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Shdowridr
08-01-2007, 11:07 AM
I'm using a barrowed HVLP gun (1.5 tip) and not sure of manufacture. I shot the base coat using this gun 20/10 psi setting with PPG Deltron 2000 DBC basecoat and the truck was perfect all over.
After about 2 hours, I started on clear coat with same gun and pressures using Deltron Concept 2042 with DCX61 hardner and DT870 reducer.
Mix rate 4-1-1.
When I got it to shoot smooth it would start to run. When I backed down the Paint volume just a touch I'd get orange peel. Adjusted air pressure to 7 or 8 at cap but had same problems. Spray pattern was oval to cigar shaped.
My ambient temp. at time of spraying was 63 degrees. (That's about as warm as it got that day). Spraying outside in homemade Visqueen spray booth with venting fan.
What do I need to do to spray this Clear Coat correctly?

88GT
08-01-2007, 12:27 PM
I'm using a barrowed HVLP gun (1.5 tip) and not sure of manufacture. I shot the base coat using this gun 20/10 psi setting with PPG Deltron 2000 DBC basecoat and the truck was perfect all over.
After about 2 hours, I started on clear coat with same gun and pressures using Deltron Concept 2042 with DCX61 hardner and DT870 reducer.
Mix rate 4-1-1.
When I got it to shoot smooth it would start to run. When I backed down the Paint volume just a touch I'd get orange peel. Adjusted air pressure to 7 or 8 at cap but had same problems. Spray pattern was oval to cigar shaped.
My ambient temp. at time of spraying was 63 degrees. (That's about as warm as it got that day). Spraying outside in homemade Visqueen spray booth with venting fan.
What do I need to do to spray this Clear Coat correctly?
You probably need faster activators and reducers

56Ford
08-01-2007, 04:47 PM
DCX61 is the universal activator for all temps..
I'd use the DCX8 activator for cooler temps and use DT860 reducer for cold temps...

Are you in a VOC controlled area? If not I'd use the 2021 Concept Clear.. It's a high solids clear that lays out better IMO. It's about the only clear I use.

JimmyPtr
08-01-2007, 06:04 PM
1.5 is too big. Most painters are shooting HS clears w/ 1.2-1.3. Try closing your fluid down a bit, use 860 & bump your pressure up a few lbs. Spray a test panel before starting on your vehicle & get the gun dialed in.

Len
08-01-2007, 07:31 PM
I agree the 1.5 is too large and, if you're using an inexpensive gun, the tip size along with marginal engineering could cause anyone to have problems laying on a good finish.

Shdowridr
08-02-2007, 10:49 AM
I double checked my tip and it is a 1.4.
I'm going to get a 1.2 if I can find on here in Alaska.
Also, I used the same spraying technique that I used with the paint since it worked well for me. That being, I shot the paint coat working from the bottom up finishing out on the roof using side to side motion.
Is that the best method for clear coat? Or does it matter?

Ed in SC.
08-02-2007, 11:31 AM
Hello Shdowridr, how do you kow the tip press. is 7 or 8 at cap ?

Shdowridr
08-02-2007, 11:40 AM
My barrowed gun has an adjustment in the handle and an inlet regulator going into the gun. I drop the inlet pressure and adjust the cap pressure by closing down my handle adjustment.
It's only a guess with pressure that low anyway.

Len
08-02-2007, 01:00 PM
Without a pressure gauge ON THE CAP you'll have no idea what the cap pressure is. It could be the same as the inlet pressure or it could be 10% of the inlet pressure. :confused:

It's best if you open the gun's internal adjustment all the way then regulate the incoming air with the valve on the handle. The inlet pressure should be regulated according to the gun manufacturer's recommendation then minor adjustments can be made from there depending on the materials and conditions that exist.

Dennis N. Schmidt
08-02-2007, 04:41 PM
This situation always amazes me. You're using clear that cost $200 a gallon with activators that go for $50 a quart and you're using an unknown spray gun at an unknown pressure. Can you explain the economy of this thinking to me. Normal inlet pressure to a clear coat gun starts at 29 at the handle (SATA Nr2000 or Nr3000) and can go as high as 50 at the handle (Sharpe Platinum) to get 10 at the aircap for an HVLP gun. The only exception to this rule of thumb that I am aware of is the Iwata LPH400LV which sprays clear at 20 PSIG (even though it claims you can do this at 16PSIG everybody I know that's any good uses 20).

You are potentially wasting $300 worth of paint by using a gun of unknown characteristics. I personally find this crazy, but apparently from the postings that appear on this board this happens all the time. Every time I see one of these types of postings I always say to myself: What are these people thinking?

Shdowridr
08-03-2007, 11:43 AM
So Dennis, I understand what you are saying about gun quality but I'm a little confused about the pressure for spraying. Are you saying I should shoot the clear coat @ 16 to 20 psi? I have to assume your talking about the inlet pressure coming into the gun.
I'm under the impression that most HVLP guns are manufatured for max. 10 psi at the cap.
From what I've read here thru the different postings, It sound's like I need a smaller tip and use different Activator and reducer due to the lower ambient temperature at time of shoot.

dcrog
08-03-2007, 12:09 PM
What Dennis was saying is that without the make, model, and possibly air cap of your borrowed gun nobody can answer your question. Every brand and model are different.

jhowell
08-03-2007, 02:39 PM
10lbs at the cap is the requirement for HVLP. However, unless you can measure the pressure at the cap, you won't know what it is. The only way around this is to have an owner's manual that states what the pressure should be at the inlet in order to achieve 10PSI.