# Spraying Polyurethane



## Vipervgts (Aug 22, 2010)

I have a metal stair case with wood treads and wood handrail. I have all the treads and hand rails in my shop. I have 2 questions.

Is spraying polyurethane a bad idea?

If not what is the sprayer prep?

Most likely going with a satin finish and if i loss some sheen I'm not concerned.

What are your thoughts?


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## Metro M & L (Jul 21, 2009)

I've done it several times with waterbased urethane through an airless. Small tip and fast hands. It will run easily if you're not careful.


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## NCPaint1 (Aug 6, 2009)

Acrylic or oil? HVLP will work well, airless with a FF tip, or maybe even the Pro Shot???


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## cardwizzard (Sep 13, 2010)

No, its actually a very good idea to spray these. If done right they will look and feel great. Make sure you are using someone who has done it before.


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## Vipervgts (Aug 22, 2010)

Wow, everyone said airless.

Our rig is compressed air setup normally for spraying cars and parts.

No good?


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## NCPaint1 (Aug 6, 2009)

Vipervgts said:


> Wow, everyone said airless.
> 
> Our rig is compressed air setup normally for spraying cars and parts.
> 
> No good?


Probably the best bet. Might take some dialing in, but will work well :thumbsup:


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## Retired (Jul 27, 2010)

Vipervgts said:


> Wow, everyone said airless.
> 
> Our rig is compressed air setup normally for spraying cars and parts.
> 
> No good?


Everyone so far. Current car rigs are non-bleeder top feed HVLPs. High transfer rate for pricy paint. Some places use conventional with pressure pots or cup guns.

What is not known is if the polyeurethane is an alkyd or a waterbourne and how both the wood and metal have been prepped.

No problem spraying either with what you have.

An alkyd poly is going to act like your car paint but flash time will be shorter. The waterbourne poly sprays best IMO if you hold the air down and crank up the material and use lots of paint. 

If both are clearcoats, unless they are some brand or formulation that has a peculiar makeup should be self priming. 

More info would be your best bet at this time. Too many unknowns.





I


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## Wolfgang (Nov 16, 2008)

Sprayed plenty of both with a convential siphon-feed air set-up. What's nice about it is you can actually get furniture quality finishes with minimal labor. The drawback is the overspray issue. Get the right needle/cap set-up, dial in the right pattern and pressure and you should be good to go.

One of the problems I've noticed with guys who dont have a fair amount of experience with the top feed HVLP guns is they seem to run into "orange-peel" issues, or sags and runs. If you've done any amount of automotive refinishing it shouldn't be a problem for you.


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## TJ Paint (Jun 18, 2009)

http://www.ppg.com/coatings/refinish/en/training/certification/Pages/default.aspx


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## Vipervgts (Aug 22, 2010)

*what would be the recomended poly?*



Retired said:


> Everyone so far. Current car rigs are non-bleeder top feed HVLPs. High transfer rate for pricy paint. Some places use conventional with pressure pots or cup guns.
> 
> What is not known is if the polyeurethane is an alkyd or a waterbourne and how both the wood and metal have been prepped.
> 
> ...


What would be the recommended poly for wooded steps?


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## Retired (Jul 27, 2010)

Vipervgts said:


> What would be the recommended poly for wooded steps?


I'll take a shot at this and recommend an alkyd poly. This will work whether the steps and risers (if any) are inside or outside. Maybe avoid the high gloss poly that can be slick if it gets wet. 

Most waterbourne polys are for interiour use. One exception is Diamond Varathane but for walking on I would still recommend the alkyd. 

An alternative is conversion varnish. which is close in nature to the auto paints you are used to. 

This problem has a solution. Pix would help.


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## Metro M & L (Jul 21, 2009)

no, flooring waterbourne like emulsion or streetshoe


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