Brush on Poly-urethanes

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EProvenzano

Brush on Poly-urethanes
« on: 2 Mar 2005, 02:01 am »
Hi guys.

I know this is a bit off topic, but I think the crowd here has been quite interested lately in cabinet building and finishing....so here's my question.

I prefer the brush on finish of solvent based poly urethanes to water based acrylics. I think the solvent poly urethanes are much easier to apply and, without too much trouble, flow to a flat (smooth) finish.
The only problem I have with these is that most common off the shelf brands including: Durethane, Varethane, etc... have considerable amber coloring.
I'm not sure if this color is inherant to these top coats or if I can find a 'premium' poly-urethane that will yeild a more transparent finish.

Your suggestions are much appreciated.
Thank you.

EP

David Ellis

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Brush on Poly-urethanes
« Reply #1 on: 2 Mar 2005, 04:24 am »
"The only problem I have with these is that most common off the shelf brands including: Durethane, Varethane, etc... have considerable amber coloring. "

Yep, they do.  I like this, but certanly understand those who don't.  The amber tint does look quite wrong on Maple.

What you seek is a "water white" finish.  I suggest a visit to a dedicated paint store for this.  The folks at Home Depot will only get confused if you tell them you want a "water white" finish.  The folks a good paint stores will know exatly what you seek and most likely have some.

Quote
I'm not sure if this color is inherant to these top coats or if I can find a 'premium' poly-urethane that will yeild a more transparent finish.


Well, I don't think these are "premium finishes", but you will probably pay about $25/gallon for the stuff.  This remains much cheaper than the very good conversion varnishes.

Quote
I think the solvent poly urethanes are much easier to apply and, without too much trouble, flow to a flat (smooth) finish.


I can't get nuthin' to apply flat with a brush :!:   I tried and tried, but with no success :(   I purchased several really fancy paint brushes too.  Argh.

EProvenzano

Brush on Poly-urethanes
« Reply #2 on: 2 Mar 2005, 05:25 am »
Thanks for the tips Dave.

By 'flat' I was speaking relative to water based acrylics.
I think the trouble is, the water based stuff dries much quicker and the brush marks dont have a chance to flow flat....as flat, I mean.

It's too bad that these urethanes tend to be amber in color. My personal choice would be to start with a clear base and add tinting to taste.

On a side note, I was visiting a local auto body shop and peered into a can of automotive clear coat (also poly-urethane base).  I could see to the bottom of a gallon can as if it were water....I know that this is probably like comparing apples to oranges, but I'd like to find something like that for use on wood.

I'll take a trek to the paint specialists soon and report back what I find.

Thanks

Mr. CNC

Polyurethane's
« Reply #3 on: 2 Mar 2005, 10:22 pm »
EP,  

You might try a "Marine polyurethane" the good ones are near, if not "waterwhite".  Another advantage, the marine finishes have uv inhibitors, less suseptable to yellowing and are generally harder.  Gloss is the most common, if you want a satin look knock it down with steel wool or a super fine scotchbrite.  I sell it, $22.50 a quart, not cheap but it is good stuff, I'm sure you could find it locally.  West Marine sells "Interlux Clipper Captain's Clear" it is waterwhite and of excellent quality.  Minwax Spar Varnish is a choice if you want a Amber look.

Neal

Charles Calkins

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Brush on Poly-urethanes
« Reply #4 on: 2 Mar 2005, 10:50 pm »
EP:
     I'vr been using a wipe on polyurethane for years with very good results. They are kind of like a polyurethane and oil combination. The most common brands are Minwax which is good but if you can find the Olympic brand that's better. It seems to have more body. The only drawback to these and all polyurethane finishes is that you can't use them over water based stains. Everything takes on an amber tone.

                               Cheers
                                Charlie

David Ellis

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Brush on Poly-urethanes
« Reply #5 on: 3 Mar 2005, 08:26 pm »
Quote
I could see to the bottom of a gallon can as if it were water....I know that this is probably like comparing apples to oranges, but I'd like to find something like that for use on wood.


I spoke with a gent that did this.  You must simply use a plasticizer in the auto urethane.  This will the stuff mixed into the auto paint that's applied to bumpers.  With this, the urethane will flex after it dries.  Without this, the urethane will crack when the wood moves.  I am sure you know somebody who can help you understand auto paint additives.

IMO, auto urethanes are many years ahead of wood finish technologically.  I don't understand the brew, but that automotive stuff is EXTREMELY hard and very clear.  It also flows well - great stuff!