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Post by hoslotcars on Oct 16, 2016 8:14:54 GMT -5
I have issues with the HS 1-2 and 3 and I find that the silicone is sticking to my master plugs (which are clear-coated) after curing. this does not happen when using other silicones which I will not name, also the silicone (after degassing) is curing too fast and becomes stringy after 10-15 minutes. please advise as I sent emails for help with no response, I am about to just drop alumilite products all together and try glenmarc products. |
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Post by hoslotcars on Oct 16, 2016 8:16:56 GMT -5
forgot to mention that I use the entire container of base and entire bottle of catalyst,
I was informed by carol it is ok to do this.
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Post by Brian on Oct 16, 2016 10:31:46 GMT -5
I may be of some help.......judging by your screen name,we are doing pretty much the same type of pours...you pour 1:87 and I pour 1:25...some of what I pour is quite small...even in 1:25 scale...while other parts take upwards of a 100 Grams or more of resin. I have had issues in the past and made the switch to Alumilite....when I made the switch I had brought some of my bad habits with me that I had picked up along the way....thus some of my experiences where like what you are experiencing with some of my first molds and resin pulls. I have issues with the HS 1-2 and 3 and I find that the silicone is sticking to my master plugs (which are clear-coated) after curing.
also the silicone (after degassing) is curing too fast and becomes stringy after 10-15 minutes.
please advise as I sent emails for help with no response,
I am about to just drop alumilite products all together and try glenmarc products
I have used HS-3 in the past...nothing wrong with it, it is available locally at the brick and mortar stores so it was more out of a convenience for me than anything else....down side ,for me at least, is that HS-3 is too soft of a RTV silicone when pressure is applied on a 2 part, 3 part, etc. etc. mold when pouring resin. What I use is HS-2 ....hard enough as to not deform when pressure is applied as in a multi part mold...I use rubber bands to get the right amount of pressure where it is needed. I have not had any issues with the HS-2 not picking up the finest of detail or issues with undercuts. I have never used HS-1....have not had the need to.
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Post by hoslotcars on Oct 16, 2016 11:26:04 GMT -5
after the silicone is mixed I turn on my vacuum pump then wait for the silicone to expand/collapse 3 times,
then at that time as I try to pour the silicone it wants to setup as the silicone starts to get stringy and clumpy.
I have to abort the whole "pour into mold box" process because of this.
I have used all 3 hs silicones with all the same results and I use the exact same process using oomoo silicones and do not have this issue.
the down side I have to order the smooth-on online as the alumilte I can purchase at the local craft store.
I just want to note that I have in the past received good batches of alumilite silicone and used with great results its just the lately the product seems to be compromised/contaminated during manufacturing.
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Post by Brian on Oct 16, 2016 12:23:37 GMT -5
....unfortunately this forum "ate" a part of my last response when I tried to go back and edit....  What is it you are trying to make molds of where you are using a vacuum pot? That seems to be where the issue is being initiated. I have never had to use one, so I wont be of much help as far as how much vacuum to pull ,etc etc. The only Alumilite silicone rubber products where degassing is either highly recommended or necessary ,from what I can find, is the Trans 40 and Plat 55......so perhaps you are doing something to the HS that was not intended and unnecessary to be done to it. If your kit was compromised/ contaminated then the chances that mine and a whole lot of others would have been as well since it all comes from the same place...on the other hand how long had your kit been sitting in a warehouse and then on a store shelf before you purchased it? Even unopened , this stuff seems to have a shelf life....I order direct and lessen the possibility of getting something that perhaps has been sitting in some hot warehouse for who knows how long and then on to a brick and mortar store for who knows how much longer.....yea the big box stores are convenient, but..... So if the oomoo silicones worked better for you why did you switch?....just curious...I too switched from brand x to brand y then to Alumilite .....if I had found something that really worked for me , I would have stayed with it....just saying. As far as the un answered e-mails......I'm no schill for Alumilite...I am pretty sure that they are in their busy season ...holiday arts and crafts, guys like me staying inside more and working on hobbies with the colder weather upon us...the usual up tick in hobby activity this time of year. Carol and Mike , Im guessing, are pretty busy with their regular assigned duties...have you tried calling yet with your questions and concerns? |
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Post by hoslotcars on Oct 16, 2016 15:10:33 GMT -5
I degass my silicone prior to pouring in my mold box because i pressure cast my molds in a pressure pot.
If i dont degass the silicone and use my pressure pot any tiny bubbles
In the silicone mold will expand and leave tiny bubble impressions in my castings ( i use 2 part mold).
Alumilite does recommend degassing silicones.
As i mentioned i use the alumilite because i can purchase locally.
Still dont know why the silicone is curing much too soon before i can even pour it in my mold box.
I never had these issues using tin cured oomoo 25 silicone,
I chose alumilite because it us less tear resistant and has a longer shelf life but will have to explore other silicones that suite my needs.
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Post by carol - Alumilite Corp on Oct 18, 2016 10:34:16 GMT -5
Hoslotcars,
I just checked my emails I don't see one from you (searching Hoslotcars), please resend and I shall answer immediately. Yes you can use the entire base and catalyst, as I said that is correct Hoslotcars. What pressure are you using, when you degas the silicone? You are correct if you are going to use pressure on the resin it is always best to degas the mold so don't get disfigured replicas of your pieces. You are using the whole container on all 3 attempts, on ratio and mixing well, this is important? Most all silicone's have around a 6 month shelf life, typically the base will show it's age, by being separated or possibly stringy/clumpy.
If you would please call me and let me know when and where you purchased your material. Which is the last one you used to give you the results you spoke of.
Regards,
Carol
800-447-9344
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Post by hoslotcars on Oct 19, 2016 8:55:41 GMT -5
thanks for your help,
Currently using smooth-on tin cured silicones with no issues.
Thanks again.
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Post by mike on Oct 20, 2016 12:08:23 GMT -5
Jumping in on this late hoslotcars, but one other question I had about your vacuum ... you mention you allow it to rise and fall 3 times? Not exactly sure what that means however once the silicone expands/rises to the top and collapses the first time, I normally allow it to go for an additional 1 minute and I remove it from the vacuum. Then I check my mold to make sure it is good and sealed one last time, then pick up the degassed rubber, blow (with my breath) over it to pop any tiny bubbles still on top and pour slowly into the corner of my mold box.
If you are allowing it to rise and fall 3 times, I'm assuming it is being degassed way too long and that the benefit of degassing is already over much sooner.
This will depend on the size of both your pump and chamber. Small pump, big chamber will take much longer to degas.
Eliminating that extra time degassing may eliminate the stringy characteristic of the rubber if its setting up faster than you are use to which as Carol mentioned is a description of potentially older material.
When we degas here, it is typically complete in less than 3 minutes from putting it in the chamber. If mixing takes 2-3 minutes, we are able to pour within 5 minutes on a normal mold/pour.
Mike
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