, ignore it - you will get it on the next coat. If you try and fix a missed spot you will leave a mark in the finish.

   Timing for a second coat involves the pinkie test. Touch the surface with your pinkie. If nothing comes off you are ready for another coat. It was tacky 5 minutes ago but not now. Apply your next coat just as you applied the previous coat. Remember, you are wet wiping not flooding. After applying the second coat, let it fully dry for 48 hours. Using 320 paper and a sanding block ligthtly sand the surface flat. Now, begin applying more coats. Do not sand between coats unless you have allowed more than 24 hours to elapse since the prior coat. Keep going till you are tired of it. The number of coats is not critical - there is no critical or right number to apply. For those who need a rule, four more coats on non-critical surfaces or six more coats on surfaces that will get abraded seems to work.

   After your last coat has dried at least over night you will have boogers in the surface. You should not have marks in the surface because you ignored application flaws. You will have dust, lint and, if you live in Texas, bug legs. Use a utility knife blade at this point. Hold it between your thumb and forefinger, near the vertical, and gently scrape the surface. Gentle is the important word - no harder than you would scrape your face. If you start scraping aggressively you will leave small cut marks in the surface. After you have scraped to the baby butt stage gently abrade the surface with 320 dry paper or a gray ScotchBrite. Clean off the surface. Apply your last coat with a bit more care than the previous coats and walk away.

   An anal person is going to have a tough time with this process. Missed spots have to be ignored. Wet wipe, don't flood. Scraping to babies butt smooth means scraping no harder than scraping a babies butt. Ignoring any of these will leave marks that are tough to get out. Getting these marks out requires some agressive sanding to flatten out the surface and starting over.

   Jim Kull

   END QUOTE

   I have never tried a wipe-on on trim. It may not work well. You'll just have to try. Of course, if you do not have good brush skills, brushing will be a real chore also. Applying varnish to vertical surfaces and cutting it in against other surfaces will not be easy. Varnish is flowed on with minimal back and forth brushing. A good natural bristle brush is also required. Your material should be thinned 10-15% for better handling and flow-out.

   You had better practise either technique on scrap wood to learn how to handle the product.

   Good Luck.....Howie.........