"Spraying Outside" & Other finishing tecniques

[Randall Kepley]

Hey guys, as talked about in another thread here and a different one in the Gallery, I had proposed to do a thread on "Spraying outside" and achieveing a great finish and I decided to also touch on a few topics about finishing in general and how to achive a "Professional" finish in sanding , staining and spraying outside. This thread will also have a second part coming next week on "How-to" take a cured topcoat and acheive a "Piano Gloss" finish is so desired. So first off lets take a look at some of the tools we'll be using and get this thing started. I kinda worked this project in while I was spraying another Cabinet today so I wound up having a handful going on, so lets go.

In the first pix is a shot of the gun I will be using along w/ 2 diff kinds of masks and the product we will be spraying. The gun is a "Graco Finex" not the cheapest gun on the planet but deff not the most expensive . Great mid-priced HVLP for wood based finishes. The topcoat is ML Campbell "Krystal" Conversion Varnish. It also should be noted that if you werent using CV and were say using "Lacquer" you could use the exact same procedure here except you wouldnt be adding a Hardner to the topcoat. Also there are 2 diff kinds of Mask. I dont think I have to say which one you should be using but alot of people think the thin white dust mask are just fine, well you be the judge, but I wont risk my lungs on it, use the filtered kind!



Close-up of the gun.


Next pix is a shot of the actual product and what you will need to get prepard for spraying. We have the CV and in this case a "Satin" finish for sheen, a graduated mixing cup in ounces a mini graduated cup in 1/10 ounces (For the catalyst)



OT- Cant be spraying w/out a little "Blue Grass" playing !



Next shot is of the CV measured at 16oz and the hardner measured at 1.75oz and ready to be mixed.



Mixing the hardner, I usually like to stir for around 2 mins . Also here is a shot of the "Speed cups" I use for product. There made by "Sata" and they have a quick release cap which allows the sprayer to go from ... say sealer to topcoat or even changing colors in just a few seconds w/out having to stop, clean your cup, remix your color or other product. Pretty good little setup.



Part 2 next post. R.K.

[Randall Kepley]

Part 2, Lets look at what we will be spraying. As stated in another thread Ill be using a piece of Black Walnut plywood which will simulate a piece of Veneered speaker, Its a scrap off of the Cabinet I was building. Now in the spirit of full disclouser the first pix is of the bare walnut. Walnut is very pretty in its raw state. Kinda grayish brown, so I decided to stain it a little darker to draw the color and pattern out a little bit.






before staining, it was throughly sanded by and air sander w/ 120 grit to open the pores of the wood to accept the stain well. The sander pictured here is made by "******" this is kinda pricey but worth its weight in gold!! It will run you around $250.00 but when you consider Ive run this sander 5-6 days a week for 11 yrs it is a work horse. It only has 9 moving parts and if you ever wear it out a rebuild kit is less than $30.00 15 mins of work and your up and running again. Believe it or not, I keep all of my air tools properly and as of yet ive never had to rebuild but one in over 20 yrs in business. In this process you will see another air sander, its a Dynabrade and is strickly a "Finish" sander it vibrates and oscillates in microns. You will see it a little later.



Here is a shot of the outside carousel we will be using



Next few shots are of our test piece ready to have its first "sealer coat" shot and a pix of the acutal "sealer coat"






It should be noted that CV is a self sealing product , meaning it doesnt need a second product as a base. Lacquer for instance can be used in a self sealing manner but doesnt have near the "Bite" as it would if you would have used a "Sanding Sealer" as your base. But CV is a wonderful self sealer. You will notice in the last pix, a nice wet coat was shot. You dont want to over do it but you also dont want to spray "Dry" which means your spraying so thin that by the time your finishing the bottom the top has started to dry. Which will result in all of your coats feeling kinda like fine sandpaper.

Part 3 coming. R.K.

[Randall Kepley]

Part 3. In part 3 we have just brought the test piece back in the shop. From the time it was carried outside, sprayed and brought back in 1min 18 seconds had elapsed on my timer. Not much time for trash to accumulate in the finish. If I was spraying an actual speaker I bet I could shoot everything in under 3 min and have it back inside before trouble could set in.



In this next pix about 35 mins has passed and the sealer coat has dried and is ready to be sanded, this one by hand. It shoud be noted that all sealer coats feel rough. What your feeling isnt trash if you have prepped properly, what your feeling is the grain being slightly raised and the fibers being froze into place. A few swipes of the sanding block will have this smooth as silk. The sanding block are 220 grit.




[IMG]http://i182.photobucket.com/albums/x294
/randallkepley/Outside%20Spray%20finishing/Picture038Medium.jpg[/IMG]




We should take a minute and talk about top coats. There a 2 main kinds of top coats. The first is your products like "Tongue oil" types. These finishes penatrate the wood it self - soaking into the fibers. When dry multiple coats are then applied to build up strength if you will. It also need to be sanded w/ steel wool in between coats not sandpaper. Most of the time sandpaper , even fine sandpaper will leave scratachs to deep for this thin finish to fill and you wind up w/ a less than desireble finish.Now this does leave a beautiful finish but takes a good while to get to your finished product , although beautiful its not very tough. Product like CV, Lacquer, Poly, Paint..... set on top of the stain and dont penetrate into the wood so these products need something to bite to, and what they bite to is the scratchs left by the sandpaper.
Care must be taken here also because most people think that the slicker you sand the more beautiful the finish will be. This is not true. You can actualy sand so smooth that product like CV ,Poly and paint wont fully stick to one another and will start to lift or seperate after awhile because of nothing to bite. Lacquer on the other hand doesnt work on this principle. Though you need to sand between coats , Lacquer will burn in or melt into the last coat . This is called bonding. The other is called cross linking.



Coat number 2

Part 4 coming. R.K.

[Randall Kepley]

Part 4 . In the next pix and for the next 2 coats it will be sanded w/ the other air sander, the Dynabrade micro w/ a 220 grit. It leave a very smooth finish w/out sacraficing the bite the next coat needs. I should also be stated that using this kind of sander isnt necessary hand sanding w/ a fine sanding block will work just as good. Also Im not going to show the pix of all 4 coats as you get the gist of whats going on here. I would like to say that after I sand , I vacumme off the wood w/ my shop vac to pull all of the dust out of the fibers and right before I spray I do one final blow off w/ the air hose before I spray which leaves zero trash to get trapped under the finish.



The next pix are of the final product after 4 coats of CV. You will have about 30-35 mins between coats before you can sand. Last coat will dry to the touch in about 15 mins and can be handled in 30 or 40 mins fully cured, hard as a rock in about in about 10 hours.









The Beauty of using CV , Lacquer and what not , is the speed in which it dries. The faster you can get something to cure the less likely you are of have air-borne contaminates flaw the finish. The last couple of pix are not as clear as the first. It was around 7:30 pm and my light was dimming outside which lowered the light in the shop. But the finish is superb, slick as glass and very deep. Ill try to take some pix outside tomorrow so you can get the full effect of just what this looks like. I hope this was some information some of you guys could use and I would be happy to anwser any question I can. Thanks for looking. R.K.

[davepellegrene]

Nice write up. I like your choice of sandpaper grit. I see so many sanding with 600- 1000 and even 1500 between coats.
I appreciate you taking the time to put this info out. I look forward to your next posts.

Dave

[Soundslike]

Looks great Randall. I can see you know your business. Thanks for sharing the knowledge you've gained through years of experience. I'll be looking for future posts...

Ron...

[arlis_1957@yahoo.com]

thanks randall, enjoyable read.

[Sibelius40]

Very informative post. I don't own a spray gun, but your post really explains a lot about how to use one to get a great finish. Thanks!

[theLinks]

Thanks for sharing your knowledge and taking the time to share! I always enjoy learning something new.
Tim

[Hosejockey61]

Nice job! I haven't had a chance to spray mine yet due to the cold around here.

[r-carpenter]

Nice write up!
I'll add a couple of points if you don't mind.
CV stinks! I mean it's a great finish but it's off-gassing for a few days after the application. So, don't bring your speakers back in to the living environment right away. Let it air out.
Air sanders work very well, but they need .... well air and lots of it. Most of the guys on this forum have **** ant pancake compressors and these just aren't going to do the job. So, keep it in mind.

What kind of gun are you using?
Roman.

[DuckHunterJon]

Very nice write up. Thanks for taking the time.I've been spraying water and oil based polyurethanes for years using both turbine hvlp and conversion hvlp guns. One thing I like is that the gun can sit for quite a while without cleaning. Can you comment on how frequent you clean the gun with the CV finishes? Also, can you go through the cleaning process? Thanks again.

[r-carpenter]

He he CV is catalyzed so you have to flush the gun with lacquer thinner after you done. Not the next minute or else but you don't want to leave it overnight.
CV is a tough finish. For that I like it. Scratch resistance is second to none.

[davepellegrene]

Might also want to touch on wearing a proper mask when spraying with hardener. Very important when spraying inside. One simple thing to remember is if you can smell it your breathing in the bad fumes. If hardener gets in your lungs it will harden and stay there.

Dave

[dlsbobby]

Might also want to touch on wearing a proper mask when spraying with hardener. Very important when spraying inside. One simple thing to remember is if you can smell it your breathing in the bad fumes. If hardener gets in your lungs it will harden and stay there.

Dave

I'm sure glad all you spray experts are posting tips cause I just sprayed my first project and it was not as "easy" as I thought it would be. Good thing it was only a mobile computer desk that I built for my measurement set up and not a speaker cab. Gonna have to practice a lot before I attempt that one. Robert.

[Paul Carmody]

I really appreciate a pro cabinetmaker telling how it's done. Which brings me to my first question: isn't Conversion Varnish extremely toxic? It's not exactly something they sell at the corner hardware store--or the big box stores for that matter. Lacquer fumes are also pretty bad for us (and the environment, so I've read). I assume this is why you rarely see lacquer at a hardware store (except for the occasional "brushing lacquer").

The idea of spraying outside seems good for dealing with overspray and general toxic fumes... however doesn't the stuff keep stinking for a while even when you bring it back in?

[davepellegrene]

I'm sure glad all you spray experts are posting tips cause I just sprayed my first project and it was not as "easy" as I thought it would be. Good thing it was only a mobile computer desk that I built for my measurement set up and not a speaker cab. Gonna have to practice a lot before I attempt that one. Robert.

You make a good point. Use guys that have been spraying for years sometimes forget how much of it comes from experience. It does really take a lot of time to learn how much paint can be applied on a vertical surface vs. a horizontal surface. It also depends on how quick the product sets up, the temperature and humidity also play a factor. If you spray a fast drying product you can flood it on pretty heavy but the down side is you can end up with a lot of orange peel if your not careful. On the flip side if you use a slow dry product it will flow out nice with less chance of orange peel but you run the risk of having it sag or run on you. Like you say practice.

Dave

[r-carpenter]

I really appreciate a pro cabinetmaker telling how it's done. Which brings me to my first question: isn't Conversion Varnish extremely toxic? It's not exactly something they sell at the corner hardware store--or the big box stores for that matter. Lacquer fumes are also pretty bad for us (and the environment, so I've read). I assume this is why you rarely see lacquer at a hardware store (except for the occasional "brushing lacquer").

The idea of spraying outside seems good for dealing with overspray and general toxic fumes... however doesn't the stuff keep stinking for a while even when you bring it back in?

None of the finishes are "mother's milk". All toxic. Even water based stuff.
CV is not "extremely" toxic. Organic Vapor chemical cartridges provide sufficient protection. It's not like 2k polyurethane, then a respirator just isn't enough to capture isocyanide. But yes, it is toxic and you MUST use the respirator. As far as off gassing, all finishes do that. CV just has a very distinctive smell to it. I say 4-5 days before it's cured and ready to go.
The benefit, aside from good resistance is that you spraying less coats and so while the fumes and over spray are toxic for you and environment, in the end you are putting less out.

[davepellegrene]

I really appreciate a pro cabinetmaker telling how it's done. Which brings me to my first question: isn't Conversion Varnish extremely toxic? It's not exactly something they sell at the corner hardware store--or the big box stores for that matter. Lacquer fumes are also pretty bad for us (and the environment, so I've read). I assume this is why you rarely see lacquer at a hardware store (except for the occasional "brushing lacquer").

The idea of spraying outside seems good for dealing with overspray and general toxic fumes... however doesn't the stuff keep stinking for a while even when you bring it back in?

A good rule of thumb is if you can smell it it is still drying. Doesn't matter what product your are using. I wouldn't take it inside until you can no longer smell it. Especially with little one's around. Some people are very sensitive to it and can get sick from it. As far as spraying with hardeners you need at least a carbon filter mask which is what Randell shows in his first post.

Dave

[bobbarkto]

In addition to the normal solvents Conversion Varnish (CV) has a relatively high percentage of formaldehyde in it.
That is largely responsible the distinctive smell.
The catalyst is acid. Don't breath the spray mist. Keep it out of your eyes and off your skin.
Use a respirator that can deal with formaldehyde and acids (most cartridges don't adequately filter both).
As with most catalyzed finishes it's not a very diy friendly product IMO.