"Welding" Lexan or plexiglass?

slydog · Dec 18, 2004

\"Welding\" Lexan or plexiglass?

I need to make some permanent, waterproof bonds between sheets of Lexan or plexiglass. It seems I saw on one of these DIY shows someone making some chemical welds with a clear liquid that actually melts/bonds the joints together.

Does anyone know of this or any process for doing this? The boxes I need to make will be totally of Lexan or plexi, and will need to be totally clear so they will be transparent, and waterproof once they are embedded in some huge blocks of ice. (lol, I know I can come up with some crazy sheet, but I'll be happy to explain more later if I can come up with a practical solution to what I am trying to accomplish.) I know this doesn't have anything to do with tractors, but you guys know what your talking about and are full of answers.

Thanks

Ken

bobodu · Dec 18, 2004

Re: \"Welding\" Lexan or plexiglass?

I'll be darned...
http://www.heatgunkit.com/accessories.php?id=42&name=Plastic+Welding+Rods
Try a Google search for "welding Lexan" or plexi or glueing same...I 'm late for my lil nappy.LOL

PineRidge · Dec 18, 2004

Re: \"Welding\" Lexan or plexiglass?

You may also want to consider that they use silicon RTV sealant to hold aquariums together some at over 100 gallons each. It is also very easy to apply with a standard caulking gun and available at stores like Home Depot or Lowe's.

aardvark · Dec 18, 2004

Re: \"Welding\" Lexan or plexiglass?

I use the Weld-On line of products from www.ipscorp.com on a regular basis at work. I use Weld On 16 mostly, since it's a clear gel that comes in a tube. I've also used Weld On numbers 3, 4 and 5, but 16 is really the easiest to use and most practical. You can see the products here:

http://www.ipscorp.com/ind_html/indprdcts.html

Lexan is the General Electric brand name for polycarbonate. I guess most "plexiglass" is also polycarbonate, but some people just use it as a generic term for clear plastic sheets, and many clear plastic sheets are acrylic rather than polycarbonate. I've found the above Weld On products that are designed for acrylic work great on polycarbonate, as well as ABS and PC/ABS blends. The specific polycarbonate epoxies are two parts from what I have seen, and it's easier to use the one part acrylic solvents, with not much reduction in performance.

Freds · Dec 18, 2004

Re: \"Welding\" Lexan or plexiglass?

I made what amounted to an aquarium out of lexan. It is actually called a sump tank and water from my saltwater tank cycles through it. There is a product that looks like clear glue that fuses the pieces together and is very strong. It can be put on in enough "layers" to fill gaps and I believe this is what you are referring to. I don't remember what it is called, but I got it at the same place I bought the sheet of lexan from. Not H-D or Lowes, although they MIGHT have it, but a place that specializes in plastics I found in the yellow pages.

Freds · Dec 18, 2004

Re: \"Welding\" Lexan or plexiglass?

I don't know all the technical jargon, but I thought there was a difference between lexan and plexiglass. I used to work in a sheet metal shop and glass companies would bring us lexan to put a break in and be used as sneeze guards. They said you couldn't break (bend) plexiglass and that it scratched easier.
It's true that many things pick up generic names that don't refer to that particular product.

slydog · Dec 18, 2004

Re: \"Welding\" Lexan or plexiglass?

I KNEW you guys would know where to look! My plans are to get the sheet goods at GE Polymer and Plastics, so I bet I can obtain what I need from them also. I didn't even think they might carry something for that purpose.

I am actually trying to come up with....an aquarium in reverse sort of. Tell me what you guys think.

This is for a huge party for a major movie premier here locally. They want a huge bar (as in alcohol type bar) made entirely of Ice. This ice sculpture company a friend works for will be providing the bar. Now where I possibly come in. They want to "imbed" or cut into each end of the front of the bar, and place a large flat screen plasma tv in each end. It has to appear if possible as if it is sitting actually in the ice. There would be a concern I'm thinking of the TV's melting the ice, or water running into/around the TV's.

My thoughts are, using thick, 1/2 to maybe 5/8, whatever looks best, Lexan, and building a box to place the TV's in. The front would be totally open. When I have the Lexan cut at GE, I can have them polish the edges, and it looks almost like clear ice then end on. I still don't know what kind of base all this ice and stuff will sit on, but my thinking is to come into the box from the bottom with all the wiring. Would anyone think I would maybe need some fans to pull the air out of the box to help cool the TV's ? Maybe two or three 3'' fans in the bottom of each box? Or with the front open, and surrounded by ice, would this even be necessary?

Do you think this kind of setup would keep the TV's dry? I'd hate to have a major short out in the middle of this production, IF I give a qoute and take this job on. I know lexan is expensive, but just to give yall an idea, I have been told there is an Ice Sculpture budget alone for this project of 40 to 45k !!!!! /forums/images/graemlins/shocked.gif Yes, some people have more money than brains! Whether I do it or not, I definitely want to see what it looks like when it's finished.

Ken

Freds · Dec 18, 2004

Re: \"Welding\" Lexan or plexiglass?

( I definitely want to see what it looks like when it's finished. )
I don't think you are alone here /forums/images/graemlins/grin.gif

I'd like to throw a couple of things out to think about.
Does the lexan need to be that thick? I'm not sure how they will build the ice bar, but if they needed to build around the lexan boxes, you could put wood jigs in them so they retain their shape and take them out to insert the TVs.

I think how much room you allow around the TV (you can always go deeper without losing the desired effect and perhaps have a lip inward that meets the size of the TV screen around the face of the box, so the actual box is say, 50 x 30, but the TV is 40 x 20) plus the fact that they are surrounded by ice will keep the TVs at a good temp, BUT... I would be VERY concerned about condensation forming inside the box walls no matter hown much air flow around the TV you have. You will definitely need to build an insulated box (2" styrofoam would probably work well), but this will take away from the ice, or opaque look you are trying to keep. If you go with a lip around the face of the box it will help hide the insulation and maybe even make it impossible to see if you can recess it a ways.

IMO. Just a couple things to brainstorm. The vision I have in my mind of this project sure looks cool, though.

aardvark · Dec 18, 2004

Re: \"Welding\" Lexan or plexiglass?

How do they plan on keeping the ice bar cold so it doesn't melt? I imagine that the refrigration system they plan on using will keep the ice from melting even without the lexan sheets. The TV's will put out some heat, but the refrigration system to keep several thousand pounds of ice from melting over a period of 6-8 hours is going to be huge, so far as I can imagine.

The company I work for makes waterproof marine electronics. If you painted the outside edges of the TV's with clearcoat it would water proof the edges for enough time for the party to end. Another option is to just keep water from dirpping on the tops of the TVs. A splash shield of sorts above the TV would keep liquid water off the top of the TV, and gravity will keep water from dripping into the sides or bottom of the TV. Fogging may be a potential issue on the display. If the ice bar can drop the temp inside the TV below the dew point, the display is going to fog in the center. Using a five sided lexan box which allows the front of the TV to stay open to ambient may be your best choice. It would keep the temp around the TV up, and expose the TV to ambient humidity rather than an artifically increased humidity. I'm sure you can make this work.

have_blue · Dec 19, 2004

Re: \"Welding\" Lexan or plexiglass?

From reading your project description, I think you should consider augment the solvent/sealer with metal fasteners. Mortise or rabbet a channel for the corner joints, and sand a light chamfer on all outside corners to eliminate sharp corner interference in the matching groove corners. Drill and countersink an appropriate number of "through holes" for 1/4 or 5/16 bolts, and drill and tap into the edges of the sheet. Dry fit the assembly to ensure alignment squareness, and a good tight fit. Dis-assemble, apply the adhesive/solvent, then bolt securely and let cure per instructions. The bolts could be galvanized or stainless for a better appearance.

With or without bolts, a good accurate fit is a must. Any gaps that must be bridged with extra adhesive or sealer will fail first.

You may need to rent some de-humidifiers for the cubicles, because you're going to have SERIOUS condensation! /forums/images/graemlins/shocked.gif

Interesting project! Good luck!

slydog · Dec 19, 2004

Re: \"Welding\" Lexan or plexiglass?

( With or without bolts, a good accurate fit is a must. Any gaps that must be bridged with extra adhesive or sealer will fail first.

You may need to rent some de-humidifiers for the cubicles, because you're going to have SERIOUS condensation! )

More very good points! I was also thinking about the condensation and expect that to be a problem. After talking to the friend last night, he says all the ice sculpting company wants is for us to build the box for them. They are taking care of placing it in the ice, putting in the TV's, and all wiring and hook up.

That makes my job that much simpler, however, I don't think they have considered alll of the possible problems you guys have brought up here.

I'm wondering, do yall think making the top panel angle towards the rear of the box so top condensation would run to the back wall and down, and also routing say a 1/4'' channel around the entire inside bottom with several weep holes drilled through the bottom in this channel to allow any condensation to drain would be a good addition? I know it wouldn't prevent condensation, but might be an added precaution to help if there was a lot of it.

Ken

Mansker · Dec 19, 2004

Re: \"Welding\" Lexan or plexiglass?

Methylene Dichloride, Ethylene dichloride, 1,1,2-trichloroethane. are solvents for glueing plexiglas. I would make the box out of 1/2 plex and make the lid 2' bigger than the box, I wouldn't add any weep holes because the melting Ice water will weep in rather than out. the surfaces to be mated have to be machined flat, I use a hypodermic syringe to transfer the solvent, if the edges are flat the solvent weeps under the plastic and seals it with a clear seal. put the tv in and seal the lid and the wire holes with clear silicone. it should be air and water tight. This should keep it from condensation and the Ice should keep the tv cool enought for the duration. Just my thoughts

PILOON · Dec 19, 2004

Re: \"Welding\" Lexan or plexiglass?

Generally acetone can be used to fuse lexan or plexi.
It will soften and fuse when it evaporates.
But then again silicone will do a good job as someone else mentioned.

Polishing the edges is accomplished with a low flame as with a butane torch.
You simply pass by with the flame straight on, not too close, in a reasonably slow speed. I kind of fan the flame from left to right carefully so as to not darken the plexi.
Practice on a scrap piece, not hard to do at all.

Cutting plexi is easily done with most woodworking tools.
Table saw, jig saw etc.
One problem is that heat is generated which can bind things up and then comes cracks.

For fine work a router is very practical.

One trick I used was to spray a bit of liquid detergent using a pump sprayer. The soap acts as a lubricant thereby preventing meltdown.

Made an aircraft windshield using a jigsaw that way.
(I formed it against the damaged unit using a Pizza Oven as the heat source)

Also use fine toothed blades.

SPIKER · Dec 19, 2004

Re: \"Welding\" Lexan or plexiglass?

wow sounds like a FUN project to get PAID for doing! /forums/images/graemlins/wink.gif

we have uesd some in the past to make gaurds in/on equipment we made, expecially usefull for stuff which requires sight while providing pritection such as doors or lids on packaging equipemnt.

we used some caulking type stuff provided by the same place that we got the poly from... also is the screen side going to be exposed to public? as viewing THROUGH ie would not work too well in my oppinion.

thickness depends on HOW they are making the bar around it? forming using blocks or freezing water around the tv enclosures?

if all you have to build is the enclosure then I would think 3/8' would be plenty unless they need it to support the ice too. then well I would think somethign like 1/2 at max would be needed this stuff is very strong and will support a good bit of weight. also there should be some sort of way to keep water from melting ice getting on the guests & floor, nothing worse than wet snooty people! /forums/images/graemlins/wink.gif

MarkM /forums/images/graemlins/laugh.gif

chim · Dec 20, 2004

Re: \"Welding\" Lexan or plexiglass?

Sounds like fun. Here's the site for a plastic welder we messed around with for a while. We had a customer who wanted to have some plastic tubing welded (in lieu of solvent-cemented) for some acid lines:

http://www.seelye-plastics.com/sales/products/products.htm

Question. Is there a low temperature limit for the operation of the TV? I don't know the technology of the plasma screen, but I have some LCD instruments that are kinda funky when it's real cold outside...................chim

slydog · Dec 20, 2004

Re: \"Welding\" Lexan or plexiglass?

Wow...lemme try and answer all those questions. We will build the box, they will cut a hole in the ice bar and put the box in it. Thanks for the info on the propane torch polishing!! That will save me some money over having GE do that part. As far as drip/drainage, that will be the ice companys problem, and man, with a ton of ice I don't know how they do it, but I'm sure interested to see. I do know they use lighted pedestals for their sculptures. As far as temps go on plasmas tv's, not sure their either, but just feeling around my big 36" tube tv, it really doesn't put out that much heat from the touch. I'm going to talk with the ice carving company about specifics later today. Thanks for all the advice!

Ken

cleatus · Dec 20, 2004

Re: \"Welding\" Lexan or plexiglass?

 I've glued 3/4 plexi with the water like solvant that the supply houses sell. These were 4' shelves 12" deep, put 2" strips on back and sides screwed to walls, with 2" strip glued to front. El Finix displayed jars of salsa, chips and mixes on these. I have not had to repair any and they have been up 6yrs. You can use their applactor bottle to add extra solvant until you see that the joint is filled. Please rember to flame polish edges before glueing.

mrcaptainbob · Dec 21, 2004

Re: \"Welding\" Lexan or plexiglass?

A table saw works great, especially if you have a variable speed on it. Slow is key here. Less heat build up. The best, however, is to use a router with a special blade. I used my Dremel to make the windows for the helm station on my boat. Then flamed the edges as was pointed out. Use a straight edge and a spiral cut bit for this job. Works great to pull the chips out. There's also special drill bits for drilling plastics. Regular ones fracure the hole walls with the chips and those cracks start traveling. That's why the spiral bits work well, too. But in any event, always flame the edges to relieve the stresses.

slydog · Dec 30, 2004

Re: \"Welding\" Lexan or plexiglass?

Well, I ended up getting a great price from the supplier to actually build the boxes for me for a little more than what I could have gotten the materials themselves. So I became the middle man and more than doubled my expense on my profit. They did a great job on the boxes and I can post a couple of pics if anyone would like to see the boxes themselves. It does make me want to buy some plexi and bonding agent and build some stuff though, but I have no idea what I might do with what I would make. Would just like to try it now and see how it turns out. Thanks again for all your advice!

Ken