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Iwata HP-CR problem/question

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  • Member since
    September 2012
Iwata HP-CR problem/question
Posted by keveuh on Thursday, October 18, 2012 2:30 AM

Hi everybody,

I own a Iwata HP CR airbrush, I've had it for 2 weeks, I've painted multiple times with it Tamiya Acrylics without any problem until yesterday.

Yesterday I first painted some x-18 semi gloss black without any problem as usual, then I flush/clean the airbrush and I decide to try some xf-56 metallic grey on a plastic spoon to see how that color looks like. So I thin it 5:6 (paint:thinner) and the PSI is at 20 as always for me. And there my problem began and it's not easy to explain so I'll try my best:

you know a double action airbrush, you press down you have air, you pull back you have paint. And you can adjust the amount of paint sprayed by how much you pull the trigger back. Well that didn't worj for me ! That's what happened: when I pulled back nothing came out, so I pulled more and more until finally painted came but of course it came a big splash of paint since at that point I was pulling back so much. Then I stop and I pull back again just a bit, a fine line starts to draw and after barely 2 seconds no more paint coming out again, so I pulled a bit more and a thicker lie appears to stop again 2 seconds laters and so on. So the thing was that I couldn't get a consistent paint flow. I always had pull the trigger back and forth to get any paint coming out. 

So I thought that there must be some paint left in there not cleaned well. So I emptied the cup and recleaned the airbrush, now my cleaning procedure is this:

- take out the needle and wipe it with windex and then with water and then wipe it dry

- put some windex in the cup and take a brush to clean it 

- then I take one of those "airbrush cleaning brushes" and I clean the inside the airburhs, you know that part where the needle goes in, from the cup to the nozzle

- then I rince this with water, I clean the nozzle cap if needed, I put the needle back in and I spray some water to rince.

So after cleaning I put paint again some amount of paint and thinner, and I have the same problem again. I'm worried something is broken. I decide to add more thinner and more thinner but that didn't work. So I checked the Iwata manual and they talk about clogging (I'm not sure what that is by the way) but I see a part called the nozzle which can actually be removed. So I empty the cup again and I decide to reclean but a bit deeper this time. I remove the nozzle and I see me red on it. And I thought, that's it !! Cause I had painted red paint as my first acrylic paint 2 weeks before and I had a bit of a hard time to clean it the first time. So I reomve that red very easily. Then I do my usual cleaning procedure and I decide to remove the trigger and the parts holding it, and I pass a brush there with first a bit of windex and then water and then dry. I also decided to clean fron the nozzle to the cup (where the needle goes) with a rush with windex and water. At that point it was lunch time so I put everything back and didn't touch it since then.

My questions then are:

- what do you think caused that problem with my paint ? Not enough pressure ?

- and mostly about the nozzle and that red thing on it, on Don's blog that this seems to be a seal but I of course didn't know that. So I wonder how critical it is that I removed that and if I could put some basic seal tape instead ?

Thank you so much for reading and helping.

Tags: iwata hp cr
  • Member since
    August 2005
  • From: Sydney, Australia
Posted by Phil_H on Thursday, October 18, 2012 3:20 AM

I love Tamiya acrylics most of the time, but I dislike the metallics because they have a fairly coarse grain and have a propensity to clog an airbrush in the blink of an eye.

Insufficient thinner and it won't flow. Too much thinner and the metallic particles settle out of suspension very quickly and block the innards of your airbrush. It's worse for gravity feed brushes - with a siphon-feed, you can swish the paint around in the jar while painting to keep the metallic pigments in suspension, but you can't do that with a gravity feed brush (well, you can if you want to splash paint everywhere)

Often, you'll get a couple of bursts of paint and then it stops. If you keep the trigger down but allow the needle to return to the closed position, you may get a brief burst of almost dry metallic particles. Pull the needle back and you'll get a short burst of paint and it stops, release and repeat as above. Time to clean the brush again.

I would use more thinner than you are at present, perhaps 2 parts thinner to one part paint and adjust the mix as required to get a smooth. even flow.

 

  • Member since
    October 2007
  • From: Scotland
Posted by Milairjunkie on Thursday, October 18, 2012 3:22 AM

keveuh

- what do you think caused that problem with my paint ? Not enough pressure ?

It sounds more like a thinning issue - try increasing your ratio of thinner & see how you get on. Different colors even from the same manufacturer sometimes require different thinning ratios, it's something that you will have to play around with until you get used to it.

If this problem lessens with more thinner, but is still apparent, it may be worth adding some flow air or retarder to your mix - you can find this in most art stores along with the acrylic paint.

keveuh

- and mostly about the nozzle and that red thing on it, on Don's blog that this seems to be a seal but I of course didn't know that. So I wonder how critical it is that I removed that and if I could put some basic seal tape instead ?

The red stuff on the nozzle threads is sealant - Beeswax is what you would normally use to reseal the threads if required - I would stay away from tape.

  • Member since
    September 2012
Posted by keveuh on Thursday, October 18, 2012 4:14 AM

Thank you for your answers. I had read about metallic paints not easy to airbrush and I understand wht now even if I didn't have any problem with a x-11 chrome silver, so it's nothing wrong with the airbrush.

I'll try to find bee wax, that's sonething I have seen a lot mentioned but I never looked for it yet and I really hope I can find that here in Finland.

  • Member since
    October 2008
  • From: Fullerton, Calif.
Posted by Don Wheeler on Thursday, October 18, 2012 11:17 AM

If you can't find bees wax, try a little lip balm.  Put some water in the cup.  Connect air and hold down the trigger without pulling back for about a minute.  If you don't see any bubbles in the cup, the seal is OK.

Don't over tighten that little nozzle.  It will break or strip.  Just barely snug it up.

Don

https://sites.google.com/site/donsairbrushtips/home

A collection of airbrush tips and reviews

Also an Amazon E-book and paperback of tips.

  • Member since
    October 2007
  • From: Scotland
Posted by Milairjunkie on Thursday, October 18, 2012 12:22 PM

keveuh

I'll try to find bee wax, that's sonething I have seen a lot mentioned but I never looked for it yet and I really hope I can find that here in Finland.

 
It's relatively easy to get in larger quantities, but these will be more than you will ever require for airbrush use, however Badger sell small tubs of it;
 
www.tempera.com are listed as a Finnish Badger distributor, so it might be worth asking them......
  • Member since
    September 2012
Posted by keveuh on Thursday, October 18, 2012 12:52 PM

Well thank you !

About the beeswax I might be lucky because there seems to be a guy living nearby who is a beekeeper so I guess he must be able to get some. I'll try to see with him otherwise I've seen some website here selling some.

I guess it doesn't matter what kind of beeswax it is ? Or is there special beeswax to use or some to prevent using ?

  • Member since
    February 2011
  • From: Monterey Bay,CA-Fort Bragg, NC
Posted by randypandy831 on Friday, October 19, 2012 9:26 PM

Phil_H

I love Tamiya acrylics most of the time, but I dislike the metallics because they have a fairly coarse grain and have a propensity to clog an airbrush in the blink of an eye.

Insufficient thinner and it won't flow. Too much thinner and the metallic particles settle out of suspension very quickly and block the innards of your airbrush. It's worse for gravity feed brushes - with a siphon-feed, you can swish the paint around in the jar while painting to keep the metallic pigments in suspension, but you can't do that with a gravity feed brush (well, you can if you want to splash paint everywhere)

Often, you'll get a couple of bursts of paint and then it stops. If you keep the trigger down but allow the needle to return to the closed position, you may get a brief burst of almost dry metallic particles. Pull the needle back and you'll get a short burst of paint and it stops, release and repeat as above. Time to clean the brush again.

I would use more thinner than you are at present, perhaps 2 parts thinner to one part paint and adjust the mix as required to get a smooth. even flow.

 

i totally agree on their metallics. they have a different grain and AB like total crap. clogging is another problem also. 

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