Devilbiss Aerograph Sprite 63 Air Leaking into Paint Cup

[Harpic]

I am restoring an old Sprite 63 and have installed new air valve assembly which works fine, no leaks and a new nozzle seal. The seal is located correctly as I have checked it using my jewellers loupe which has a miniature LED light. The nozzle is not blocked as air comes through okay. Everythingairbrush (on-line parts Seller and Specialist) can't seem to suggest anything else. So any one here have a clue as to why air is leaking into the paint cup? tested using just water. Thanks guys.

 

[Malky]

Can you put up a picture of your Sprite 63, it seems there several different models and if you just how old it is, that would also help some, one of the usual causes for this could be a build up of paint or debris on the needle tip, it's also important to be sure that the little ring of space between the nozzle cap and nozzle as well as checking that the inside of that cap is also clean, often blacking debris from the tanks of older compressors can build up in there and around the ring, if you look inside the form the back it should look just as polished as the outside.

Among other possible reasons, the nozzle and/or needle could be slightly off center so something else to check, and with the needle out, if you run your finger tip over the nozzle cap you should be able to lightly feel the extreme tip of the nozzle, if yo can't this could mean that the nozzle is to far back and possibly missing a seal around it's threads, if it's a drop in nozzle it may not be seated properly.

As I said put up some photos if you can and let us know if there is bubbling in the cup when you try to run fluid through it, everything I mention here is based on thinking the leak is from the front end, if it is coming form the trigger cavity a damaged seal on top of the valve could be the culprit.

 

[Harpic]

Can you put up a picture of your Sprite 63, it seems there several different models and if you just how old it is, that would also help some, one of the usual causes for this could be a build up of paint or debris on the needle tip, it's also important to be sure that the little ring of space between the nozzle cap and nozzle as well as checking that the inside of that cap is also clean, often blacking debris from the tanks of older compressors can build up in there and around the ring, if you look inside the form the back it should look just as polished as the outside.

Among other possible reasons, the nozzle and/or needle could be slightly off center so something else to check, and with the needle out, if you run your finger tip over the nozzle cap you should be able to lightly feel the extreme tip of the nozzle, if yo can't this could mean that the nozzle is to far back and possibly missing a seal around it's threads, if it's a drop in nozzle it may not be seated properly.

As I said put up some photos if you can and let us know if there is bubbling in the cup when you try to run fluid through it, everything I mention here is based on thinking the leak is from the front end, if it is coming form the trigger cavity a damaged seal on top of the valve could be the culprit.

Pics attached. I t has a new diaphragm/plunger. Nozzle is clear and needle tip can be seen sliding in and out of the nozzle. The tiny bush/gland on the needle is there and fits well. There is no leak around the hose coupling either. Air comes from the nozzle but also bubbles into the cup. Thanks guys much appreciated.

 

[Malky]

Pics attached. I t has a new diaphragm/plunger. Nozzle is clear and needle tip can be seen sliding in and out of the nozzle. The tiny bush/gland on the needle is there and fits well. There is no leak around the hose coupling either. Air comes from the nozzle but also bubbles into the cup. Thanks guys much appreciated.

Thank you, if your are 100% sure everything is clean at the head I am pretty sure that the nozzle sits too far back, this makes me think that there should be seal round the nozzle threads where the nozzle meets the brush, so as a little test try a tiny slither of PTFE tape on there, not too much but just enough to make the nozzle sit a tiny fraction of a milometer further forward, I have a feeling you see a difference by by trying that, if you do it needs a seal or you can just leave the tape on which will do the same job, I had hoped to see it with the needle protector off so I could see the nozzle but I hope this helps

 

[jord001]

I will have a look at my super 63's they have the same front end i have the 0.12 and the 0.66 setups i can post up pics of how it's supposed to look. give me a short while, got to get stuff sorted from camping.

Lee

 

[Malky]

I will have a look at my super 63's they have the same front end i have the 0.12 and the 0.66 setups i can post up pics of how it's supposed to look. give me a short while, got to get stuff sorted from camping.

Lee

You are one super cool dude

 

[Harpic]

Thank you, if your are 100% sure everything is clean at the head I am pretty sure that the nozzle sits too far back, this makes me think that there should be seal round the nozzle threads where the nozzle meets the brush, so as a little test try a tiny slither of PTFE tape on there, not too much but just enough to make the nozzle sit a tiny fraction of a milometer further forward, I have a feeling you see a difference by by trying that, if you do it needs a seal or you can just leave the tape on which will do the same job, I had hoped to see it with the needle protector off so I could see the nozzle but I hope this helps

Pics attached below. thanks once again for your interest in helping this novice..

 

[Harpic]

You are one super cool dude

Thank you so much, I feel so near yet so far..

 

[Harpic]

Thank you, if your are 100% sure everything is clean at the head I am pretty sure that the nozzle sits too far back, this makes me think that there should be seal round the nozzle threads where the nozzle meets the brush, so as a little test try a tiny slither of PTFE tape on there, not too much but just enough to make the nozzle sit a tiny fraction of a milometer further forward, I have a feeling you see a difference by by trying that, if you do it needs a seal or you can just leave the tape on which will do the same job, I had hoped to see it with the needle protector off so I could see the nozzle but I hope this helps

Also small O-ring seals I have thanks.

 

[jord001]

Ok this is the 0.12 not much to see really and slightly out of focus (phone camera lense up against a jewellers loupe) Apart from there's paint in the nozzle which needs cleaning.




This is the 0.66 and is a more focused pic.



Hope this helps a bit, there's nothing to them, o ring on the nozzle and drop them in. the nozzle cap holds them central. This is what you should have on yours.

Lee

 

[jord001]

You are one super cool dude

I try

 

[Malky]

Ok this is the 0.12 not much to see really and slightly out of focus (phone camera lense up against a jewellers loupe) Apart from there's paint in the nozzle which needs cleaning.

View attachment 45228


This is the 0.66 and is a more focused pic.

View attachment 45229

Hope this helps a bit, there's nothing to them, o ring on the nozzle and drop them in. the nozzle cap holds them central. This is what you should have on yours.

Lee

Nice one Lee I found some similar pics on google and saw that it is drop in nozzle, so I am pretty sure that when the nozzle goes in it isn't seating properly and there not sealing, I just had a look at trouble shooting on Don's airbrush tips and his info there seem to confirm that assuming everything at the head is 100% clean, so I think replacing the seal is cure, looking at the front where the nozzle enters the brush itself the there could be a scratch or dent where the rubber meets it which could also be the cause.

If I tag @Don Wheeler maybe he can shed some light on this for us we simply have to get thing thing fixed

 

[jord001]

Good idea Malky. Not a lot to go wrong at the front.

Lee

 

[Harpic]

Ok this is the 0.12 not much to see really and slightly out of focus (phone camera lense up against a jewellers loupe) Apart from there's paint in the nozzle which needs cleaning.

View attachment 45228


This is the 0.66 and is a more focused pic.

View attachment 45229

Hope this helps a bit, there's nothing to them, o ring on the nozzle and drop them in. the nozzle cap holds them central. This is what you should have on yours.

Lee

Yes I do have them, just bought 10 new ones and fitted one. The screw on cap that fits over the nozzle seemed to push against the nozzle a bit and pushed the nozzle with seal into the housing, is that correct? What do the sizes relate to O/Dia of the O-ting seal or thickness there of or?

 

[Malky]

Yes I do have them, just bought 10 new ones and fitted one. The screw on cap that fits over the nozzle seemed to push against the nozzle a bit and pushed the nozzle with seal into the housing, is that correct? What do the sizes relate to O/Dia of the O-ting seal or thickness there of or?

I'm sure the sizes Lee mentions are the nozzle sizes/openings, the 0.12 being super fine and 0.66 being larger, but each will probably have different size ting unless only the tip of the nozzle is different.

 

[jord001]

I think its only the nozzle ends that are different, the o rings fit both sizes. and yes i was referring to the nozzle sizes.

Lee

 

[Harpic]

I think its only the nozzle ends that are different, the o rings fit both sizes. and yes i was referring to the nozzle sizes.

Lee

Sorted. Thanks to Malky for pics I had put the nozzle seal on the nozzle instead of behind/underneath it. Now working 99% Trigger made new one or the new trigger cam piece? I have no drawings or parts list so not sure. Tiny air leakage past the trigger into the nozzle. Got new air valve plunger c/w seal so? But spraying fab. Thanks to everyone for all your help. I have also got my Humbrol one working as adjusted the relationship between air nozzle and fluid nozzle in suction type brush.

 

[Malky]

Sorted. Thanks to Malky for pics I had put the nozzle seal on the nozzle instead of behind/underneath it. Now working 99% Trigger made new one or the new trigger cam piece? I have no drawings or parts list so not sure. Tiny air leakage past the trigger into the nozzle. Got new air valve plunger c/w seal so? But spraying fab. Thanks to everyone for all your help. I have also got my Humbrol one working as adjusted the relationship between air nozzle and fluid nozzle in suction type brush.

Excellent news, the pictures are actually credited to Lee, but he will be just as pleased as I am that you got to the bottom of it, we love success here so we sometimes try to cause it, , when you have your whole arsenal working to your liking please start a thread with photos of everything you've restored, many will be happy to see what you've done and can even learn from it, what your doing a fantastic way to learn your way around airbrush maintenance, I hope you actually intend to use your brushes because if you apply yourself half as much to art as you have to your restoration, you'll do very well indeed

I'm happy as a pig in excremente right now mate, very well done

 

[Harpic]

Excellent news, the pictures are actually credited to Lee, but he will be just as pleased as I am that you got to the bottom of it, we love success here so we sometimes try to cause it, , when you have your whole arsenal working to your liking please start a thread with photos of everything you've restored, many will be happy to see what you've done and can even learn from it, what your doing a fantastic way to learn your way around airbrush maintenance, I hope you actually intend to use your brushes because if you apply yourself half as much to art as you have to your restoration, you'll do very well indeed

I'm happy as a pig in excremente right now mate, very well done

Yes all sorted. Everyairbrush suggested I needed to increase the spring rate of the air valve spring by tightening the screw a little. Working 100% now. and yes I am no artist but doing okay with stencils and even cutting a couple of my own and have done some nice stuff. Starting to airbrush onto my walls at home now...have done a couple of crash helmet restorations where I did the outside of the shells in Crazy Camou freehand no masking no stencils. Thanks again to all and now got 5 excellent for different tasks...

 

[jord001]

Glad you got it sorted. The Devilbiss are a great airbrush. Malky almost brought one a few years back. I got mine cheap and restored them like you have.

Lee