Played around with some fake welds and got something that is pretty close to the N-filter.
I’ll go with something a little thicker and more ripples on the Ion arm.
Welp…This is some bad ass work. I always love seeing actual build threads. Bravo sir.
Im jelly!..
Mega nice work so far!
Did some more work today. Originally I was going to leave the N-filter off the master so people could add their own size,
but the more I thought about it the more I liked the idea of having it cast into the body and since this shell is mostly for me
to play with I went with that.
I like the way the 2.75" N-filter looks so even if somebody wanted to replace it you could cut it off and cover the hole with
the same size or larger.
I started with a 2" pipe coupler and end cap.
The end cap I sanded flat then tilted the edge sander a few degrees and sanded around the edge to get a slightly rounded look. Then I cut a groove around the edge to hold the weld line.
Next I glued the cap and coupler together and drilled pilot holes for the filter holes.
I didn’t drill the holes out all the way because it would be hard to pull a cast out of the mold and this way I have the option
of even or odd spaced holes with little touch up.
Then came the fitting, I have always liked the look of the smaller N-filter, the 3" never really looked right to me.
For the fake weld line I used a hot glue gun with a very small tip and a fan to cool the glue fast.
Without the fan the glue will just flow into a smooth line but if you can cool the glue fast enough you can make uneven
flows and if you go really slow you can even make small weld ridges.
It’s a little easier to see with some primer on it.
The weld line looks more realistic once you paint it and rub some silver on it.
I’m going to do the same thing with the ion arm just thicker welds and more ridges.
More updates as they happen!
I feel like I spent half the day sanding circles!
Almost done making parts, next will be lots of touch up and painting.
Finished the Ion Arm today, the weld is pretty close to what I wanted but it’s hard to make nice ripples with hot glue,
I’ll have to find something else to use in the future to make a smooth flow.
Next up is to make the mold and see how a cast looks.
As always awesome work!
I love seeing clean, crisp shell scratch builds 
Amazing work!
Another small update, finally glued the top and bottom together and got everything primed and ready for a gloss coat.
Hopefully this weekend I can make the mold for the Ion Arm.
Bravo! Great build.
You did an amazing job on this sucker!
:shock: Wow, Stellar work man!
Thanks guys, so far I’m really happy how it’s turning out.
And now more of the ion arm!
First I made a box to hold the master and pour the silicone into.
This box will give me 1/2" silicone on the sides and top which is the minimum thickness I use on vertical walls
that need to hold their shape well.
I use rice to figure out how much silicone I’m going to need.
Next up is preparing the master.
Normally I prime then use a high gloss enamel paint on my masters but if there is detail like the weld lines I don’t
want to fill in with paint I will just prime and apply my release agent on that.
Petroleum jelly is a great release, I usually heat a little up, brush it directly on and wipe it off really good paying close
attention to any areas with lots of detail.
The primer will soak up enough of the release to make it a little like Teflon but keeping a lot of detail.
One thing about silicone is, although it does stick to everything it doesn’t really bond to much, so as long as your master
doesn’t have a porous surface like wood or plaster you don’t need much release agent if any at all.
Now the master is ready to be sealed in the mold box.
Normally any cracks you would want to seal with non sulphur clay to keep the silicone from leaking out but the joints
are really tight so just the petroleum jelly is enough.
Now for the the fun part, making pudding!
I use some Mold Max25 for this project from smooth-on.com.
Normally I get my silicone from aeromarineproducts.com but smooth-on has 2.2lb trial sizes that come out to around
900ml of silicone which are handy when you don’t need very much.
Most silicons are mixed by weight so I use a shipping scale that can do grams and ounces.
And silicone is thick and a pain to mix so bring a strong arm and an even stronger mixing spoon.
I found an old table saw wrench that works well.
The curing agent and silicone are like oil and water so at first they just slide around.
But after a while they will mix just be sure to get the bottom and corners well.
After mixing there will be a lot of bubbles.
It’s not a big problem if you pour it in a slow thin line or if you have a vacuum chamber you can suck the bubbles out.
So into the pot…
And start the de-gassing, works great on marshmallows too.
I usually have to burp it a few times so it doesn’t overflow.
The bubbles don’t start until around 20-25 bars and to really pull most of them out you need a chamber that will get to
Next up I start to slowly fill the box letting the silicon flow around and over the master so I don’t trap any bubbles.
If I didn’t have a vacuum chamber I would have to do a thinner pour like…
The thin line of silicone pulls out most of the bubbles so even without de-gassing you can still get a really smooth
mold.
I fill it right to the top so when it’s flipped over for casting there won’t be any sag.
Most silicone needs to cure at room temperature so keep it above 60f.
After 20 hours it’s time to pop it out of the box.
And then remove the master from the silicone.
Here is where some people freak out and break the master or the silicone mold.
Start on a corner peeling the silicone away from the master, you can also massage the sides of the mold to break
it away from the master, just remember that silicone doesn’t form a bond with much it just grips everything even if you use
release agent.
If the master is something you can’t peel or get a grip on to pull out compressed air works great too.
The silicone will puff up like a balloon and the master usually pops out.
I needed to make a silicone filler for the inside of the mold to save on material and weight, also when using faster
curing resins you need to be careful not to have a large mass of resin or the heat will get out of control and ruin the cast.
A piece of pipe stuck in some clay works as the mold but I was a little short on silicone to fill it all the way to the top.
In cases like this you can use old pieces of the same type of silicone to top it off.
You can even use small shavings in your silicone as a filler for larger projects to save money.
I have seen people use an old meat grinder to make little pieces for mixing.
Finally I added a piece of silicone to hold it in place over the mold.
When bonding cured silicone to fresh I will make sure it clean and cut up the surface a little to work the
liquid silicone into it.
In the next few days I will have more on pulling a cast from it.
Questions and comments are always welcome!
Such neat and professional work. Also I’m highly jealous of your degaser.
Casting time!
And this is how it looks ready for resin.
For this test I’m using Smooth-Cast 310 also from Smooth-On.
It is one of the slowest curing resins they have, this way I can play around with de-gassing the resin before
the pour and not use the pressure chamber.
I used the trial size again which makes about 750ml, great for a test run.
The resins are measured by volume so I’m using my handy solo-measuring-cup.
A while back I got sick of buying mixing containers with measurements on them and ether trying to clean or
throw them away so I made my own cheap system.
Take a clear solo-cup that you will make your marks on and put another cup inside.
Next take an accurate liquid measurement cup and start adding water to your cup in whatever steps you need,
marking on the bottom outside cup at each step.
Now whenever you need precise measurements just drop a clear cup inside your marked cup and fill it to the line.
Saves a lot of time and money.
This mold needs 320ml of resin so I pour 160 of part A…
And 160 of part B.
People have different ways they like to mix but this is how I do it.
I get 3 cups, one for A, one for B and one for a clean mix.
The thinner less viscous liquid goes into the thicker because there will be less waste left in the cup.
After a quick stir making sure to get the sides and bottom dump it all in the third cup and stir again.
The third clean cup mix is to make sure no unmixed resin from the sides or bottom ends up in your mold.
I’m sure some of you have seen parts with odd soft spots that never really cure, this is usually why.
Next is de-gassing.
Normally I use very fast curing resin so I don’t have time for the vacuum chamber but the 310 has a pot life of almost
20 minutes which is plenty of time.
And pouring…
If possible you want the resin to run down the wall of the mold so it doesn’t splash and make more bubbles.
I was just a hair short from topping it off.
And after about 3 hours it’s ready to pull.
Fresh pull!
No bubbles at all!
I did a quick paint and some silver rub on the welds to see how it looks.
Next to the master.
The back.
And i put a few parts on to see how it looks on the shell master.
Yep that works for me!
One big thing I did learn from this project is the slower curing resin is the way to go if you have a vacuum chamber
to de-gass. I did a pour in my bumper mold which is normally prone to bubbles even with pressure casting and it
was pretty much bubble free.
I’m going to try the slower black resin which has a 5 minute pot time and see if that works.
Sometime in the next few weeks I should be starting on making the fiberglass shell for the pack shell, more updates then.
This song plays in my head when I look at this thread.
Thanks AJ, but when did you get time to bust out a rhyme?
:roland:
Beautiful cast! If you use a square plug though you save even more resin and weight
Actually I’m planning on making a better plug later, I was just short on silicone.
And I was impatient and wanted to play with it.
And I was lazy, the piece of pipe was sitting right there.
And, well, I’m a slacker.
There I admitted it.
Slacker would be the last thing I’d call you, you’ve done a fantastic job.