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Kyle Wheeler
Posted: May 14, 2010 08:50 PM
Tip Build Up
I am having tip build up none stop. Once I clean the build off the cap and the tip within a couple minutes the cap is covered again. Frustrating! I am spraying 2lb PFSI soya (Demilac). I use a Fusion AP and spraying at 1100 PSI with a 02 chamber. Is the chemical to hot?

Another questions I have is on the settings I should use to spray with a 01 chamber? I know everyone says learn how to spray with a 02 but I have a heck of a time getting the finish smooth.

How smooth should a good sprayer be able to get the finish when spraying between 16" O.C. framing?

Any suggestions on spray techniques?
steven argus
Posted: May 15, 2010 11:27 PM
We get less crud on the tip at lower temps. Depending on the foam, we run at least two clean tips a day.

If you're taking pics for your website, stand back and make the foam look nice. If you're trying to make money, squint when you look at the foam.
Posted: May 16, 2010 06:43 AM
pretty much...I've been foaming a couple years now and the inspectors aren't really too fussy on how it looks. However...when the temp/pattern is just right it isn't too hard to make it look good.

IF you're wondering about the temperature...call your supplier. I was told when the foam goes on wet and finishes rising in four seconds, you're good.

That's a pretty good rule of thumb in my experience but that is also limited ;)

How long have you been spraying? Maybe we were in the same course
Posted: May 16, 2010 03:15 PM
I thumb over the tip all day and can usually keep it off as I go. Once I start to see the pattern going in differen directions, I will take a carpet knife and clean around. If that doesn't work, then I will use a pin wheel.

I remember when we first started, I use to have temps turned up to 145 and 155, now I very rarely go over 125 and 135 even when its cold outside.

We sprayed yesterday all day at 110 on the A and 115 on the B and Hose side. It was cloudy at in the low 80's.

The one thing to keep in mind about the temps is the hotter your material going through the gun, the more viscous the material will be. A scratch on your chamber or side seals won't be as big of a deal at 115 degrees as it will at 145.

Either way, clean your tip as you go even if it is only with your thumb (gloves on) knocking off build up at the tip. When you need to keep your spray pattern looking nice, clean around your tip and use the pinwheel.
Kyle Wheeler
Posted: May 16, 2010 07:51 PM
I do not want to sound like an idiot but what is the pin wheel you refer to?

For the Canadians, is there anyone who sprays PFSI Soya? I am running the A side, B side and the hose heat at 100 on a H25 Fusion AP 02 chamber at 1100 PSI. I realize the ambient temp. changes the where you set the temps. but am I where I should be with the temps? I know I should be able to call the supplier but I do not believe anyone there has been on the end of the gun. I would like to actual speak to someone who has the same equipment and sprays the same chemical?

If it was not for this site I would be left figuring this business on my own. I appreciate all the posts on this site. I have learned a lot on here.

I have been spraying for 3 years and still have a lot to learn about this business.
Posted: May 17, 2010 06:05 AM
"The one thing to keep in mind about the temps is the hotter your material going through the gun, the more viscous the material will be."

the hotter the material the less viscous it will be...which is why we heat our products,,,the resin is more viscous than the iso,,heating "thins" the fluid allowing it to flow easier...

from wikipedia:
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear stress or tensile stress. In everyday terms (and for fluids only), viscosity is "thickness". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity. Viscosity describes a fluid's internal resistance to flow and may be thought of as a measure of fluid friction. For example, high-viscosity magma will create a tall, steep stratovolcano, because it cannot flow far before it cools, while low-viscosity lava will create a wide, shallow-sloped shield volcano. Put simply, the less viscous something is, the greater its ease of movement (fluidity).[1] All real fluids (except superfluids) have some resistance to stress, but a fluid which has no resistance to shear stress is known as an ideal fluid or inviscid fluid. The study of viscosity is known as rheology..
monday monday...it was all,,i hoped it would be,,,

I have over 10 years of experience specifying and installing open and closed cell spray foam. I've sold my business but I'm still selling for the new owners and consulting on large and custom specific jobs. 

I've expanded my knowledge into t

Posted: May 17, 2010 11:40 AM
OK, have you checed the air coming through the end of the gun? This can lead back to the trigger or before if you don't have good air supply. I've had a chunk of air line slug clog up the air line to the point where I wasn't getting much air through the tip.

Just another suggestion!
Posted: May 17, 2010 08:55 PM
Dude, we do things a little different down here...LOL.

Watery was what I was shooting for. The hotter the material going through the gun, the better chance for a problem to occur, therefore making it less viscous.

You took it straight out of Wikepedia didn't you. I had to look for myself, cause I hate being wrong.

Thanks for the correction dude!

Pin wheel is the little brass drill bit thingy that they charge you $25.00 for if you buy seperate. Should have come with your Fusion AP.

P.S. If you are spraying up in the air, get used to the build up. It happens! Once your pattern begins to split up, clean out and start again.
Chad Ferriss
Posted: May 18, 2010 06:36 PM
Im a fellow canuck! if you have issues while spraying and have no access to anyone call jt at sprayfoam nation in OHIO he knows his stuff and is a stand up guy! he can help with any issue!347-982-4228
Posted: May 19, 2010 06:14 AM
we dont see much buildup or chamber occlussion with the open cell products,,
we do with closed cell foam...
make sure to clean the chamber with the drill bit every time you set it down for a break as well..it will "glaze" the chamber from sitting there leading to further possiblity of occlussion when you start up again...
lately i have been turning off the airpurge and putting a blast of brake cleaner down the hole and then doing the drill bit thingy,,,not sure if this helps,,but subjectively,,it seems to get the chamber cleaner with less pattern deformation when we start shootin...
and thumbin the air cap works well too...
Posted: May 19, 2010 11:23 AM
Two things to think about, make sure your spray air is on. That is the little screw on the top right side of the gun when you are holdinf the gun. Another is a release agent such as PURA Insulation release. It come in a 10 OZ can and can be sprayed on anything you do not want foam to stick to.
Posted: May 20, 2010 01:44 PM
Try a ClearShot Gun!!
chad harris
Posted: May 20, 2010 04:56 PM
Your running too cool for starters, 115 to 125 degrees on line heat and preheaters, you should be able to find the perfect setting somewhere between them temps, your tip build up shouldnt be quite as bad then. You may even get a little better yield.
Yvan Richard
Posted: Jun 01, 2010 11:28 PM
From what I have read the higher the heat the greater chance of the pattern starting to finger. I am spraying at 135 both A & B and also the hose. If I bring down the heat slightly will I get a nicer pattern?
Yvan Richard
Posted: Aug 18, 2010 11:58 PM
If you want inexpensive pin vises, I called a jeweller and they sent me 3 for $30 CDN. They deal with little tiny bits all the time. Also for the bits just call a bit supplier. I purchased the .042 for the AP Fusion, I got 20 for $10 CDN.
Edward Brassington
Posted: Aug 22, 2010 08:54 PM
To get a smooth spray pattern try using an 00 tip. we have found that there is a lot less over spray and you can control the foam a lot better. Spray onto the rising foam. We usually spray around the frame, then spray from stud to stud in a circular motion. This way you can keep the trigger open for most of the stud bay. With Polarfoam soya spraying at between 111 and 115 seems to be best. Also keep your hose out of the sun where possible. We insulated all our hoses with 3/4 foam pipe wrap, it made a huge difference.
Kyle Wheeler
Posted: Aug 31, 2010 09:38 PM
Thanks northernsprayer. Just wondering if I can get your email address to shoot you an email about a couple of other questions regarding the wrapping of the hose?
clint moore
Posted: Sep 01, 2010 11:20 AM
1). check the ports in the air cap and make sure they are clean.
2). The white seal inside the retaining cap, the air cap should not push through it. this is what seals the air flow to the cap.
3). chamber housing o-ring, this is the o-ring at the front of the housing where the chamber comes through. when the chamber retracts the air cap seals at the retaining ring(white o-ring)and at the housing. If you notice there is a o-ring pressed in at the front of the housing. this o-ring seals the back of the air cap.
4). Needle valve. if you are pointing the gun away from you it is the nipple on top of the gun on the right side.if this is closed you are getting minimal air clean off to your tip. from a full closed position open the valve one full turn.
6). Disconnect the hose manifold from your gun,remove the air cap. If you notice there is a hole on the front of the housing offset from where the chamber is. this is the passage for the clean off air. if there is no air coming through then the passage is clogged. remove the housing and clean it out as well as the passage from the trigger spool.
7).Most manufacturers have recommended temps. for their materials. But these are just starting temps. These will vary depending on your ambient(outside to substrate temp. The Hotter it is the lower the material temp., Colder it is the higher the temp. Always best to do a test section to see foam performance(yield). remember that the material in the hose does not have the immediate set temp material unless you have recirculated the material through the hose,not just the drum.Spray out the material in the hose and watch for the change in the foam.
clint moore
Posted: Sep 01, 2010 11:42 AM
Also - PURA release spray...READ THE MANUFACTURER USES LIST WITH THIS PRODUCT. Stupid is as Stupid does.
Daniel X
Posted: Sep 06, 2010 11:39 PM
I spray 2lb. with an AR4242 mixing chamber almost exclusively, I dunk the air-cap in solvent until I can get it completely clean and then I use some of the fusion gun grease that comes in the little toothpaste style tube to keep overspray or buildup from sticking to it. If I get to much buildup, to often, I turn my temps. down.

What are you others talking about when you say you "thumb the air-cap"... Do you mean you push your thumb onto it and force air backwards?

I've never heard of a pin-vise being called a pin-wheel either?

Lose 100 pounds of pressure and move your gun further away from the work if you want it to look smoother...

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