Archive for the ‘spraying’ Category

Dialing in HVLP

October 25, 2007

Some guys struggle with the HVLP. I think if more guys felt more comfortable about how they work, more guys would use them. For the purpose of this article I will be using the ICI Sanding Sealer only because I happen to be shooting it this week.

On the HVLP (top photo) you see two dials, one is the air flow (how much air goes through the gun) and the other is material flow aka fluid knob (how much paint goes through). The arrow on the upper knob (air flow) is set at about the 7 o’clock mark. Max air flow is at 12 o’clock. The knob only works from the 12 o’clock to 6 o’clock mark but you can turn it either way. So if we turn the knob to the right to 5 o’clock, it is the same as turning the knob to the left at 7 o’clock. Hope that makes sense.

The second photo shows how thin the material is. You know how when you pour a thick paint in a bucket the paint sort of accumulates on the surface before it levels out? We can’t have that happen with an HVLP. The paint when poured into itself should dissipate immediately into itself. I have my sanding sealer a bit on the thin side but not by much and only because I was shooting a light dusting coat of tinted sealer.

Once the paint is mixed up and in the cup, turn the fluid knob all the way in and then back it out 2 full turns. Start by shooting with the air flow at the 6 o’clock which should be ‘OFF’. Then while squeezing the trigger, start by turning the air flow to the 9 o’clock mark. It should produce paint at least air through the gun at this point. If not, turn the fluid knob another full turn out. If still nothing, your material may be too thick. You can at this point open the air control knob all the way to 12 o’clock to confirm. If still no material, the gun is blocked up or material is too heavy.

If all goes well, you should be able to shoot materials through the gun with the material flow open slightly and air flow set at 7 or 8 o’clock. I NEVER shoot anything at 12 o’clock, that’s when I eat lunch, no seriously 12 o’clock is over kill and does nothing but cloud up the room.

Assuming you have paint through the gun, turn the air off again and very slightly turn air pressure up a hair or until the paint is coming out like a fine spray. If you cut off the air flow the gun should spit the paint out. Dial-in where the minimum air is needed to shoot a fine spray from the tip of the gun. The knob is very sensitive, use very small increments for adjustment.

Once you get the hang of that, you can adjust the fluid knob more to move materials quicker.

See also: HVLP Maintenance and HVLP Transfer Efficiency

HVLP Transfer Efficiency

October 23, 2007

There is no argument that an HVLP [High Volume Low Pressure] Sprayer pulls its own weight. I recall the first day, first job I used my first HVLP unit. I had a stained trim house all prepared on the drying racks and all I had to do was shoot some sanding sealer on the trim. I suppose two guys brushing the trim for an hour and a half isn’t bad but the HVLP did the whole trim package in under 30 mins., nice. Needless to say, the HVLP paid for itself time and time again.

Besides its time saving abilities, the HVLP when dialed in properly will save on materials too. Take notice in the photo of the spindles above, that is the extent of the overspray. I shot 2 coats of Zinsser Odorless Oil primer on those bare poplar spindles before carpet and shot the oil finish after carpet. The photo shows the accuracy and transfer efficiency is incredible.

See also: Cleaning your HVLP

Full Sheen Ahead

October 22, 2007
Most everyone seems to appreciate higher sheen or gloss finishes when it comes to trim and molding, the shinier the easier to clean.

Personally, I prefer a true semi-gloss to semi-satin finish and I have been known to mix 50/50, equal parts to achieve the sheen I like. Sometimes I like high-gloss on stained stair systems then other times I like true satin finishes.

Regardless of your preference, this topic covers how to achieve a full sheen that holds gloss levels true to its formulation. There is no known paint to me that holds gloss regardless of 1 coat, 2 coats or 3 coats. Typically you’ll experience this, the second coat is shinier than the first coat and the 3rd coat is shinier than the second coat. So when does the sheen stop getting shinier and become true to its formulation?

The answer depends on what is under the finish paint. For example, if we paint a PVC casing with semi-gloss, the dried finish is going to be shiner than if you painted a piece of primed wood. The PVC will not absorb sheen but the primer coat will. Not all primers absorb sheen the same. Some primers if not sanded will not absorb any sheen and the same primer sanded will. I’ve been known to do one coat of an oil primer on bare wood and one coat of an acrylic primer prior to two coats of finish. Again, not all primers and finishes are equal. Generally primers dry flat, I know of one primer that dries like an eggshell and that is ICI Gripper. Because Grippers sheen is eggshell, you are already one step ahead over a flat primer to achieve a full sheen.

Regardless of which primer you choose, the absolute best finish will come from one coat of primer sanded smooth and a second coat of primer not sanded, and then apply 2 coats of semi-gloss. I know, four coats of paint is not realistic and many homeowners do not want to pay for it, but it looks great!

See also: Iridescent White Trim as seen in above photo along with SW Totally Tan.

Clean-n-Dip Review

October 9, 2007

Just a short product review on Back to Nature’s Clean-n-Dip. I primarily use Clean-n-Dip for cleaning sprayer parts. It has no odor, contains no methylene-cloride, caustic or other harsh chemicals, easily cleans up with water and will not burn the skin.

The product starts to work immediately but works best if you place the parts in a can and let the sprayer parts soak about 15 minutes or so. I use a stiff toothbrush to periodically loosen heavy paint buildup. Clean-n-Dip can be reused.

The product removed oils, sanding sealer and acrylics fairly easy. I had a few stubborn areas that required M.E.K. to soften the fully cured varnish. I recommend this product. Be sure to shake and mix well and stir occasionally while you use it. You can use a paint strainer to removed the crud and pour the cleaner back into a container or coffee can.

HVLP Maintenance

October 8, 2007
This small article will cover some basics on HVLP maintenance. I’m bad about cleaning up my HVLP until it’s a problem and this unit is overdue. The HVLP sprayer is a huge benefit on the job but if its not cleaned thoroughly after each use, you will most likely run into problems the next time you use it.
I start by removing the check valve assembly and tubing then separate the two pieces and remove the check valve and clean all parts real good. A good sprayer cleaning kit is a must. The kits designed for cleaning sprayer parts will help speed up the process of a full teardown.
This is the check valve removed and covered in paint. When spraying, try to keep the cup in an upward position and you will minimize the amount of paint that gets through to the check valve. If the check valve becomes covered in paint like the photo, the sprayer will not work properly.
Don’t forget to clean the fittings both on the gun housing and the cup housing where the tubes attach.
Next I remove the air cap, nozzle and tip assembly and clean all the parts good.
Using a socket wrench I remove the fluid nozzle and clean it.
Obviously this needle is in bad shape. CAUTION: if you have dried paint visible on the needle, try to remove it here before you pull the needle out of the housing. If you were to pull this needle out like you see it in the photo, it will pull the packing out with it and then you will need to repack.
Unscrew the fluid or material flow knob and remove the spring and pull the needle carefully out to clean it.

Here is the needle. The needle should be clean spotless. Once clean, run the needle through your fingers to see if you can feel anything you may have missed.

Setup doors to spray

April 21, 2007

If you are considering spraying doors with either an HVLP or airless, here is simple setup, probably one of the more common methods used. There are a number of door stacking systems available for our line of work.

Here are a few things to know before you stand them up.

1) Shop-vac the floors and put heavy construction paper down, not plastic or do like some do and shoot them on the concrete or subflooring.
2) Group doors together to prime edges with a short nap roller the day before you plan on spraying the doors. Sand and prepare for paint.
3) Use a 1” nail and door shims to tack doors together.
4) Nail approximately 3-4” in from the edge for better stability
5) Let everybody around you know to stay back while spraying. Post a sign. I almost sprayed a homeowner who slipped in the house without my knowing.
6) Allow overnight to dry before removing from paper. The doors should remove cleanly as long as you don’t puddle paint between the bottom edge of the door and the paper.
7) A 4′ whip hose comes in handy for better flexibility.

In new construction, many of the doors are MDF and require all six surfaces be painted or warranty is VOID. The MDF doors tend to warp much easier than solid wood doors. It’s a PITA but save yourself the headache of callbacks and prime the tops and bottoms.

About the Photo

The green walls and doors photo is fairly hi-res. Two things worth mentioning, the coarse edges on the doors from the factory will not get smooth with multiple coats of paint. It’s best to treat the edges with an oil-primer covering any bare MDF and sand it well for finish. Simply applying acrylic to the edges will only raise the MDF fibers and make them sharp enough for someone to cut their hands or fingers. Also, the reflective green paint is one coat of ICI Dulux 1410 over bare drywall.

Baluster Spray Rack

April 21, 2007

This racking system has been around for some time. You can place the rack on saw horses to position them at a more comfortable height. Here is some information for those who never made one, used one, or seen one. Many of the balusters we see have a ¾” peg on the bottom that will insert easily into a ¾” deep hole in a 2 x 4.

One eight foot 2 x 4 will accommodate 50 spindles spaced an inch and 7/8 apart on center and will allow you to turn them if necessary. For larger balusters you may need to insert one in every other hole. Click photos to enlarge.

Spraying Trim & Doors

April 20, 2007

We receive many compliments on our woodwork and doors. Here is how we do it. We use a Titan 440i airless sprayer set at no more than 1800 psi utilizing a FF210, FF211 and FF311 (FF -Fine Finish) Tip producing automotive-like finishes without the high-gloss.

All proper steps are performed to make sure the trim and doors are fully prepped for finish. We apply ICI Dulux 1407 semi-gloss twice mixed in a iridescent-like white for that beautiful reflective finish. The compliments alone say that this combination of finish paint, color and how its applied is a huge hit for the homeowners.

Spraying Balusters Down

April 18, 2007

One simple method for painting balusters when you have the opportunity to paint them before installation is to set them up on a 2×4. The balusters in the photo have a ¾” pin on the bottom so we are able to drill into the 2×4 to stand them up.

The balusters were delivered to the job bare poplar. In order for us to achieve a high-gloss finish, we sprayed them twice with Zinsser Cover-Stain Oil-based primer and sanded each flute individually. Sanding for this project took 22 hours. We finished with ICI Dulux 1407 semi-gloss.

It’s important to measure accurately for each hole before you drill. Take the time to do this and when you spray, set them up turned on an angle. The photo shows them positioned flat edge out, do sharp edge out. Make one pass on an angle going one direction, then coming back the opposite direction with one pass will get two edges at once.

 

Stick to metal

April 14, 2007

In the residential repaint market we often see chipped paint on metal surfaces such as metal door hinges, cabinet hardware etc. If it’s not chipped paint its rust spots coming through the paint. A simple fix is a can of bonding primer sprayed to the metal then finished with your choice of acrylic paint. A common problem in the new home market is peeling paint on bi-fold door hinges. Often contractors will paint doors with an airless sprayer and go directly over the hinge with latex paint. The paint often chips away the moment the doors are re-hung. A quick light coat of a bonding primer will keep the paint on the hinge.