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Discussion Starter · #1 ·
Typically I have used oil based brush on polyurethane for finishing shelves or furniture and a Danish oil for finishing small turned ornaments. However, I have a 7' long rough sawn board that I am looking to finish for a laundry room shelf. Does anyone have some suggestions for a good finish that will protect against laundry room chemicals, and highlight the rough sawn look of the board?
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I am not really looking to learn to use epoxy at the moment, but am open to being told that is the best option (if it is). I have considered trying to learn how to apply a lacquer or shellac, but for spraying I currently only have a cheap purple Harbor Freight HVLP spray gun that I have not yet used successfully and a small pancake compressor (2.6CFM at 90PSI).

Bonus points if it applies easier than brush on polyurethane (I hate painting / finishing). Also if it can easily be applied around corners without drips and runs, that would be great for this other shelf I am working on.
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The laundry room is not a good place for rough sawn surfaces that has lots of small places to catch and hold powders and liquids. The rough surfaces will be exceedingly difficult to clean. This is the place for smooth impervious surfaces that are easy to keep clean. If you must use rough sawn, then an epoxy pour that will show the wood but fill the roughness and leave a smooth cleanable top surface is the only option I can think of.
 

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Discussion Starter · #3 ·
The laundry room is not a good place for rough sawn surfaces that has lots of small places to catch and hold powders and liquids. The rough surfaces will be exceedingly difficult to clean. This is the place for smooth impervious surfaces that are easy to keep clean. If you must use rough sawn, then an epoxy pour that will show the wood but fill the roughness and leave a smooth cleanable top surface is the only option I can think of.
I had not thought of the rough surfaces catching and holding small particles, that is a good point. This is mainly planned as a high shelf to keep items out of the reach of a toddler so it might not be that big of an issue (above adult eye level), but I will have to consider that. I was wondering if a spray on finish could remove some of the issue of snagging on wood but I was not sure if that would require too many coats to work well.
 

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I had not thought of the rough surfaces catching and holding small particles, that is a good point. This is mainly planned as a high shelf to keep items out of the reach of a toddler so it might not be that big of an issue (above adult eye level), but I will have to consider that. I was wondering if a spray on finish could remove some of the issue of snagging on wood but I was not sure if that would require too many coats to work well.
I would suggest a Pre-Cat Conversion Varnish. The water bourns are, in my opinion, as good as the solvent based. The finish is nearly bullet proof and the mil layers finished very thin. I use t regularly for anything that might take a beating such as cabinet interiors, drawer boxes, and table tops.
 

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Discussion Starter · #5 ·
I would suggest a Pre-Cat Conversion Varnish. The water bourns are, in my opinion, as good as the solvent based. The finish is nearly bullet proof and the mil layers finished very thin. I use t regularly for anything that might take a beating such as cabinet interiors, drawer boxes, and table tops.
I have not heard of Pre-Cat finishes before. A quick google search comes up with several comparisons between "Pre-Cat Lacquer" and "Conversion Varnish". Is Pre-Cat a sub-type of conversion varnish? It sounds like Pre-Cat already has a catalyst mixed in, where as a Post-Cat requires mixing at the time of application. A water based would certainly be convenient for cleanup if it applies well. If I purchased some of this I would of course read the instructions on the can, but do you have any tips for application?

Typically I work in my basement, do these have a strong odor that might permeate the house? I can apply them outside if appropriate. I won't soon forget the time I stupidly used some rust remover in the basement - we smelled it for days (weeks?) throughout the house. Most of the time when I use polyurethane the smell dissipates pretty quickly.
 

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There is no way that you will be able to spray anything with a compressor spec of 2.6CFM at 90PSI
What does your HVPL gun specs call for? That is what you must go by.
Also, I dont think any finish will look good with a rough sawn surface
 

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@haathi
Nitro- Cellulous vs Pre-Cat Lacquer.
Lacquer has been around for around 100 years as a commercial grade finish. Around 20 years ago or so, a catalyzed lacquer appeared and made the old nitro-cellulous lacquer 'ancient history'. In most but not all cases, it is pre-catalyzed at the factory. Some are pre-catalyzed at the paint store and dated. Not too long ago, one could buy the catalyst and mix it himself. Well this led everyone to think they were chemists even though some of them couldn't spell their own names. They tried to change the ratios to what they thought would be better for themselves and screwed up the ratios and then try to return the product. The vendors and manufacturers came to the conclusion that only they should do the mixing. And that is the end of the story.
Anyway, the new pre-catalyzed lacquers are way, way superior to the old nitro cellulous lacquers to the point the KCMA (Kitchen Cabinet Manufacturers Association) strongly does not recommend the old Nitro Cellulous lacquers. The application of either one is the same but the end product results is vastly different.
 
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Discussion Starter · #8 ·
There is no way that you will be able to spray anything with a compressor spec of 2.6CFM at 90PSI
What does your HVPL gun specs call for? That is what you must go by.
Also, I dont think any finish will look good with a rough sawn surface
The spray gun I have calls for 6 CFM at 40 PSI, but does not have a spec for 90 PSI (and my compressor does not have a CFM spec for 40 PSI). I have seen several reviews (youtube and otherwise) suggesting the Harbor Freight purple guns could be used with small pancake compressors for short spraying sessions, so I was at least hopeful it might be feasible. However I assume based on your comment 2.6 CFM is way too low to spray finishes in your experience. I appreciate the advice, even if it was not what I was hoping to hear.

I appreciate a nicely planed and finished board and use them for the projects I have done to date, but the saw marks on this board seemed pretty interesting and worth an attempt to save. I did not think through the fact that a finish would not apply very well to the rough saw marks until you and YomanBill pointed it out.
 

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@haathi
You sais "The spray gun I have calls for 6 CFM at 40 PSI, but does not have a spec for 90 PSI (and my compressor does not have a CFM spec for 40 PSI)".

Keep in mind that we are concerned in what the gun needs. Then we must .find out if the compressor can provide it.
The gun calls for 6 CFM at 40 PSI. So forget about the 90 PSI because you only need 40 PSI and are good there. Normally most compressors give the amount of CFM the compressor can provide at several different PSI"s. This is somehow available somewhere, you just have to find it.
The greater the PSI needed, the lesser the CFM that can be produced and conversely, the lesser the PSI needed, the greater amount of CFM that can be produced.
Air compressors are versatile and important at times. If at all possible, see if you can eventually upgrade to at least a 30 Gal. Compressor. Comes in handy to inflate tires when the seasons change.
 

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Discussion Starter · #12 ·
@haathi
You sais "The spray gun I have calls for 6 CFM at 40 PSI, but does not have a spec for 90 PSI (and my compressor does not have a CFM spec for 40 PSI)".

Keep in mind that we are concerned in what the gun needs. Then we must .find out if the compressor can provide it.
The gun calls for 6 CFM at 40 PSI. So forget about the 90 PSI because you only need 40 PSI and are good there. Normally most compressors give the amount of CFM the compressor can provide at several different PSI"s. This is somehow available somewhere, you just have to find it.
The greater the PSI needed, the lesser the CFM that can be produced and conversely, the lesser the PSI needed, the greater amount of CFM that can be produced.
Air compressors are versatile and important at times. If at all possible, see if you can eventually upgrade to at least a 30 Gal. Compressor. Comes in handy to inflate tires when the seasons change.
I could not find the manual yesterday. Located the manual today, and my compressor is rated for 3.7 CFM at 40 PSI, so still well below the required 6 CFM. Thank you for the pointers.

I would love to upgrade to a larger compressor someday, but for now my pancake has surprisingly met all of my needs except for finish spraying. I can fill it up and unplug it, and then easily carry it outside to top off two cars worth of tires, a small trailer, the lawnmower, and have air to spare. I have used it for my 18 and 23 gauge nail/brad gun without issues. It was really convenient to carry upstairs when building my closet shelves. Until now, when it decidedly will not work with an HVLP. So for now it sounds like I need to either look for an LVLP gun as Yomanbill suggested or keep my eyes open for a good deal on a larger compressor and continue with my paint brush or spray cans of poly. I can work with that.
 

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I could not find the manual yesterday. Located the manual today, and my compressor is rated for 3.7 CFM at 40 PSI, so still well below the required 6 CFM. Thank you for the pointers.

I would love to upgrade to a larger compressor someday, but for now my pancake has surprisingly met all of my needs except for finish spraying. I can fill it up and unplug it, and then easily carry it outside to top off two cars worth of tires, a small trailer, the lawnmower, and have air to spare. I have used it for my 18 and 23 gauge nail/brad gun without issues. It was really convenient to carry upstairs when building my closet shelves. Until now, when it decidedly will not work with an HVLP. So for now it sounds like I need to either look for an LVLP gun as Yomanbill suggested or keep my eyes open for a good deal on a larger compressor and continue with my paint brush or spray cans of poly. I can work with that.
This one will probably work:
Specs say 4.2-6.0 cfm. You just might have to stop spraying once in a while to let the compressor catch up. I have this model and it works great. It comes with a pretty small cup, so it's good for small jobs. Larger cups are available on Ebay.
 

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If he times an area and knows about how long it will run he should do fine. I'll spray , stop and let the compressor build and hit the next area. Most times unless it's hot and using lacquer you have to use strategy to get a clean look. I usually run my gun full blast.

The harbor freight purple guns had a good reputation amungst DIY woodworkers and some pro's, Don't know now..
 

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Agree with @Rebelwork. A few things to add based on the way I know it:

Because your gun is rated at 6 CFM at 40 PSI does not mean you will spray at 40 psi. The pressure you spray at is based on the material you are using, how thick it is, etc. Material made for spraying only, like automotive finishes, will give you a recommended pressure to use to get the best finish. With wood finishes that might be applied in many different ways, you probably need to figure out the best pressure to use through experimenting and experience. Air tools and compressors are usually rated for cfm at 40 and 90 psi to give us away to compare equipment. It's my understanding that those two levels were chosen because 40 psi is a common pressure to spray at and 90 is a common pressure for air tools.

Second, the 6 cfm rating is most likely what the gun needs if you hold the trigger in constantly. If you are on and off with the air flowing through the gun (like Rebel said), it will use less air. Also, if you spray at less than 40 psi, it will use less air. If you spray over 40 psi, it will use more.

Your compressor rating of 3.7 cfm is probably the maximum it can put out continuously, like if you hold the trigger of the gun in all the time.

As an example, lets say on average you are triggering the gun for 30 seconds out of one minute and working at 40 psi. Your gun will be using 3 cfm (half of its rated 6 cubic feet per minute). Your compressor should be able to keep up with that because it produces more (3.7).

So before you decide you need a new compressor or gun, try what you have. The big thing is you don't want the pressure in the compressor tank to drop down close (say within 10 psi) of the pressure you want to spray at. You always lose pressure through the hoses and fittings, so the pressure at the gun will be lower than at the tank. That's why you see guys with a pressure gauge and adjuster on their guns. The pressure coming into the hose doesn't matter, it's the pressure at the gun you care about. If you run the gun so much that the pressure at the gun goes below what you want to spray at, your pattern and quality will go down. The gun might even start to spit. So, watch your pressure and stop spraying for a minute or two and let the compressor catch up if you have too. Unless you are spraying large surfaces where the gun needs to run a lot, you might be OK with what you have for now.
 

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Discussion Starter · #18 ·
Okay, thank you all for the advice. I plan to try to spray with what I have rather than buy new at the moment. The question becomes when will I get a chance with a toddler to keep me busy... But I will try to update here when I find what works for me.
 
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