Gluing acrylic

[magic]

I'm having the hardest time gluing 2.5 inch squares of acrylic to each other. The material has been prepared correctly.

With a hypo-bottle and weldon 3, the solvent only penetrates partially (3/4 of an inch from the edge) . Applying solvent from 4 directions still leaves a gap in the center.

Using weldon 16, from a tube and spreading it on one surface then pressing both pieces - then rubbing them a bit to make the solvent flatten and fill all gaps looks good initially- but leaves fine crazing between the parts. (Do I just need a heavy weight and a jig to avoid the parts sliding around?)

What is the best technique you bond larger pieces of acrylic? (Again, the surface is prepared correctly.

[magic]

On further examination.... it's possible that what appears as small streaks are really air bubbles that have been "worked" into long thin lines as I rubbed the parts back and forth.

So the question is... What method/technique/tools should I use to apply a complete and even coat of the 16 over a 2.5 inch square surface? I don't care if it seeps out the sides.

[jerry_stanek]

Have you tried putting a couple of drops in the center and the placing the second piece on top and using a vacumn baor just a piece of plastic film and your vac table to pull it down.

[magic]

I don't have a vacuum table or chamber.... yet. But I have lots of weights. Actually if #16 is used, I believe that it's so thick that a small air bubble may not be able to work it's way out in the short time it takes for the pieces to set-up.

The manufacturer advises that you can mix 10 percent of #3 with #16, making the viscosity lower.... They also advise that the solvent may be applied by brush. I don't see how brushing it on will leave a flat surface...... but I'm going to try anyway (Maybe I can find a sponge the solvent won't destroy)

I'd sure like to hear from someone who's already been there.

Possibly there is a technique where you have a spacer on one end of the material and force all the air, that way.

Maybe the idea is to make a dam using #16 and pour a skim-coat of #3 in the middle.

Could the trick be to assemble, at an angle so the solvent starts at the top and works it's way down the face?

I haven't tries the last three BUT I did try dipping the part (in #3) then pressing it down on the other part and even though it was only a second, or so, the solvent was already drying where the material was at it's highest point - (the solvent ran away from that edge, in an instant).

Thank you.

[john_l]

I have had success two ways in the past.

1- Hold the pieces together flatly and with more pressure and then capilary (sp?) action will draw the weldon in farther... its pretty neat.

2- Use the hypo to drop a puddle in the center before you put them together and then go around the outside too.

[magic]

Ahhh!!! the puddle followed by going around the outside. That's tomorrows test.

Does it make a difference if it's cast Acrylic or extruded?

Will #4 work better then #3?

Thanks very much

[wayne_walker]

Magic,

I do a lot of ABS plastic and I use the cheep foam painters brush. I use Weldon 2354 which is a waterthin glue. I coat both pieces and then stick them togeather.

I recommend you give a foam brush a shot.

Good Luck

Wayne

[magic]

si senior

[rhfurniture]

Is Acrylic and ABS the same?
Just wondered for future ref.
R.

[magic]

Not quite - but solvents that bond acrylic will also work on Styrene.

I think the answer is to put an 1/8 inch spread of the #16 all over the surface and squeeze the parts together, starting at one end - so as to work any air bubbles out.

This leaves a lot of excess solvent oozing out the sides but in this case, it will do what I need.

[dakers]

i found this on google, may answer the reason for any bubbles would be outgassing. so the foam brush idea probably works the bubbles out as the glue outgases.

Plexiglass, lucite, acrylic....All the same stuff

Methylene chloride is the solvent of choice here, too, and all the
commerical product responds well to this stuff. It is virtually impossible
to exclude bubbles from a lucite weld as the solvent outgases micro bubbles
of chlorine just as the stuff starts to setup. Weldon #3 is just methylene
chloride with a small amount of dissolved lucite in it. Weldon #16 is a
thick glue like substance and is in a tube and not as runny as #3. These
are the normal commercial glues for the non-chemical buyer.

[frank134]

Another thing might be the type of Weld-On you are using. There is Weld-On 4 which dries slower.

[magic]

#4 does not seep far enough between the surfaces.

I've discovered the answer through trial and all the help on the forum.

Thanks all for your input.

[rb99]

What is the answer you found?

RB

[magic]

LOTS of #16. squeeze the parts together. Apply pressure while slipping the parts back and forth oppisit the side where air bubbles are and work them out. Clamp when done.

The pieces are cut oversize to begin with and will be trimmed. Then sanded and polished until I have cubes.

Come to think of it... I just could have poured these without all the trouble.

[frank134]

May I ask what are you making?

[magic]

70 cubes with a polished, diamond-shaped hole through & through.