DIY Hydroponic Trays

[early420]

So I have some 4'x8' white ABS plastic sheets I have used for multitude of projects. I have never had to cut long straight lines in this material before however I have cut pieces out of the middle using an angle grinder. The lines were acceptable for what I was doing at the time but they were somewhat 'wavy'. I am trying to construct a set of custom trays to fit in some nonstandard dimensions (28inches wide 3.5ft long).

So two questions: First can anyone offer advice on the best way to cut long straight lines in ABS? I am limited to hand tools (skil saw, rotozip, angle grinder, jig saw, table saw and similar tools).

Second, can anyone suggest how to 'weld' the corners together? I've read acetone will do the trick but I'm hoping someone here has attempted this project before and might be able to offer some advice or insight.

Thanks!

early

 

[SmilinBob]

I'd use the table saw to ensure straight lines. Epoxy to put it back together.

If you can't cut a straight line with a table saw then you shouldn't be using it.

 

[early420]

ABS doesn't cut like wood. It has a tendency to chip and melt. Cutting a straight line in ABS is not like cutting OBS, or Ply, or Cement board, or tile, or marble, or pressure treated lumber, or drywall or concrete. I appreciate your suggestions but I'm looking for a more detailed comment from someone who had had hands-on-experience tooling this material.

Thanks.

early

 

[reckon]

I'd use the table saw to ensure straight lines. Epoxy to put it back together.

If you can't cut a straight line with a table saw then you shouldn't be using it.

EPOXY will net you approx. 30% bond strength of the parent material: ABS = FAIL

so, I'd say, if you can't give out sound advice, maybe you shouldn't be posting, eh?



I'm a plastics fabricator with nearly 35 years experience:

the easiest way to cut ABS is with a table saw, use a high tooth count blade, and run the speed fairly high,...you need to push abs through fairly quickly, as the saw blade will heat the material, and it'll start to melt if you go too slowly,..obviously the blade needs to be SHARP, don't try it with an old saw blade.

for small or very large cuts, you can stick the sheet abs to a sheet of plywood with GOOD double stick tape, and then run both through the saw together as one piece. for skilsaw cuts, the rule of thumb is don't try and cut where you'll have MORE than 50% drop or support the drop so it doesn't bend while you are cutting.

for thin (3/16" or thinner) ABS you can simply score it with a box cutter, using a straight edge for a guide,...and then give it a good snap, and it will break very cleanly,...if you get the abs at or colder than room temp, this is very easy, try it on a hot 85 degree day and it likes to bend, not snap. You can dress/de-burr the edges with a paint scraper, or a single bastard file.

ABS can be routed very easily, again, run the material through quickly, or run the router along quickly and run the router speed fairly high, use a sharp bit (fluted doubles work best with ABS)

for bonding nothing on planet earth save thermal welding bonds ABS BETTER than MEK (methyl ethyl ketone), get both surfaces square, and clean, wipe on MEK with a q-tip on both surfaces, and push together, you should see some molten ABS ooze out of the crack,.....clamp, tape or wedge for 2-4 hours till completely set, and the two pieces are now chemically WELDED together.

they make small squeeze bottles with needle tips JUST for bonding the styrenes (ABS is styrene), check TAP PLASTICS for online, and any local plastics shop should carry them.
for the squeeze bottles the slickest way to bond, is to get everything setup: corners square, everything measured twice, then clamp loose, and run the squeeze bottle down the crack where the two pieces meet, and it'll wick into the joint, then tighten up the clamps.
when we'd bond BIG heavy things, we'd take 0.040 diameter copper wire, and use that as a spacer, then run the MEK along the seam, while another guy behind you pulls the wires allowing the pieces to come into compressed contact with each other: ridiculously strong bonds.

you can also thermally weld ABS using one of these things:
http://www.harborfreight.com/catalogsearch/result/?category=&q=plastic+weld

I'd suggest the MEK above, and if it's not strong enough THEN we'll get into plastic welding, which will take an entire thread, but just so you know there is another option for bonding.

that should do ya

 

[early420]

Thank you recon. Exactly what I was looking for. I am very familiar with MEK as we use it often at work. So I feel confident that I can make these trays using what I already know and the information you have provided.

Thanks again Recon!

early

 

[ShroomDr]

not exactly related to the specific topic being discussed, however these are my DIY Hydroponic tables.


$6 Oil pan from walmart. They can hold (1) 5Gal container, or (6) 1Gal botanicare square containers.

 

[!!!]

Good info reckon.

Awhile back I tried cutting plexiglass with a table saw but it would melt back together due to the heat of the blade. Ended up having my friend use a water gun following the blade to cool it down quickly enough to stop it from melting. I avoided a Darwin award and it worked beautifully.

 

[what the]

ABS doesn't cut like wood. It has a tendency to chip and melt. Cutting a straight line in ABS is not like cutting OBS, or Ply, or Cement board, or tile, or marble, or pressure treated lumber, or drywall or concrete. I appreciate your suggestions but I'm looking for a more detailed comment from someone who had had hands-on-experience tooling this material.

Thanks.

early

Perhaps you should thank smilin' bob since his table saw recommendation you so rudely dismissed is the tool to use.

Also, sometimes 30% is strong enough. I have built PVC tables with epoxied dado joints. The PVC broke before the joint when I finally dismantled them. Obviously PVC is a different animal than ABS but the point about dismissing epoxies is flawed. It depends on how strong that connection needs to be. That stress will be much different than in the middle of the field for example.

 

[reckon]

Perhaps you should thank smilin' bob since his table saw recommendation you so rudely dismissed is the tool to use.

Also, sometimes 30% is strong enough. I have built PVC tables with epoxied dado joints. The PVC broke before the joint when I finally dismantled them. Obviously PVC is a different animal than ABS but the point about dismissing epoxies is flawed. It depends on how strong that connection needs to be. That stress will be much different than in the middle of the field for example.

actually Smilin' Bob is the rude one........that kinda comment just ticks me off, sorry if I overly offended anyone, I was only trying to mildly offend

so thank you for your input, but for the record: I DOUBT you'd even get 30% bond strength with epoxy, as epoxy contains no solvents,....so when you bond ABS with epoxy you get COHESION, not ADHESION,..in other words it's stuck on with suction, and will pop off and leak almost immediately (these are drip trays I imagine),...and yes PVC is VINYL with several side chains, and chloride,...sometimes it's chlorinated even further to retard burning, CPVC,....and those you can bond with an epoxy, as pvc has a MUCH more open celled structure than ABS,..........so you're comparing apples to armadillos.

I imagine duct tape would be "strong enough", why not use that?

also look at the fact you have to measure, mix, and there is a limited working time with epoxy, and then clean up.......so you get more work on your part, and crappy bond to boot! wow that sounds awesome!


the BEST tool to cut ABS is a water jet, CNC laser, or CNC table router if you want to get down to brass tacks,.......BUT as the op stated, he has hand tools (although I don't consider a tablesaw a hand tool)

I built my cats a custom covered 6ftX4ftX4ft catbox out of 3/16 ABS, using nothing but a skilsaw, a box cutter, and some squares,.......the thing even has it's own 25cfm ventilation system (computer fan/ac adapter),...I used MEK to bond it, and now 8 years later it's still a solid one piece unit,...and we sit on it all the time like a bench seat.

you glue with epoxy all you like, but it's the wrong bonding agent for ABS, and more difficult to use..........look it up.



peace, love, and cross linked monoamines

 

[City Twin]

reckon has a handle on it.

I used to build and repair “ANVIL” type road cases back in the day. We laminated the abs sheets with Bull Dog brand contact cement. It’s not an easy job since the cement would only melt the abs for a short time for lamination.

We cut with strong arms and sharp razor knives. A table saw can be used with carbide tips and care in feed. Also double cut hand jig saw blades, but those were more a pain and only used for thicker abs to repair on site.

Edge gluing I don’t know. We couldn’t do it. There may be products developed that I’m unaware of. (Ah - MEK. Cool)

I’ve not used a plastic welding kit but have one on my shop wish list.

Be Safe

 

[early420]

Thanks for your continued clarification everyone.

These trays will in fact be used to catch run off from a drip system.

I really appreciate all the advice EVERYONE has offered!

Thanks!

Early

 

[what the]

actually Smilin' Bob is the rude one........that kinda comment just ticks me off, sorry if I overly offended anyone, I was only trying to mildly offend

so thank you for your input, but for the record: I DOUBT you'd even get 30% bond strength with epoxy, as epoxy contains no solvents,....so when you bond ABS with epoxy you get COHESION, not ADHESION,..in other words it's stuck on with suction, and will pop off and leak almost immediately (these are drip trays I imagine),...and yes PVC is VINYL with several side chains, and chloride,...sometimes it's chlorinated even further to retard burning, CPVC,....and those you can bond with an epoxy, as pvc has a MUCH more open celled structure than ABS,..........so you're comparing apples to armadillos.

I imagine duct tape would be "strong enough", why not use that?

also look at the fact you have to measure, mix, and there is a limited working time with epoxy, and then clean up.......so you get more work on your part, and crappy bond to boot! wow that sounds awesome!


the BEST tool to cut ABS is a water jet, CNC laser, or CNC table router if you want to get down to brass tacks,.......BUT as the op stated, he has hand tools (although I don't consider a tablesaw a hand tool)

I built my cats a custom covered 6ftX4ftX4ft catbox out of 3/16 ABS, using nothing but a skilsaw, a box cutter, and some squares,.......the thing even has it's own 25cfm ventilation system (computer fan/ac adapter),...I used MEK to bond it, and now 8 years later it's still a solid one piece unit,...and we sit on it all the time like a bench seat.

you glue with epoxy all you like, but it's the wrong bonding agent for ABS, and more difficult to use..........look it up.



peace, love, and cross linked monoamines

Yeah I agree with all that. You obviously have more experience with this than I do. I just wanted to point out that epoxy connections can be strong enough (maybe not for ABS, I don't have any experience with that). As engineers like to say "Any idiot can overbuild something!" So duct tape may not have the durability you're looking for. But like I wrote, in my case the epoxy connection (Along with the geometry of the dado joint) had a sufficient yield strength for the application. It was readily available. It worked.
And this was for a flood table with a fairly sizable hydrostatic load, not a drip pan.

 

[dtfsux]

As a teenager building speaker boxes, I used to use a skill saw and 2x4 to cut straight lines. Clamp the 2x4 to the material. It takes a little measuring to place the 2x4 in the right spot, but once you do, you run the saw right against the 2x4 for a nice straight line.

I mention this because sometimes cutting a large 4x8 sheet of xyz on a table saw can be tough for one person.