jerry
New Member
Posts: 14
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Post by jerry on Dec 10, 2017 14:51:33 GMT -5
I'm building a steering wheel from scratch, making the steel skeleton and the two piece MDS molds. Of course when I finish the mold halves I will varnish then clearcoat the molds. Before pouring I will not only use a quality mold release but dust with powder too. Now for the question. I'm scared about getting bubbles in the casting. Will be using the slow set 15 (tan) with a mold volume of abut 72 cubic inches. Should I hold the mold vertical and pour the resin in from the top or poke four holes and pour horizontal?
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Post by mike on Dec 14, 2017 8:22:41 GMT -5
I would pour vertically but any way you do it, you will theoretically have a negative draft or flat area that could hold air bubbles.
My first suggestion is to pour a wheel with NO ARMATURE in it. Just pour a straight resin wheel. Yes, this is a test piece that will likely be scrap however what you learn from the first piece will significantly help you understand the best way to pour it when the armature is in it.
How I'd approach the first one is to pour vertically (almost like it is pictured but turned slightly left) so the arc on the inside are vertical as well. I would also clamp the bottom half and flex the top side open to make it easier to access and pour. Then tilt the mold a little flat (45 degree angle) and allow the resin to pour out of the mix bucket right on to the mold surface ... like you pour a beer into a tall glass to avoid a big foam head on it. This avoids the stream out of the bucket from cascading down and making air bubbles as it hits the mold ... like the bottom of a waterfall.
Once you've poured it half way up to the opening, stop pouring, tilt and tap the mold to get any trapped air moving up to the top. Then continue to pour and close the mold, pour and close the mold until you are all the way to the top. I like to continue to over pour the mold (yes its messy) but ensures nothing but resin is in the mold and then quickly clamp the top and allow to cure.
That is how I would approach it.
Mike
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jerry
New Member
Posts: 14
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Post by jerry on Dec 15, 2017 18:02:59 GMT -5
Mike, I like your suggestion of a test pour. What I intend to do is bolt both halves together in several spots to insure no leakage. This will also help with thumping half way thru the pour to insure no gaps open up. With a test pour I'll also be able to tell if both halves line up correctly. Way I figure it I'll only have about a 10 minute window to get the entire pour done because the amount of resin I need will generate it's own heat and speed the process. The curved spokes will not get resin and I intend to seal those areas with clay. I'm going to start practice pour this afternoon with a beer or two or...'till I get it right!
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jerry
New Member
Posts: 14
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Post by jerry on Feb 23, 2018 18:12:49 GMT -5
Been a while, weather is warming a bit and have been working on the molds for the steering wheel. I have made a "half pipe" mold to test pour before doing the real wheel. Notice the steel half wheel has bumps welded to half the wheel and the other half is smooth. I did this to see if the resin would separate from the steel core if twisting is applied (road rage?). Both sets of molds have 4 coats of urethane clear coat and of course mold release will be applied before the pour. Question is where should I pour from? I intend to have the molds clamped together and set vertically. Should the entry point be between the spokes (short part of outer wheel) or at the top where the spoke spacing is largest? Worried about trapping air in the little pockets where the spokes meet the outer wheel. Attachments:
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Post by Admin on Mar 2, 2018 13:37:19 GMT -5
Hi Jerry, Pour from the shorter segment between the spokes. Follow Mike instructions for filling the mold beginning with the mold on a 45 degree angle. This will be your best bet at not trapping air. Thanks, Don
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jerry
New Member
Posts: 14
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Post by jerry on Mar 4, 2018 17:51:17 GMT -5
Today I did a test pour on the half wheel. Learned several things. Need to spray the release on the entire mold not just the part where resin is SUPPOSE to go. Need more clamping force all the way around which means I'll drill lots more holes and bolt the mold together in about 10 spots. Outside temp was 75 degrees F and 17% humidity but the resin didn't set as fast as I thought it should. I demolded it after 4 hours and it's still very soft. Is that normal? Attachments:
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Post by carol - Alumilite Corp on Mar 7, 2018 20:05:00 GMT -5
Jerry,
Did you warm the mold itself, that definitely would help. It looks like your using white resin and that often can take a bit longer then the tan AlumiRes RC3. Obviously it has been more than 4 hours now did it cure all the way? If you would like to give me a call or email me, carol@alumilite.com, I would be happy to get your number for a young man who has done so many steering wheels and is always been happy to help others with any issues they may be having. He has had trials and tribulations over the years with steering wheels. This is a bit more complex application than many of the others that can be done with molds and resin casting.
He has encounter and over come most of the obstacles with the steering wheel.
Regards,
Carol
800-447-9344
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jerry
New Member
Posts: 14
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Post by jerry on Mar 11, 2018 9:48:18 GMT -5
Think I found the problem. I mixed A and B together by weight and not volume. I'll look around the shop for something simple to mold and see if things turn out better.
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Post by carol - Alumilite Corp on Mar 12, 2018 7:50:54 GMT -5
Good to hear Jerry,
I hope that the contact I gave you was valuable, did you see pictures?
Regards,
Carol
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jerry
New Member
Posts: 14
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Post by jerry on Mar 12, 2018 8:57:01 GMT -5
Sorry Carol but the contact just goes to voice mail and no return call yet.
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jerry
New Member
Posts: 14
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Post by jerry on Mar 12, 2018 19:27:59 GMT -5
Well I'm not doing well! Did a test cast today, made a matchbox car mold in proto-putty (silicone) then mixed 50/50 Slow Set 15 by volume mixed well and gently poured. While the resin was still transparent I could see bubbles forming. After two hours the resin had set enough to de-mold but the bubbles has risen to the surface and almost created foam. Not sure if I'm using the wrong stuff or having a reaction to the silicone. Any inputs?
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Post by carol - Alumilite Corp on Mar 14, 2018 14:41:56 GMT -5
Jerry,
That looks like moisture from something or somewhere Jerry. How old is the resin Jerry?
I will see if I can contact him for you.
Regards,
Carol
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jerry
New Member
Posts: 14
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Post by jerry on Mar 14, 2018 23:31:22 GMT -5
Carol, I think you are correct about the moisture. When making the proto-putty mold it's necessary to "cure" the silicone with water and I think it may have still been damp. Good eye. Thanks. Do I need to degas the Slow Set 15?
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Post by carol - Alumilite Corp on Mar 16, 2018 15:27:43 GMT -5
If you have the equipment to do that yes I would you have plenty of open time in the Slow Set 15, Jerry.
Have a wonderful weekend Jerry and to all in the forum. See you Monday!
Regards,
Carol
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jerry
New Member
Posts: 14
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Post by jerry on Mar 24, 2018 10:05:03 GMT -5
Well, here it is. When I did test cast there were some problems. First, test of small pieces took hours to set up enough to de-mold, and foaming was caused by water in the mold. Learning process. When I calculated the amount of resin necessary I kept adding to err on the side of to much resin. This included the diameter of the cast, how long it was and just for good measure add some more. You can see by the picture the "puck" that was left over. One more thing, with 48 oz of resin mixed it heats up quickly and thereby speeds up the set time greatly. I tested the heat of the "puck" and it was 165 degrees. If you have ever done body work and used Bondo you will understand how, after mixing, it spreads just fine and all of a sudden it's unusable. Now I have to sand and polish then figure out exactly how to do the hub with horn button. The hub of a '39 is square just to make things a bit difficult. Attachments:
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