First Time; BUBBLES!!! ARGH!!!

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randyrls

randyrls

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Feb 2, 2006
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Well I decided to do a pen with stamps for our two sons (they both work for the Post Office). I wanted to embed the stamps under resin. I tried but don't like the PSI technique of pasting the stamps to a wooden tube.

Well my first casting attempt has numerous tiny bubbles in the finished cast. The bubbles extend all around the blank. I used Castin Craft from the local Michaels.

I glued the stamps to the tube, and sprayed it with several coats of clear acrylic lacquer as sealer. I allowed to dry to two days before casting.

The casting went OK, and I was careful not to stir any bubbles into the resin. 4 drops of catalyst to an ounce of resin. Painted the tube and stamps with resin to make sure that no voids were created.

I am thinking that I may need to gently warm the tubes and stamps before casting. The blank has very small bubbles all around the tube just above the surface of the stamps.

I really don't want to go the whole pressure pot and compressor route.

Any ideas on what I did wrong are appreciated.
 
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Randy,

Do as Mannie said and heat your PR in a hot water bath to make it water thin. Then you bubbles will completely disappear. You don't NEED vacuum or pressure for PR. Pressure will ensure no bubbles but it is in no way required.

I don't worry about mixing bubbles into it either. With the resin so water thin, the bubbles almost jump out.....

Just look close to make sure you don't have bubbles form on the stamps themselves during the pour. Have a sharp poker available to pull any bubbles that do form to the surface before the PR gels.

Good luck!
 
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I made a pen for our mailman when he retired. I didn't want to play with casting at that time so I applied stamps to a painted tube then built it up with CA. (over 100 coats) Turned out great but if I had to do it over I would glue a tube in a piece of wood then turn it down to just under size, apply the stamps then finish with CA.

I wish I had pictures but it really did happen.
 
PTownSubbie said:
Randy,

Do as Mannie said and heat your PR in a hot water bath to make it water thin. Then you bubbles will completely disappear. You don't NEED vacuum or pressure for PR. Pressure will ensure no bubbles but it is in no way required.

I don't worry about mixing bubbles into it either. With the resin so water thin, the bubbles almost jump out.....

Just look close to make sure you don't have bubbles form on the stamps themselves during the pour. Have a sharp poker available to pull any bubbles that do form to the surface before the PR gels.

Good luck!
Click to expand...

Fred is right on the money. But here are the steps i would take before the casting process.

1. paint your brass tube(ie: powdercoating it or spraypainting it)

2. next apply your stamps in the desired pattern

3. apply a nice thin layer of CA over the stamps using either Thin or Medium. Allow to dry for approx 2 days or place in toaster oven on 150(this must be checked w/ a thermometer for accuracy, you dont want the temp much higher than that) for about 20 minutes and then you should be able to get away with 1 day as opposed to 2. (just my experience. and may not work for you)

4. As Fred and others will say, do a warm water bath however you prefer. I use an ultrasonic cleaner with the heat setting which is generally around 140-160 degrees for around 8-10 minutes. Apply your 4 drops of MEKP per oz and stir for about 30 sec mixing thoroughly.

5. Then of course put them in the molds and pour your resin. I use dental picks to manipulate the bubble from around the tubes while they are in the molds. If you are using Freds molds, you may even be able to rotate the blank using the plugs while it is in the mold which will help tremendously!

Hope this helps!
 
I to use a dental pic with a curve on it when casting materials around tubes. I watch and watch it. For me it seems that there always bubbles that want to come out as it begins to get thick
 
Hundreds of casts....Bubbles!!! ARGH!!!! But not as many as I had at the beginning. You have received some excellent advice...Don't think I can add to it except for one: Do pay attention to the acvice...
Do a good turn daily!
Don
 
All good advice. I am new to casting. I have made 3 sets of Sierra tubes with resin saver molds. The first thing I did was put my cup of resin in a cup of hot tap water and let it sit while I was setting everything else up, at least 5 minutes, usually a little more. Then mix and pour. I had no bubbles in all six of the tubes. I did destroy the artwork on some of the tubes, but that is another problem for posting.

Morton
 
Thanks for the advice. I went to the local Woodcraft and purchased a couple extra sets of tubes. Painted the tubes white and will heat them to make sure they are completely cured. Made a holder for the cups I use for the resin so I can dunk them in hot water.

Thanks again.....
 
Randy, if you plan on doing a lot of casting then watch for a sale on the jewelry (sonic) cleaner from Harbor Freight. It has vibration and heat. I think I got mine for around $40 with coupon and sale.
 
randyrls said:
Thanks for the advice. I went to the local Woodcraft and purchased a couple extra sets of tubes. Painted the tubes white and will heat them to make sure they are completely cured. .
Click to expand...

Just be sure you understand that 'dry to the touch' does NOT mean
that it is cured. Until it is cured, it can still react with other things like
resin. Evaporative cure stuff (like water based paints) may cure by
drying. But anything solvent based, you should read the instructions
carefully. Dry isn't enough.

Lacquer is a great example of this. Dries to the touch in minutes, takes
weeks to cure. There's still a lot of activity going on there even though
it feels dry.
 
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