#2
Quote by skylerb
http://www.spraygunworld.com/products/CAT/CATMiniJetW.html

^ Is it worth it? Can it do bursts, solid colors, clear coats, etc.?
I'm going to be using HOK Catalyzed polyurethanes, if it makes a difference.
If that's not a good gun, any recommendations?

Also, what should I use to clean it when I'm done spraying?

Thanks!



I haven't heard of CAT, so I can't comment.

I have however heard of Devilbiss:

Click Here

That kit has three guns, so you can keep one for primer and sealer, one for base coats and one for lacquer.

You are making a good choice with the HOK Urethane Enamels, best money can buy and what I use. It is only really the Primer and Clear coats that are Catalyzed.

Make sure you stick to that system. Don't be tempted to use someone elses reducer etc. Ideally, use there primer (KD2000) sealer (important-Ko Seal), then the colour coats, Intercoat clear between layered colours or artwork (SG100) and I like their UC35 clear coat. You can use UFC35 is you wish, but UC35 is tougher against chemicals and still has a fantastic, deep clear gloss.
Also, use their KC20 panel wipe, after sanding etc to keep contaminants off of your work.

The first question, when buying a spray gun, is not what one, but what one can I power?

You will need a beefy compressor with a large receiver to properly use HVLP guns.

That is why I use minijets, because they can go as low as 6CFM, which means I dont need an enormous receiver.

What compressor will you be using?

The other thing that many people don't know, is that when using a compressor for paint, the air needs to be dry and CLEAN.

Big compressors are not usually oilefree, so you need filtration to remove oil and other particles.

Then a water trap. But a water trap is not enough. All it does, is collect condensed water that may come out of the receiver. The actual air, runs at close to 100% humidity, so you need to try and dry that a little and it is here, where things can get complicated/expensive.

The cheapest method, is to use a desiccant dryer. You can make these or buy one (Devilbiss make a nice cheap one) or you cna use a "Desiccant Snake". This is a length of hose, with desiccant in it, that dries the air while you use it.

Or, I like these: Click Here

Dirt and water in your air, ruins many paint jobs.

I use one of these. Click Here

To clean your gun and bits, just buy some Gun Wash, which is cheap thinners and is very cheap to buy, by the Gallon.
Last edited by Skeet UK at Dec 7, 2008,
#3
Thanks, that's great!
I'm a little confused, though. I don't really care if the the gun is HVLP or not, if you recommend a non-HVLP, then I'd go with that, you obviously know what you're talking about. Is the one you linked to mini jet or hvlp? (Sorry, I know very little about spray guns :P ).
As for the compressor, I think I'm going to be using my uncle's (he owns an auto shop, he said they don't really do much painting, but that his friend used it once), so I'll have to check with him.
If his won't work, I'll just buy/rent one, most likely buy, because I can't find anywhere that rents them :P
#4
Quote by skylerb
Thanks, that's great!
I'm a little confused, though. I don't really care if the the gun is HVLP or not, if you recommend a non-HVLP, then I'd go with that, you obviously know what you're talking about. Is the one you linked to mini jet or hvlp? (Sorry, I know very little about spray guns :P ).
As for the compressor, I think I'm going to be using my uncle's (he owns an auto shop, he said they don't really do much painting, but that his friend used it once), so I'll have to check with him.
If his won't work, I'll just buy/rent one, most likely buy, because I can't find anywhere that rents them :P



He probably has a 3Horse power one, if it is mobile.

Do you intend to do a lot of this? If you are arty, or interested, you can make money spraying motorcycle parts in wicked colours/effects. Even if there is no artwork on them, it really isn't that hard, but it is time consuming, so Pro's will charge probably $100 an hour. You can get 10 hours in just prepping a bad motorcycle tank, BEFORE you start laying any colour down.

HVLP stands for High Volume Low Pressure. This means, that it uses LOTS of air (big guns can use 19 cubic feet a minute) but the pressure at the nozzle (air cap) is only 10psi, so it causes less over spray, which means less material (paint) wasted and a better finish.
LVLP is the opposite and as good as HVLP, but only found on smaller nozzled guns, then there is conventional, which have higher output pressures at the nozzle, so less controlled finish.

TCP Global do a Dessicant Snake. You need to filter oil and water out of the air, but not to the extent you would need for breathing air.

Minijet. These are smaller spray guns, usually with smaller nozzles (0.8-1.2mm) and are designed for spraying smaller areas, touchup etc, so are perfect for guitars. They can be HVLP, LVLP or conventional.

Gravity feed. These have the paint container on the top, so they are fed with paint via gravity. The alternative, is suction feed. These use more air, are more unwieldy because of the big paint tin at the bottom and also waste paint, because you cant use all of the paint.

Air consumption. OK, spray guns use air. Normally, the specification will state, X CFM at X Psi. Small minijet's with 0.8-1mm nozzles will use around 4-7 CFM at around 30-50 psi.

Compressors. Smaller compressors, don't need oil in them, so try and get one of those if it will suit, because then you don't have to worry about filtering out the oil from the air.
They have receivers, to store the air in and the compressor is on the top. Smaller ones are 25l (about 5 Gallons) then 50l (10 gallons) 100l (20 gallons).
They will also tell you what pressure they can compress to, around 120-150 psi for most smaller ones and also a FREE AIR DELIVERY number in CFM.
This is the important one. This one tells you, how quickly it can replenish the air in the receiver.

So if you have a unit that can provide 7CFM and a spray gun that uses 13CFM, you can use the spray gun, but very quickly, it will use all of the air in the tank and the compressor will not be able to fill it quick enough..You will have to start and stop and also, puts more wear on the compressor.

If you borrow or buy a compressor, you should learn where the switch is to empty it and also where the drain plug is (always bottom). You need to open this to let the water out that is made when you compress air.

You should do it before you use it, every time. Lost of water builds up quite quick, which reduces the capacity of the receiver and also, naturally, puts more water out into the air line.

If you do buy one, it is worth buying the very biggest that you can afford.
If you do a lot of spraying, you may want an air fed hood to use rather than a respirator, which uses air. Then air tools also use masses if air.

You also need to think about how to dry and ventilate where you paint.

I use an Infra Red outdoor heater.

These use infra red light, to emit heat, but they do not heat the air, they only heat solid objects.

So, you don't need to worry about having warm airflow around your part as it dries, just clean air, and one of these or more, so it dries all over.

I have both a stand for some items and a rotating hanger (like a spit in a Kebab house) that rotates slowly, exposing all of the part, to this light and curing it evenly.
Last edited by Skeet UK at Dec 7, 2008,
#5
Awesome! Just one last question, it's about paint...
With the HOK paints, how would I use them over something like a maple top or bare wood, with stain instead of paint? Would a grain filler like Z-Poxy and clear be all I needed, or are there other steps?
#6
Quote by skylerb
Awesome! Just one last question, it's about paint...
With the HOK paints, how would I use them over something like a maple top or bare wood, with stain instead of paint? Would a grain filler like Z-Poxy and clear be all I needed, or are there other steps?


Well you wouldn't paint a figured top, so I assume you mean with clear coat?

I live in the UK so I don't know what Z Poxy is.

Any time you want to paint wood or clear coat it, you need to use a clear sanding sealer. This is really, just very thin varnish.

So, if you want to stain it, do that first.

Then grain fill it (sanding sealer) then clear coat it.

For painting wood. Grain filler (sanding sealer), then Primer, then colour coats, then clear coat.

If you are using HOK, make use of their KO seal, Primer sealer.

You can apply this to prepared original finishes that you have sanded etc, before you apply colour, or use it over their or someone else's Primer.

This makes a barrier between the primer/original finish, to stop any colour coats being affected by them..A worthwhile step.
#7
Z-Poxy is listed as an epoxy grain filler on LMII, so I guess it would work for this.
I'd test on a piece of scrap first anyway, just to make sure there's no weird reactions or anything.
Thanks for all your help!
#8
Quote by skylerb
Z-Poxy is listed as an epoxy grain filler on LMII, so I guess it would work for this.
I'd test on a piece of scrap first anyway, just to make sure there's no weird reactions or anything.
Thanks for all your help!


Sounds good.

Don't forget a progress thread, pics etc
#10
CAT or Ca Techologies are decent devilbiss and Binks also make great guns.  If your doing the small work like guitars a combo of a touch up gun with air brush may make sense.  For larger work a standard spray gun could be right.  This company has all parts for Binks & Devilbiss.