MY DESCRIBED SET UP IS FOR A GRAVITY FEED! Your in no-mans land with a siphon feed.
I stopped using one of those over 30 years ago, not saying they cant produce a nice finish as I used one many years long ago I just no longer remember how to set one up correctly!
Back then I didn't know how to set one correctly! I didn't even know there was a wrong way to be honest.

My suggestion Buy some new guns!
If you lived closer to me I would loan you mine.
Mine are older top of the line Devilbiss back when they were new and they still perform like new. Tech has come a long way since then and their are even better guns to buy now!
Tekna under the Devilbiss brand comes to mind. BUT f you can get a deal on an older good gun who cares?

I myself have been shopping Iwata and SATA products.

Doright wrote:MY DESCRIBED SET UP IS FOR A GRAVITY FEED! Your in no-mans land with a siphon feed.
I stopped using one of those over 30 years ago, not saying they cant produce a nice finish as I used one many years long ago I just no longer remember how to set one up correctly!
Back then I didn't know how to set one correctly! I didn't even know there was a wrong way to be honest.

My suggestion Buy some new guns!
If you lived closer to me I would loan you mine.
Mine are older top of the line Devilbiss back when they were new and they still perform like new. Tech has come a long way since then and their are even better guns to buy now!
Tekna under the Devilbiss brand comes to mind. BUT f you can get a deal on an older good gun who cares?

I myself have been shopping Iwata and SATA products.

Ive only done cabinets and interior wood with it,does a great job.It should work. Not going to give up.
Changing out my air hose today.Currently 1/4 moving up to 3/8 and much shorter.Air tools have always had cfm restrictions.

Air flow CFM is critical when painting NOT PSI You have to have the flow.
Smallest fitting in your system should be you Hi flow quick connections at the end of your 3/8 air hose.
My System has 1 inch pipe through out my shop with 3/8 air hose taps where needed leading to My Air drier/ Air filter set up and on to my one and only Regulator in my system in the Paint booth followed by 25 feet of 3/8 air hose and Hiflo quick connections for my paint guns.

Even my water trap after my Air compressor is made from 1 inch pipe and fittings, I have some flex lines in the system but even they are very large 3/4" Very large so no restrictions in flow (CFM)

If your primer is looking like this it doesn't look good for Base and Clear which are very expensive, doubly so if you have to redo it. I think Darrel does furniture restoration he would probably be more familiar with your gun, NFT5 is another good source as are others I strongly suggest a new thread in Body and paint addressing your current problems to get others advise.

https://www.youtube.com/watch?v=nss-j0H0ADg

https://www.ebay.com/itm/275585873645?c ... gJ5SvD_BwE

Once you take all the restrictions out of your system and add Hi flo air quick connects You will have a Brand new Gun! I remember when I first made the change to Hi flow fittings It Made a very dramatic change in my Guns very dramatic it was like having new guns! I had to learn how to paint all over again!

Another thing about air flow
I do not run a Regulator at my compressor! My air system sees Tank pressure throughout the shop until it gets through my air drier filter on my booth and then is plumbed to a Devilbiss Regulator Then I adjust the regulator to the pressure gauge ON the Base of my gun when wide open NOT at the regulator gauge itself! So the only pressure I am concerned with is the air pressure at the base of the gun Only.

Do not run multiple Regulators! i.e. one at compressor and another at Paint booth. It will restrict air flow and cause fluctuations.
Use a Hi quality regulator preferably one designed for Paint guns as they will be designed for Hi flow. a Regulator is not a regulator their are good ones and a lot of cheap China made junk beware.

Great thx,I had just finished hooking up new 3/8 hose and high flow fittings then I read your post.Doh! Didnt even think about removing the regulator that came with the compressor. So back up in the attic I go.My new one is 3/8.

So got the regulator and 3/8 hose sorted and wow. Real air now. My tools will now do what their supposed to do.

Mixed up some more primer this time with my scale. Triple beam. Ran it through my viscosity cup. Ford #4. Looking at the lemmer chart. TDS says 50-70 sec with Zahn #2. Crossed over to Ford cup about so 60-80 sec. I got 120 seconds. Probably because of temp of primer. So tds says for 4:1:1 add 26.8 grams thinner to 200 primer 30 hardener
Which by the way was not quite enough for one coat, 350 grams would be about right. Anyway added 8 grams of thinner to get the 70 secs on Ford cup.

Mask on and away we go. Worked awesome ,port reg at about 5 psi. Air valve open. Fluid 3 turns out from closed.

Pics look better BUT no cats meow yet its Hard to tell BUT looks like mix may have been a little thin? In first pic where light has bright reflection looks like a Bit of orange peel and a little dry spray????? Technique maybe???? To thin maybe?????
Must maintain gun distance, Watch the Wet edge as it lays down, don't whip gun, slow but not too slow of passes, maintain 50% over lap each pass. maybe up pressure a few lbs? When and if your getting orange peel.
Again please Post thread with pics in Paint and body section, Get others opinions!!! get them involved !!!!!!

Mixing paint by weight is new to me and I did buy a nice digital Scale to start mixing my paint by weight on my next paint mixing job!
However using Viscosity measurement tools is all new too me? I always measure and mix by the measuring cup please explain what you got their???? Never heard of these before I may need to buy some?

I generally don't reduce my stuff ever unless instructions say you have too..
Base coat I always mix per instructions and I never reduce beyond that!
Clear even when instructions say it can be reduced I never do because I like to use it strait because I like a Heavy build of clear so I can Cut it once with 1200 grit and polish once with twisted wool and then refine with two sessions of Swirl remover on foam pads 1st white pad then Blue pad or white pad then Black pads just depends on color of base coat. and then my cut and Buff is done.
No multiple sanding sessions for me of Multiple Buffing sessions beyond described above.


Glad you got your air working 3/8 is still kinda small for general plumbing, I like BIG and No restrictions just takes the problem out of the equation. Yes it costs more BUT you cant take it with you PLUS I cant stand doing things twice. in this hobby doing things twice means spending more money AND I hate listening too the controller of my money!!!!!!! Not that she has much say in what I do but I still have to listen to it.

So sanded 180 again,Im getting good at this lol.
Checking viscosity is what I learned spraying cabinets .So you go by tds for seconds to match tip.Problem is there's several kinds ,so different times.
Worked much better as I reduced to what the tds said as un thinned.

2 coats today,20 min apart.I just let the gun sit.Checking pot life its about 2.5 hours. Using the scale I can mix in a tin bowl,easy clean.Accurate measuring also since Im new to this.
Mixed 400g primer 70g hardener 15g thinner.About 400ml, worked well only had a little left.

A pic.

Dennis, the old method of checking paint viscosity, before shooting it, was to use a Zehn's cup (sp?). After mixing the paint, you poured a bit into a funnel, which had a specific size hole in it. You counted the drops as they came out, in relation to how many seconds it took. I haven't seen any modern paint manufacturer recommend this method is a long time. Guess it isn't necessary with today's paints.
Certainly helped with the old enamels, both acrylic, and synthetic. Lacquer, not so much.

Yeah you guys in the business know just by mixing and how it runs off the stir stick.Why my primer is thicker I have no idea? It was mechanically shaken.Garage is cooler than 70f so maybe thats it?

The fellow at the paint store did mention I may have to reduce 10-25%.

The upol clear coat also has viscosity on their TDS @ 17-19 sec with a Zahn #2