The Kilns first burnout

Just as I thought, the new kiln made a huge difference. It was also a lot less time consuming not having to go constantly check  on it like the older one. The FTX  Cast results were superb! by far the best casting. the FTX Green resin on the other hand was not  that great.

FTX Cast

FTX Green

Despite the FTX Cast,working so well, there are a few disadvantages to printing using this resin such as it being very brittle and breaking very easily as well as it taking double the amount of time to print. I am finally seeing some light at the end of this tunnel.....I am hoping to get the FTX Green resin to the same finish as the FTX Cast.

New Kiln

I have just purchased a new Kiln, its a whole 2.1kw more powerful than the older one. This means that I will be able to get to the required temperatures a lot faster. This kiln is also programmable so I am able to preset the required temperatures/times giving me a more accurate result. Cant wait to try it out!

Inaccurate casting results

After weeks and weeks of casting, I feel that my results are inaccurate. This is due to me using an older manual Kiln that isn't able to 'hold' at specific temperatures for the required period of time.
Initially I felt that the old kiln would suffice as the workshop does its fair share of lost wax casting and it worked perfectly, however I now feel the need to purchase a new as resin casting needs requires a more accurate burnout.

Whats the investment?

After some browsing on the TDM forum, I saw that a jeweller used 36 parts water to 100 parts investment (Plasticast). I decided to give this a try as well as use the existing investment powder used for normal wax castings.

The results are as follows : (Normal Investment Powder)

 

(Plasticast Investment 36:100)

 

 

The normal jewellery investment powder cast very similarly to the Plasticast Investment powder which means that the investment powder might be the problem.

 

Same old, same old (burnout)

After realizing that the resin can only cure to a certain point (colour doesn't change) I decided to have a go with the burnout. Instead of doing a quick 2 hour burnout I decided to do the usual burnout that we did in the workshop (6 hour)

As you can see, it was a complete failure as the shape didn't even cast properly. cant help but feel that the investment powder cant handle the heat of the 2 hour burnout, causing it to cast bad surfaces.

Reaching Boiling Point

After attending the Jewellery council meeting the other night, I was advised to try boiling the resin in the microwave as the usual problem with resins was it absorbed to much of moisture whilst being invested which caused it to swell during burnout hence distorting the casting due to the investment sometimes cracking. I decided to see the difference between just using the UV curing station and boiling it in the microwave.

Both pairs of earrings were cured for 23 hours

Flask 1 - contained just the cured earrings while Flask 2 - was UV cured as well as boiled in the microwave for 150 seconds.

Flask 2 results were better than the casting I had done the previous day however I feel that it didn't help much in terms of the finish.

Flask 1 results were better than flask 2 but there is still the need to cure porosity....I think I should gradually drop the temperature next time.

Flask 2 (results) :

 

Flask 1 (results) :

 

 

UV Curing Station

I have finally tested out my new and improved UV station. It seems to have worked well as it is exactly the same colour as the initial test in the printers curing station. the single earring at the top of the image was the initial cure done in the ProJet.

I was extremely lucky that I made the UV curing station when I did because the one in my printer has just stopped working. I have tried replacing the bulb but it still refuses to switch on. The printer will have to go back to the authorized reseller sometime next week to see what's wrong, however I am still able to continue printing with the machine in the interim.

Dehydrating Light

After flashing the piece 20 times, and having to come back and switch on the curing unit every 10 minutes, I decided to invest in a little curing station. I purchased a biltong dehydrator because that is essentially what flashing does, it removes all the moisture from the resin.

 

I left a freshly printed pair of earrings in the dehydrator for 24hours and didn't see the result I was hoping for. The UV light actually sped up the process and if I kept using the 40w bulb that came with the dehydrator id have to wait for over 2 weeks for it to cure properly. The addition of UV lights were needed in my dehydrator.

 

 

Above are images of the new UV lights  installed in my dehydrator

 

20 Flashes

After reading that the pieces need to be cured more, I printed and flashed 20 times (200 minutes) in the ProJet's curing chamber.

There is a noticeable colour difference between the previous prints that were cured for just 2 cycles


 I also read about investing the flask and letting it sit for 20 min before putting it into a preheated kiln (1700'F)  and doing a 2hour burnout as opposed  to 6 or 8. So I decided to give it a try.

Initially I had forgotten to put the flask in, it was put in after 60 min which resulted to the investment exploding in the kiln.

I then re-invested and put it in the pre-heated kiln after 20min. There was no explosion, thank God.
These are the results

 

I found that the surfaces are porous, maybe I need to cure for longer?

Curing the Resin

Getting extremely frustrated with the casting not working well, I decided to sit and do some homework as to where I am going wrong because these resins were cast in my workshop before and even the green resin wasn't as bad as my current results. After spending a while looking at trouble shooting forums, I stumbled across a TDM forum, this forum was compiled of problems and solutions involving 3D printing and casting. After reading for a bit I noticed a member talking about how the piece needed to be cured for a longer amount of time.

 

Maybe this was were I was going wrong? because I was told that I only needed to cure for 2 cycles.

Printing Rings Sideways

Having my printing and casting done by a company in Johannesburg, I noticed that they always print rings to the side as opposed to upright. After questioning why this was done I was told that it is a time saving technique that they use when printing as it saves more than half the time printing it on its sides as opposed to upright.  I decided to give this a try.

 

As you can see from the pictures above, it was not a successful print. This had happened to me before at design@50 and the only way to overcome this was to add a 5 degree angle to the article being printed.

 

After printing with a 5 degree angle of the ring, the print was a success.

Back to the Green

Having had so many problems with the FTX Cast resin and its cartridges, I decided to go back to printing using the FTX Green resin as I found it less problematic as well as not having any other cartridges of the Cast resin. The pendant was printed in parts and then cast.

 

The prints were successful it just needed to be invested and cast

 

After an 8 hour burnout, these were the results. it was a better cast than before however it was still horrible. Extremely frustrated that the casting isn't working out.