Welcome to the SeeMeCNC Community

Just finished installing my mag arms and j-head. took a bit of tweaking the arms but here is some pics of one of my first prints with the new upgrades...

Bill

Looks good, Bill!

Thanks, Love your tag line....

Bill

nice looking print.
It looks like a Steves hot-end not a J-Head ?

It's a j-head...

what's your experience so far, do you like the new setup?

what did you end up using for your settings?

Using kiss 10 10 5 retraction settings and 203 temp

You get your ams and nozzle on yet?

I'm working on an improved extruder design right now

Bill

not yet, i was undecided whether or not i was going to sell off my rostocks and parts, but for now seems like im going to hold on to them.
I got it assembled but in my testing the jbweld used to hold the spheres to the screws weren't strong enough even after careful prepping. I need to go find some stronger epoxy. I hear 3m weld 420. works better.

bplemmons wrote:Just finished installing my mag arms and j-head. took a bit of tweaking the arms but here is some pics of one of my first prints with the new upgrades...

Bill

Can you explain what you did to "tweak the arms"?

Carl

cambo3d wrote:not yet, i was undecided whether or not i was going to sell off my rostocks and parts, but for now seems like im going to hold on to them.
I got it assembled but in my testing the jbweld used to hold the spheres to the screws weren't strong enough even after careful prepping. I need to go find some stronger epoxy. I hear 3m weld 420. works better.

I agree that the 3M 420 would be stronger but you need a separate applicator gun and mixing nozzles, the price is really up there.
If you do manage to snag some and get it applied, please let us know the results and where we can get the stuff without having
to take out a second mortgage.

I'm curious how the JB weld reacts to the magnets since it's just an epoxy with a metal filler. I think for this application pure epoxy would be better or better yet putting a fiber layer in.

I hear the epoxy they use for golf clubs works great when your worried about shear forces.
http://www.golfworks.com/product.asp?pn ... 1257712462

Otherwise I'd just stick to a high quality epoxy like West Epoxy or something. I'll see how it goes for me eventually, reality likes correct me.

Eaglezsoar wrote:

cambo3d wrote:not yet, i was undecided whether or not i was going to sell off my rostocks and parts, but for now seems like im going to hold on to them.
I got it assembled but in my testing the jbweld used to hold the spheres to the screws weren't strong enough even after careful prepping. I need to go find some stronger epoxy. I hear 3m weld 420. works better.

I agree that the 3M 420 would be stronger but you need a separate applicator gun and mixing nozzles, the price is really up there.
If you do manage to snag some and get it applied, please let us know the results and where we can get the stuff without having
to take out a second mortgage.

you can get it online, I haven't had to chance to see if any local hardware stores sell it.

cambo3d wrote:not yet, i was undecided whether or not i was going to sell off my rostocks and parts, but for now seems like im going to hold on to them.
I got it assembled but in my testing the jbweld used to hold the spheres to the screws weren't strong enough even after careful prepping. I need to go find some stronger epoxy. I hear 3m weld 420. works better.

Did you soak the cap screws and chrome balls in acetone? Did you mix the JB weld 1:1 even ratio?

elqisqeyano wrote:

cambo3d wrote:not yet, i was undecided whether or not i was going to sell off my rostocks and parts, but for now seems like im going to hold on to them.
I got it assembled but in my testing the jbweld used to hold the spheres to the screws weren't strong enough even after careful prepping. I need to go find some stronger epoxy. I hear 3m weld 420. works better.

Did you soak the cap screws and chrome balls in acetone? Did you mix the JB weld 1:1 even ratio?

quote from above statement
"but in my testing the jbweld used to hold the spheres to the screws weren't strong enough even after careful prepping."

Cambo3d, you have me a little concerned about the reliability of the arms. If you had problems with the JB Weld
others are having problems too. If you decide to continue on and make these work please let us know what you
used. I know that we mentioned the 3M 420 and the epoxy made for Golf shafts but you can't spend a small
fortune testing the different glues. The 3m 420 online at Amazon is close to $100 after you buy the epoxy, the
applicator gun and the twisted tips. The Golf epoxies are around the $15 area. My point is there is probably dozens
of high quality epoxies out there. Your thoughts would be appreciated if you have any at this point.
I had Bill print out the parts for the magnetic arms and I thought all would be well until you discovered the JB Weld is
not going to work long term.

Eaglezsoar wrote:Cambo3d, you have me a little concerned about the reliability of the arms. If you had problems with the JB Weld
others are having problems too. If you decide to continue on and make these work please let us know what you
used. I know that we mentioned the 3M 420 and the epoxy made for Golf shafts but you can't spend a small
fortune testing the different glues. The 3m 420 online at Amazon is close to $100 after you buy the epoxy, the
applicator gun and the twisted tips. The Golf epoxies are around the $15 area. My point is there is probably dozens
of high quality epoxies out there. Your thoughts would be appreciated if you have any at this point.
I had Bill print out the parts for the magnetic arms and I thought all would be well until you discovered the JB Weld is
not going to work long term.

I ordered the 3m scotch weld 420, it was $22 from mcmastercarr, i didn't' get the applicator gun. I'm just gonna push it out by hand. I have used the 3m type before and you can push it out by hand. takes little more effort but you can do it without the applicator. I should have it tomorrow so i can test.

Eaglezsoar wrote:Cambo3d, you have me a little concerned about the reliability of the arms. If you had problems with the JB Weld
others are having problems too. If you decide to continue on and make these work please let us know what you
used. I know that we mentioned the 3M 420 and the epoxy made for Golf shafts but you can't spend a small
fortune testing the different glues. The 3m 420 online at Amazon is close to $100 after you buy the epoxy, the
applicator gun and the twisted tips. The Golf epoxies are around the $15 area. My point is there is probably dozens
of high quality epoxies out there. Your thoughts would be appreciated if you have any at this point.
I had Bill print out the parts for the magnetic arms and I thought all would be well until you discovered the JB Weld is
not going to work long term.

I've had one failure of the JB Weld early on. I think the issue is you can't get much of a mechanical connection with the chrome balls. After the failure, I took a piece of painter's tape, punched a hole about the diameter of the top of the 3mm cap screw in it, and draped it over the ball, then abraded the exposed surface with 320 grit sandpaper, and cleaned with acetone. I haven't had an issue yet, but I've only run about 30 hours since then.

Thanks Broose, that is a good idea!
I will try that during assembly.

If the adhesive doesn't have something to hang on to, it will fail. A chrome surface is very "slick" when it comes to glue. Sanding it dull is a great idea!

g.

If the adhesive doesn't have something to hang on to, it will fail. A chrome surface is very "slick" when it comes to glue. Sanding it dull is a great idea!

I like the hole in tape idea. Do you guys think it would be too extreme to use a dremel to abraid that part of the surface on the bearings?

barnett wrote:

If the adhesive doesn't have something to hang on to, it will fail. A chrome surface is very "slick" when it comes to glue. Sanding it dull is a great idea!

I like the hole in tape idea. Do you guys think it would be too extreme to use a dremel to abraid that part of the surface on the bearings?

You should try it and tell us how it works. My guess is the sandpaper probably doesn't dig as deep as a dremel grinder but conforms better to the surface for more even abrasion. Maybe a dremel sanding wheel would work well.

Sorry I don't have a camera around, but I did use the dremel on 12 bearings just now. I taped them leaving a circular area I wanted to roughen, and then gently applied the coarsest sanding drum I had to the exposed surface (bearing and tool were hand held). Sparks flew and I had to be gentle or else I would make facets in the bearings. I also have a small diamond file that I used briefly to finalize a few.

My only concern is that I may have roughened too large an area on some of them.

Tape removed, they are soaking in the acetone now (with screws).

I was kind of sloppy on the first bearing I tried the jb weld on. For the rest, I might tape them off again, being careful to not touch the cleaned roughened surface.

Well I didn't tape them off, I just did a sloppy job on all of them. If this works, then there is hope for all of you because I seem to have very low skill attaching screws to bearings.

It got all over, I kept knocking down my little holders with the magnets in them ... and then the magnets would pull different bearings together before the epoxy had set. It was like a Jerry Lewis movie.

But they are all sitting under some hot lights now.

barnett wrote:I like the hole in tape idea. Do you guys think it would be too extreme to use a dremel to abraid that part of the surface on the bearings?

Werner Berry used both tape and a Dremel for the magnets on the original BerryBot3D. Here's a photo.

http://forums.reprap.org/file.php?1,fil ... .27.35.jpg

Why not just use two magnets IOW "magnet-ball-magnet" think the magnet are easier to glue than the ball


Anders SWE