Advice needed for working with plastics

[Painless]

I'm currently working on some enclosure designs for my new dry cell, the problem I'm having (as always) is with cutting the plastic both accurately and without it taking all day with a junior hacksaw. I have an old SaberSaw, the blade it came with was OK for the kitchen cutting board I used as the end plates on my last cell, but is too aggressive for cutting acrylic. I took one of my old hacksaw blades this morning (much finer toothed) and *cough* "made" a new blade for my SaberSaw. It worked fairly well, however, it was very prone to bending and seemed to weld the plastic back together as it went due to the heat of friction (the saw only runs at one speed).

It seems that I need something which I can run slower for plastics, plus, if I do get the money together to purchase something better I want it to be able to make very accurate and straight cuts.

Can anyone make any recommendations? Links would be great.

Russ.

[coffeeachiever]

Sounds like you need a band saw. At least it seems to me like that would work. You can get a small one at a pawn shop here for about 30-40 bucks. (we have lots of crack heads).

[coffeeachiever]

Here's a link for diy with the plastics.

http://www.sdplastics.com/acrylic.html

Hope this is what you are looking for.

[Painless]

Here's a link for diy with the plastics.

http://www.sdplastics.com/acrylic.html

Hope this is what you are looking for.

Thanks, Coffee, that's definitely a help.

It's interesting that it says to cut acrylic at high speed with a sabre saw.

[Painless]

This is interesting:



<dl><dt>Viscous cementing</dt><dd> Viscous cements are used for joints that can't be cemented with capillary or soak cementing, either because the joint is difficult to reach or because the parts don't fit properly. Viscous cement is thick and will fill small gaps. It can make strong transparent joints where solvent can't. You can make your own viscous cement by dissolving chips of clear acrylic sheet in a small amount of solvent.
Apply a small bead of cement to one side of the joint, join the pieces, and tape or clamp in place until cured.
</dd><dt></dt></dl>I wonder if this will give us a joint that is a) hydrogen proof and b) electrolyte proof ?

I wonder what is required for the 'solvent'?

[coffeeachiever]

All the sites I have read seem to be printing the same instruction manual. None of them specify a solvent. They do however sell pre made viscous cement. If I were to try and make my own, I suppose I would start trying with a solvent like MEK (methyl ethyl keytone). Let the chips sit in it overnight and see what happens. All hardware stores carry MEK.

[Captain Charlie]

Since I have built hundreds of cases using PLEXIGLASS, OR LUCITE, (same stuff different companies) you'll need a decent table saw, with a good 10" lade. The blade should have at least 80 teeth. When you cut leave the paper on. It will save scratching and you'll be able to write on it when measuring.

Remember to cut the side pieces 1/4" smaller than the top and bottom pieces as the pices, if they are 1/8" thick. that way the end pieces can be cut square and will fit correctly.

You'll need an acetone type solvent. Made for sealing the plastic. Use a hypodermic needle, a large one, maybe 50cc. after the pieces are cut place one on top of the other. and by capiliary action apply the solvent at oen end and it will run to the other and in less than 30 seconds it will be fused.

I'm suggesting building a box because the videos I saw with dry cells called for metal rods. If you intend to place the dry cell in a box, you mentioned a pelican box I believe, this will work.

You'll need to get some sort of clamps to hold the top on unless you want a sealed unit with your elbors, filler holes, and check valves etc, then you could seal the top as well. If you want to dress up the cut edges use a small propane torch and lick the flame along the edges. It will flame polish them and make them nicer.

I have made 100 gallon fish tanks with this method. My main work was building large cases that held butterflys, (not alive) in flight, on driftwood etc.

I hope this helped.

Now if I can find someone to show me a finished diagram of a dry cell and tell me what -NNNNNNNN NNNNNNN+ means I'd be happy.


Captain Charlie
FLATBROKE CHARTERS
TALLAHASSEE FL.

[Q-Hack!]

I use one of these to make my initial cuts and then file smooth with a flat file clamped to the table. Takes a while, but makes for real smooth lines. Also doesn't gum up my table saw.

http://www.dremel.com/en-us/AttachmentsAndAccessories/Pages/AttachmentsDetail.aspx?pid=543

[Painless]

I use one of these to make my initial cuts and then file smooth with a flat file clamped to the table. Takes a while, but makes for real smooth lines. Also doesn't gum up my table saw.

http://www.dremel.com/en-us/AttachmentsAndAccessories/Pages/AttachmentsDetail.aspx?pid=543

Hmm, I have a dremel and one of the quick change attachments. That disc sure is a strange shape, how does it work different to the regular cutting discs?

[Q-Hack!]

Hmm, I have a dremel and one of the quick change attachments. That disc sure is a strange shape, how does it work different to the regular cutting discs?

If you go too fast it will still gum up, but it seems to work better than something with triangular teeth. I have also use what looks like a cut-off wheel designed for plastic. They also work, but again go slow or it melts rather than cuts. The cut-off wheel for plastic that I had were in the Dremel Quick change form. Haven't seen them in the stores for the last month or so. If you can find them, I think they are actually better.

[Painless]

The problem I have with the dremel, apart from the battery charge barely lasting 5 minutes, is that it doesn't seem to have the torque to even get through 1/4" plastic no matter how gently I go. The disc just stops.

[mytoyotasucks]

I'm currently working on some enclosure designs for my new dry cell, the problem I'm having (as always) is with cutting the plastic both accurately and without it taking all day with a junior hacksaw. I have an old SaberSaw, the blade it came with was OK for the kitchen cutting board I used as the end plates on my last cell, but is too aggressive for cutting acrylic. I took one of my old hacksaw blades this morning (much finer toothed) and *cough* "made" a new blade for my SaberSaw. It worked fairly well, however, it was very prone to bending and seemed to weld the plastic back together as it went due to the heat of friction (the saw only runs at one speed).

It seems that I need something which I can run slower for plastics, plus, if I do get the money together to purchase something better I want it to be able to make very accurate and straight cuts.

Can anyone make any recommendations? Links would be great.

Russ.

There is a hand saw mand just for cutting plastics.

http://mytoolstore.com/starrett/hack05.html

[Q-Hack!]

The problem I have with the dremel, apart from the battery charge barely lasting 5 minutes, is that it doesn't seem to have the torque to even get through 1/4" plastic no matter how gently I go. The disc just stops.

Well, there's your problem...;) I have the plug in the wall version Dremel. In fact, I don't think I own any battery operated tools any more. Not since the purchase of pnumatic :D

[Painless]

There is a hand saw mand just for cutting plastics.

http://mytoolstore.com/starrett/hack05.html

That looks like a decent saw, unfortunately, I have to stay away from manual tools when I can unless its for very short use.

[Painless]

Well, there's your problem...;) I have the plug in the wall version Dremel. In fact, I don't think I own any battery operated tools any more. Not since the purchase of pnumatic :D

I really wish I had bought the plug in dremel.