Bonding Lexan?

Use methylene dichloride and add 10% glacial acetic acid. This will give you a good strong joint without crazing.

The edge prep needs to be reasonably flat, I would get excellent results having an edge from a router or a table saw (Carbide blade, zero set on the teeth.) Slight imperfections give the solvent room to wick with capillary action and they disappear with the melting of the plastic.

If you were trying to laminate two smooth faces, what works is to put a puddle of the solvent on one sheet and carefully place the second sheet on top slowly squishing out the excess. The trick here is to have the lower sheet larger than the upper sheet and also to cut drip catching troughs around the edge. If any of the solvent runs over the edge it will mar the lower surface. Trim to final size after the solvent evaporates.

Dave,

Find a plastics wholesaler in your area. Most of them usually have a retail outlet for the offcuts and sometimes you can get whole stock as well. They would definitely have the cement. My local supplier sold me a 6 oz. tube of cement for Lexan for about $4. Sorry, but I don't remember the name.

You don't need to rough up the surface either. The cenent melts and welds the Lexan together.

Grrr.. Reminds me of a plactics shop in downtown Atlanta (Never could remember the name). Lots of offcuts at good prices, and supplies. =20

They got bought up by GE plastics, moved into a big new industrial park building, and now, no more offcuts, no small sales. They're as good as gone to me.

Also, a good surplus stuff outlet disappeared recently, buy not before I snagged about 100 lbs of black delrin round stock (3" to 6") for $2.00 per lb. =20

To reply, please remove one letter from each side of "@" Spammers can't possibly be human. so it must be OK to kill them.

Loctite Prism 401 works very well. It's usually impossible to break the bond without bending the lexan. I've used it for years for small machine guards with no problems or complaints.

401 will frost the lexan near the bond line. If cosmetics are important, there is a "non-blooming" equivalent to 401 that will sacrifice a bit of strength. I don't know the part number off the top of my head, but details should be on Loctite's web site. I buy it from McMaster-Carr.

Since these are instant adhesives, you need to plan ahead to get the best results. I usually assemble things on a steel table with a layer of wax paper, and use the table and a few heavy blocks of steel to fixture the parts. Use the table top as a guide to slide the parts together in the proper alignment.

Ned Simmons

Almost ANY "hobby shop" will have a variety of solvent type "cements" for plastics including Lexan & Acrylics...

_-_-bear

na wrote:

Seek out a supplier of Lexan/Plexiglas, yellow pages under plastic.

David Jones djonesLSidaho.com

The maker or Lexan, GE, recommends methelene chloride for solvent bonds. For minimal fill requirements, dissolve Lexan pellets in methelene chloride up to 5%. Acrylic cements often have acrylic already added, so they may be somewhat less effective. Joints should be well fitting and clean for best results. Slight, continuous pressure during the drying will improve the bond. Methelene chloride can be obtained through chemical suppliers. If you can find acrylic cement which contains solvent only (no Acrylic), it will probably be okay. Search for "Weld-On" made by Industrial Polychemical Service. They may even have a cement made for PC.

Billy,

I used to work with Lexan all the time and straight methylene chloride is a bitch to work with as it is a little too hot and tends to craze and leave white spots.

Try the 90% methylene dichloride and add 10% glacial acetic acid. This flows well, dries strong and crystal clear.