Noob questions, The Machine

A bit of background. I learned to diy the old fashioned way. I grew up on a farm. The bug never left me and as I take on new projects I always run into something where, if only I could make this part a little different, things would work so much better.

3D printing has gotten silly inexpensive, so its high time I moved away from bailing twine and barbed wire and started working with this new fangled plastics stuff.

Printers are the new wild wild west and there are a mind numbing range of options out there, even when you narrow it down in price range.

Uses: I`m looking at a printer as a practical adjunct to my DIY habit. Some of the stuff I build will be immersed in salt water, so that narrows down materials requirements considerably. ABS and poly-carbonate are two materials I know will hold up in salt water. Another project I have in mind is a cold smoker manfold adapter for my smoker. Typically it should not be exposed to temperatures above 90F, so I probably have a wider range of materials I can use. We can probably up the tolerance to 120F to make up for those 'oops' moments.

If I was happy with the standard sized bed I think I would go for the all metal Wanhao i3 clone as it seems a good compromise between cost and quality and the company is legit. Unfortunately, one of the very first projects I want to take on will be around 12" x 8" x 10" in size. I could probably shorten the height a little, but the width is important. This size, if I want to print it in one piece, eliminates a lot of printers.

The Tevo Black Widow delivers on bed size (14.5" x 9"), the company appears to stand behind their products when things go wrong and the stock machine appears to be capable of quite good prints. That's also about as much as I want to spend on a machine right now. Actually it ticks quite a few boxes. The frame is well constructed and rigid and the kit fits together quite well. Assembly instructions are mostly good and there is a large community for support. It can usually print well right out of the box, though I'm told it is wise to check the hot end for finish before using it. The biggest downside seems to be component quality variability. They are quite willing to ship replacement parts though.

My question is around a large bed and how that might affect printing. ABS is probably the first material I'll use (salt water), so I plan to enclose the printer. Will I start to run into temperature uniformity issues on such a large bed? Are there down sides in general to such large prints?

Are there downsides to doing small prints on a large bed? One I can think of might be location accuracy. I know that in manufacturing, robots that work in xyz space need periodic re-teaches to correct for the inevitable drift that comes from tiny differences in movement over time. I don't know if that would be an issue with such a low volume fabricator though.

Do you guys who have been printing for a while find yourself running into limitations in what you print because of bed size? Other than the one project mentioned, I can`t think of anything else I would need to print in that size. In fact, I`ve not seen any Black Widow owners doing prints that require that bed size. OTOH, I wonder if, once you have a larger bed, useful projects will come to mind.

I`ve got a million other questions spinning in my head right now, but the above will do for a first post.

Fred.

Edit: One other obvious question. Is there any other printer in the $350 to $550 range I should consider?

If you want to use a large print envelope... It is very helpful to have a heated bed and some flavor of Auto Bed Leveling mix. Some very big bed printers print on acrylic sheets (like the gCreate gMax 1.5+) I wouldn't even bother trying to print ABS on a 16" x 16" print without a heated bed. But it does PLA just fine. The PLA sticks so hard you need a razor blade scrapper to get it off the bed. (And in fact, that is part of the reason I'm going back to glass for a print surface. I can just unclip it, put it in the freezer, and my print comes off it!)

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I`ve got a million other questions spinning in my head right now, but the above will do for a first post.
Edit: One other obvious question. Is there any other printer in the $350 to $550 range I should consider?

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My vote would be to put together a RepRap printer kit and use it as a learning experience.

Thanks for the reply Roxy.

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Originally Posted by Roxy

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My vote would be to put together a RepRap printer kit and use it as a learning experience.

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Well that really narrows it down then. Only a couple of hundred different companies to look at. :D Seriously though, every time I take another look it seems like I find 5 or 6 more companies offering printer kits. Tevo is one of a hand full Chinese companies offering Prusa i3 kits that is regularly mentioned and has good feedback. I`m one of those analytical types that likes to evaluate everything on offer before making a decision, but I think in this case that is not possible.

I will most definitely go with a heated bed and an enclosed print area.

If you're printing large parts in ABS you'll want to heat your chamber (not just a heated build plate). This can be done inexpensively with a low-wattage hair dryer ($10-20) and a temperature controller ($40-60).

I suggest a temperature of 50c, this is warm enough to keep the ABS from warping but not so hot that it will fry your electronics.

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Originally Posted by djprinter

If you're printing large parts in ABS you'll want to heat your chamber (not just a heated build plate). This can be done inexpensively with a low-wattage hair dryer ($10-20) and a temperature controller ($40-60).

I suggest a temperature of 50c, this is warm enough to keep the ABS from warping but not so hot that it will fry your electronics.

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^^ This is good advice. Even without the heat chamber mod an enclosed chamber with a heated platform will reach 40-45C. One key thing you are eluding to are printing higher temp materials and a larger build volume. That means not only are you going to want the ability to enclose, and have a heated bed you are going to need an all metal hot end. That to me points at the Ultimaker 2+ Extendedd. If you can give up the large build chamber than a modified Flashforge or Qidi would fit the bill.

When printing with ABS hacking up a larger model and bonding the pieces together is what I typically do. Gel superglue works like a champ this way. The thing with large builds is they take a long time and it really sucks to get 10 or more hours and the material into it only to have it fail.

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Originally Posted by Todd-67

... That to me points at the Ultimaker 2+ Extendedd.

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If someone were to drop one of those in my lap for $800 I wouldn't say no, but that's way above my budget. I missed out by a day on a used Flashforge Creator Pro for $550. At that price I would probably have given up on the larger bed for now.

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When printing with ABS hacking up a larger model and bonding the pieces together is what I typically do. Gel superglue works like a champ this way. The thing with large builds is they take a long time and it really sucks to get 10 or more hours and the material into it only to have it fail.

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I have no design experience, so I have no idea how slicing and gluing might affect structural integrity on a part.

I'm of half a mind to go back to the original plan and buy the base Tevo Tarantula kit for $330 CAD and play with that to really understand what my needs are. I would imagine there is quite a learning curve for 3d modeling and printer setup to get whats in my head to turn into a real usable part.

I normally like to buy once and, other than minor mods, be done with it. There is not much technical info on these low end printers, so even when I buy one with an 'all metal' head, it is not clear what that really means or if I can work with higher temperature parts. Everyone seems to have all metal hot ends these days, but I imagine that they are not all created equal.

Materials is a whole other can of worms. I've been looking into PETG for the last couple of days. It looks to hit all the marks with a bonus of no/little toxic fumes while printing. The one downside is for some things I would want to bond to PVC, ABS, or acrylic. There are lots of good bonding options for poly-carbonate and ABS, but only one for PETG.

Hmm, buy a cheap printer (that works) and loads of different materials? Or maybe a lottery ticket...

The inexpensive option is not a bad route to go when you are starting from scratch experince wise on not only printing but modeling as well.

Most printers do not have all metal hot ends. The have metal nozzles and a metal guide tubes but use a PTFE tube in them as a heat brake. That cant take the heat of nylon and PC. The upgrade is cheap though.

Slicing up a model for bonding back together is not hard. You use tounge and groove, rabbit joints and pins/holes. Think wood working. A quality superr glue combined with those methods is very strong.

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Originally Posted by Todd-67

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Most printers do not have all metal hot ends...

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I double checked and both Tevo's have clone E3Dv6 all metal hot ends. My impression was that a lot of the cheap kits had moved to this clone. I may be wrong though. I've seen multiple reviews now and the Tevo clone hotends do work

Thing is that the E3D genuine is rated to 300C, but the clones are only rated to 260C. I have no idea why that is. It could just be the thermistor, it could be... anything else...

Too many unanswered questions. Go cheap and learn really does seem like the best option.

go for the black widow and do the sensible thing and just don't go anywhere near abs.

pet-g is damn near as cheap these days, much much easier to use, doesn't need a heated chamber and is resistant to just about all chemicals, also food contact safe so it won't kill your fish :-)
$25 a kg and cheaper: https://www.amazon.com/eSUN-filament...rds=esun+pet-g

Abs is way more hassle than it's worth. I mean way way way more hassle !

I'd also be inclined to try pla in the salt water setting - can't see any problems, also unlikely to poison your fish.
Bear in mind that abs filament often has additives to help the printing process and isn't considered food safe as it can leach chemicals.
Tropical Fish in tanks seem to spend their lives just looking for ways to die ;-)

If you don't have tropical fish - ignore all the fish references :-)

I spent 6 month fighting abs before I came to my senses. Haven't touched it in the 2.5 years since and never needed to.

There are a bunch of new abs beaters coming on the market as well.
I can thoroughly recommend innofil's new Pro 1
has to be the easiest filament to print I've yet tried. Costs more than pet-g - but you're pretty much guarenteed perfect prints every time.

As far as bed size goes. Mine are 9x6x6 inches and to be honest in 3 years I've yet to need anything bigger.
What i tend to find is that if I need to make a large thing I'll design a 3d printed part that attaches to a cheap existing 'thing' and do it that way.

As an example - my dad wanted some longer pegs to attach his pigeon decoys to.
So instead of printing long plastic pegs I simply made an adaptor that you inserted a cheap tent peg into and then slotted the existing pigeon stick in the top.
Gave a 10 inch extension for bugger all money and a lot less printing.

The thing to bear in mind is that 3d printing is slow. So what i do is look for stuff - often from a pound store that i can use with a 3d printed adaptor.

Another example. I have a tassimo coffee machine. So when making a pod holder for the kitchen. rather than printing it in one piece I made it in 3 quick to print pieces that were either joined together by bamboo skewers (1 pence each) or lengths of metal bbq skewers (12 for £1). That way I could make a much taller pod holder - and after a quick wipe with acetone, the stainless steel bbq rods look really good, for minimal printing and bugger all money.

Basically as long you are practical and used to making things - you probably won't ever need to print anything really big.

Curious Ardvark is expressing his opinion which he is entitled to, as am I, but I would take it as just that. I disagree with him more often than not.

ABS is not hard to print if you know what you are doing. A lot of people do it. The industrial high end companies like stratasys customers go through a lot of ABS. :-) I use it almost exclusively as it is very durable for snap fits and impact resistance if you have your settings correct and you can print other materials if you have a dual head machine for dissolvable supports. It also post processes well. Brittle ABS prints are results of improper extrusion/heat parameters and infill/shell settings.

In your initial posts you mentioned mentioned you wanted to print parts for use where heat is involved for your smoker and you also mentioned the use of Polycarbonite. Heat is best handled with a semi crystalline structure material as they don't creep and loose strength with heat at their glass transitional zone. That would be nylon. PC and ABS are amorphous and while way better than PLA at temps are not the material of choice because of degrading strength properties and creep. Both PC and Nylon require high temp metal hot ends. PLA is horrible in heat situations even though your temps that you listed are well below where it should be a problem the part probably will not last long.

Absolutely DO NOT use an item printed in PLA in a salt water tank. PLA degrades in a few ways. Moisture is the base then you have chemicals such as chlorine which is high in saltwater. Heat and bacteria are the other enemies which your tank requires to be sustained. I have salt water reef tanks as well. The constant flow of water in the tank with the dissolved abrasive salt will not be good. I know this because before HIPS came out I used PLA as a disolvable support structure for ABS prints. See the video below on how it's done. I have a unit very similar to this one.

https://www.youtube.com/watch?v=uWYn5wJ72zY

PLA is great for a lot of applications and it is easy for noobies. I print almost exclusively for prototype parts for consumer retail goods as I am a mechanical engineer so it just isn't for me most of the time. No one polymer is. There are so many different ones for a reason. The application dictates the tools.

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Originally Posted by Todd-67

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The application dictates the tools.

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That about says it all.

Ardvark, I understand your dislike of ABS. Its stinky and somewhat hard to work with. For your applications, it offers no benefit.

For many of my applications I need the following: chemical resistance to salt water and its constituents, reasonable strength, some pliability, the ability to easily bond to itself and other similar materials, the ability to be or become water tight at no or very low pressure.

The first and last eliminate a number of materials. ABS hits all the marks and works very well. For the few people I know 3d printing parts, it is the go to material. I know of one individual who has recently printed and built a ball valve assembly using ABS.

For some idea of the applications, have a look at this thread. http://reefcentral.com/forums/showth...2547305&page=5 The page I linked to shows the ball valve assemblies. Page 8 shows a generic filter that is used to hold a wide variety or media.

The big downside to ABS is that it produces noxious fumes while printing. I live in an apartment so that is a large concern to me.

Polycrbonate meets many of the requirements, but I'm not sure how water tight it can be printed or made. PETG sounds like an awesome material, but I have no idea if it comes off the printer water tight. Its chemical resistance means vapor polishing is impossible.

I'm thrilled to hear you have a salt water tank Todd. You know what I'm looking for.

Thank you both for your comments they have been very helpful.

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Originally Posted by fredk

The big downside to ABS is that it produces noxious fumes while printing. I live in an apartment so that is a large concern to me.


I'm thrilled to hear you have a salt water tank Todd. You know what I'm looking for.

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The fumes are way overblown when you have an enclosed printer.

Funny you're a member of ree central as well..... I will have to check that thread out. I only hang out there in the winter. That is when I have time. The printing stuff is an everyday professional thing.

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Originally Posted by Todd-67

The fumes are way overblown when you have an enclosed printer.

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Having grown up on a farm through the '70s and '80s I watched a lot of the older guys handling chemicals without protection and doing maintenance/trouble shooting with bare hands. Lots of them ended up with not so good outcomes. I'm cautious when it comes to anything potentially noxious.

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Funny you're a member of ree central as well..... I will have to check that thread out. I only hang out there in the winter. That is when I have time. The printing stuff is an everyday professional thing.

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I've been a member of RC for a very long time. Lots of interesting stuff going on there.

It's cool that you are printing professionally. My impression is that most people at the moment are doing fun stuff, so don't pay as much attention to material properties. I see a lot of potential for customized fittings for many tank plumbing and filter needs, but the materials have to hold up over time.

I wonder if RC could benefit from a dedicated 3D printing thread in the DIY area. It is an ideal application of the technology.

Done. Ordered the Black Widow. In the end I decided I did not want to deal with the up front fiddling with the Tarantula to get it more stable for printing.

Its only money... :)

Thanks all for your help.

polycarbonate is probably the hardest material to print with I've yet come across. Even the guys at polymaker who gave me the pc plus - can't tell me how to print it lol
The sheet of buildtak they gave me - did stick to the pc, permamently. I mentioned this to them and they said: yes that happens. And it's shrinkage makes abs look positively stable.

You will need not only a high temp all metal hotend but a sealed heated building chamber and some kind of magic print surface that even the people who make the filament can't advise on.

todd - I said use pet-g, personally I like pla - but if it doesn't work in salt water - then use pet-g.

fred - whether or not a 3d printed part is water tight is largely down to the way it's printed. Anything that isn't watertight can be painted with varnish, or any of the propriatary 3d print smoothing compounds around.
pet-g has much better layer bonding than abs, prints on an unenclosed machine and isn't much more expensive than abs. It also has a lot less shrinkage, which helps reduce micro gaps in the structure.

The fumes from abs are not as much of the problem as it's shrinkage and all the acetone you end up breathing in.
Yes people use it, I suspect many of them do so beacuse they haven't bothered to look seriously at the alternatives. The materials advances in 3d printing filaments in the last few years is just astonishing.

Another material you might want to look at is ninjatek's Armadillo. It's a rigid supertough material, that apparently prints easily. Handling it you'd think you were holding some kind of hardened nylon. I believe they said it was polyurethane.
Pretty impressive stuff.
I haven't tried it yet - but had along talk to the ninjatek guys and handled a few prints. The only thing that impressed me more this year materials wise, was a fibreglass composite from an italian company (maybe spanish). That was as light and strong as traditional fibreglass and printed - again - on an unenclosed machine.

Then you have innofil's new Pro 1 - easily the best material I've printed with for ease of use.
Lots of different applications depending on how hot and how fast you print it. Also food contact safe.

Like i said, I did spend 6 months exclusively using abs - it will teach you an awful lot about how to calibrate your printer and how not to get frustrated when yet another print fails. But as an end use material I was never impressed, and it's just been left way behind by the new guys on the block.

Keep a close eye on ebay for the guy selling the returned Flashforge Creator Pros. I got some very good deals on like new printers that just needed a little adjustment to get them going. Even with shipping I paid less than half of new. It is a small gamble but worth it I think.

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Originally Posted by fredk

If someone were to drop one of those in my lap for $800 I wouldn't say no, but that's way above my budget. I missed out by a day on a used Flashforge Creator Pro for $550. At that price I would probably have given up on the larger bed for now.


I have no design experience, so I have no idea how slicing and gluing might affect structural integrity on a part.

I'm of half a mind to go back to the original plan and buy the base Tevo Tarantula kit for $330 CAD and play with that to really understand what my needs are. I would imagine there is quite a learning curve for 3d modeling and printer setup to get whats in my head to turn into a real usable part.

I normally like to buy once and, other than minor mods, be done with it. There is not much technical info on these low end printers, so even when I buy one with an 'all metal' head, it is not clear what that really means or if I can work with higher temperature parts. Everyone seems to have all metal hot ends these days, but I imagine that they are not all created equal.

Materials is a whole other can of worms. I've been looking into PETG for the last couple of days. It looks to hit all the marks with a bonus of no/little toxic fumes while printing. The one downside is for some things I would want to bond to PVC, ABS, or acrylic. There are lots of good bonding options for poly-carbonate and ABS, but only one for PETG.

Hmm, buy a cheap printer (that works) and loads of different materials? Or maybe a lottery ticket...

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I agree completely with Todd. ABS has a learning curve but with study and diligence it is easy to print and makes really nice prints. PETG is a good alternative but has its downfalls also. It is more flexible than ABS and on thin parts this will become more prevalent.
PLA is great for a lot of things and good to get started with. However, it is "brittle" and forget heat. I made drain covers for my kitchen sink and the hot water is enough to start to soften the PLA slightly. It will in time degrade around water also. I am testing this in the sink!! It works fine for this application but I know it won't last.

I haven't used nylon yet but it does require high temps and it is also extremely hygroscopic being that it can saturate in under 24 hours so storage is critical.

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Originally Posted by Todd-67

Curious Ardvark is expressing his opinion which he is entitled to, as am I, but I would take it as just that. I disagree with him more often than not.

ABS is not hard to print if you know what you are doing. A lot of people do it. The industrial high end companies like stratasys customers go through a lot of ABS. :-) I use it almost exclusively as it is very durable for snap fits and impact resistance if you have your settings correct and you can print other materials if you have a dual head machine for dissolvable supports. It also post processes well. Brittle ABS prints are results of improper extrusion/heat parameters and infill/shell settings.

In your initial posts you mentioned mentioned you wanted to print parts for use where heat is involved for your smoker and you also mentioned the use of Polycarbonite. Heat is best handled with a semi crystalline structure material as they don't creep and loose strength with heat at their glass transitional zone. That would be nylon. PC and ABS are amorphous and while way better than PLA at temps are not the material of choice because of degrading strength properties and creep. Both PC and Nylon require high temp metal hot ends. PLA is horrible in heat situations even though your temps that you listed are well below where it should be a problem the part probably will not last long.

Absolutely DO NOT use an item printed in PLA in a salt water tank. PLA degrades in a few ways. Moisture is the base then you have chemicals such as chlorine which is high in saltwater. Heat and bacteria are the other enemies which your tank requires to be sustained. I have salt water reef tanks as well. The constant flow of water in the tank with the dissolved abrasive salt will not be good. I know this because before HIPS came out I used PLA as a disolvable support structure for ABS prints. See the video below on how it's done. I have a unit very similar to this one.

https://www.youtube.com/watch?v=uWYn5wJ72zY

PLA is great for a lot of applications and it is easy for noobies. I print almost exclusively for prototype parts for consumer retail goods as I am a mechanical engineer so it just isn't for me most of the time. No one polymer is. There are so many different ones for a reason. The application dictates the tools.

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Originally Posted by wirlybird

It will in time degrade around water also. I am testing this in the sink!! It works fine for this application but I know it won't last.

I haven't used nylon yet but it does require high temps and it is also extremely hygroscopic being that it can saturate in under 24 hours so storage is critical.

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PLA won't degrade for a long time in water alone. It needs bacteria and heat such as in a landfill (or fish tank) along with the moisture. Detergents and chemicals design to breakdown organics such as drain cleaner (lye). heat and adgitation speed up the process just like in the video I use a heated ultrasonic parts cleaner with a water/lye mix. PVA will melt in straight water. Heat and agitation will speed that process up as well. Alternatively to the ultrasonic cleaner you could use a fish tank heater in water with a pump to create a strong current for pretty cheap that I would think would work almost as well.

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Originally Posted by Todd-67

PLA won't degrade for a long time in water alone. It needs bacteria and heat such as in a landfill (or fish tank) along with the moisture. Detergents and chemicals design to breakdown organics such as drain cleaner (lye). heat and adgitation speed up the process just like in the video I use a heated ultrasonic parts cleaner with a water/lye mix. PVA will melt in straight water. Heat and agitation will speed that process up as well. Alternatively to the ultrasonic cleaner you could use a fish tank heater in water with a pump to create a strong current for pretty cheap that I would think would work almost as well.

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Interesting. I guess I was a little vague! I am interested to see how it hold up as a drain screen in normal day to day usage in a kitchen sink. Not the most scientific study! I actually made these to fill in the drain hole. Ever set a colander in the sink to have it tip when the feet go in the drain. So these just make the bottom of the sink level by covering/filling the drain.

pla is not brittle.
Hit it with a hammer and it doesn't shatter, it usually dents.

What it is, is harder and stiffer than abs. But print it thin and it flexes at least as well as abs.

A lot of a 3d prints properties are down to how the thing is printed. I probably design my pla stuff to the capabilities of the material better than most. But right from the first pla print I've had absolutely none of the supposed issues people claim for it.

Abs on the other hand was just a hassle from the first day to the last.
I don't have an enclosed printer - so abs was never going to be fun.

If you have an enclosed printer and you like acetone - give it a go.

Just be aware there are alternatives that don't have any of the built in hassle of abs.

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Originally Posted by curious aardvark

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fred - whether or not a 3d printed part is water tight is largely down to the way it's printed.

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So I'm learning. From what I've read, if I want stronger parts with better inter layer adhesion, I want to go to a larger nozzle. The supposed advantages are that the previously laid down layer retains more head, it will bond better as the new layer is laid down. It also speeds printing considerably. For aquarium parts I think I should actually consider the E3D volcano. As a start, I will get the largest nozzle my head supports.

For water tightness, is that all down to inter layer bonding?

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Anything that isn't watertight can be painted with varnish, or any of the propriatary 3d print smoothing compounds around.

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I don't think varnish will hold up long term in salt water. I'd have to talk to the smoothing compound manufacturers to see what might leach into water and how well those compounds hold up. It is definitely an option.

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pet-g has much better layer bonding than abs, prints on an unenclosed machine and isn't much more expensive than abs. It also has a lot less shrinkage, which helps reduce micro gaps in the structure.

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If I can print water tight from the get go, its almost 'holy grail' product for my application. If plain pet-g turns out to be too flexible, I can always go for a carbon fiber reinforced product.

Bonding would be the one issue. The only product available to bond to other plastics like PVC or acrylic it Weldon 40, a rather expensive two part bonding agent. If it works and this is the only down side, I can live with that.


The fumes from abs are not as much of the problem as it's shrinkage and all the acetone you end up breathing in.
Yes people use it, I suspect many of them do so beacuse they haven't bothered to look seriously at the alternatives. The materials advances in 3d printing filaments in the last few years is just astonishing.

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Another material you might want to look at is ninjatek's Armadillo. It's a rigid supertough material, that apparently prints easily. Handling it you'd think you were holding some kind of hardened nylon. I believe they said it was polyurethane.
Pretty impressive stuff.
I haven't tried it yet - but had along talk to the ninjatek guys and handled a few prints. The only thing that impressed me more this year materials wise, was a fibreglass composite from an italian company (maybe spanish). That was as light and strong as traditional fibreglass and printed - again - on an unenclosed machine.

Then you have innofil's new Pro 1 - easily the best material I've printed with for ease of use.
Lots of different applications depending on how hot and how fast you print it. Also food contact safe.

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Great info, thanks. I'm at the "you don't know what you don't know stage, so its hard for me to even know where to look for info on new plastics.

Edit: Regardless of the material I work with, I plan to enclose the machine. I've spent enough time around injection mold machines (very large ones) to understand how finicky plastic can be. Since I'm concerned with long term structural integrity, I want to manage the print environment as much as possible.

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Originally Posted by fredk

So I'm learning. From what I've read, if I want stronger parts with better inter layer adhesion, I want to go to a larger nozzle. The supposed advantages are that the previously laid down layer retains more head, it will bond better as the new layer is laid down. It also speeds printing considerably. For aquarium parts I think I should actually consider the E3D volcano. As a start, I will get the largest nozzle my head supports.

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It really depends on what your accuracy requirements are. A larger nozzle will print faster but I am not sure it has the advantages that you are citing. A normal .4mm nozzle can be setup to produce those exact same results. Extrusion width, your multiplier, and extrusion temps are you friends. These parameters are in your slicer.

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Originally Posted by fredk

For water tightness, is that all down to inter layer bonding?

I don't think varnish will hold up long term in salt water. I'd have to talk to the smoothing compound manufacturers to see what might leach into water and how well those compounds hold up. It is definitely an option.

If I can print water tight from the get go, its almost 'holy grail' product for my application. If plain pet-g turns out to be too flexible, I can always go for a carbon fiber reinforced product.

Bonding would be the one issue. The only product available to bond to other plastics like PVC or acrylic it Weldon 40, a rather expensive two part bonding agent. If it works and this is the only down side, I can live with that.

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Water tightness is going to rely pretty heavy on your shell/perimeter settings. Lots of perimeter/top/bottom layers. You and I both know that coating anything in a saltwater environment is something to proceed with extreme caution.

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Originally Posted by fredk

The fumes from abs are not as much of the problem as it's shrinkage and all the acetone you end up breathing in.
Yes people use it, I suspect many of them do so beacuse they haven't bothered to look seriously at the alternatives. The materials advances in 3d printing filaments in the last few years is just astonishing.

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You don't breath in acetone during printing. It's a solvent that dissolves ABS. You use acetone as a method of smoothing, creating slurry, or cleaning the bed with Kapton tape. What you are smelling during printing is the styrene. ABS = Acrylonitrile Butadiene Styrene. Does it smell? The short answer is yes. The real answer is that when processed at the correct temps the toxicity of the fumes is minimal. ABS when burned as in a fire condition is very toxic which is why they have flame retardant grades for certain applications (molding option) but that is not what we are doing. Extrusion temps are below injection temps. If it were toxic when processing OSHA would be all over the injection molding industry as it and nylon are the most processed plastics on a large scale and they don't require breathing aspirators for the workers. Can it irritate some peoples noses? Certainly.

Like i stated before the application defines the application. Material selection is based application. The array of thermoplastics is pretty wide ranging and application specific. Check out the range of what is out there on matweb http://www.matweb.com/search/MaterialGroupSearch.aspx Each of these has a use as matweb just covers the most common for each category not the full range from Dow, Bayer, GE, etc.... Yes the printing industry has brought out a lot of filaments but they are based on existing polymers with a modifications to make them easier to print. I use a lot of the stuff that is out there. There are applications for all of it.

Quote:

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Originally Posted by fredk

Edit: Regardless of the material I work with, I plan to enclose the machine. I've spent enough time around injection mold machines (very large ones) to understand how finicky plastic can be. Since I'm concerned with long term structural integrity, I want to manage the print environment as much as possible.

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Controlling the environment as much as you can is a very wise approach.

if you enclose it leave a door.

the trick to pla is cooling fast, so that;s one material that you don't want to print in an enclosed setup.

back to the cold smoking - thing - that I know a LOT about.

what sort of setup are you talking about ?

Quote:

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Originally Posted by curious aardvark

if you enclose it leave a door.

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Well how exactly am I gonna get in there without a door? Like I'd ever do something that silly... ;)

OK, I get your point. I need a way to print cold as well. I plan to make a stand out of 8020 quickframe. I'll work out a way to make the panels easily removable for access around the printer. I've learned the hard way that you should always make your equipment as accessible as possible.

Quote:

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the trick to pla is cooling fast, so that;s one material that you don't want to print in an enclosed setup.

back to the cold smoking - thing - that I know a LOT about.

what sort of setup are you talking about ?

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I have a Green Mountain Grill tailgate smoker (live in an apartment). I built a cold smoker attachment using a section of stovepipe, There is nowhere underneath to pipe the smoke into the smoker so I want to make something that is going to both block a partially open lid and direct the smoke in and down/around the items I wish to smoke.

I could probably MacGyver something from existing materials, but a 3d printed manfold would be much more elegant.

OK, Printer ordered. Again. Hopefully the transaction goes through without all the drama this time...

From all the reading I've been doing, all the low cost large bed printer kits out there have issues with powering the heat bed. Either the bed is greatly under powered and has trouble getting up to temp in a reasonable amount of time, or you get a great heat up time, but the main board and/or PSU can't handle the power draw.

The Tevo's 370 x 250 mm bed heater draws 400 - 500 watts of power. The silicone heat beds of similar size start at 400w and go up from there.

Other builds have a smaller PSU and ~150w heatbed that will not get to the 100C+ needed for some materials.

I'm only guessing, but I suspect it is the $499 price point companies are trying to hit that has got them where they are now.

I don't understand the main board chain of supply, but I would imagine that there is a market for a board properly designed to handle 500-600w at 24v.

I'm going to try controlling the heat bed separately using 24v out from the PSU though an SSR or mechanical relay. I may actually just shell out the money for a real Omron SSR and be done with it. If the PSU lets out its magic smoke I can upgrade to a proper Meanwell 600w PSU.

The internets claim I don't need to spend this much money for a relay, but I don't know that any of this 'Internets' has the appropriate training to make this call.

Now, lets see if the shippers can beat Santa. :)