Iwata HP SB Plus airbrush problem

[michaelp]

I was using my Iwata HP SB Plus airbrush earlier and noticed that the paint flow seemed to reduce a bit, this happened until the cup was empty. I am normally ok mixing paints, I only use Humbrol Enamel paints thinned with white spirit. After I had finished I cleaned the airbrush the same way as I always do, later today I went to use it again and I usually blast some white spirit through first before adding the thinned paint but no white spirit would flow through.

I am guessing that the nozzle is blocked but I dont know how to unblock such a small nozzle, it is currently lying in some white spirit.

Any advice would be much appreciated.

Thanks in advance

Michael

[John Tomlinson]

Cellulose thinners is more likely to be successful in softening enamel paint that has dried inside the airbrush. Before you try this, be sure that you are only soaking metal parts, as cellulose can soften plastics.

 

Once the paint in the airbrush is soft, you may be able to persuade it to move by carefully pushing a piece of thin wire through the nozzle - do this very gently to avoid damage and don't apply a lot of force.

 

If you can get the nozzle partly clear I'd then spray cellulose thinner through the airbrush to help clear any residue, then try another soak.

 

From your description it sounds as if this problem may have been building for a while, until you finally reached the point that it blocked. I have an old Badger airbrush, not an Iwata, and do find the cellulose helps deep clean at the end of a session.

 

Please note cellulose is quite harmful if breathed in, and I'm really not being over cautious in saying so. I've had whiffs in the past and it made me feel quite sick. If you are going to attempt the above, I'd suggest you try outdoors, or at worse next to an open window, spraying towards it.

 

John.

[michaelp]

Thanks for your reply John I will get some thinners.

[Mick Bonwick]

Have you tried back-flushing? If the blockage is a small (!) piece of detritus, this will possibly clear it from the nozzle. Don't be tempted to eject the remaining fluid through the nozzle, just tip it out.

 

Are you able to see through the nozzle from the wide end? Remove the nozzle and look through it at a piece of white paper. If you can't see the paper the nozzle is the problem. Sharpen a wooden cocktail stick to a very fine point, soak it in white spirit and use this to poke through the nozzle.

 

If you still have a problem, send me a PM and we can go through several processes to clear this type of blockage.

[michaelp]

Thanks for your reply and the offer of help Mick, before I cleaned the airbrush I put some white spirit in the paint cup, put my finger over the nozzle end and work the trigger back and forth, air bubbles could be seen forming in the cup but not bubbly as usual.

[michl080]

I agree that is may be a good idea to soak the airbrush in thinner, but I don't think the nozzle is blocked. At my Iwatas, the needle sits within the nozzle and peeks out at the front side. So if you can see the needle and move it inwards with the trigger, the nozzle can't be blocked. If you pull the trigger, can you hear the air blow somewhere or is it just completely blocked? The HP-SB has Teflon seals, so if you can't identify the problem, you may submerge the whole device in thinner. However, I would remove the air valve assembly first.

 

Michael

[ColinK]

I’ve had a few blockages too, caused by a build up of dried paint. If I can’t clear the blockage with thinners, I give it a blast from a can of ‘liquid reamer’.  It’s worked every time, but best done outdoors.  Once that has done its work, its been a case of dismantle the airbrush and give it a thorough clean.

 

Good luck.

[Brocp]

Try spraying thinner without the colour cup on, just squirt some in to the side. If it sprays like this, the problem is in the shaft of the colour cup. I've had this issue before.

[michaelp]

I have already tried that, the result is the same but thanks for the suggestion.

[blueeighties]

Just cleaning with thinners is not sufficient and will lead to paint build up over time, resulting in the issues you have. Liquid airbrush reamer is the only really effective way of cleaning deposits. Mick at Durham Trains sells it, or I have some in the workshop you can buy if needed. I can show you how to strip and clean if needed too.

And regarding the previous comment about nozzle blocking not being possible as the needle in it will keep it clear....I'm sorry that's incorrect. We are not talking big deposits here, we are talking of very small specs or build ups of micron thickness. The nozzle and needle combos are so finely machined and toleranced that it takes microscopic amounts to prevent them functioning properly. A good example of this is that whilst looking clean to the naked eye, the airbrush components can still be very 'dirty' and need deep cleaning .

[meil]

The answer is to properly clean your brush every time you finish using it. That is completely dismantle it and clean thoroughly in thinners.

[Mick Bonwick]

28 minutes ago, meil said:

The answer is to properly clean your brush every time you finish using it. That is completely dismantle it and clean thoroughly in thinners.

 

If you read through the complete thread you will see that this has been done on a regular basis. Whilst what you say is true, the way that you say it is not particularly helpful.

[John Tomlinson]

I have no knowledge of Iwata products, and I wonder if new heads can be bought and if so what the likely cost would be?

 

The Badger product I've used for years is now on its second head and second needle, neither of which cost that much, so this could be worth thinking about if all else fails.

 

John.

[John Tomlinson]

13 hours ago, blueeighties said:

Just cleaning with thinners is not sufficient and will lead to paint build up over time, resulting in the issues you have. Liquid airbrush reamer is the only really effective way of cleaning deposits. Mick at Durham Trains sells it, or I have some in the workshop you can buy if needed. I can show you how to strip and clean if needed too.

And regarding the previous comment about nozzle blocking not being possible as the needle in it will keep it clear....I'm sorry that's incorrect. We are not talking big deposits here, we are talking of very small specs or build ups of micron thickness. The nozzle and needle combos are so finely machined and toleranced that it takes microscopic amounts to prevent them functioning properly. A good example of this is that whilst looking clean to the naked eye, the airbrush components can still be very 'dirty' and need deep cleaning .

This is so right. I've had an airbrush head cleaned by simply blowing thinner through it that looks clean and you can see through the nozzle. Then drop it in cellulose thinner and gently agitate and all sorts of bits float out! Scary.

 

John.

[PaulCheffus]

41 minutes ago, John Tomlinson said:

I have no knowledge of Iwata products, and I wonder if new heads can be bought and if so what the likely cost would be?

 

The Badger product I've used for years is now on its second head and second needle, neither of which cost that much, so this could be worth thinking about if all else fails.

 

John.

Hi

 

Spares for my Iwata CR are around  £23 for the nozzle and £9 for the needle. I would think the price for spares for the OP's airbrush to be similar.

 

Cheers

 

Paul

Edited October 4, 2019 by PaulCheffus

[meil]

On 04/10/2019 at 09:33, Mick Bonwick said:

 

If you read through the complete thread you will see that this has been done on a regular basis. Whilst what you say is true, the way that you say it is not particularly helpful.

No it hasn't - it's clear that the brush has not been properly cleaned. Spraying a bit of thinners through the brush is just not good enough.

[Mick Bonwick]

3 hours ago, meil said:

No it hasn't - it's clear that the brush has not been properly cleaned. Spraying a bit of thinners through the brush is just not good enough.

 

The original poster was asking for help, not criticism. All of the other responses offered advice, suggestions and help, while yours did not. You gave us the benefit of your opinion, I have given you the benefit of mine. 

[michaelp]

Just a quick update, the nozzle on my airbrush was found to have hardened paint inside which has now been removed thanks to a suggestion from a couple of members to use liquid reamer, that and gentle persuasion helped remove the paint, another problem with the nozzle was found, where the nozzle screws up to the airbrush the seal between the two parts was not too good. 

Again thanks to another suggestion from an RMWeb member beeswax was carefully applied to the nozzle thread only and screwed in place with only finger tight pressure, and I am happy to report that the airbrush is working fine now.

Thank you very much to all who took the time to post advice and tips and for the offers of help to resolve the problem.