JB Weld set up

[Newboater]

Probably should have asked before I started but anyway. I am using the standard 4-6 hour set-up time JB Weld epoxy to set my motor mounts and was wondering how long you leave the tape in place to keep a neat line, but still have enough time for it to be removed and the JB weld not run.
Thanks

[oscarel]

Won't that depend on the ambient temp?

[Newboater]

Yes to a degree but it is inside on my dining room. I figure 4-6hrs is set up time so I will start checking it in about 3 1/2 hours I guess

[martin]

Speak with Travis (kfxguy) on this forum, I believe he uses JB Weld & the tape method your using.

[oscarel]

Speak with Travis (kfxguy) on this forum, I believe he uses JB Weld & the tape method your using.

You beat me to that one, I've seen posts before where he gave some advice. He has some of the best lines using JB.

[Newboater]

Okay I will give him a shout. I will post pics tomorrow of how it turns out in the boat building thread under "My First Build"

[ray schrauwen]

I do a test piece first to learn the best time to remove tape.

Once it is pretty much set sometimes I use a wetted finger to smooth the edges before and or after the tape comes off.

[Newboater]

Thanks I think it came out pretty good. A wet finger trick is very good, I actually wet a popsicle stick for edge realignment.

[kfxguy]

I answered him via ok but because someone else may need this info I'll post it here too. First off it was 68f in my shop. I use the regular cure time jb weld. Use a heat gun once you apply it on low setting. That will soften the jb up. Use a 1/2" wide brush and brush the jb out to make it even paying special attention at the tape line. Make it taper to the tape line and make it thin as possible. I waited one hour last night and pulled my tape. You can wait up to 4 hours but beware if you have the jb thick over the tape line, when you pull it, it will be stringy and you'll have to do like new boater said and smooth it back down. Any questions I'll be glad to answer.

[boredom.is.me]

And if anyone is curious, you pretty much do the same thing with epoxy and silicone.

[Newboater]

Okay tape removed and motor mount done, smoothed over with a popsicle stick and water.

[ray schrauwen]

Great job! Better than me!

[Tamelesstgr]

What are you using to dye the epoxy?

[Newboater]

What are you using to dye the epoxy?
That is the standard color of the regular JB weld. I was thinking I could always paint it black if I decide I don't want to leave it grey.

[Newboater]

Great job! Better than me!

Thank you I was happy being it was my first time.

[kfxguy]

What are you using to dye the epoxy?



I've done some experimenting with it because I'd like it to be black in just one step, however I have not accomplished that yet.

Here's what I've found:

Epoxy dye: it'll dye it but it makes it rubbery. It never really gets hard like it normally would. Not good on a motor mount because it didn't seem to grab as well either.

Graphite: it takes a lot of powder to make it turn black. It does not feel as strong either.

For the sake of you guys, I'm going to try something else tonight. I got a can of finer graphite powder from west systems and I'm going to try it.


Normally what I do is once the jb weld is cured, I scuff it up and put a nice smooth coating of epoxy that I dyed black with epoxy dye. It comes out flawless when I do this. It's another step but it comes out how I want it. I honestly don't trust west systems (it is some badass epoxy don't get me wrong) for motor mounts in a single. There's a lot of stress on it and I know jb weld will hold. There's some top record holders here on this forum that use it too, if it's good enough for them, it's good enough for me.


Hahaha not sure why/how I got off track with expressing jb welds goodness lol

[Newboater]

Can you paint the JB weld? I was thinking of painting it black.

[kfxguy]

Can you paint the JB weld? I was thinking of painting it black.

I don't see why not.

[ray schrauwen]

Prep first like any surface to paint.

[kfxguy]

Experiment tonight for you guys. From left to right:

1) jb weld with graphite. It did not like to mix, was hard so work with and took a lot to get it almost black. Do not recommend. You can tell it's clumpy in the photo.

2) Jb weld with nothing added.

3) jb weld with 5 drops of super concentrated black epoxy dye. This dye goes a long way. Two drops will turn twice the amount of clear epoxy black vs the amount of jb weld. It just requires too much to turn the jb weld black.

Tomorrow I'll test the hardness of each one and post back.



http://i218.photobucket.com/albums/cc243/ltzguy/5054C074-992B-4B29-8777-F294D72571A6.jpg (http://s218.photobucket.com/user/ltzguy/media/5054C074-992B-4B29-8777-F294D72571A6.jpg.html)

[Newboater]

I would think graphite being a lubricant would effect the strength, probably best choice is to leave it grey or just paint it. Curious about the result though.

[kfxguy]

I would think graphite being a lubricant would effect the strength, probably best choice is to leave it grey or just paint it. Curious about the result though.

Yes I thought that too. However, I use it in clear epoxy with great results. I think it's because it's actually a powder instead of a liquid. I'll post the results/impressions on the perceived strength tonight.

[Tamelesstgr]

Thanks for doing this, I really struggled with messy epoxy lines on my 32 mono, would like to do a better job on my next build.

[kfxguy]

Ok I have some info for you guys. The jb that I used ropy dye, no. Not going to work unless you need rubbery epoxy. It was completely flexible. I could dig my nail in it and pull on it and it would spring back.

The graphite dyed jb weld was just as stiff and strong (perceived when I snapped them both in half) and the regular jb. Maybe you could experiment with it and just tint it dark grey and not try to get it black like I did and it might be a decent method.

[kfxguy]

Here's some pics of the epoxy lines. I'll be posting them in my 34" mono build thread also.

http://i218.photobucket.com/albums/cc243/ltzguy/1A50E160-9538-4BA7-AF20-AC954E83E4B4.jpg (http://s218.photobucket.com/user/ltzguy/media/1A50E160-9538-4BA7-AF20-AC954E83E4B4.jpg.html)

http://i218.photobucket.com/albums/cc243/ltzguy/F98745B1-5969-47E1-8A37-EF98459E95FA.jpg (http://s218.photobucket.com/user/ltzguy/media/F98745B1-5969-47E1-8A37-EF98459E95FA.jpg.html)


http://i218.photobucket.com/albums/cc243/ltzguy/111409D2-25C5-456D-B05B-52692F231739.jpg (http://s218.photobucket.com/user/ltzguy/media/111409D2-25C5-456D-B05B-52692F231739.jpg.html)


http://i218.photobucket.com/albums/cc243/ltzguy/D3F0673B-6C97-4145-843B-0525AE0AB8CC.jpg (http://s218.photobucket.com/user/ltzguy/media/D3F0673B-6C97-4145-843B-0525AE0AB8CC.jpg.html)

[T.S.Davis]

It's funny how everyone has different experiences. I've never had any luck with JB Weld. In fairness though, I haven't tried it since the plastic hull days. If you have something that's working go for it.

Not looking to sidetrack ya's but wanted to share.

Tom C. from our club turned me on to a different approach. He's been modifying his mounts for easy in and out so that in event of a motor hiccup he can get a new one in the boat in under 5 minutes. It can be the difference for us with as much as we deal with on race days around here.

He doesn't use the black pieces of carbon plate that Travis has JB'd in. Basically the face plate and tail ring is attached to two piece of angle that run length wise. Those angle pieces are then bolted to rails that are epoxied to the hull. In a mono the rails tie the transom, the bottom, and the motor mount together. Zero hull twist from motor torque. The best part is that you can have the whole assembly in your hand in under a minute. Pretty sure his are modular so to speak. Each boat is the same so he may well have a spare motor already in a mount so that he could drop a whole assembly right back in. No fiddling with motor screws between heats. He can literally swap a motor and still call three heats before he has to run again.

[kfxguy]

It's funny how everyone has different experiences. I've never had any luck with JB Weld. In fairness though, I haven't tried it since the plastic hull days. If you have something that's working go for it.

Not looking to sidetrack ya's but wanted to share.

Tom C. from our club turned me on to a different approach. He's been modifying his mounts for easy in and out so that in event of a motor hiccup he can get a new one in the boat in under 5 minutes. It can be the difference for us with as much as we deal with on race days around here.

He doesn't use the black pieces of carbon plate that Travis has JB'd in. Basically the face plate and tail ring is attached to two piece of angle that run length wise. Those angle pieces are then bolted to rails that are epoxied to the hull. In a mono the rails tie the transom, the bottom, and the motor mount together. Zero hull twist from motor torque. The best part is that you can have the whole assembly in your hand in under a minute. Pretty sure his are modular so to speak. Each boat is the same so he may well have a spare motor already in a mount so that he could drop a whole assembly right back in. No fiddling with motor screws between heats. He can literally swap a motor and still call three heats before he has to run again.



Interesting. I'm all for better ways of doing things. Got any pics to illustrate?

[T.S.Davis]

haha Not on me. I'll have to get something. I have one at the house I did that way in a sporty. I'll snap a pic later.

[Newboater]

Doesn't Traxxas have a similar concept. I think they have a modular frame that allows you to pull motor, esc ,radio and servo out all in one unit. same idea right

[kfxguy]

Doesn't Traxxas have a similar concept. I think they have a modular frame that allows you to pull motor, esc ,radio and servo out all in one unit. same idea right

Awesome. Hopefully it's something better than what I'm using. $30 each mount is getting expensive. I have heard there's a new mount coming to market hopefully soon. ;) ;) ;) ;)

[Newboater]

Here is a picture of what I think might be similar

[T.S.Davis]

Sorta. That doesn't really add any structure in my opinion. Tom's stringers are epoxied in and much heavier.

[Newboater]

No structural support, it is held in by rc style body clips. I was thinking more along the lines of the removability

[rearwheelin]

Sorta. That doesn't really add any structure in my opinion. Tom's stringers are epoxied in and much heavier.perhaps something similar to this ?

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