OP
OP
Both of the Meguair's I mentioned are car polish compounds I believe.
Acrylic Fabrication Q & A
- Thread starter Turbo's Aquatics
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TherealplexiG
Well-Known Member
@Floyd R Turbo
I might have missed it here or the other thread. If you have spaced the baffles 2" or 3" apart, how do you get to the middle baffle after bonding it on the first side (front pane), if there are 3 inline? How do you reach middle baffle while gluing the front and side assembly to the back. If you know am sayin?
Although i read the post thrice stating about setting up a fence for routing the edges. I was not been able to understand, how do you set it all up fair and square?
I might have missed it here or the other thread. If you have spaced the baffles 2" or 3" apart, how do you get to the middle baffle after bonding it on the first side (front pane), if there are 3 inline? How do you reach middle baffle while gluing the front and side assembly to the back. If you know am sayin?
Although i read the post thrice stating about setting up a fence for routing the edges. I was not been able to understand, how do you set it all up fair and square?
OP
OP
Yup, that can be tricky.
Generally what I do is first, bond one end panel to the front as that is the important joint.
Then I set up the up/down triple baffle to bond all 3 at the same time. I put the pins in the 2 outer baffles and look at the center one to see if there is enough of a gap in there where I can leave it unpinned. This is not always the case, usually because in order to get one of the outer baffles to hold the pins in right, I have to add weight. Sometimes, the baffle touches at one end and has a gap on the other, sometimes it's sitting with so much of a gap I can't run solvent in that at all (and even if I could, it will splash out bad when pulling the pins).
You have to take this scenario as it comes. If the gap is tight, I add a pin at each end and then I run solvent on the center baffle and pull the pins, then I run the solvent on the other 2 baffles and pull. An of course, make sure the baffle edges line up with the bottom edge so that I don't have to scrape a bunch later. And usually, add a ton of weight to make sure the joints are clear (this can be tricky with baffles close to each other)
If the gap is loose, then I will run solvent on one outer baffle (usually closest to the bonded end panel) and pull the pins one at a time while leaving pins positioned at the ends of the center baffle, watching those closely as I pull the pins, and they will usually "seat" as I pull the outer baffle pins. Sometimes you can pull all but one pin on the outer baffle, runt he solvent in the center one quick, then pull the pins and let it settle in, then run the 3rd baffle.
Usually, until you run both outer baffles and pull the pins, the center baffle will "float" so you have to plan this out ahead and move rather quickly.
The other option to all of this is to run the 2 outer baffles normally (but at the same time) and then just wick in solvent on the center baffle to essentially tack it in place. It will look bad but this baffle only serves to direct water under it, there's no pressure on it, so it's not a structural joint. If you don't care what the joint looks like, then don't fret it. Just make sure that is the back side joint so you don't see it all the time
TherealplexiG
Well-Known Member
Thanks Mr. Turbo,
I kinda get it, and would surely experiment the above stated practically. I know it aint no one sure way to skin a pig.
Adding weights to get a clearer bond would warp the outer surface (the back panel) inwards to some extent compromising structural integrity. You sure about it?
I kinda get it, and would surely experiment the above stated practically. I know it aint no one sure way to skin a pig.
Adding weights to get a clearer bond would warp the outer surface (the back panel) inwards to some extent compromising structural integrity. You sure about it?
OP
OP
No this is not true, if the 3 panels are the same dimension. We're talking about micrometers. Distances that matter when bonding, but don't make a difference after that (not visibily noticable)
OP
OP
Set up a rigid fence that is a distance from the router bit that is approximately the width of the piece you are performing final edge prep on. Pass the panel between the fence and the router bit.
TherealplexiG
Well-Known Member
I rephrase it, How do you set the fence square? Because it should be dead on, can't give it any excess tolerance. As i understood one blade is little bit bigger than the other one on the router bit. so how do you measure the distance from the bit to the fence? and how do you set it square at 90 deg angle. It would be so easy to explain in person, might take a few seconds. Its difficult in words.
OP
OP
You don't need to square any fence. I was looking for a pic to explain it but can't. You don't have a fence or anything around the router bit. The position of the fence opposite the bit is not relevant, because whatever piece you pass between the fence & router is riding against the fence on that edge and the other edge is on the router bit getting cut, meaning once the pass is complete, by default the 2 sides are parallel (perfectly).
So what you do it rough cut all of your pieces then pass them all one by one with the fence at the same position for the initial cut. Then you bump the fence a bit, flip all the pieces, and make the next pass. Repeat this a few times with smaller and smaller adjustments until you are at your desired final dimension.
So that's parallel edge prep. But what you are asking about it squaring - that is completely different, but you only need to get 2 edges square with respect to each other, and the fence technique takes care of the others. For squaring, I use a jig that attaches to one prepared edge and then forms a perpendicular reference edge to one side, which rides along the fence in the setup described above and forces the router to therefore cut an edge parallel to that fence, and thus, perpendicular to the edge the jig is riding on.
My "jig" is nothing but a squared part that has a notch cut along one edge with another piece of acrylic bonded to it, then I double-stick-tape that to the project piece. No fancy sled for this guy.
So what you do it rough cut all of your pieces then pass them all one by one with the fence at the same position for the initial cut. Then you bump the fence a bit, flip all the pieces, and make the next pass. Repeat this a few times with smaller and smaller adjustments until you are at your desired final dimension.
So that's parallel edge prep. But what you are asking about it squaring - that is completely different, but you only need to get 2 edges square with respect to each other, and the fence technique takes care of the others. For squaring, I use a jig that attaches to one prepared edge and then forms a perpendicular reference edge to one side, which rides along the fence in the setup described above and forces the router to therefore cut an edge parallel to that fence, and thus, perpendicular to the edge the jig is riding on.
My "jig" is nothing but a squared part that has a notch cut along one edge with another piece of acrylic bonded to it, then I double-stick-tape that to the project piece. No fancy sled for this guy.
OP
OP
quick paint drawing
OP
OP
Quick paint drawing #2
I called arkema today and spoke with someone about the differences between Plexiglas g and pmacs. first, she did confirm plain paper is pmacs. she also said pmacs does not have the same tolerances as Plexiglas g but she would not expand on that. so I guess I didn't really accomplish anything. lol.
OP
OP
I use a polished laminate then spray on furniture polish. Lemon scented. Makes it smell lemony fresh and the surface is slick enough that paper masked acrylic slide across it like an ice cube.
OP
OP
My understanding is that PMACS and Plex-g come off the exact same line at the exact same factory. Once the sheets are tested, if they are under the passing line for G but still "good enough for government use" then they stamp them for PMACS. Things like:
Thickness variation out of tolerance
Black flecks
Surface variances (blemishes)
Bubbles
Clarity (fogginess)
Think about it like this. In a microprocessor factory like AMD, they will produce single, dual, and quad core. Now anyone who knows enough about AMD (at least, a few years back) when you want to overclock and things like that you can also unlock additional cores on a dual core. This is because they (at least used to) produce the quad core and dual core processors on the exact same factory line, it's just that one or two of the cores didn't test up to spec. So they lock those cores and sell it as a dual core, which means they don't have to have 2 production lines and they don't have wasted product. Most of the time they will all test fine and they just lock 2 cores because the need to have dual core in stock and they don't want 2 production lines. While this example might not be wholly accurate, it's just for comparison/explanation.
PMACS and G come off the same line. It's just a way of not wasting what most would consider perfectly good product. G is considered to be Museum Quality and comes with a guarantee. PMACS is not and does not. The difference is usually negligible, and considering that in order to get that warranty honored if you don't buy $100,000 worth of G per year, you would have to completely unmask a full sheet and inspect it for flaws before you touch it with so much as a razor blade before they would honor the warranty for you...it's like the Tommy Boy line "Hey, if you want me to take a dump in a box and mark it guaranteed, I will" not saying G is junk, but the guarantee is, to the lay person.
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TherealplexiG
Well-Known Member
@Lowell Lemon
@Floyd R Turbo
I have to make these octagonal cubes size 12 inch, 15 inch and 20 inch. Render attached.
the thickness im gonna max out is 10 mm, coz those tanks would be hardly filled upto the brim, i can do that on a strip heater and let it cool on a form as you had mentioned. Whats the form like, is it made of wood? How are the cavities (Male female type)? and lastly where does the end meet and when to put a bevel there?
@Floyd R Turbo
I have to make these octagonal cubes size 12 inch, 15 inch and 20 inch. Render attached.
the thickness im gonna max out is 10 mm, coz those tanks would be hardly filled upto the brim, i can do that on a strip heater and let it cool on a form as you had mentioned. Whats the form like, is it made of wood? How are the cavities (Male female type)? and lastly where does the end meet and when to put a bevel there?
Lowell Lemon
2500 Club Member
@TherealplexiG ,
You will need seven strip heater zones with a wood form to the inside dimensions of the finished parts to wrap the sheet around. If you want to minimize the seam appearance you should seam at one of the bevels (22.5 degree) estimated by looking at your drawings. CR Clark makes the best heater set ups with multiple heat zones but they are expensive. However the CR Clark machines would give you thebest results.
You will need seven strip heater zones with a wood form to the inside dimensions of the finished parts to wrap the sheet around. If you want to minimize the seam appearance you should seam at one of the bevels (22.5 degree) estimated by looking at your drawings. CR Clark makes the best heater set ups with multiple heat zones but they are expensive. However the CR Clark machines would give you thebest results.
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