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  1. #1
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    Default What am I doing wrong?

    Over the past 2 months Peter (_fly_) has been helping me - a beginner when it comes to casting pen blanks. After spending 2 hours yesterday, we were not able to determine the cause of my current problem.

    Basically I am trying to cast clear water-slip inkjet decals. Process is
    1. Prime tube using acrylic grey automotive primer (Tube was roughed up with 180 grit paper before spraying)
    2. Spray 1 coat of white automotive acrylic lacquer
    3. Print decal and spray 2 coats with 'rattle can' clear acrylic lacquer (White Knight brand from Bunnings)
    4. Water slide decal and used wet close-cell foam pad to 'squeeze' out air bubbles
    5. Cast with clear polyester resin at 55 PSI in pressure pot over night.

    (Each step was allowed to dry before moving to the next step)

    _DSC3244.jpg_DSC3246.jpgThe problem is that the day after turning there were a couple of small (approx. 2mm sq) silver spots which appearded to be underneath the decal. The pen has been inside the house for 2 weeks since turning and finishing and during this time the silver patches have increased in size and are now 2 -3 cm sq, and growing.The decal does not appear to be effected. Peter had not seen this before and could not offer any suggestions. Our 'best bet' was possibly a reaction between the resin and the automotive lacquer, but we could not come up with any reason why this would be so. There are some small air bubbles seen using a loupe, but these appear to be above the decal and higher up in the resin than the silver blotches.

    I had the opportunity to discuss this with Amos over the phone last night, but it was not something which he had seen and was inclined to go with our best bet of some sort of reaction between the primer, automotive white lacquer, White Knight lacquer, the decal itself or the polyester resin. But whatand how to resolve the problem?

    The thumbnail image on the left is the actual size of the pen (1/2" diameter). The image on the right is about 8x magnified when the 'larger image' is view on my monitor. The pen is cast on a 7mm 'Slimline" tube. The gold blurr showing above the pen adjacent to the top silver patch is the pen clip.

    One question which Amos and Peter asked was why did I cast under pressure? Simple answer is that I had just finished setting up the pressure pot (and vacuum) and wanted to try my first resin casting (Seemed like a good idea at the time.) It seems that casting under pressure was not necessary and leaving over night under pressure was also unnecessary.

    My first thought was that the problem was an air bubble, but now I think not. The image on the left shows 2 stages of the progression of the problem -
    Firstly the fault appeared after a couple of hours as a grey smudge (circled in red) and then progessed to silver spots which have grown into the areas circled in green.

    The image on the right shows the top silver area from a side on angle and I do not see any evidence of a bubble, but it does appear as if there is some breaking down of the clear film of the decal and / or the automotive white acrylic lacquer. (circled in green)

    There is no doubt that I have done some things wrong and I would appreciate any suggestions as to how to avoid the problem in my next attempt. Watching Niel's (Dai Sensei) video again this morning , I am reasonable confident the the mixing of the resing and casting using a resin saver mould is not the cause - 2% MEPK.

    Bob

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  3. #2
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    Default

    The only differences in my method is I use the spray clear acrylic again between steps 4 & 5, I don't cast under pressure, plus I paint on resin over blank before casting.

    Looking at your cast could be two things. The first is the labels used are reacting with the paint and/or resin - what type are you using? The other is that the pressure is causing the tube to flex some how debonding the transfer.
    Neil
    ____________________________________________
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  4. #3
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    Quote Originally Posted by dai sensei View Post
    The only differences in my method is I use the spray clear acrylic again between steps 4 & 5, I don't cast under pressure, plus I paint on resin over blank before casting.

    Looking at your cast could be two things. The first is the labels used are reacting with the paint and/or resin - what type are you using? The other is that the pressure is causing the tube to flex some how debonding the transfer.
    Thanks Neil. Resin is Nuplex Clear Ortho Casting Resin and decal is Clear Water slide decal for inkjet printers from Renascent College in Warrandyte.

    Using the clear spray between steps 4 & 5 was something discussed in my conversation with Amos last night. It seems that you, Amos and Peter are unanimous in respect of not using the pressure pot for these casts.

    Am I correct in assuming that resin painted on the tube before casting does not have to 'set' before the resin is poured?

    Bob

  5. #4
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    Can't say I am familiar with that brand of decal sheets, it is always worth doing trial runs to see how they react, I tried quite a few before settling on a brand that worked. If other recommended that brand I'm sure they would probably be OK. I can't remember what brand I used to be honest in the end.

    Quote Originally Posted by Oldgreybeard View Post
    Am I correct in assuming that resin painted on the tube before casting does not have to 'set' before the resin is poured?
    I used the catalysed resin painted on, I always worry about un-catalysed in case it doesn't go off, painting it on ensures it is completely covered in resin thus minimising the chance of entrapped air on the tube.
    Neil
    ____________________________________________
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  6. #5
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    Quote Originally Posted by dai sensei View Post
    Can't say I am familiar with that brand of decal sheets, it is always worth doing trial runs to see how they react, I tried quite a few before settling on a brand that worked. If other recommended that brand I'm sure they would probably be OK. I can't remember what brand I used to be honest in the end.
    Peter (_fly_) has used the decal sheets from Renascent College, but only the type for use in Laser printers.

    Has anyone used the inkjet version from Renascent College or is there another brand that they would recommend ?

    Thanks
    Bob

  7. #6
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    I had the same problem and unable to solve it. I have moved away from waterslide decals for clear casting and moved to vinyl paper. Have great results with it. I to use a pressure pot for air bubbles and never had an air bubble in a cast as the bubbles move to the surface. No need to worry about painting tubes either as the vinyl paper is white and self adhesive.

  8. #7
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    Quote Originally Posted by daryl1 View Post
    I had the same problem and unable to solve it. I have moved away from waterslide decals for clear casting and moved to vinyl paper. Have great results with it. I to use a pressure pot for air bubbles and never had an air bubble in a cast as the bubbles move to the surface. No need to worry about painting tubes either as the vinyl paper is white and self adhesive.
    Thank you Daryl.
    Can you print on the vinyl paper with standard Canon inkjet cartridges?
    Do you need to use a clear sealer over the vinyl paper print to isolate it from the poly resin?
    What brand of vinyl paper and where do you buy it?
    Bob

  9. #8
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    Looked mine up, see here http://www.decalpaper.com.au/inkjet-decal/clear/

    I also got their white ones too
    Neil
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  10. #9
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    Yes, your Cannon inkjet printer will be fine. Just print using the highest quality setting. No need to seal the paper after printing. I get my paper from the same supplier that is posted on your inquiry by Neil (decalpaper.com) in Redfern, Sydney. They are very prompt. If you like to pm me I will give you some tips and tricks for using the paper. It is very easy to use.

  11. #10
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    Quote Originally Posted by daryl1 View Post
    ..No need to seal the paper after printing...
    Actually, with the ones I use if the decals are not sealed (as per instructions on packet), they can smudge when wet for transferring
    Neil
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  12. #11
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    I don't use the decal (waterslide paper) paper anymore. Just the vinyl paper which has a clear plastic peel off backing. I never have any problems with smudging as the ink dries quickly and the resin doesn't have an affect on the print. I copy and paste the image into Microsoft Word text box for resizing to fit the brass tube. You can also change the background colour if you wish even though the vinyl paper is white, I still create a white background as it is a little crisper. Before printing check which way the paper goes into the printer tray. My printer, the paper goes in with the print side down. Even if you print on the clear backing, no problems, just turn the paper over and print again. Only loss is some ink that has been used. With vinyl paper np more dunking in water to separate from the backing, just peel off. I use Diggers clear casting resin and catalyst from Bunnings.

  13. #12
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    Thanks again to Daryl and Neil.

    At this point I think that the best move would be to try the decal supplier you both have used. I am unsure as to whether I should continue with the clear paper as opposed to the solid colour background that you are using, Daryl.

    What I am looking to do (apart from the current pen which is for my daughter's 50th birthday) is to print images for promotional pens.PaulsDragUte.jpg

    Such as this image, which they want on the Bullet Pen. The problem I anticipate is that the image (which is supplied by the client) will not necessarily be in the correct aspect ratio to suit the pen blank and they may not really want a white background. Sure I could get around this in Photoshop, but that's just another process which has to be done.

    Probably will have to do some more work in Photoshop for this one as they are now talking of having a 'chequered flag' background . They propose to hand the pens out to sponsors, etc.

    Any thoughts would be appreciated.

    Bob
    Last edited by Oldgreybeard; 13th May 2015 at 06:12 PM. Reason: Deleted duplicate word.

  14. #13
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    Default silver bubbles

    the silver bubbles are a result of the resin not adhering to the surface below, often it is caused by early removal of blanks from the mould (whilst the resin is soft and slightly flexible) or you touched the blank and oils from your fingers prevent the resin from sticking

    If you paint the resin on first you can sometime over come this and provide a better surface to cast onto.

    Personally I just use adhesive vinyl paper

  15. #14
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    Quote Originally Posted by salty72 View Post
    the silver bubbles are a result of the resin not adhering to the surface below, often it is caused by early removal of blanks from the mould (whilst the resin is soft and slightly flexible) or you touched the blank and oils from your fingers prevent the resin from sticking
    Thanks for the advice - you could be right on both counts.
    Even though the blanks were in the pressure pot for about 14 hours the temperature in the shed would have been down to less than 10*C overnight in Melbourne. The top of the blanks was slightly 'sticky' when I removed them but not so the sides or bottom.

    I did not wear gloves when I applied the transfer or when inserting the tubes into the resin saver moulds and there is a corelation with the area of the silver patches and where I would have been holding the tubes when inserting them into the molds. In all the videos I have viewed on this subject, I have not noticed any of the presenters wearing gloves other than when mixing the resin and catalyst. Is it normal to do so or how do others ensure that oils from thier hands do not contaminate the surface?

    Bob

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